Dissertations / Theses on the topic 'Broilers (Chickens) – Feeding and feeds – Storage'

Assignment (MPhil)--University of Stellenbosch, 2004.
ENGLISH ABSTRACT: The aim of this study was to evaluate the performance and profitability of different dietary specifications for broiler chickens slaughtered at 35 days of age. Two trials were performed to evaluate different production parameters. The results of these trials were compared to the predicted results of the EFG broiler model. No carcass data were available for the two trials mentioned above. Therefore, in order to evaluate the accuracy of the broiler model when predicting carcass characteristics, two published data sets (Leeson et al., 1996a) were used. Predicted and actual values were compared, evaluated and discussed. Two broiler trials were performed. In Trial One the amino acid density decreased throughout the range of three treatments from prestarter to finisher diets. In Trial Two the amino acid density decreased only in the four finisher diets. The main difference between predicted and actual results was the response to body weight. The model predicted a steady increase in feed intake to compensate for the lower dietary specifications while body weight did not change significantly. This increase in feed intake seems to be enough to maintain body weight. Trial birds also increased their feed intake as dietary amino acid density decreased, but this compensation seemed to be too low to maintain body weight compared to the control diet. The birds may find it easier to compensate when they have time to adapt to the specification. There is evidence in the literature that birds need seven days to adapt their feed intake to a lower feed specification (Leeson et al., 1996a). It can be speculated that the trial birds started to loose body weight due to a lower amino acid intake in this period. The model seems to adapt feed intake immediately after a change in diet specification. The simulation on literature data lead to the following conclusions: 1) Broilers posses the capacity to increase their feed intake with at least 65% should finisher diets with lower amino acid and energy concentrations be supplied. If only the energy concentration of finisher diets were decreased, the increase in feed intake will be around 30%. (see Table 16 and 23) 2) The accurate prediction of feed intake from the given dietary specification has a major influence on the accuracy of the prediction of broiler performance. 3) Amino acid density and DLys:ME ratio plays a significant role in the control and prediction of feed intake. The EFG broiler model is based on sound scientific principles. The model is comprehensive and can be used for a wide range of environmental and management conditions as well as dietary conditions. The nutritionist can use the model with confidence to assist in practical feed formulation. The actual strength of the model lies in the time and money being saved compared to practical trials.
AFRIKAANSE OPSOMMING: Die doel van hierdie studie is om die prestasie en winsgewendheid van braaikuikens te bepaal wanneer voere met verskillende digthede tot op 35 dae gevoer word. Twee eksperimente is uitgevoer om produksieresultate te evalueer. Die resultate van hierdie eksperimente is met die voorspelde waardes uit die EFG simulasie-model vergelyk. Aangesien geen karkasdata vir bogenoemde eksperimente beskikbaar was nie, is twee gepubliseerde datastelle gebruik om hierdie deel van die model te evalueer (Leeson et al., 1996a). Twee braaikuiken eksperimente is uitgevoer. Eksperiment Een het uit drie behandelings bestaan waarvan die aminosuur-konsentrasie vanaf dag een tussen behandelings verskil het. In Eksperiment Twee het die aminosuur-konsentrasie net in die vier afrondingsdiëte verskil. Liggaamsmassa op 35 dae het die grooste verskil tussen voorspelde- en werklike waardes getoon. Beide voorspelde en werklike innames het in albei eksperimente verhoog soos wat aminosuur-konsentrasie afgeneem het. Voorspelde liggaamsmassa het egter konstant gebly terwyl werklike data 'n afname in liggaamsmassa getoon het. Dit bleik dat die voorspelde toename in innames voldoende was om massa te onderhou terwyl die voëls in werklikheid nie genoeg gekompenseer het nie. Leeson et al., 1996a het tot die gevolgtrekking gekom dat braaikuikens minstens sewe dae benodig om hul voeriname by 'n nuwe spesifikasie aan te pas. So 'n stadige aanpassing kan daartoe lei dat energie- en aminosuur-inname daal indien 'n dieet met laer spesifikasie gevoer. Dit sal daartoe lei dat die kuikens liggaamsmassa verloor. Uit die literatuur simulasies is die volgende afleidings gemaak: 1) Braaikuikens besit die vermoeë om voerinname in die afrondingstyd met minstens 65% te verhoog indien 'n afrondingvoer met laer amiosuur- asook energiekonsentrasie gevoer word. Indien net die energiekonsentrasie verlaag word, sal die inname met sowat 30% verhoog. 2) Die akkurate voorspelling van inname is krities vir die akkurate voorspelling van produksieparameters. 3) Aminosuur-digtheid en DLys:ME speel 'n belangrike rol in die beheer en voorspelling van voerinname by braaikuikens. Die EFG braaikuikenmodel is op suiwer wetenskaplike beginsels geskoei. Die model is omvattend en kan vir 'n wye reeks van omgewings- en bestuurstoestande asook dieet-spesifikasies gebruik word. Die voedingkundige kan die model met vertroue gebruik om met praktiese voerformulering by te staan. Die model kan die formuleerder baie tyd spaar aangesien praktiese eksperimente ingeperk kan word.

Corrigenda inserted behind title page. Bibliography: leaves 275-306. The pattern of body growth and intestinal development of an Australian strain of broiler chicken, the Steggles x Ross (F1) in response to different diets was studied. Five experiments were designed to examine the pattern of growth and mechanisms involved. In four other experiments, the mechanisms underlying the gross response of the broiler chicks to dietary ingredients, anti-nutritive factors and growth enhancers were examined. Results indicated that a rapid development of the small intestine preceded significant overall body growth. Body growth would, however, depend more on the various physiological events such as those related to mucosal growth and renewal, digestive enzyme function, and nutrient transport. Some of the differences observed in productivity of broiler chickens on different diets were traced to events at the intestinal level.

The main objective of the study was to determine how phase feeding manipulation affects growth performance, feed cost, carcass characteristics and quality of meat from broiler chickens. A total of 180 day old un-sexed broiler chicks (Cobb 500) were separated into 3 dietary treatments of 60 birds per treatment and each treatment was replicated 3 times with 20 birds per replicate. The dietary treatments were as follows: T1 (starter 1-7 days; grower 8-21 days; finisher 22-35 days), T2 (starter 1-14 days; grower 15-21 days, finisher 22-35 days) and T3 (starter 1-14 days; grower 15-28 days; finisher 29-35 days). Feed intake and body weight gains were recorded weekly in kilograms. Average daily gain and feed conversion ratio were computed weekly. At day 35, the chickens were slaughtered and 12 representative breast muscles from each treatment were used for the determination of muscle pH (pH1, pH24 and pH48) and colour coordinates (Lightness – L*, redness – a* and yellowness – b*) in triplicate at 1 hour, 24 hours and 48 hours post-mortem.Feed intake (FI), feed conversion ratio (FCR), average daily gain (ADG) and average body weight at slaughter (ABW) were not significant (P>0.05) amongst the treatments. The most cost efficient feed (which accumulated the cheapest cost feed per kg were) T1 (R11.32) and T3 (R11.32) although there was a slight difference in the gross profit of these treatments T1 (R45.71) and T3 (R44.48). Carcass characteristics were the same (P > 0.05) across the treatments except for the wing, thigh, drumstick and the breast (P < 0.05). T2 had the highest wing weight (166.63±8.60), T1 (113.03±8.60) and the lowest in T3 (74.46±8.60). The thigh weight were greater (P<0.05) in T2 (185.69±4.34); T1 (185.54±4.34) compared to T3 (166.97±4.34) which was lower. Treatments 1 (204.17±6.57), T2 (197±6.57) had heavier (P<0.05) breast weights than T3 (186.06±6.57). Dietary treatments had no significant effect (P > 0.05) on pH of the breast meat. No differences were observed in colour during the 1 hour period after slaughter. At 24 hours after slaughter, the L* values were different (P < 0.05) in T1 and T2 (44.3 ± 0.37; 43.7 ± 0.37), respectively, T1 and T3 were the same. The a*-values were different (P < 0.05) at 48 hours after slaughter for T1 and T3 (4.5 ± 0.27; 3.4 ± 0.27), T2 was the same as T1. It was therefore, concluded that since manipulation of starter phase did not have adverse effects on growth performance, gross profit, slight statistical difference in meat quality attributes and carcass characteristics. Therefore, the manipulation of starter diet has the potential to be used in broiler production.

This study was conducted to assess the effect of including Tenebrio molitor larvae (T. molitor L) as a protein source in different diets on broiler performance, carcass characteristics and meat quality. A total of 144 day-old Cobb-500 chicks were randomly allocated into three treatment groups, each was allocated 16 birds and reared in 9 identical pens. Experimental diets used were as follows: T1 Control (no T. molitor L inclusion); T2 and T3 contained levels of T. molitor L at 5 percent and 10 percent of dry matter (DM) intake, respectively. Body weights (BW), average daily gain (ADG), feed intake (FI), and Feed conversion ratio (FCR) were measured for the 1st experimental chapter. For the second experimental chapter; live weights (LW) of broilers were recorded before slaughter and thereafter carcass weights (CW), meat yield (weights of breast, thigh, drumstick and wing) were recorded. The dressing percentage (DP percent) was also calculated. Breast muscles were sampled for meat pH and colour measurements. The LW of birds from T1 (0 percent T. molitor L) were significantly different (P<0.05) from both T2 (5 percent T. molitor L) and T3 (10 percent T. molitor L) which were similar to each other, with T2 exhibiting the highest live weights (2166g) and the control treatment exhibiting the lowest live weights (2018.3g). In CW, T1 was significantly different (P<0.05) from T2 while it was similar (P>0.05) to T3. The dressing percent of T1 was significantly different (P<0.05) from T2 and T3 which were similar to each other, with T2 having the highest dressing percentage (78, 2 percent) and T1 having the lowest DP percent (66 percent). The breasts in T2 were significantly higher and different (P<0.05) from both T1 and T3 which were similar to each other. The drumsticks in T3 were significantly different (P<0.05) from T1 while they were similar to T2 with values with T2 having highest values. After 45 minutes of slaughter, a significant difference (P<0.05) was observed in L⃰ among all treatments. In redness (a⃰), T3 was significantly different from T1 but was similar to T2 and all treatments in this study exhibited a darker red meat, with T3 muscles exhibiting darker red colour than the other treatments. Similar results were observed in yellowness (b⃰), where the breast muscles from T3 were more yellow than the other treatments. After 24 hours of slaughter, T2 L⃰ values were significantly different (P<0.05) from both T1 and T3 which were similar to each other. It was also found that the broiler chickens given diet with no T. molitor L inclusion (T1) had lower values of BW, FI, ADG and FCR throughout the experiment than those that were in T2 and T3 with 5 percent and 10 percent T. molitor L inclusion levels, respectively. However, it was also found that although broilers with 5 percent T. molitor L inclusion (T2) in their diet had high ABW and ADG than the broilers with 10 percent T. molitor L inclusion (T3), the T3 birds compared favourably to T2 birds as they required low feed intake to reach the same slaughter weight due to high FCR. It was, therefore, concluded that T. molitor L meal can be incorporated into the diets of broilers to produce heavy birds either at 5 or 10 percent. However, although 5 percent T. molitor L inclusion yields heavier carcasses, the 10 percent T. molitor L inclusion compared favourably to 5 percent inclusion since it required low feed intake to reach the same slaughter weights and there were slight differences on meat quality attributes between the two treatments.Thus T. molitor L at 10 percent inclusion levels was the best inclusion level to enhance broiler growth performance, carcass yield, meat yield and meat quality.

A procedure was developed to examine factors contributing to skin strength of meat-type chickens. Skin breaking strength was initially measured in lines of chickens divergently selected for high (H) and low (L) juvenile body weight, their reciprocal crosses (HL and LH), and an F₂ generation derived from HL and LH matings. Skin of chicks from the LL line was weakest, that from the HH and LH matings strongest, and that from HL and F₂ matings was intermediate. Percentage heterosis for breaking strength was significantly positive while percentage recombination was not significant. Skin breaking strength and protein, fat, moisture, and total collagen concentrations of skin from the breast, thigh, and back of male and female commercial broilers were then examined in response to diets containing relatively wide or narrow ratios of calories to protein (C:P). Comparisons were made at 28, 42, and 56 days of age. Chickens fed diets containing wider C:P ratios had weaker skin than those fed diets with narrower C:P ratios, with the differences being greater at older than at younger ages. Males had stronger skin than females. Among body sites, breast skin was stronger than thigh skin with that from the back being intermediate in strength. Skin breaking strength did not appear to be consistently associated with either the protein, fat, or collagen concentrations in the skin. Skin from broiler chicks fed diets with differing C:P ratios was also examined histologically. Males had stronger and thinner skin than females, with the differences in thickness due primarily to differences in the thickness of the hypodermis. Regardless of sex, feeding diets containing wider C:P ratios resulted in weaker and thicker skin. The thicker skin was associated with an increase in the thickness of the hypodermis and a decrease in the thickness of the dermis and epidermis. With the exception of differences between back and thigh skin, increases in breaking strength occurring between skin from different sites were associated with a reduction in total skin thickness and in the thickness of the hypodermis. It was concluded that increased hypodermis thickness and/or decreased thickness of the dermis and epidermis reduced skin strength. Two experiments were conducted in which skin strength was examined in relation to heat stress and supplemental ascorbic acid. In the first experiment, chicks fed diets containing 0 or 100 mg of ascorbic acid per kg of diet were subjected to either a constant ambient temperature of 23C, a constant ambient temperature of 32C, or a treatment consisting of 32C from 1600 to 1200 hr and 400 from 1200 to 1600 hr (32/400). Both heat stress and supplemental ascorbic acid tended to increase collagen concentrations in the skin, but differences in breaking strength were inconsistent in response to these treatments. Supplemental ascorbic acid, however, partially alleviated reductions in body weight due to heat stress but did not decrease body temperatures of heat-stressed chicks. In the final experiment, diets containing either 0, 200, or 400 mg/kg of supplemental ascorbic acid were fed to chicks maintained at ambient temperatures of 23 and 34C. Contrary to previous observations, ascorbic acid failed to ameliorate the depressive effect of heat stress on body weight. Supplemental ascorbic acid tended to reduce adrenal, bursa of Fabricius, and spleen weights but had no effect on heterophil and lymphocyte numbers or ratios. Adrenal ascorbic acid concentrations were not significantly affected by supplemental ascorbic acid and plasma ascorbic acid levels were inconsistent among treatment groups. Neither supplemental ascorbic acid nor heat stress significantly influenced skin strength. It was concluded that supplemental ascorbic acid was not beneficial in improving skin strength in commercial broiler chicks.
Ph. D.

