Dissertations / Theses on the topic 'Poultry, Effect of stress on Poultry'

Previous studies indicated that exposure of broiler cockerels to acute heat for 24 hr at five days of age increased their survivability when exposed to high ambient temperature prior to market. Since they were conducted at low relative humidity, the aims of the present study were to determine if higher relative humidity affected the response and to investigate the physiological basis of the response. The early, neonatal, heat stress consisted of increasing ambient temperature to between 35.0 to 37.8 C for 24 hr at five days of age in half of the pens (early heat stress) while the remaining pens were kept at 29.4 C (early control). At 6 wk of age a second, late, juvenile, heat challenge was administered. Ambient temperature in half of the early heat stressed pens and early control pens was gradually increased to between 35.0 to 37.8 C for 8 hr on two consecutive days. Significantly lower mortality during the second heat challenge was observed in the early heat stressed birds. This reduction in mortality ranged from 75 to 90% of that seen in the early control birds. Additionally, there were no deleterious effects on body weight, body weight gain or feed efficiency caused by exposure of birds to early heat stress. Feed restriction or administration of a commercially available electrolyte package to the water had no effect on the ability of the birds to withstand high ambient temperature. Water consumption, core and surface body temperature were increased upon exposure to late heat; however, there were no significant differences between the early heat stressed and early control groups. There was a significant reduction in plasma T₃ concentration in the late heat stressed birds. No significant differences in plasma glucose were observed among the heat treatment groups. A significant increase in total plasma protein occurred during the first sampling period during late heat stress, with values returning to control levels during the second sampling period. No significant differences between the early heat stressed and early control groups were observed in plasma T₄ and total plasma protein during late heat. Heterophil to lymphocyte ratio was lower in the early heat stressed group than in the early control group during the second day of late heat exposure These results indicate that thermotolerance can be induced by exposing broiler chicks to 35.0 to 37.8 C for 24 hr at 5 days of age with no adverse effects on performance. Although the mechanism by which Early, neonatal, heat exposure induces thermotolerance is unknown, it is clear that it does not resemble acclimation.<br>Master of Science

Thesis (M.S.)--West Virginia University, 2010.<br>Title from document title page. Document formatted into pages; contains v, 88 p. : ill. (some col.). Includes abstract. Includes bibliographical references.

Thesis (M.S.)--West Virginia University, 1999.<br>Title from document title page. Document formatted into pages; contains viii, 69 p. : ill. (some col.) Vita. Includes abstract. Includes bibliographical references (p. 58-62).

Initial experiments evaluated the impact of hematocrit on a birds ability to adapt to stress and what physiological mechanisms occurred to maintain oxygen carrying capacity (OCC). A final experiment was conducted to obtain proteomic evaluation of protein expression in monocytes of unstressed broilers. In initial experiments, ACTH treatment was applied to hematocrit separated broilers. Experiments evaluated effects of ACTH on broilers with low (19 to 22%, Experiment 1; 18-21%, Experiment 3), high (25 to 28%, Experiment 1; 24 to 27%, Experiment 3) or non-selected hematocrit levels (Experiment 2 and 3). After 4 d of ACTH, all treated birds had significantly increased (P < 0.1) pCO2, HCO3-, and corticosterone levels, indicating as stress raises pCO2, HCO3- must rise to maintain acid base balance. Birds not selected for hematocrit had significant drops in pO2 when given ACTH. Broilers compensate for low OCC through release of red blood cells from storage sites, indicated by decreases in organ hemoglobin and increases in hematocrit and blood hemoglobin when birds are given ACTH. Accelerated red blood cell formation does not appear to occur, because erythropoietin decreases following administration of ACTH to non-selected birds. ACTH induced stress, increased hemoglobin and hematocrit only in birds with low or non-selected hematocrit, suggesting high hematocrit birds prior to stress have an adaptive advantage during stress. Higher hematocrit prior to stress apparently provides ample OCC during stress. Unselected birds appear to require initiation of an inflammatory response to adapt to stress which can be noted by increases in total white blood cell count, monocytes, and heterophils and decreases in lymphocytes. High hematocrit birds appear less susceptible to stress effects by maintaining leukocytes at a constant level, while in non-selected birds lymphocyte percents drop. Proteomics was conducted on avian monocytes to reveal proteins related to immune functions, 3229 proteins were identified, with 46 involved in immune functions of professional antigen presenting cells. This protein data provides a means of comparing monocytes of stressed and unstressed animals in the future. In conclusion, evaluated hematocrit is advantageous in adaptation to stress through maintenance of high OCC, acid base balance and immune cells.

Litter is a possible source of <i>Campylobacter</i> colonization for broilers as well as contamination of crops when used as fertilizer. A survey of Arkansas broiler litter indicated that <i>Campylobacter</i> recovery rates were higher in pine shavings and rice hulls than sand. Two experiments utilized three types of litter, which were artificially contaminated with <i>Campylobacter</i>. After 24 hours no <i>Campylobacter</i> could be recovered from any sample. <i>Campylobacter</i> growth was also examined for used pine shaving litter in varying conditions: aerobic atmosphere, micro aerobic atmosphere (6% O₂), and moisture content. <i>Campylobacter</i> was recovered for all treatments at the initial sampling, and by the 12 hour sampling time, only the added moisture and micro aerobic atmosphere yielded recoverable <i>Campylobacter</i>. This research suggests that without birds present in the house to shed fresh <i>Campylobacter</i> cells onto the litter, that the litter itself is incapable of harboring the bacteria long enough to colonize sequential flocks.

Salmonella enteritidis has recently emerged as a potential pathogen in poultry products. The growth of S. enteritidis in poultry is affected by several factors such as storage temperature, pH, water activity, modified atmosphere and the presence of preservatives. All of these factors may act alone or in combination with each other resulting in a synergistic, antimicrobial effect.<br>In this research, initial storage studies were done to determine the effect of various atmospheres (air, vacuum, oxygen absorbent and gas packaging) on the microbial changes of packaged chicken thighs followed by challenge studies with a strain of S. enteritidis$ sp{ rm{NAST}}$. Chicken thighs were packaged in Cryovac bags and stored at 4 and 12$ sp circ$C for up to 28d. Changes in headspace gas composition, pH, drip loss, color and odor were monitored at each sampling day.<br>The effect of various packaging treatments, dipping solutions (chitosan (0.2%w/v) and potassium sorbate (0.2%w/v)) and low dose irradiation (1.5 & 3.0 kGy) on the growth of S. enteritidis$ sp{ rm NAST}$ and on the shelf-life of chicken thighs stored at 4 and 12$ sp circ$C was also investigated. (Abstract shortened by UMI.)

The magnetic immuno-polymerase chain reaction assay (MIPA), was developed for the detection of Campylobacter jejuni and Campylobacter coli initially in milk and chicken products. After 18 hours pre-enrichment the MIPA could detect 420 cfu g-1 of chicken and 63 cfu ml-1 of artificially contaminated milk. MIPA was then applied for the detection of C. jejuni / C. coli in cloacal swabs and in retail poultry, where the sensitivity was found to be comparable to cultural methods. However, results were available significantly faster, within 24 hours compared to the 4-5 days of cultural methods. MIPA was also evaluated as a technique for the detection of "viable but non-culturable" (VBNC) forms in