A study was conducted using commercial broiler breeders with the males fed a diet containing, either 120/0 or 140/0 protein and body weight maintained at either 900/0 or 1000/0 of that recommended by the primary breeder (fed separately), or allowed to eat from the female feeders (controls). Female feeders in the separately fed pens were equipped with especially designed grills, which denied access to the males. The male feeder in these pens was elevated so that females were denied access.

Males fed separately (body weight 90% or 1000/0, and dietary protein 120/0 or 140/0) had a significantly higher percentage fertility (4.20/0) than males allowed to eat with the females. No differences in percentage fertility were found among the four separately fed groups. No differences were noted in percentage hatch of fertile eggs among any of the treatment groups.

Males eating from the female feeders had significantly heavier body weights and testes weights at 65 weeks of age than breeder males in the separately fed, groups. Mean body weights were 3819g and 4773g at 35 weeks of age, and 4192g and 5443g at 65 weeks of age for males eating separately and eating with the females, respectively. Furthermore, males in the control group had significantly larger breast angle measurements when compared with the separately fed males. No differences were observed in foot scores and semen concentration among males in the various treatment groups.

Master of Science

This study was designed was to determine the effects of additive supplementation of Moringa oleifera leaf meal on growth performance, digestibility, digestive organ size, intestinal integrity, bone ash content and bone breaking strength, as well as meat yield and quality of broiler chickens. A total of 2400 day-old unsexed Cobb-500 broiler chicks were randomly allocated to 5 treatment groups: T1, positive control, 668 g/ton Salinomycin and 500 g/ton Albac; T2, T3 and T4 contained graded levels of MOLM at 1 percent, 3 percent and 5 percent of dry matter (DM) intake, respectively; and T5, a negative control (0 percent additives) in a complete randomized design experiment. Except for week one, FI and FCR was highest (P < 0.05) in T4 birds; while T1 birds had the highest FI in the period of 22 to 27d (P < 0.05). Throughout the production period, birds supplemented with MOLM had the highest BW (P < 0.05) than the birds fed the control diets. Feed intake (FI) and feed conversion ratio (FCR) among treatments was highest (P < 0.05) in T4 birds during the period of 8 to 14 d; and was highest (P < 0.05) for T1 birds in the period of 22 to 27d. Protein efficiency ratio (PER) and energy utilization efficiency (EEU) ratios were statistically significant among treatments (P < 0.05). However, dietary treatments had no effect (P > 0.05) on the weights of the heart, liver, spleen, or the gizzard, although the bursa for T2 birds was the lightest (P < 0.05); while gizzard erosion score was highest in T2 birds. All of the nutrients measured, except for fat, had negative intercepts that were significantly different (P < 0.05) from zero, indicating the presence of endogenous fecal losses. Tibiae length (TL) was highest in T2. The dried defatted weight (DW) was heaviest (P < 0.05) for T3 (11.20 ± 0.347) and T5 (11.08 ± 0.328). A positive correlation (r = 0.667; P < 0.01) between TW and DW was observed. There were no dietary effects on bone breaking strength (BBS), but T1 tibiae had highest resistance to breaking force (T1 > T4 > T3 > T2 > T5). Calcium was highest (P < 0.05) in T1; and lowest inT2 and T5. Phosphorus levels were lowest (P < 0.05) in T1; and highest (P < 0.05) in T5 compared. The highest Ca: P ratio was obtained in T4 (P < 0.05); while the ash percent was highest (P < 0.05) in T1. Drip loss increased as L* values increased; and a negative correlation was observed between L* and pH. On D1, C18: 0 and C22 in T2, while C15:0 was highest in T4. On D1, C20:2, C20:3n6 and C22:6n3 were highest in T2 (P < 0.05); T4 had the highest C18:3n6 (P < 0.05), while C20:2 was highest in T5 (P < 0.05). The P/S ratio on D1 was highest in T4; while n-6/n-3 was highest in T1; and n-3 was highest in T3. On D8, the n-3 was highest in T1 (P < 0.05). Results of the current study show that supplementation of M. oleifera leaf at additive levels of up to 5 percent of the bird’s DMI does have the potential to influence the bird performance without any detrimental effects on nutrient utilization, bird health, bone strength and/or meat quality, which can be concluded that MOLM enhanced the bird’s genetic potential for optimal productivity.

Thesis (MScFoodSc)--Stellenbosch University, 2013.
ENGLISH ABSTRACT: Modern consumers are health conscious and are shifting towards more naturally produced products such as free range chicken. Commercial broiler strains are not suitable for free range rearing and an alternative genotype is needed that will serve the South African market with the acceptable meat quality as a broiler. The objective of this study was to investigate the effect of production system (free range and intensive reared) and genotype (Broiler (COBB™), Ross 308 X Potchefstroom Koekoek hybrid and Potchefstroom Koekoek) on chicken meat quality. This was quantified on the morphological, physical (pH, colour, drip and cooking loss, water holding capacity and tenderness), chemical composition (moisture, protein, fat, ash contents and fatty acid profile), sensory quality and consumer preference of various chicken meat portions. The results of this study indicate that genotype had a more pronounced effect than production system on the morphological and growth properties of chicken meat, as well as on the sensory characteristics and consumer preference. The broilers had the best (P ≤ 0.05) feed conversion ratio (FCR), highest average daily gain (ADG) and European production efficiency factor (EPEF), followed by the Hybrid and then the Potchefstroom Koekoek. For each genotype, the free range chickens produced heavier (P ≤ 0.05) live weights than intensively reared chickens. Despite the poorer growth performance and efficiency of the medium growing Hybrid birds, they had less mortality and fewer leg disorders than the broiler. Additional to these factors, the Hybrid Free Range had higher thigh, drumstick and wing yields (P ≤ 0.05) than the broiler. When investigating the correlation between the chemical and sensory data, it was observed that the Hybrid scored significantly higher (P ≤ 0.05) in both flavour and aroma than the Broiler and Koekoek genotypes for both production systems. For colour, pH and polyunsaturated to saturated fatty acid ratio (PUFA:SFA), the effect of production system was more pronounced than the effect of genotype. Rearing chickens in a free range environment increased the PUFA:SFA ratio (P ≤ 0.05), making it beneficial to human health. Free range rearing resulted in lower muscle pHu (P ≤ 0.05), darker (L* value) (P ≤ 0.05), less red and yellow (a* and b* value) (P ≤ 0.05) chicken meat. It also influenced the chemical composition in different carcass portions; for example, a lower fat content in the thigh and higher protein in the breast of the Broiler. Correlation with the sensory results indicated that juiciness, tenderness, chicken aroma and chicken flavour are the main drivers of liking for consumer’s preference towards chicken meat. The consumers predominantly preferred the Hybrid (P ≤ 0.05) in a blind tasting session, but when information was given on the production system of a chicken product, the consumers lean more towards a free range reared product than an intensive reared product. This indicates that consumer perception plays an immense role in consumer decision making. Cluster analysis was also performed to ascertain whether the consumers differed in their degree of liking of the intrinsic character of the respective chicken samples. Three different clusters of consumers were identified: 1) Consumers that prefer free range reared chicken meat, 2) Consumers that prefer intensively reared chicken meat, 3) Consumers that prefer both free range and intensive reared chicken meat. In conclusion, the Hybrid seems to be a viable option for free range production systems in South Africa, without negatively affecting the overall quality of the meat or consumer acceptance.
AFRIKAANSE OPSOMMING: Moderne verbruikers is baie meer gesonheidsbewus en verkies meer natuurlik geproduseerde produkte soos vrylopende (free range) hoenders. Die kommersiële braaikuiken is nie geskik vir vrylopende produksie nie en `n ander genotipe word benodig wat die Suid-Afrikaanse mark sal kan voorsien met aanvaarbare vleiskwaliteit vergelykbaar met dié van die braaikuiken. Die doel van hierdie navorsing was om die effek van produksiestelsel (vrylopend en intensief) en genotipe (braaikuiken (COBB™), Potchefstroom Koekoek en Ross 308 X Potchefstroom Koekoek kruising) op die morfologiese, fisiese (pH, kleur, drip- en kookverlies, waterhouvermoë en taaiheid), chemiese samestelling (vog-, proteïen-, vet-, asinhoud en vetsuurprofiel), sensoriese kwaliteit en verbruikersaanvaarbaarheid van verskeie hoender vleis porsies te bepaal. Hierdie navorsing het getoon dat genotipe `n groter invloed gehad het as produksiestelsel op die groei en morfologiese eienskappe van die hoenders, asook op die sensoriese eienskappe en verbruikersaanvaarbaarheid. Die braaikuiken, gevolg deur die Ross X Koekoek kruising en dan die Koekoek, het die beste (P ≤ 0.05) voeromsetverhouding (FCR), gemiddelde daaglikse toename (GDT) en Europese produksie effektiwiteitsfaktor (EPEF) getoon. Vir elke genotipe het die vrylopende hoenders swaarder (P ≤ 0.05) lewende massa by slag getoon. Ten spyte daarvan dat die Ross X Koekoek kruising swakker groei en effektiwiteitsresultate getoon het, het hulle laer mortaliteite en minder been breuke en beserings as die braaikuiken gehad. Die Ross X Koekoek kruising wat vrylopend groot gemaak is, het ook swaarder dy, boud en vlerkie massa (P ≤ 0.05) as die braaikuiken getoon. Die navorsing het ook getoon dat kleur, pH en die poli-onversadigde tot versadigde vetsuur verhouding (PUFA:SFA) meer beïnvloed is deur die effek van produksiestelsel as genotipe. Die hoenders wat in ʼn vrylopende omgewing grootgemaak is se PUFA:SFA verhouding is hoër as dié van intensiewe boerdery, wat dit voordelig maak vir menslike gesondheid. Vrylopende hoenders se vleis is donkerder (L*) (P ≤ 0.05) en het ook laer rooi, geel (a* en b*) en pH (P ≤ 0.05) waardes getoon. Produksiestelsel effek het ook variërende chemiese waardes in verskillende karkas porsies tot gevolg gehad: ʼn laer vetinhoud is gevind in die dy en ʼn hoër proteïeninhoud in die borsies van die braaikuikens wat vrylopend grootgemaak is. Korrelasies met die sensoriese data het ook getoon dat sappigheid, taaiheid en hoendervleis geur die grootste dryfvere is in verbruikersaanvaarbaarheid. Tydens die verbruikerstoetse waar die verbruikers die gaar hoendervleis blind geproe het, het die verbruikers oor die algemeen meer gehou van die Ross X Koekoek kruising in vergelyking met die ander hoender genotipes (P ≤ 0.05), maar sodra inligting oor die verskillende produksiestelsels gegee is, het die verbruikers aangedui dat hulle hoenders wat vrylopend groot gemaak is, verkies. Dit dui daarop dat persepsies ʼn baie belangrike rol speel in die verbruiker se finale besluitnemingsproses. Statistiese segmentasietegnieke is ook op die data uitgevoer ten einde te bepaal of verbruikers in groepe verdeel kan word wat betref hul voorkeur van die sensoriese of intrinsieke eienskappe van die hoenderprodukte. Drie verskillende groepe is geïdentifiseer, nl. verbruikers wat 1) vrylopende hoender vleis verkies; 2) intensiewe hoender vleis verkies; 3) beide vrylopende en intensiewe hoender vleis verkies. In die lig van bogenoemde resultate wil dit voorkom of kruisteling tussen die gewone braaikuiken en die Potchefstroom Koekoek ʼn moontlike opsie is vir die Suid-Afrikaanse vryloop hoenderbedryf. Hierdeur word daar van vrylopende produksie stelsels gebruik gemaak sonder om die vleiskwaliteit of gebruikers aanvaarbaarheid negatief te beïnvloed.

Thesis (MSc. Agriculture (Animal Production)) -- University of Limpopo, 2014
Two experiments were conducted to determine the effect of moringa seed meal supplementation on productivity and carcass characteristics of Ross 308 broiler chickens. The first experiment determined the effect of moringa seed meal supplementation on productivity of Ross 308 broiler chickens aged one to 21 days. Two hundred and fifty unsexed day-old Ross 308 broiler chicks were randomly allocated to five dietary treatments, replicated five times, and each replication having 10 chickens. A completely randomized design was used. The chickens were fed on a grower diet supplemented with 0 (M0), 5 (M5), 10 (M10), 15 (M15) and 20 (M20) g of moringa seed meal/bird/day. Moringa seed meal supplementation had no effect (P>0.05) on feed intake, metabolisable energy intake, nitrogen retention, feed conversion ratio and live weight of unsexed Ross 308 broiler chickens. Moringa seed meal supplementation improved (P<0.05) growth rates of unsexed Ross 308 broiler chickens aged one to 21 days. A moringa seed meal supplementation level of 13.3 g/kg DM feed optimized growth rate of Ross 308 broiler chickens aged one to 21 days. The second experiment determined the effect of moringa seed meal supplementation on productivity and carcass characteristics of female Ross 308 broiler chickens aged 22 to 42 days. The chickens weighing 558 ± 10 g/bird were randomly allocated to five treatments with five replications having 10 birds. The chickens, aged 21 days, were allocated to the treatments in a completely randomized design. The chickens were fed on a grower diet supplemented with 0 (FM0), 5 (FM5), 10 (FM10), 15 (FM15) and 20 (FM20) g of moringa seed meal per kg DM. Moringa seed meal supplementation had no effect (P>0.05) on feed intake, growth rate, feed conversion ratio, live weight, metabolisable energy intake, carcass weight, breast meat weight, abdominal fat pad weight, liver weight, heart weight, thigh weight, meat flavour, juiciness and tenderness of female Ross 308 broiler chickens. However, moringa seed meal supplementation improved (P<0.05) nitrogen retention and gizzard weights of female Ross 308 broiler chickens. vi It was concluded that moringa seed meal supplementation improved growth rate of unsexed Ross 308 broiler chickens aged one to 21 days. Similarly, moringa seed meal supplementation increased nitrogen retention and gizzard weights of female Ross 308 broiler chickens aged 22 to 42 days.

The objective of the study was to determine the effects of Aloe ferox inclusion in drinking water on growth performance, blood biochemistry, physico-chemical characteristics, fatty acid profile and oxidative stability of broiler meat. The importance of A. ferox as a medicinal plant and factors that influence its utilization by communal poultry farmers were also investigated by use of a questionnaire survey. The survey revealed that the majority of respondents (84.6%) faced health challenges in their chickens and many relied (96.2%) on A. ferox to treat diseases and control parasites. The study also revealed that the choice of medicine (traditional or conventional) was influenced (P<0.05) by level of education and income. In the second phase of the research, a total of 600 Ross 308 day-old broilers, were randomly put in 6 treatment groups with 4 replicates, each having 25 birds. Fresh aqueous A. ferox leaf juice (ALJ) was administered in drinking water at a dosage of 20ml/litre to T1, T2 and T3 from day one to day 35, day one to day 14 and day 15 to day 28, respectively. Birds in T4 and T5 (positive controls) were treated with terramycin at the recommended dosage of 14g/litre of drinking water from day one to day 6 and from day 15 to 20, respectively; and birds in T6 (negative control) received distilled water from day 1 to 35. Feed Intake (FI), average daily gain (ADG) and feed conversion ratio (FCR) were calculated for the 5 week trial. After slaughter, carcass characteristics particularly dressing percentage (DP) and relative organ weight (ROW) were calculated. Serum biochemistry was also determined. For meat quality, pH and color were recorded 45 minutes and 24 hours after slaughter from the breast muscle. Fatty acid profiling and oxidative stability were determined using meat samples from the breast and thigh muscles. The results for growth performance showed that thebirds which were given A. ferox for the first two weeks (T2) consumed significantly (P>0.05) more feed (189.4g) than those in the negative control (159.6g) at the beginning of the starter phase. Subsequently, their ADG recorded on day 7 (27.1g) and day 14 (43.1g) were significantly (P<0.05) higher than the negative control (22.8g and 36.2g, respectively). Significant treatment effects (P<0.05) for FCR were reported in the 4th week for the birds that received A. ferox throughout (T1: 3.5). Carcass characteristics were not significantly (P>0.05) affected by A. ferox inclusion in drinking water. The highest high density lipoprotein (HDL) values (2.78 mmol/L) were yielded in T2and T3 had the lowest values (0.61mmol/L) for low density lipoprotein (LDL). For physico-chemical properties, no significant effects (P>0.05) of treatment on pH, colour, cooking loss and tenderness were observed. However, the group treated with A.ferox throughout the production cycle, had the highest pH (6.2), lowest lightness (38.5), highest redness (4.1), highest tenderness (13.86N) and the lowest cooking loss (12.6%). Significant treatment effects (P<0.05) were observed on the composition of the PUFA eicosatrienoic acid (C20:3c8, 11, 14(n-6)) of the breast muscle which was significantly lower in the A. ferox treatment groups than the positive controls. For the thigh muscle, there were significant (P<0.05) treatment effects on composition of palmitoleic acid (C16:1c9) and g-linolenic acid (C18:3c6, 9, 12 (n-3)). No significant (P>0.05) effects were found on oxidative stability of both thigh and breast muscles. In conclusion, the wide use of A. ferox by communal chicken farmers showed its importance as a medicinal plant. Apart from it being an effective medicinal plant, A. ferox inclusion in drinking water results in improved FI, ADG, reduced in LDLC and better g-linolenic and palmitoleic acid composition in the meat.

Three potential probiotics, Lactobacillus acidophilus, Lactobacillus casei and the fungus Scytalidium acidophilum were prepared in different ways. They were evaluated for their effects on performance and immune responses in broiler chickens in two 6-week trials. In the first trial, probiotics were orally administered at the ages of day 1 and day 8. There were no differences between live and disrupted cells. However, cobalt-containing cells had improved effects numerously in comparison with non cobalt-containing cells. As a result, these three disrupted probiotics, each in two different concentrations, were sprayed onto a mash basal feed before pelleting in the second trial. Improved feed intake (up to 6%) and body weight gain (up to 7%) were observed in all probiotic treatments. The anti-KLH IgA and IgG titers of probiotic-treated chickens were not significantly different from the negative controls in both trials. In summary, disrupted and cobalt-containing probiotics were proved to enhance the performance of broiler chickens and are promising for commercial application. In addition, a new fungal mycelium, Scytalidium acidophilum, was suggested to be a good probiotic to improve the growth of broilers.

Thesis (MscAgric (Animal Sciences))--University of Stellenbosch, 2005.
Broiler diets are supplemented with feed phosphates to ensure that adequate available phosphorus is provided in the diet to meet the bird’s requirements. These feed phosphates make a considerable contribution to the total available phosphorus in the diet and small differences in their availability may have significant effects on whether the bird’s requirements are met or not. The variation in availability of phosphorus between feed phosphates belonging to different classes and between feed phosphates of the same generic class is well documented.

The potential of lignin and mannanoligosaccharides (MOS), as alternatives to antibiotic growth promoters was evaluated in broilers. Dietary treatments included: (1) negative control (CTL-, antibiotic free); (2) positive control (CTL+, 11 mg/kg virginiamycin); (3) MOS (diet 1 + Bio-Mos: 0.2% to 21 d and 0.1% thereafter); (4) LL (diet 1 + 1.25% Alcell lignin); (5) HL (diet 1 + 2.5% Alcell lignin). Bodyweight and feed conversion were not different when broilers were fed the CTL+, MOS, LL or HL diet. Birds fed MOS or LL had increased jejunum villi height (P < 0.05) and greater goblet cell number per villus (P < 0.05) when compared to those fed the CTL+ diet. MOS and LL increased (P < 0.05) the cecal populations of Lactobacilli and Bifidobacteria when compared to CTL+ fed birds. However, Lactobacilli and Bifidobacteria loads were lowest (P < 0.05) in birds fed the CTL+ or HL diet. Litter E. coli load was reduced (P < 0.05) when birds were fed MOS than when fed the CTL+ diet, but comparable to LL or HL fed birds. In birds challenged with pathogenic strains of E. coli (O2 and O88 serotypes) and fed the MOS or HL diet, the cecal population of total E. coli was lower (P < 0.05) than those fed the CTL+ diet; LL fed birds tended to have lower E. coli load than CTL+ fed birds. In summary, birds fed the MOS or LL diet had comparative advantage over CTL+ fed birds as evidenced by increased cecal populations of Lactobacilli and Bifdobacteria, increased villi height and greater goblet cell number in the jejunum, lower E. coli load in the litter, and lower cecal population of E. coli after an in vivo challenge with pathogenic strains of E. coli. Therefore, MOS and lignin could be regarded as natural alternatives to antibiotic growth promoters in poultry production.
Key words. Antibiotics, mannanoligosaccharides, lignin, gut health, broilers.

Barred Rock chickens were offered diets that had been pelleted at 55° or 85°C. In an 8-week feeding trial, the subjects receiving pellets processed at the higher temperature experienced significant (P ≤ .05) weight gain over those receiving the diet processed at 55°C. Although feed consumption for this treatment increased as well, the difference was not significant (P ≤ .05). Chemical investigation revealed that metabolizable energy and bioavailability of lysine of both heat treatments were similar. Starch availability as measured by in vitro enzyme susceptibility, however, was lowered by increased heat application. In a second experiment, the feeding behavior of 12-16 week old cockerels offered diets of varying particle size, resulted in significant (P ≤ .05) increases in feed consumption rate and therefore decreases in total feeding activity for birds offered pellets and crumbles as compared to mash and reground pellets. No differences were noted in meal size, meal frequency, interval between meals, or total consumption. In a parallel experiment, no differences were noted in the behavioral parameters of birds receiving diets pelleted at 55, 70, or 85°C of similar density and particle size. Mash controls, however, experienced significantly (P ≤ .05) decreased consumption rate and concurrent increase in feeding activity. The beneficial effects experienced with pelleting can therefore be attributed to the reduction in total feeding activity that allows an increased proportion of net energy to be utilized in support of growth.
M.S.

Thesis (MSC. Agriculture (Animal Production)) --University of Limpopo, 2014
Two experiments were conducted to determine the effect of moringa seed meal supplementation on productivity and carcass characteristics of Ross 308 broiler chickens. The first experiment determined the effect of moringa seed meal supplementation on productivity of Ross 308 broiler chickens aged one to 21 days. Two hundred and fifty unsexed day-old Ross 308 broiler chicks were randomly allocated to five dietary treatments, replicated five times, and each replication having 10 chickens. A completely randomized design was used. The chickens were fed on a grower diet supplemented with 0 (M0), 5 (M5), 10 (M10), 15 (M15) and 20 (M20) g of moringa seed meal/bird/day. Moringa seed meal supplementation had no effect (P>0.05) on feed intake, metabolisable energy intake, nitrogen retention, feed conversion ratio and live weight of unsexed Ross 308 broiler chickens. Moringa seed meal supplementation improved (P<0.05) growth rates of unsexed Ross 308 broiler chickens aged one to 21 days. A moringa seed meal supplementation level of 13.3 g/kg DM feed optimized growth rate of Ross 308 broiler chickens aged one to 21 days. The second experiment determined the effect of moringa seed meal supplementation on productivity and carcass characteristics of female Ross 308 broiler chickens aged 22 to 42 days. The chickens weighing 558 ± 10 g/bird were randomly allocated to five treatments with five replications having 10 birds. The chickens, aged 21 days, were allocated to the treatments in a completely randomized design. The chickens were fed on a grower diet supplemented with 0 (FM0), 5 (FM5), 10 (FM10), 15 (FM15) and 20 (FM20) g of moringa seed meal per kg DM. Moringa seed meal supplementation had no effect (P>0.05) on feed intake, growth rate, feed conversion ratio, live weight, metabolisable energy intake, carcass weight, breast meat weight, abdominal fat pad weight, liver weight, heart weight, thigh weight, meat flavour, juiciness and tenderness of female Ross 308 broiler chickens. However, moringa seed meal supplementation improved (P<0.05) nitrogen retention and gizzard weights of female Ross 308 broiler chickens. vi It was concluded that moringa seed meal supplementation improved growth rate of unsexed Ross 308 broiler chickens aged one to 21 days. Similarly, moringa seed meal supplementation increased nitrogen retention and gizzard weights of female Ross 308 broiler chickens aged 22 to 42 days.

Thesis (M.Sc. (Animal Production)) -- University of Limpopo, 2014
Two experiments were conducted to determine the effects of supplementing diets with effective microorganisms on intake, growth and carcass characteristics of Ross 308 broiler chickens. The first experiment determined the effect of supplementing diets with effective microorganisms on performance of unsexed Ross 308 broiler chickens aged one to three weeks. Two hundred unsexed day-old chicks were randomly assigned to five treatments with four replications, each replication having ten birds. A complete randomized design was used. The chickens were fed a grower diet supplemented with 0 (EM0), 30 (EM30), 50 (EM50), 70 (EM70) or 100 (EM100) ml of effective microorganisms per litre of water. Effective microorganism supplementation did not improve (P>0.05) diet and metabolisable energy intakes of the chickens. Effective microorganism supplementation reduced (P<0.05) growth rate and live weight of the chickens. Poorer (P<0.05) feed conversion ratios were observed in chickens supplemented with effective microorganisms. However, effective microorganism supplementation improved (P<0.05) crude protein retention of the chickens. Supplementation with effective microorganisms reduced (P<0.05) mortality rate of the chickens from 10 to 0 %. The second experiment determined the effect of supplementing diets with effective microorganisms on performance of male Ross 308 broiler chickens aged 22 to 42 days. The chickens were randomly allocated to five treatments with four replications, each replication having 10 birds. The chickens aged 21 days, weighing 474 ± 2g, were allocated to the treatments in a complete randomized design. The chickens were fed a grower diet supplemented with 0 (EMM0), 30 (EMM30), 50 (EMM50, 70 (EMM70) or 100 (EMM100) ml of effective microorganisms per litre of water. Effective microorganism supplementation did not improve (P>0.05) intake, DM digestibility, metabolisable energy, feed conversion ratio, fat pad weight and meat sensory attributes of the chickens. Effective microorganism supplementation reduced (P<0.05) growth rate, live weight and carcass weight of the chickens. However, effective microorganism supplementation improved (P<0.05) crude protein retention and crude protein content of meat of the chickens. Supplementation with effective microorganisms reduced (P<0.05) mortality of the chickens from 5 to 0 %. v It is concluded that effective microorganism supplementation to the diets of Ross 308 broiler chickens reduced growth rate and live weight of the chickens. However, effective microorganism supplementation improved crude protein retention and crude protein content of the meat of broiler chickens. Supplementation with effective microorganisms reduced mortality of the chickens to zero.

This investigation was conducted in the rural community of Cuambo, located in the northeast of Imbabura province, in the Mira river basin of Salina parish, at 1530 meters above sea level and with an average temperature of 19 C. The principal objective of this investigation was to evaluate the effect of four levels of substitution of fish meal for earthworm meal in broiler chicken diets. The fieldwork occurred in two stages over the course of 20 months: A. Creation of the feed: This step lasted from the installation of an earthworm culturing area through the cultivation, harvest, and drying of the worms until obtaining the flour and then the feed with the respective formulas and acquisition of primary materials. B. Cultivation of broiler chickens: This was carried out in a community member's house adapted to function like a chicken coop that had been previously prepared to receive the chicks. The study lasted 7 weeks. A completely random design (CRD) was used with five treatments and five repetitions per treatment, with five chickens per experimental unit. ANOVA, Tukey analysis at 5%, and orthogonal polynomial analysis were used to evaluate the data. The factor under study was the percentage of earthworm flour in a basic diet. The treatments were as follows: T0: Control (Pronaca commercial feed) T1: 100% earthworm meal T2: 75% earthworm meal T3: 50% earthworm meal T4: 25% earthworm meal Analyzed variables: Weekly weight gain, Weekly food conversion, Accumulated food conversion, Total food consumption, Efficiency index, Yield, Organoleptic analysis, Economic analysis. From the results obtained, we conclude that treatment 0 (T0) is the best because it gave the best results in weight gain, food conversion, efficiency index, yield, and cost of production. In the organoleptic analysis T4 received the most points for appearance and flavor; T3 received the most for color, smell, and texture. The treatment with greatest acceptability was T4, with the most points. In production costs, the least expensive was T1, but it is not recommended for use because the chickens had poor results in the studied variables.

Experiments were conducted to investigate the effects of dietary fat, vitamin E(Vit. E) and selenium(Se) supplementation on the performance, fatty acid(FA) composition, lipid oxidation on blood and the oxidative stability of muscle tissues (breast and thigh) during refrigerated storage of broiler chickens fed high levels of flaxseed(FXS). Four hundred and eighty d-old broiler chicks were fed experimental diets for a 3 wk period, which consisted of the combination of two dietary fat sources: fullfat soybean(FFSB) and FXS; 3 Vit. E levels: 10, 40 and 80 IU/kg and two Se levels: 0.15 and 0.30ppm (Exp. I). Four hundred and forty d-old chicks were fed on FFSB diets supplemented with 10, 80, and 160 IU of Vit. E/kg, FXS diets supplemented with 10, 40, 80, 120, 160 and 200 IU of Vit. E/kg, corn-soybean based diet (control), and on a commercial diet for 21 days (Exp. II). For Exp. III, 1680 (840 of each sex) d-old broiler chicks were raised up to 41d. Three basal diets containing 10% FXS and 3 levels of Vit. E: 60-, 90- and 160 IU/kg were formulated for 3 age periods: starter (0--3wk), grower (3--5 wk) and finisher (5--6wk). Three groups of birds were fed these basal diets, while 3 other groups were fed the diet containing 160 IU of Vit. E either during the starter, grower or finisher phase (diets supplemented with 60 IU/kg were given in the two remaining phases). (Abstract shortened by UMI.)

Thesis (M. Tech.(Agriculture: Animal Production)) - Central University of technology, Free State, 2012
A 42-day feeding trial involving 180 day old broiler chicks was carried out at Glen Agric Institute ARC poultry section to study the effects of whole hatchery waste meal (WHWM) as an alternative in broiler diets. In this study whole hatchery waste meal (WHHW) replaced fish meal (FM), protein for protein, in broiler diets at 0, 10, 20, and 30% levels. One hundred and eighty broiler chickens were grouped, 45 birds per treatment which were further replicated 3 times (15 birds per replicate) in a completely randomized design. Feed and water supply were offered to birds ad libitum while standard management practices were meticulously adopted. Samples of the two test ingredients were sent to a lab for chemical analysis and the results indicated that FM had higher content of crude protein (73.18%) while that of WHWM was 4226. The calcium phosphorus ratio was 16.6:1 for WHWM as against 1.5:1 in the FM. The results also indicated a higher content of Ash% and Ether extract for WHWM (18.12) and (23.94) respectively. The higher ash content could be due to the high content of eggshell at the time of processing. At the end of the feeding trial broiler performance, blood, carcass characteristics and the economic benefit of using WHWM in broiler diets were determined. Blood and meat samples were collected and sent to the pathology laboratory at the University of the Free State, Bloemfontein for hematological and meat characteristics analysis. Results for broiler performance showed that broilers fed diet 2 had highest values for feed intake (118.25g/bird/day), weight gain (50.16g/bird/day) and daily protein intake (29.08g/bird/day) while those fed with diet 3 were superior in the efficiency of feed conversion (2.31). The highest value of abdominal fat 1.12% was observed in birds fed diet 2. The highest live mass was observed in birds fed diets containing no WHWM (2.83), while non significant difference were observed in live mass of birds fed diet 1, 3 and 4. Broilers fed control diet had highest mean values for eviscerated weight (2.20kg) and dressing percentage (77.86%). Blood samples were sent for analysis of White blood cells (WBC), Red blood cells (RBC) and Haemoglobin (HGB), Hematogrit (HCT), Mean corpuscular volume (MCV), Mean corpuscular haemoglobin (MCH) and Mean corpuscular haemoglobin concentration (MCHC). The results showed marginal variations in blood parameters. White blood cell counts were higher for birds fed control diet (519.59 x 103/1) than those fed WHWM (484.93 X 103/1). Non significant differences (P > 0.05) were observed on the HGB of all treatment groups including the control group. RBC counts of T1-T3 were not significantly different from each other but statistically significantly different from T4 (30% WHWM). The highest value of 2.67 106/ mm3 was observed in birds fed a higher level of WHWM. High RBC and HGB counts in the birds fed WHWM are an indicative of higher oxygen carrying capacity. The HCT and MCH results showed nonsignificant differences between T1, T3 and T4, except T2 which was significantly different from the other treatment groups. The MCV values for T1-T4 were 132.58, 126.47, 129.15 and 128.15 10'15L respectively. The highest and lowest values were recorded on T1 and T2 respectively. The feed costs decreased with an increase in the level of WHWM in broiler diets. The lowest feed cost/kg weight gain of R8.69 recorded for broilers fed on diet three. This agrees with several studies which documented the use of hatching waste in poultry diet as means of reducing feed cost (Babiker et al 1991; Abiola, 1999; Abiola, 2000; Abiola and Onunkwor 2004). It can be concluded that 10% of FM can be replaced with WHWM in broiler diets without adverse effects on growth, hematological and carcass traits.

Thesis (MScAgric (Animal Sciences))--University of Stellenbosch, 2011.
ENGLISH ABSTRACT: In recent years, the aim of the production of broilers became more focused on the increase of the performance of the birds in order to increase profit. To obtain an increased performance with broiler chicks, it is necessary to look at the development of their gastrointestinal tract, the feed requirements and the ability to digest certain nutrients in the period post hatch. Research have shown clear evidence of increased performance of chicks by the inclusion of certain carbohydrate and protein sources in the prestarter diets, but in contrast to this there are also some research that found no significant effects on the performance of broilers when certain carbohydrate and protein sources were included in the pre-starter diet. Therefore, the purpose of this study was to investigate the effect that a product containing specific carbohydrate and protein sources, included in the pre-starter diets of broiler chicks, would have on their performance. It was believed that the products to be tested would result in increased performance of the chicks in the following growth phases. Special emphasis was placed on the average daily gain (ADG), feed intake, cumulative feed intake, feed conversion ratio (FCR), European production efficiency factor (EPEF) and the protein efficiency ratio. Different inclusion levels of the different raw materials were investigated in the first trial. Three raw materials and a control were compared using a summit dilution process at 100:0, 66:34, 50:50, 34:66 and 0:100. Specific production parameters such as ADG total live weight gain, feed intake per week, cumulative feed intake, FCR, EPEF and PER were measured and calculated in order to determine if there were any significant differences between the treatments with the different raw material inclusions on the performance of the chicks. No significant differences (P>0.05) were found between the 13 treatments for the ADG, total live weight gain, feed intake per week, cumulative feed intake, FCR, EPEF and PER. The results therefore indicated that there were no significant differences between the different inclusion levels of the different raw materials and no significant differences for the production parameters for animals receiving diets with various levels of the three raw materials. It is thus concluded that these raw materials can be successfully utilised in pre-starter diets of broiler chicks. The effect of the contribution of sugar to the metabolisable energy (ME) of the raw materials was tested in a commercial grower trial. The three raw materials had inclusion levels leading to supply of either 12% or 18% of the ME in the form of sugar. No significant differences were found between the seven treatments for ADG, total live weight gain, feed intake per week, cumulative feed intake, FCR, EPEF or the PER. It was concluded that the percentage in contribution of sugars between 12 and 18% to the ME of the prestarter diets had no significant effects on the production parameters tested.
AFRIKAANSE OPSOMMING: Met die produksie van braaikuikens word daar deesdae al hoe meer klem gelê op die verhoging van die produksie van die kuikens om dan dus ‘n verhoging in die wins te bewerkstellig. Om hierdie verhoogde produksie by braaikuikens te kan bereik, is dit nodig om na eienskappe van die kuiken soos die ontwikkeling van die spysvertering stelsel, die nutrient- behoeftes van die kuiken en die vermoë om sekere nutriënte te kan verteer in die periode na uitbroei. Sommige navorsing het gewys dat die insluiting van sekere koolhidraat – en proteïen bronne in die voor-aanvangs diëete van braaikuikens, lei tot ‘n positiewe effek op die produksie van die kuikens, waar ander navorsing geen effek gevind het nie. Daarom was die doel van die huidige navorsing gewees om te toets wat die effek van die insluiting in die voor-aanvangs dieet van braaikuikens ‘n sekere produk met ‘n spesifieke koolhidraat –en proteïen bron samestelling op die produksie van die kuikens sal wees in die daaropvolgende fases. Dit was verwag dat die insluiting van hierdie produkte in die voor-aanvangs diëte van braaikuikens ‘n positiewe effek sou hê op die produksie van die kuikens. Spesiale klem was gelê op die parameters soos gemiddelde daaglikse toename (GDT) voer inname, kumulatiewe voer inname, voeromset verhoudings (VOV) Europese produksie doeltreffendheids- faktor (EPEF) en die proteïen doeltreffendheids faktor (PER). Verskillende insluitings vlakke van die verskillende produkte wat getoets is, is in die eerste proef ondersoek. Die drie produkte is deur middel van ‘n piek verdunnings proses by verhoudings van 100:0, 66:34, 50:50, 34:66 en 0:100 met mekaar vergelyk. Spesifieke produksie- parameters soos die GDT, lewende massa, weeklikse voer- inname, kumulatiewe voer- inname, VOV, EPEF en die PER is gemeet. Geen betekenisvolle verskille (P>0.05) was vir die 13 behandelings verkry nie. Die resultate het derhalwe getoon dat daar geen betekenisvolle verskille tussen die verskillende insluitings vlakke van die onderskeie produkte was nie en dat daar geen betekenisvolle tussen die produksieparameters van die kuikens wat die diëte met die verskillende insluitingspeile van die drie roumateriale ontvand het, was nie. Daarom is tot die slotsom gekom dat hierdie roumateriale suksesvol in die vooraanvangsdieet van braaikuikens aangewend kan word. Die effek van die bydrae van die suiker tot die metaboliseerbare energie (ME) van die produkte was in ‘n kommersiële groei proef getoets. Die drie rou materiale was by beide 12- en 18% ingesluit. Geen betekenisvolle verskille (P>0.05) was vir die sewe behandelings vir GDT, lewende massa, weeklikse voer- inname, kumulatiewe voer- inname, VOV, EPEF en PEF verkry nie.

Thesis (MScAgric (Animal Sciences))--University of Stellenbosch, 2011.
Includes bibliography.
ENGLISH ABSTRACT: The objective of this study was to evaluate the use of Musca domestica (common house fly) larvae meal, as protein source, for broiler production. This was done by investigating the nutritive value of house fly larvae meal together with its total tract digestibility, potential toxicity and carcass characteristics of the broilers supplemented with house fly larvae meal. The proximate analysis of house fly larvae meal show that it contained, on a dry matter basis, a gross energy value of 20.10 MJ/kg, 60.38% crude protein, 14.08% crude fat and 10.68% ash and that the house fly pupae contained a gross energy of 20.42 MJ/kg, 76.23% crude protein, 14.39% crude fat and 7.73% ash. House fly pupae meal had the closest match of amino acid profile when compared with the ideal amino acid profile required by broilers and it has arginine relative to the lysine content closer to the ideal amino acid profile than the house fly larvae meal. The essential fatty acid, linoleic acid, was found at levels of 26.25 and 36.27% of the total fats for the house fly larvae and pupae meal respectively. House fly larvae meal supplementation did not induce gizzard erosion or showed toxicity (regarding the gastro intestinal tract, immune system and organ stress) in broilers. Results revealed that house fly pupae meal had higher total tract digestibilities for most nutrients than of the house fly larvae meal. House fly larvae meal had a crude protein total tract digestibility of 69% and that of pupae meal was 79%. Both larvae and pupae meal had high amino acid total tract digestibilities of all the amino acids analysed. The house fly larvae and pupae meal had an apparent metabolizable energy (AME) value of 14.23MJ/kg and 15.15MJ/kg respectively. The larvae meal total tract crude fat and crude fibre digestibilities were 94% and 62% respectively. The pupae meal total tract crude fat and crude fibre digestibilities were 98% and 58% respectively. House fly larvae meal supplementation in a three phase feeding system significantly increased average broiler live weights at slaughter, total feed intake, cumulative feed intake as well as average daily gain (ADG) when compared to commercial maize: soya oil cake meal diet. In direct comparison of larvae inclusion levels with fishmeal in isonitrogenous and isoenergetic diet, no significant differences were observed between a 10% house fly larvae and a 10% fish meal diets regarding performance characteristic. The 25% house fly larvae meal diet yielded significantly better average broiler live weights at slaughter, total feed intake, cumulative feed intake (from the second week until slaughter) as well as average daily gain when compared to the 25% fish meal diet in the growth phases. Carcass characteristics of the 10% larvae, 10% fishmeal and commercial diets were compared. Chicks that received either the 10% house fly larvae meal or 10% fish meal supplementation produced significantly heavier carcasses and breast muscle portions than the chicks that received the commercial maize: soya oil cake meal. No treatment differences were found regarding breast and thigh muscle colour or pH. This study showed that house fly larvae meal can be regarded as a safe protein source that can be used to replace other protein sources and that has the ability to promote broiler performance without having any detrimental effects on carcass characteristics.
AFRIKAANSE OPSOMMING: Die doel van die studie was om die effek van Musca domestica (gewone huisvlieg) larwe meel, as ‘n protein bron, in braaikuikens te evalueer. Dit was gedoen deur die nutrient waarde van huisvlieg larwe meel saam met die totale spysvertering verteerbaarheid, moontlike toksiesiteit en karkas-eienskappe van braai kuikens te evalueer. Laboratoruim analiese toon dat huisvlieg larwe meel 20.10 MJ/kg bruto energie, 60.38% ru- protein, 14.08% ru- vet en 10.68% as bevat en huisvlieg papie meel 20.42 MJ/kg bruto energie, 76.23% ru- protein, 14.39% ru- vet en 7.73% as bevat. Huisvlieg papie meel stem die meeste ooreen met die idiale amino suur profiel soos wat benodig word deur braaikuikens en dit het ‘n arginien tot lisien verhouding wat die meeste ooreenstem met die idiale amino suur profiel in vergelyking met huis vlieg larwe meel. Die essensiele vet suur, linolien suur, was geanaliseer teen vlakke van 26.25- en 36.27% van die totale vette onderskeidelik vir huisvlieg larwe- en papie meel. Huisvlieg larwe meel vervanging het nie spiermaag erosie of enige ander toksiese effekte te veroorsaak nie. Resultate het getoon dat huisvlieg papie meel, in vergelyking met larwe meel, het ‘n hoër totale spysvertering verteerbaarheid vir meeste van die nutrient. Die huisvlieg larwe meel het ‘n totale ru- protein spysvertering verteerbaarheid van 69% en die van papie meel van 79%. Beide larwe en papie meel het hoë amino suur spysvertering verteerbaarheid. Larwe meel en papie meel het skynbare metaboliseerbare energie waardes van 14.23MJ/kg en 15.15%MJ/kg onderskeidelik. Die larwe meel het ‘n ru-vet en ru- vesel spysvertering verteerbaarheid van 94% en 62% onderskeidelik, waar die papies ‘n ru-vet en ru- vesel spysvertering verteerbaarheid van onderskeidelik 98% en 58% het. Huisvlieg larwe meel vervanging in ‘n drie fase voer stelsel het getoon om die gemiddelde braaikuiken lewende gewigte by slag, totale voer iname, sowel as die gemiddelde daaglikse toename te verhoog waneer dit vergelyk word met ‘n kommersiele mielie- soya olie koek dieet. Geen mekwaardige verskille was waargeneem toe die 10% larwe meel dieet direk met die 10% vismeel diet vergelyk was rakende enige produksie einskappe gemeet nie. Die 25% larwe meel dieet het merkwaardig beter gemiddelde braaikuiken lewende gewigte by slag, totale voer iname, sowel as die gemiddelde daaglikse toename getoon wanneer vergelyk word met die 25% vismeel dieet gedurende die verskeie groei fases. Karkas eienskappe van die 10% larwe meel, 10% vismeel en die kommersiele diete was gevergelyk. Kuikens wat 10% larwe meel en 10% vismeel in die diete ontvang het, het swaarder karkasse gelewer met swaarder borsie massas wanneer vergelyk word met die kommersiele mielie- soya olie koek dieet. Geen behandelings verskille was gevind rakende die borsie- en dy spier kleure of pH nie. Die studie toon dat huisvlieg larwe meel as ‘n veillige protein bron kan beskou word, wat gebruik kan word om ander protein bronne te vervang. Huisvlieg larwe meel het ook die vermoë om braaikuiken produksie te verhoog sonder om enige negitiewe effekte rakende die karkas eienskappe te toon nie.

Thesis (MScAgric)--Stellenbosch University, 2008.
ENGLISH ABSTRACT: Different substances were evaluated and compared to an antibiotic, in terms of their effect on nitrogen - and amino acid digestibilities. Two digestibility trials and one performance trial were conducted. Trials one and two apparent nitrogen (AND)- and amino acid (AAD) digestibilities were determined from digesta collected at the terminal ileum (ileal digestibility method). In Trial 3 the substances were evaluated in terms of their potential to improve production performance. Broilers were fed a maizesoya based diet throughout the three trails. In the first trial, garlic and a commercial prebiotic (Bio-Mos®), were tested and compared in terms of AND and AAD, to an antibiotic (doxycyclin, Doxyvete-SOS). A starter and finisher diet were fed as either mash or pellets. The garlic was included at 8g/kg, 13g/kg and 18g/kg to the starter and finisher diets. Bio-Mos® was added at 1g/kg, 2g/kg and 3g/kg to the starter diet, and 0.5g/kg, 1g/kg and 1.5g/kg to the finisher diet. The doxycyclin was added at 0.3 g/kg. None of the treatments had any beneficial effects in terms of AND. Feeding a pellet seem to have some negative effects in terms of AND. In general most of the treatments did not show any improvement in AAD at any determination period (day 21, 28 or 35). At day 21 and day 35, the mash diet supplemented with 18g/kg garlic had a negative effect on AAD, when compared to the negative and positive control. It doesn’t seem that feeding either a mash or a pellet had an influence on the effects exerted by the different treatments. In the second trial the influence of Bio-Mos®, a blend of organic acids, probiotics and electrolytes (Acid-Pak 4-way®) and a medium-chain triglyceride (MCT) were evaluated and compared in terms of AAD and AND, to the effect of an antibiotic, doxycyclin. The starter and finisher diets were fed as a mash. Bio-Mos® was included at 1g/kg, 2g/kg, and 3g/kg in the starter diet, and at 0.5g/kg, 1g/kg, 1.5g/kg in the finisher diet, respectively. Acid-Pak 4-way® was included at 0.4g/kg, 1g/kg and 1.6g/kg for both the starter and finisher diets. Medium-chain triglycerides (MCT) were allocated at 3g/kg, 3.6g/kg, 4.2g/kg for the starter diet, and 2.1g/kg, 2.7g/kg and 3.4g/kg for the finisher diet. An antibiotic, doxycyclin, was included at 0.3 g/kg. With AND, no treatment had any significant effect for the entire experimental period. At day 21, the treatment supplemented with MCT (3.4g/kg) had the most significant beneficial effect on AAD, when compared to the negative- and positive controls, as it increased AAD for the majority of the amino acids. The treatment with Acid-Pak 4-way® (1g/kg) had the most significant negative effect on AAD when compared to the positive control. At day 28, the treatments with Bio-Mos® (0.5g/kg and 1.5g/kg) and Acid-Pak 4-way® (0.4g/kg) had the most significant beneficial effect on AAD when compared to the positive control. It increased AAD for more than half of the 17 amino acids evaluated. The treatment supplemented with MCT (2.7g/kg) has shown the most significant negative effect on AAD, when compared to the positive control. In the third trial the effect of Bio-Mos®, Acid-Pak 4-way® and MCT on production performance was evaluated, and compared to the effects of the presence or absence of doxycyclin. Body weight (BW), body weight gain (BWG), feed intake (FI) and feed conversion ratio (FCR) were measured. The starter and finisher diets were fed as a mash. Bio-Mos®, MCT and Acid-Pak 4-way® were included at 3.0g/kg, 4.2g/kg and 1.6g/kg, respectively in the starter and finisher diets. Birds were weighed (per pen) on arrival and on days 7, 14, 21, 28, 35. Feed intake (FI) per pen was measured at days 7, 14, 21, 28 and 35, and mortality was recorded daily. In terms of BWG, Acid-Pak 4-way® had a higher BWG, when compared to the negative control, Bio-Mos® and MCT. It can be concluded that Bio-Mos®, Acid-Pak 4-way®, as well as MCT can be a possible alternatives to antibiotic supplementation. These three treatments did not necessary prove to be more effective than antibiotics, but are definitely competitive alternatives.
AFRIKAANSE OPSOMMING: Verskillende behandelings is geëvalueer en vergelyk met ‘n antimikrobiese produk, in terme van hul uitwerking op stikstof - en aminosuur verteerbaarhede. Twee verteringstudies en produksieprestasie studie is uitgevoer. In die eerste twee studies is die skynbare stikstof (AND)- en aminosuur (AAD) verteringskoöeffisiënte bepaal deur gebruik te maak van digesta wat by die terminale ileum ingesamel is (ileale verteringsmetode). In die derde studie is die produksie prestasie van braaikuikens op ‘n gebalanseerde metaboliseerbare energie (AME) rantsoen, soos beïnvloed deur die verskillende behandelings, geëvalueer. In die eerste studie is knoffel en ‘n kommersiële prebiotikum (Bio-Mos®) geëvalueer en met ‘n antibiotikum (doksisiklien, Doxyveto-SOS) in terme van AND en AAD vergelyk. Beginner- en afrondingsrantsoene is as ‘n meel of pille gevoer. Die knoffel is teen 8g/kg, 13g/kg en 18g/kg in die rantsoen ingesluit. Bio-Mos® is teen 1g/kg, 2g/kg en 3g/kg in die beginner rantsoen en teen 0.5g/kg, 1g/kg en 1.5g/kg in die afrondingsrantsoen, ingesluit. Die antibiotikum is teen 0.3g/kg in beide rantsoene ingesluit. Geen van die behandelings het enige positiewe invloed op AND gehad nie. Deur ‘n verpilde rantsoen te voer het sekere negatiewe invloed op AND gehad. Oor die algemeen het geen behandelings enige positiewe invloed op AAD gehad nie. Op dag 21 en 35 het die insluiting van knoffel teen 18g/kg in ’n meel rantsoen ’n negatiewe invloed op AAD gehad, wanneer dit met die negatiewe- en positiewe kontroles vergelyk is. Dit blyk nie dat om ‘n pil of meel te voer enige invloed op die invloede van die verskillende behandelings gehad het nie. In die tweede studie is Bio-Mos®, ‘n organiese suur (Acid-Pak 4-way®) en ‘n medium-ketting trigliseried (MCT) geëvalueer en met ‘n antbiotikum, doksisiklien (Doxyveto-SOS) in terme van AND en AAD, vergelyk. Beginner- en afrondingsrantsoene is gevoer as ‘n meel. Bio-Mos® is teen 1g/kg, 2g/kg, and 3g/kg in die beginner rantsoen en teen 0.5g/kg, 1g/kg, 1.5g/kg in die afrondingsrantsoen, ingesluit. Acid-Pak 4-way® is teen 0.4g/kg, 1g/kg en 1.6g/kg vir die beginner –en afrondingsrantsoene ingesluit. Die MCT is teen 3g/kg, 3.6g/kg, 4.2g/kg in die beginner rantsoen en teen 2.1g/kg, 2.7g/kg en 3.4g/kg in die afrondingsrantsoen ingesluit. Die antibiotikum is ingesluit teen 0.3g/kg. Geen behandelings het enige betekenisvolle invloed in terme van AND gehad nie. Op dag 21 het MCT (3.4g/kg), in vergelyking met die negatiewe- en positiewe kontrole, die grootste positiewe invloed op AAD gehad. Acid-Pak 4-way® (1g/kg) het, in vergelyking met die positiewe kontrole, ‘n positiewe invloed gehad op AAD. Op dag 28, het Bio-Mos® (0.5g/kg en 1.5g/kg) en Acid-Pak 4-way® (0.4g/kg) die grootste positiewe invloed op AAD gehad. Die behandeling met MCT (2.7g/kg) het die mees negatiewe invloed op AAD gehad. In die derde studie is die insluiting van Bio-Mos®, Acid-Pak 4-way® en MCT getoets om die invloed op braaikuiken produksie prestasie te evalueer, en te vergelyk met die invloed van die insluiting of afwesigheid van ‘n antibiotikum. Liggaamsmassa (BW), liggaamsmassa toename (BWG), voerinname (FI) en voeromsetverhouding (FCR) is gemeet. Beginner- en afrondings rantsoene is gevoer as ‘n meel. Bio-Mos®, MCT en Acid-Pak 4-way® is onderskeidelik teen 3.0g/kg, 4,2g/kg en 1.6g/kg in die rantsoen ingesluit. Die kuikens is met aankoms (per hok) geweeg, asook op dae 7, 14, 21, 28, 35. Voerinname per hok is gemeet op dae 7, 14, 21, 28 en 35. Mortaliteite is daagliks aangeteken. Die insluiting van Acid-Pak 4-way® het in vergelyking met die negatiewe kontrole, Bio-Mos® en MCT insluiting ‘n hoër BWG tot gevolg gehad. Die gevolgtrekking wat gemaak kan word is dat Bio-Mos®, Acid-Pak 4-way® en MCT gebruik kan word as ‘n moontlike alternatief vir antibiotika insluiting. Hierdie drie behandelings was nie noodwending meer effektief as die antibiotika nie, maar het wel bewys dat dit kompeterende alternatiewe is.

Thesis (MScAgric (Animal Sciences))--University of Stellenbosch, 2011.
Includes bibliography.
ENGLISH ABSTRACT: A growth and digestibility trial was conducted comparing the effect of an experimental enzyme at three different inclusions. A negative control containing no enzyme additions and a positive control containing a proven commercial enzyme were compared in a maize-soybean diet noting the performance of broilers and the digestibility of the grower feed. The commercial enzyme was a granular product with a xylanase activity of 38114.29 nkat/g and the second enzyme (ABO374) was a liquid experimental product with a xylanase activity of 1426.86 nkat/ml. Five diets were used i.e. control basal diet without enzyme supplementation (negative control), basal diet supplemented with the commercial enzyme (positive control) and three basal diets supplemented with the test enzyme at various inclusion levels (ABO 50, ABO 100 and ABO 200). The positive control was supplemented with 200 g/ton of the commercial enzyme; ABO 50 was supplemented with ABO374 at an inclusion level of 2671 ml/ton, ABO 100 with 5342 ml/ton and ABO 200 with 10684 ml/ton. Supplementation with the test enzyme (ABO 50) significantly improved BW at 23 days of age by 4.6 % (1107.4 g vs 960.96 g) and at 37 days of age by 3.2 % (2311.75 g vs 2237.81 g) over the negative control. Body weight gain for the total period of the trial was significantly improved by 3.24 % (64.32 g/bird/day vs 62.24 g/bird/day) the test enzyme supplementation (ABO 50) when compared to the negative control. During the starter phase, test enzyme supplementation (ABO 50) led to an improvement of 4.58 % (1.25 vs 1.31) in FCR in comparison with the negative control. The FCR for the total trial obtained by the test enzyme supplementation was significantly lower than the FCR obtained by the positive control. The highest EPER obtained for this trail was by the test enzyme supplemented diets and this was significantly higher than the EPER obtained by the positive control. It is clear from this growth trial that the test enzyme (ABO374) at an inclusion level of 2671 ml/ton outperformed the commercial enzyme and that it has the potential to improve the production performance of broilers on a maizeSBM based diet. The total tract digestibility method and total collection method was used to conduct the digestibility trial. The total tract digestibility method measures the difference between the amounts of each nutrient consumed from the amounts of each nutrient excreted in faeces. Only apparent digestibilities are reported for the digestibility trial. Apparent digestibility does not take the endogenous protein fraction in the faeces into account. The endogenous protein fraction is derived from digestive enzymes and proteins from the intestinal walls that are secreted into the digestive tract. The grower negative control, positive control, ABO 50, ABO 100 and ABO 200 diets used in the production trial were also used in the digestibility trial. Supplementation with the test enzyme showed no significant improvements on the apparent digestibility of dry matter, organic material, ash, crude protein, metabolisable energy or crude fibre. No significant improvements in the apparent digestibility of the amino acids (threonine, arginine, valine, lysine, methionine, cysteine and isoleucine) were noticed either and thus the digestibility of the grower feed were not influenced by the addition of enzymes due to the supplementation of the test enzyme ABO374. Pelletisation of the grower diets could have lead to the inactivation of the enzyme due to the high temperature at which pelletisation takes place. Another possible reason why enzyme supplementation did not increase nutrient digestibility, may be that the breakdown of non-starch polysaccharides by the enzymes led to an increase in the concentration of oligosaccharides in the small intestine of the birds, thus leading to the decrease in nutrient absorption Key words: body weight, body weight gain, feed conversion ratio, European production efficiency ratio, maize, soybean meal, apparent digestibility, dry matter, organic material, ash, crude protein, metabolisable energy, crude fibre, xylanase, pellitisation.
AFRIKAANSE OPSOMMING: ‘n Groei en vertering studie was uitgevoer om die effek van ‘n eksperimentele ensiem wat teen drie verskillende insluitingsvlakke by ‘n basale dieët bygevoeg is te vergelyk met ‘n negatiewe kontrole wat geen ensiem bevat het nie en met ‘n positiewe kontrole wat ‘n kommersiële ensiem bevat in ‘n mielesojaboon oliekoek dieët op die produksie vermoë van braaikuikens en die verteerbaarheid van die groei voer. Die kommersiële ensiem was ‘n granulêre produk met ‘n xylanase aktiwiteit van 38114.29 nkat/g en die eksperimentele ensiem (ABO374) was ‘n vloeistof produk met ‘n xylanase aktiwiteit van 1426.86 nkat/ml. Vyf diëte was gebruik nl. ‘n basale dieët met geen ensiem byvoeging (negatiewe kontrole), basale dieët met die byvoeging van die kommersiële ensiem (positiewe kontrole) en drie basale diëte wat met die byvoeging van die eksperimentele ensiem teen drie verskillende insluitings vlakke (ABO 50, ABO 100 and ABO 200). Die kommersiële ensiem was by die positiewe kontrole bygevoeg met ‘n insluitings vlak van 200 g/ton, ABO374 was bygevoeg by ABO 50 met ‘n insluitings vlak van 2671 ml/ton, ABO 100 met 5342 ml/ton en ABO 200 met 10684 ml/ton. Die byvoeging van die eksperimentele ensiem (ABO 50) het gelei tot die betekenisvolle verbetering van die liggaamsmassa van die voëls by die ouderdom van 23 dae met 4.6 % (1107.4 g teenoor 960.96 g) en by die ouderdom van 37 dae met 3.2 % (2311.75 g teenoor 2237.81 g) teenoor die negatiewe kontrole. Liggaams massa toename vir die hele periode van die studie was betekenisvol verhoog met 3.24 % (64.32 g/kuiken/dag teenoor 62.24 g/kuilen/dag) met die byvoeging van die eksperimentele ensiem (ABO374) teenoor die negatiewe kontrole. Voeromset verhouding was betekenisvol verbeter met 4.58 % (1.25 teenoor 1.31) toe die kommersiële ensiem bygevoeg was teenoor die negatiewe kontrole. Die hoogste europese produksie effektiwiteits verhouding wat verkry is vir die hele studie periode is deur die byvoeging van die eksperimentele ensiem (ABO374). Hierdie groei studie dui dus duidelik aan dat die gebruik van die eksperimentele ensiem (ABO374) baie beter resultate as die kommersiële ensiem opgelewer het teen ‘n insluitings vlak van 2671 ml/ton, dus het ABO374 die potensiaal om die produksie potensiaal van braaikuikens op ‘n mielie-sojaboonoliekoek dieët te verbeter. Die totale spysverteringskanaal verteerbaarheid metode was gebruik om die verteerbaarheid studie uit te voer. Die totale spysverteringskanaal verteerbaarheid metode meet die verskil tussen die nutriënt inhoud van die voer en die nutriënt inhoud van die mis. Slegs die skynbare verteerbaarheid van nutriënte word vir hierdie verteerbaarheidstudie gerapporteer. Skynbare verteerbaarheid sluit nie die endogene proteïenfraksie wat afkomstig is van verteringsensieme of die proteïene afkomstig vanaf die spysverteringskanaal se intestinale wande af in nie. Die negatiewe kontrole, positiewe kontrole, ABO 50, ABO 100 en ABO 200 groei diëte gebruik in die produksie studie is gebruik vir die verteringsstudie. Die byvoeging van die eksperimentele ensiem het geen betekenisvolle resultate opgelewer ten opsigte van droë materiaal, organiese material, as, ru-proteïen, ru-vesel of metaboliseerbare energie nie. Daar was ook geen betekenisvolle resultate opgelewer wanneer die eksperimentele ensiem bygevoeg was nie ten opsigte van die verteerbaarheid vir aminosure (treonien, arginien, valien, metionien, sisteïen en isoleosien) nie en dus is die verteerbaarheid van die groeivoer glad nie beïnvloed deur die byvoeging van die eksperimentele ensiem nie. Die verpilling van die groei voer mag dalk gelei het tot die inaktivering van die eksperimentele ensiem deur dat dit blootgestel was aan hoë temperature. ‘n Ander moontlike rede vir die mislukking van die ensiem kon gewees het dat die afbreking van die nie-stysel polisakkariedes deur die ensiem kon gelei het tot die verhoging van die oligosakkariede konsentrasie in die laer spysverterings kanaal en dus kon dit lei tot ‘n verhoogde deurvloeitempo, gevolg deur ‘n afname in die absorpsie van nutriënte. Sleutel woorde: Liggaamsmassa, liggaamsmassa toename, voeromsetverhouding Europese produksie effektiwiteits verhouding, mielie, sojaboonoliekoek, skynbare verteerbaarheid, droëmaterial, organiesematerial, as, ru-proteïen, ru-vesel, metaboliseerbare energie, verpilling.

Orientador: Marcelo Alexandre Prado
Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos
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Mestrado
Mestre em Ciência de Alimentos

Seven experiments were carried out to investigate the involvement of carbohydrate and lipid metabolism on the incidence of Sudden Death Syndrome (SDS) in broiler chickens. Hepatic arachidonate level decreased after 1 h postmortem. The decreased level of hepatic arachidonate previously observed in SDS birds was, therefore, associated with the post-mortem aging. Broiler chickens fed diets high in glucose monohydrate (cerelose) were more susceptible to SDS mortality than broilers fed diets high in corn starch or corn-soy. Feeding broilers a high cerelose diet increased the levels of plasma calcium, total protein, triacylglycerol, and uric acid compared to broilers fed corn starch diet. Broilers fed cerelose diet also showed the higher incidence of leg abnormality than broilers fed corn starch or corn-soy diets. Daily intraperitoneal injection with 0.25 ml of L(+) lactic acid solution (100 mg lactic acid/ml) to broilers over a 7-d period failed to reproduce the SDS incidence, whereas intravenous injection of 40% lactic acid solution (200 mg lactic acid/kg body weight) resulted in 100% incidence of SDS-type mortality. No SDS-type mortality was observed with the intravenous injection of 40% sodium lactate solution (200 mg sodium lactate/kg body weight). Disturbance of physiological acid-base balance might be a factor in the SDS-type mortality. Suboptimal thiamin level in broilers fed cerelose diets was observed. Thiamin supplementation to cerelose diet improved the thiamin status of the broilers. Mortality due to SDS was decreased when thiamin hydrochloride was supplemented to cerelose diet at the level of 0.6 and 2.8 mg thiamin hydrochloride/kg diet, respectively. Thiamin supplementation, however, did not change the liver pyruvate dehydrogenase activity and the proportion of pyruvate dehydrogenase in the active form. Disturbance of acid-base balance was postulated to be associated with the incidence of SDS. Other genetic, nutritional, and environmental factors are likely to modify the incidence by affecting the acid-base status of the chicken.
Graduation date: 1993

The increased demand for breast meat of broiler chickens has challenged researchers to investigate management techniques that could be used to increase the production of this valuable commodity. Two experiments were conducted in this study; the first investigated the effect of early feeding of newly hatched broilers on breast meat yield (BMY) at market weight, and the second focused on improving BMY of broilers exposed to short daylengths by feeding higher than conventional levels of dietary protein. In the first experiment, of the 528 eggs set in the incubator, half were placed, at day 18, in hatching trays containing a commercial broiler starter feed whilst the others (the held group) were hatched conventionally. Six chicks from both fed and held groups were sampled at nine-hour intervals from the time that the first chicks hatched for a subsequent period of 36 h. After measuring their body weight these chicks were euthanised and dissected in order to measure their breast and yolk weights. Body protein, lipid and water contents were measured on each chick. At day 21, six birds from the fed and held groups were sampled, and body weight, breast weight and body protein content were measured. The yolk sac weight for fed birds was significantly reduced compared to that of held birds (P < 0.001). Both fed and held birds had the same breast weight at hatch, but at day 21 the mean breast weight of the fed birds was significantly heavier than of held birds (P < 0.05). The birds that were removed first from the hatcher had a reduced breast muscle weight compared to those that were removed last. In the second experiment, a total of 3200 day-old broiler chicks were reared in eight light-tight rooms. Four lighting regimens (12L: 12D, 16L: 8D, 20L: 4D and 24L: 0D) were randomised between rooms, with each light treatment being replicated twice. Each room was divided into four pens and 100 chicks in each pen received one of four dietary protein treatments. At day 35, three birds from each pen were sacrificed so that measurements could be made of breast, thigh, drum and wing weight, and carcass chemical composition. Breast weight increased as daylengths increased except in birds that were fed low protein diet (143 g protein/kg feed). High levels of dietary protein increased breast weight in birds on all other daylengths except for those on 12 h which showed a reduced breast muscle weight when dietary protein content was increased. The results of the first trial suggests that breast meat yield could be improved if newly hatched chicks are offered feed immediately after hatch, however the hypothesis that this increment was due to an overall increase in body protein content in the first few days after hatching could not be corroborated. The results further showed that held birds do not withdraw nutrients from breast muscle to maintain growth at hatch, this is because birds that stayed longer in the hatchery without feed showed increased breast muscle weight compared to those that were removed first. The second trial could not identify a suitable feeding programme to overcome the problem of a lower breast muscle weight that results from the use of 12 h of lighting compared to that when long daylengths are used. Highest breast weight was obtained when birds were fed high protein diet at 20 h. More research is required to further investigate the combined effect of early feeding and daylength on breast meat yield in broiler chickens.
Thesis (M.Sc.)-University of KwaZulu-Natal, Pietermaritzburg, 2012.

Broiler production is an important animal production enterprise with potential to make high returns. Increasing feed efficiency and early body weight gain has always been a top priority in the broiler industry. The general objective of broiler nutrition is to maximise production performance and profitability . Nutrition is of major importance in raising chicken, and feed is a major input in poultry production systems, accounting for over 60% of total production costs in commercial poultry sector Renkema (1992). The cost of feed is therefore often a constraint especially in developing countries. For instance, Onyenokwe (1994) observed that high cost of feed ingredients in many African countries has caused many poultry farmers to abandon the industry. The continued rise in feed prices is due to competition for some of the ingredients with human e.g. sorghum, wheat and maize. Broiler farmers are therefore forced to use combinations of feed ingredients of low cost to obtain savings and avoid any further loss of profits. It is therefore important to give special attention to feed and feeding since the rate of feed consumption increases rapidly with advancing age of the birds and good nutrition is reflected in the bird's performance and its products. The profitability of a broiler enterprise depends on the efficient conversion of feed to meat. Broilers have the ability to convert the feeds into meat with a high efficiency. For instance Morris and Njuru (1990) reported that broilers have much higher daily rates of protein deposition than layer chicken strains. This implies that fast-growing strains would require greater daily protein intakes than slow-growing ones. In the past, the major criteria for assessing the performance of broilers has been growth rate and feed conversion ratio (FeR). Diet specifications and feeding programmes have been aimed at maximising these two parameters whereby overall flock performance is calculated based on the total weight of chicken produced from total feed deliveries. With the new developments in understanding of nutritional factors affecting broiler growth and carcass composition, it is now possible to apply sophisticated and yet efficient approaches to feeding broilers.
Thesis (M.Sc.)-University of KwaZulu-Natal, Pietermaritzburg, 2005.

Fertility of Broiler Breeders (BBs) has been researched over many years with inconclusive findings. Genetic selection and improvements in growth traits have had negative effects on fertility of BB. One explanation is related to overweight birds, resulting in the inability of birds to copulate successfully, with no cloacal contact. The requirements of CP for egg production in BB females have been quantified, but there is less literature on how CP affects fertility in male BBs. The objective of this experiment was to investigate the effects of feeding BB males different dietary CP intakes (10.4, 12.4, 14.2, 17.8, 19.3 and 20.1 g CP/bird/day) on fertility in flocks with natural mating and in birds that were artificially inseminated (AI). Results showed that birds consuming 10.4 and 12.4 g CP/bird/day resulted in weight loss (between 24.9 and 23.6% and 26.5 and 22.4% below target BW) over the 29 weeks of the experimental period in both natural mating and individual pens respectively. Intakes of higher protein content (17.8- 20.1 g CP/bird/day) however resulted in BW gain over the experimental period. Hatch percentage across all CP intakes throughout the duration of the study was found to be high, ranging between 75- 100 and 80-95 % in AI and naturally mated birds respectively, and not affected by CP intakes. Similar results for predicted fertility using the methods published by Brillard & Antoine (1990) and Wishart (1997) were found; however Brillard & Antoine (1990) is more lenient requiring less outer perivitelline layer (OPVL) sperm/mm2 to pronounce an egg fertile. Improved fertility predictions could have been made by using examination of inner perivitelline layer (IVPL). There was a tendency for a superior response in predicted fertility from birds with a protein intake of 14.2 g CP/bird/day. This intake also least affected the BW of the male birds and thus 14.2 g CP/bird/day can be recommended for optimal BB male performance.
Thesis (M.Sc.Agric.)-University of KwaZulu-Natal, Pietermaritzburg, 2010.

Thesis (Ph. D. (Animal Production)) -- University of Limpopo, 2020
A study was conducted to determine the effect of dietary crude (CF) levels of (3, 4, 5 and 7 %) on feed intake, digestibility, growth rate, feed conversion ratio (FCR) and live weight of male Ross 308 broiler and indigenous Venda chickens aged 1 to 42 days. The study, also, determined the effect of dietary CF level on the gastrointestinal morphology and digesta pH of gut organs of male Ross 308 broiler and indigenous Venda chickens aged 42 days. Dietary CF levels affected (P<0.05) feed intake, growth rate and live weight of male Ross 308 broiler and Venda chickens aged 1 to 21 days. A dietary CF level of 3.9 % optimized feed intake, while 4.5 % dietary CF optimized growth rate and live weight in male Ross 308 broiler chickens. However, dietary CF levels of 4.4, 4.8, 5.9 and 4.7 % optimized feed intake, growth rate, FCR and live weight, respectively, of male Venda chickens aged 1 to 21 days. Therefore, dietary CF level for optimal productivity depended on the breed of the chicken and production parameter of interest. Higher dietary CF levels decreased (P<0.05) crude protein (CP), neutral detergent fibre (NDF) and acid detergent fibre (ADF) digestibility values in male Ross 308 broiler chickens. Dietary CF levels of 3.8, 3.7 and 4.1 % optimized dry matter (DM) digestibility, metabolizable energy (ME) intake and nitrogen retention, respectively, in male Ross 308 broiler chickens aged 14 to 21 days. Increased dietary CF level, also, decreased (P<0.05) NDF and ADF digestibility values in male Venda chickens aged 14 to 21 days. Dry matter and CP digestibility values, ME intake and nitrogen retention of Venda chickens were optimized at dietary CF levels of 3.5, 3.7, 3.3 and 4.1 %, respectively. Feed intake of male Ross 308 broiler chickens aged 22 to 42 days were affected (P<0.05) by dietary CF level; and it was optimized at a dietary CF level of 6.4 %. Increased dietary CF level resulted in poorer growth rate, FCR and live weight of male Ross 308 broiler chickens. However, dietary CF levels of 4.5, 5.8, 6.4 and 5.7 %, optimized feed intake, growth rate, FCR and live weight, respectively, of male Venda chickens aged 22 to 42 days. Dietary CF levels of 3.4, 4.4, 3.7 and 4.4 %, optimized DM, CP and NDF digestibility values, and nitrogen retention, respectively, in male Ross 308 broiler chickens. However, dietary CF levels of 5.1, 5.3, 4.9, 10.1 and 5.1 % optimized DM, CP, NDF and ADF digestibility values, and nitrogen retention, respectively, of male Venda chickens. Therefore, dietary CF level for v optimal response in the chickens depended on breed, age and production variable of interest. The GIT weight of male Ross 308 broiler chickens was optimized at a dietary CF level of 4.1 %. In increased dietary CF level in male Ross 308 broiler chickens increased gizzard weights and decreased small intestine weights (P<0.05). Dietary CF levels of 6.3, 5.9 and 8.0 % optimized GIT, gizzard and caecum weights, respectively, in male Venda chickens. The small intestine weight of male Venda chickens was not affected (P<0.05) by dietary CF level. Caecum weight of male Venda chickens increased (P<0.05) with higher dietary CF level. However, caecum weights of male Ross 308 broiler chickens were not affected (P>0.05) by dietary CF level. The GIT and small intestine lengths were affected (P<0.05) by dietary CF level in male Ross 308 broiler chickens. Dietary CF levels of 5.6 and 5.5 % optimized GIT and small intestine lengths, respectively. However, in male Venda chickens, GIT and small intestine lengths were not affected (P>0.05) by dietary CF level. Digesta pH of the proventriculus and gizzard were affected (P<0.05) by dietary CF level in male Ross 308 broiler and Venda chickens. Different dietary CF levels of 5.5 and 7.4 % optimized the proventriculus and gizzard digesta pH in male Ross 308 broiler chickens, respectively. However, dietary CF levels of 4.2 and 4.3 % optimized the proventriculus and gizzard digesta pH values, respectively, in male Venda chickens. The two breeds of chickens had similar digesta pH values of the crop, proventriculus, gizzard and large intestines. However, male Venda chickens had higher (P<0.05) small intestine digesta pH values than male Ross 308 broiler chickens aged 42 days. Caecum digesta pH values of Ross 308 broiler chickens were higher (P<0.05) than those of Venda chickens aged 42 days. The second study was conducted to determine the effect of sodium bicarbonate supplementation level in the drinking water on feed intake, digestibility, FCR, growth rate, gut organ weight, length and digesta pH of male Ross 308 broiler and Venda chickens aged 22 to 42 days. The study, also, determined the effect of sodium bicarbonate supplementation level in drinking water on types of bacterial species in crop and gizzard digesta, as well as its effect on meat quality of male Ross 308 broiler and indigenous Venda chickens. Increased sodium bicarbonate vi supplementation level increased (P<0.05) water pH. Supplementation levels of 8.9, 2.04, 2.97 and 2.97 g of sodium bicarbonate per litre of drinking water optimized water intake, feed intake, growth rate and live weight of male Ross 308 broiler chickens, respectively. In male Venda chickens, there was a strong and positive relationship between sodium bicarbonate supplementation level and water intake of Venda chickens. A single supplementation level of 3.8 g of sodium bicarbonate per litre of drinking water optimized growth and live weight of male Venda chickens. There was a negative relationship between sodium bicarbonate supplementation level in the drinking water and NDF digestibility of male Ross 308 broiler chickens. Supplementation levels of 2.63, 6.67 and 7.0 g of sodium bicarbonate per litre of drinking water optimized DM and CP digestibility values, and nitrogen retention, respectively, in male Ross 308 broiler chickens. However, supplementation levels of 3.2 and 4.52 g of sodium bicarbonate per litre of drinking water optimized DM and NDF digestibility values, respectively, in male Venda chickens. There were negative relationships between sodium bicarbonate supplementation level in the drinking water and CP digestibility and nitrogen retention of male Venda chickens. Supplementation levels of 5.7, 2.2, 3.8, 7.6 and 7.2 g of sodium bicarbonate per litre of drinking water optimized proventriculus, gizzard and small intestinal weights, and GIT and small intestines lengths, respectively, in male Ross 308 broiler chickens. However, a sodium bicarbonate supplementation level of 2.8 % optimized proventriculus weights of male Venda chickens; the other digestive organ weights and lengths of Venda chickens were not affected (P>0.05) by sodium bicarbonate supplementation level. Sodium bicarbonate supplementation in the drinking water affected bacterial species found in the crops and gizzards of the chickens. There were different bacterial species found in the crop and gizzard digesta of male Ross 308 broiler and Venda chickens. Meat colour (L*, a* and b*) of the breasts and thighs of both breeds of chickens were not affected (P>0.05) by sodium bicarbonate supplementation. However, the redness (a*) values of the breast meat of male indigenous Venda chickens were higher (P<0.05) than those of breast meat from male Ross 308 broiler chickens. Sodium bicarbonate supplementation level did not affect (P>0.05) breast meat tenderness, juiciness, flavour and overall acceptability values and meat pH of Ross 308 broiler chickens. Supplementation levels of 3.6, 3.2 and 4.7 g of vii sodium bicarbonate per litre of drinking water optimized meat juiciness, flavour and shear force of male Venda chickens, respectively. It was concluded that sodium bicarbonate supplementation in the drinking water affected growth, NDF digestibility and bacterial species composition of male Ross and Venda chickens. Sodium bicarbonate supplementation level for optimal response in chickens depended on the breed and production variables of interest.
VLIROUS

Thesis (M. Tech. Agriculture, Tshwane University of Technology, 2011.
To increase local growth linkages of smallholder broiler enterprises in rural areas a single-phase, on-farm processed, mash diet, consisting of boiled and ground full-fat soya beans and ground yellow maize grain fortified with lysine, methionine and selected mineral nutrients was first developed and then tested. Financial analysis showed that net operating expenses of broiler enterprises that used the experimental diet were higher than those of similar enterprises using the control diet, but differences in net operating income were only significant in one of the two runs of the experiment. The main economic benefit of using the experimental diet was the added value to the local economy, which increased from 20 % of the retail value of broiler chickens in the case of enterprises using the control diet to 70 % when using the experimental diet.

Thesis (BSc. Agriculture (Animal Production)) -- University of Limpopo, 2019
An experiment was conducted to determine the effect of bovine colostrum feeding period after hatching on performance and carcass characteristics of male Ross 308 broiler chickens. The experiment was based on 0, 12, 24, 36, 48 and 72 hours of liquid bovine colostrum feeding after hatching of broiler chickens. The experiment commenced with 180 male Ross 308 broiler chicks with an initial live weight of 42 ± 2g per bird and was carried out for six weeks. The chicks were randomly assigned to six treatments with three replications, resulting in 18-floor pens with 10 chicks per replicate. A complete randomized design was used in this experiment. Data was analysed using the General Linear Model (GLM) procedures of the Statistical Analysis of system, Version 9.3.1 software program. Where there were significant differences, mean separation was done using the Turkey test at the 5% level of significance. A quadratic regression model was used to determine the optimum productivity of the experiment while a linear model was used to determine the relationships between bovine colostrum feeding period and responses in the variables measured. Feed intake during Week 1, growth rate during Week 3 and feed conversion ratio (FCR) during Weeks 2 and 3 of the growing period of male Ross 308 broiler chickens were not affected (p>0.05) by bovine colostrum feeding periods after hatching. Similarly, bovine colostrum feeding had no effect (p>0.05) on diet dry matter (DM), neutral detergent fibre (NDF), acid detergent fibre (ADF) and ash digestibilities in male Ross 308 broiler chickens aged 14 to 21 days. Bovine colostrum feeding period after hatching had no effect (p>0.05) on nitrogen retention (N-retention) in male broiler chickens aged one to 21 days. Similarly, gut organ digesta pH, length and weight of male Ross 308 broiler chickens aged 21 days were not improved (p>0.05) by bovine colostrum feeding after hatching. However, bovine colostrum feeding improved (p<0.05) feed intake during Weeks 2 and 3 of the growing period of male Ross 308 broiler chickens. Similarly, bovine colostrum feeding after hatching improved (p<0.05) crude protein (CP) digestibility in male broiler chickens aged 14 to 21 days. Metabolisable energy (ME) intake of male Ross 308 broiler chickens aged one to 21 days was improved (p<0.05) by bovine colostrum feeding period after hatching. Similarly, growth rate of male broiler v chickens during Weeks 1 and 2 was improved (p<0.05) by colostrum feeding after hatching. Feed conversion ratio of male broiler chickens during Week 1 was improved (p<0.05) by bovine colostrum feeding period after hatching. Bovine colostrum feeding after hatching improved (p<0.05) live weight of male Ross 308 broiler chickens at the ages of 7, 14 and 21 days. Nitrogen retention and FCR of male Ross 308 broiler chickens aged 22 to 42 days were not affected (p>0.05) by bovine colostrum feeding after hatching. In addition, live weights of male Ross 308 broiler chickens aged 35 and 42 days were not affected (p>0.05) by bovine colostrum feeding period after hatching. Similarly, bovine colostrum feeding had no effect (p>0.05) on gut organ digesta pH, large intestine lengths, breast and drumstick weights and breast meat juiciness of male Ross 308 broiler chickens aged 42 days. However, bovine colostrum feeding improved (p<0.05) feed intake and growth rate of male Ross 308 broiler chickens aged 22 to 42 days. Live weights of male Ross 308 broiler chickens aged 28 days were improved (p<0.05) by bovine colostrum feeding period after hatching. Similarly, bovine colostrum feeding after hatching did not affect (p<0.05) diet DM, CP, NDF, ADF and ash digestibilities in male Ross 308 broiler chickens aged 35 to 42 days. Metabolisable energy intake of male broiler chickens aged 22 to 42 days was improved (p<0.05) by bovine colostrum feeding period after hatching. Similarly, GIT, small intestine and caecum lengths and crop, proventriculus, gizzard, small intestine, caecum, large intestine, carcass and thigh weights of male Ross 308 broiler chickens aged 42 days were improved (p<0.05) by bovine colostrum feeding after hatching. Bovine colostrum feeding after hatching improved (p<0.05) breast meat tenderness, flavour and shear force of male Ross 308 broiler chickens aged 42 days. It is concluded that reasons for differing responses to bovine colostrum feeding periods of up to 72 hours after hatching are not clear. Therefore, further studies in which longer bovine colostrum feeding periods are used after hatching are recommended.
National Research Foundation (NRF)

This research reported here was carried out to examine alternatives to antibiotic growth promoters as a result of their being banned in the animal feed industry. Four experiments were conducted to evaluate the efficacy of non-medicated feed additives as replacements for antibiotic growth promoters in broiler feeds. The additives used were enzymes (a new thermo-tolerant powder enzyme called TXAP, phytase, lipase and a new phytase enzyme derived from E. coli called phyzyme XP), organic acid (Acid Pak), prebiotic (Bio-Mos®) and probiotic (All-Lac XCL). Mashed maize-soya based feeds were used in all the experiments, which were conducted in litter-floor pens. The first experiment was a dose-response trial. Broilers in eight replicate pens of 50 males and 50 females were fed unsupplemented feeds and five additional feeds containing increasing levels of TXAP, from 0.5 to 2.5 g/kg to 42 d. The second experiment used enzyme TXAP with two different enzymes (phytase and lipase), individually or in combination. Six replicate pens of 50 males and 50 females were fed either unsupplemented feeds or one of six additional feeds treated with TXAP, lipase, phytase , a combination of TXAP and lipase, a combination of TXAP and phytase or a combination of all the three enzymes . This trial continued for 42 d. In the third experiment three types of TXAP (Lot 1, 2 and 3) were used, with fixed levels of xylanase and amylase but varying levels of protease activities (4000, 2000 and 1000 U/kg for Lot 1, 2 and 3, respectively) in combination with phyzyme XP for 35 d. The fourth experiment used mannan-oligosaccharide (Bio-Mos®), organic acid (Acid pak 2x), probiotic (All Lac XCL 5x), individually or in combination and an antibiotic growth promoter (Zinc bacitracin) for 42 d. The chickens in this experiment were challenged with Clostridium perfringens (CP) at 21, 22 and 23 d to determine the efficacy of these additives for replacing antibiotics in hindering the effects of CP on the villus surface area. The dose-response trial did not show any significant improvement in broiler performance with any level of inclusion of enzyme TXAP. The results from this study showed some beneficial effects with the use of enzyme TXAP when fed alone and at a young age. Its use when combined with other enzymes and at later stages of growth needs further investigation. Feed additives in experiment 4 prevented the negative effects of CP as the treated chickens did not have lesions on their villus surfaces. The conditions under which these trials were conducted appeared to be such that little benefit was derived from the use of any of the feed additives used. It is possible that under less-hygienic conditions such as those in commercial operations greater benefits from these additives may be realised.
Thesis (M.Sc.)-University of KwaZulu-Natal, Pietermaritzburg, 2006.

This study was conducted to investigate the effects of varying levels of dietary lysine and feed allocation, on the performance of female broiler breeders. In trial 1, 900 Cobb breeders from 26 to 45 weeks of age were used. The first four treatments had a fixed level of lysine throughout the experimental period, with 1200, 1070, 930 and 800 mg Lysine/bird/day and the last two treatments had their levels of lysine changed every two weeks, with treatment five started off with 1200 mg lysine/bird/day followed by a gradual decrease up to 975 mg lysine/bird/day at 45 week old, while treatment six started with the lowest level of lysine, 800 mg/bird/day and at 45 week old the intake was 1025 mg/bird/day. The rations provided 1900KJ ME/ day, the birds received 160 g of feed/day. Dietary lysine did not affect body weight, egg production, or egg composition. There were no significant differences in age at 50%, or peak production. Birds receiving 1070 and 1025 mg lysine/bird.day had a slightly, but not significantly, higher production in the current study. Birds receiving 1200 mg lysine/bird.day had the highest body weight and the lowest egg production. In trial 2, 900 broiler breeder hens were used. Protein intake and feed allocation were changed for each treatment at 26, 38 and 50 weeks and ending at 60 weeks. Birds on T1 were fed a constant CP content (145 g protein/kg) but a decreasing feed allocation (175 to 145 g/d). Those on T2 had a constant feed allocation (160 g/d) and a decreasing CP (166 to 124 g/kg) while those on T3 had varying levels of protein (166, 124 and 166 g/kg) and feed allocation (160, 160, 145 g/d). Mean cumulative protein intakes were 5.2, 5.3 and 4.8 kg/bird and mean energy intakes were 417, 412 and 402 MJ/bird for T1, T2 and T3 respectively. Body weights differed significantly at the end of the trial (P<0.05) with T2 showing the highest weight gain. However, egg production, egg weight and egg output were not affected by treatment. These breeders did not benefit from the additional protein and energy provided in the first and second periods by T1 and T2 (vs. T3), nor did they benefit from the additional energy provided in the final ten weeks of production by T2.
M.Sc.Agric. University of KwaZulu-Natal, Pietermaritzburg 2013.

The aim of this study was to evaluate the effects of broiler maternal dietary lysine intake on progeny performance. Three experiments were conducted with chicks hatched from Cobb 500 breeders at 38, 48, and 60 weeks of age. Breeder hens received six dietary treatments (T1-T6) from 26 to 60 weeks of age, which allowed an intake of 800, 930, 1070, and 1200 mg lysine/bird/d (T1-T4) respectively. An intake of 800 mg/bird/d at 26 weeks was increased by 25 mg every two weeks to provide 1225 mg lysine/bird/d at 60 weeks (T5). An intake of 1200 mg/bird/d at 26 weeks was reduced by 25 mg every two weeks to supply 775 mg lysine/bird/d at 60 weeks (T6). A total of 320, 401, and 390 chicks were hatched from breeder hens at 38, 48, and 60 weeks of age respectively. Immediately after hatching, 270, 384, and 384 unsexed chicks from breeder hens at 38, 48 and 60 weeks of age respectively, were placed in an environmentally controlled room and randomly allocated (within a treatment) to single-tier cages (80 × 50 cm). Nine chicks from breeders at 38 weeks of age and 8 chicks from breeders at 48 and 60 weeks of age were placed in each pen, keeping chicks from the same treatment group together for 21 d. Chicks were fed ad libitum with a commercial broiler starter crumble for 21 d and water was provided ad libitum throughout the duration of each trial. Feed intakes (FI), body weight gain (BWG) and feed conversion ratio (FCR) were measured weekly. Data were subjected to analysis of variance using a generalized linear model of GenStat 12th edition. Simple linear regression model of GenStat 12th edition was used where appropriate. Significant improvements in offspring feed intake and body weight gain from 7-21 d were observed in chicks hatched from young breeder flocks (38 weeks) with low dietary lysine intakes (800, 930 and 950 mg/bird/d). The effect of maternal dietary lysine intake on offspring performance disappeared with the aging of the breeder flock (60 weeks). It was concluded that lower maternal dietary lysine intakes (800, 930 and 950 mg/bird/d) may improve feed intake and body weight gain from 7-21 d of broiler chicks hatched from younger breeder flocks (38 weeks).
Thesis (M.Sc.)-University of KwaZulu-Natal, Pietermaritzburg, 2011.

Thesis (M. Sc. Agriculture (Animal Production)) -- University of Limpopo, 2019
Two experiments were conducted to determine the effect of dietary methionine level on productivity and carcass characteristics of Ross 308 broiler chickens. In each experiment, the diets were isocaloric and isonitrogenous but with different dietary methionine levels. Five diets were formulated to contain dietary methionine levels of 4, 5, 6, 8 or 9g/kg DM. The first experiment commenced with 300 unsexed Ross 308 broiler chickens with initial average live weights of 42 ± 2g per chicken. The chickens were randomly assigned to five treatments with five replications, resulting in 25-floor pens with 12 chickens per replicate. The second experiment commenced with 150 male Ross 308 broiler chickens with initial average live weight of 637 ± 12g per chicken. The chickens were randomly assigned to five treatments with three replications, resulting in 15-floor pens with 10 chickens per replicate. A complete randomized design was used in each experiment. Data was analysed using the General Linear Model (GLM) procedures of the statistical analysis of variance, Version 9.3.1 software program. Where there were significant differences, mean separation was done using the Tukey test at the 5% level of significance. A quadratic regression model was used to determine the optimal productivity of the chickens while a linear model was used to determine the relationships between dietary methionine level and responses by the chickens in the variables measured. The treatments for the first experiment were UM4 (4g methionine/kg DM), UM5 (5g methionine/kg DM), UM6 (6g methionine/kg DM), UM8 (8g methionine/kg DM) and UM9 (9g methionine/kg DM). Feed intake, growth rate, feed conversion ratio (FCR), metabolisable energy intake and nitrogen retention of unsexed Ross 308 broiler chickens aged one to 21 days were not affected (P>0.05) by dietary methionine level. Similarly, dietary methionine level did not have any effect (P>0.05) on diet crude protein (CP), acid detergent fibre (ADF), neutral detergent fibre (NDF) and fat digestibilities in unsexed Ross 308 broiler chickens aged 14 to 21 days. Dietary methionine level did not have any effect on live weights of broiler chickens at 21 days. Live weights of unsexed Ross 308 broiler chickens aged 7 or 14 days were not improved (P>0.05) by increasing dietary methionine level from 4 to 9g/kg DM. Crop, gizzard and small intestine weights and crop, proventriculus and gizzard digesta pH values of unsexed Ross 308 broiler chickens aged 21 days were not affected v (P>0.05) by dietary methionine level. Similarly, dietary methionine level did not improve (P>0.05) caecum and large intestine lengths of unsexed Ross 308 broiler chickens aged 21 days. However, dietary methionine level affected (P<0.05) dry matter (DM) and ash digestibilities of unsexed Ross 308 broiler chickens aged 14 to 21 days. Proventriculus and large intestine weights, gastrointestinal tract and small intestine lengths of unsexed Ross 308 broiler chickens aged 21 days were improved (P<0.05) by increasing dietary methionine level. In addition, increasing dietary methionine level increased (P<0.05) small and large intestine digesta pH values of broiler chickens aged 21 days. Thus, dry matter digestibility, live weights at day 7 ad 14, caecum length, large intestine length and digesta pH were optimized at different dietary methionine levels of 7.26, 5.29, 4.99, 6.80, 4.84 and 6.37g/kg DM feed, respectively. The treatments for the second experiment were MM4 (4g methionine/kg DM), MM5 (5g methionine/kg DM), MM6 (6g methionine/kg DM), MM8 (8g methionine/kg DM) and MM9 (9g methionine/kg DM). Dietary methionine level did not have effect (P>0.05) on feed intake of male Ross 308 broiler chickens aged 6 weeks. However, dietary methionine level improved (P<0.05) feed intake of male Ross 308 broiler chickens aged 4 or 5 weeks. Live weights of male Ross 308 broiler chickens aged 28 days were not affected (P>0.05) by dietary methionine level. However, live weights of male Ross 308 broiler chickens aged 35 and 42 days were affected (P<0.05) by dietary methionine level. Similarly, dietary methionine level affected (P<0.05) DM, CP, ADF, NDF, fat and ash digestibilities of male Ross 308 broiler chickens aged 35 to 42 days. Thus, dietary methionine levels of 6.93, 7.70, 6.85 and 11.27g/kg DM optimized dry matter, CP and fat digestibilities, and live weight of male broiler chickens aged 42 days. Dietary methionine level did not affect (P>0.05) FCR, growth rate and metabolisable energy intakes of male Ross 308 broiler chickens. Increasing dietary methionine level from 4 to 9g/kg DM improved (P<0.05) nitrogen retention of male Ross 308 broiler chickens aged 22 to 42 days. Dietary methionine level did not have any effect (P>0.05) on proventriculus, gizzard, caecum and large intestine weights, caecum, small and large intestine lengths, and crop, gizzard, caecum and large intestine digesta pH values of male Ross 308 broiler chickens aged 42 days. Crop and small vi intestine weights and gastrointestinal tract lengths of male Ross 308 broiler chickens aged 42 days were improved (P<0.05) by dietary methionine level. Similarly, dietary methionine level affected (P<0.05) proventriculus and small intestine digesta pH values of male Ross 308 broiler chickens aged 42 days. Thus, dietary methionine levels of 6.558 and 7.851g/kg DM optimized broiler chicken crop weight and GIT length. Dietary methionine level affected (P<0.05) carcass organ weights of male Ross 308 broiler chickens aged 42 days. Increasing dietary methionine level increased chicken breast meat weight. However, there was no clear trend for the other carcass organs. Meat flavour and shear force values of male Ross 308 broiler chickens aged 42 days were not affected (P>0.05) by dietary methionine level. However, dietary methionine level affected meat tenderness and juiciness. Thus, dietary methionine levels of 10.09 and 13.32g/kg DM optimized broiler chicken meat tenderness and juiciness. .
National Research Foundation (NRF) and VLIROUS

Thesis (M. Sc. Agriculture (Animal Production)) -- University of Limpopo, 2018
Two experiments were conducted to determine the effect of replacing maize meal with a low tannin sorghum meal (Macia) on productivity, gut morphology, carcass characteristics and bone morphometrics of Ross 308 broiler chickens aged one to 42 days. In each experiment, a total of 160 Ross 308 broiler chickens were assigned to a complete randomized design with 5 treatments, replicated 4 times with 8 chickens per replicate. Five diets were formulated to contain sorghum replacement levels at 0, 25, 50, 75 and 100% to meet the nutrient requirements of Ross 308 broiler chickens. Data was analysed using statistical analysis of variance. The first experiment determined the effect of replacing maize meal with a low tannin white sorghum meal on productivity and gut morphology of unsexed Ross 308 broiler chickens aged 1 to 21 days. Feed intake, growth rate, feed conversion ratio, live weight, N-retention, caecum and large intestine digesta pH, large intestine lengths, crop, gizzard, caecum and large intestine weights, gut intestinal villi height, crypt depth and villi height to crypt depth ratio of unsexed Ross 308 broiler chickens were not affected (P>0.05) by the treatment effects. However, replacement of maize meal with sorghum meal improved (P<0.05) metabolisable energy intake and small intestine digesta pH values. It was concluded that maize meal can be replaced by a low tannin white sorghum meal in the diet without adverse effects on unsexed Ross 308 broiler chickens aged one to 21 days. The second experiment determined the effect of replacing maize meal with sorghum meal on productivity, gut morphology, carcass characteristics and bone morphometrics of Ross 308 male broiler chickens aged 22 to 42 days. Replacing maize meal with sorghum meal had no effect (P>0.05) on feed intake, feed conversion ratio (FCR), live weight and nitrogen retention (N-retention) of male Ross 308 broiler chickens aged 22 to 42 days. Replacing maize meal with sorghum meal improved (P<0.05) ME intake and growth rate of the chickens. Caecum and large intestine digesta pH, GIT, caecum and large intestine lengths, small intestine, caecum and large intestine weights, gut intestinal villi height, crypt depth and villi height to crypt depth ratio, drumstick, thigh and wing weights, drumstick, thigh and wing colour, meat sensory evaluation, meat pH and bone morphometrics of male Ross 308 broiler chickens were not affected (P>0.05) by replacement of maize meal with sorghum vii meal. It was concluded that maize meal can be replaced by a low tannin white sorghum meal at 25, 50, 75 and 100% levels without causing adverse effects on productivity and carcass characteristics of male broiler chickens aged 22 to 42 days. Key words: Low tannin sorghum meal, Maize meal, Broiler chickens, Growth rate, Carcass characteristics.
National Research Foundation (NRF)

The objective of the study was to evaluate the effect of an exogenous multi-blend enzyme ( -glucanase and xylanase) on the performance of the broiler chickens and laying hens fed diets based on wheat and barley. Experiments were conducted on a flock of broilers and two flocks of laying hens. In both cases feed and water were provided ad libitum. The enzyme effect of enzyme addition on the broiler performance involved 2080 day-old male and female chicks in 48 pens, allocated one of four dietary treatments (0, 50, 100 or 200g/ton enzyme supplementation), to 35 days of age. On day 35, ten birds from each treatment were sacrificed for the analysis of the digestive organs weight (gizzards and livers). The trial was divided into two phases: a starter (1 to 21 d) and grower (22 to 35 d). Feed consumption was measured weekly and birds were also weighed weekly. The investigation of enzyme effect in laying hen diets involved 896 birds for each specific period. Each replicate consisted of four cages (four birds per cage) with a common feeder; 16 hens/pen of 56 pens. Eggs were weighed three times a week, feed consumption weekly and birds every weeks. The addition of a multi-blend enzyme significantly improve body weight, body weight gain, food intake, and feed conversion ratio for both sexes (P<0.05) in broiler chickens. There was a significant improvement in egg production in laying hens (P<0.05). Egg weight and egg mass were not significantly improved. Wheat and barley have cell wall components (arabinoxylans and -glucans respectively) which have a negative effect on the nutritive value of these feeds and therefore performance in poultry fed diets based on these ingredients. Addition of an exogenous multi-blend enzyme( -glucanase and xylanase) could help reduce these effects and improve performance and digestibility values in poultry. The null hypothesis was there will be no difference between supplemented and un-supplemented diets based on wheat and barley in performance of poultry. The results of this study suggest that the inclusion of 50 g/ton enzyme helps improve poultry performance, especially in young birds.
Thesis (M.Sc.)-University of KwaZulu-Natal, Pietermaritzburg, 2010.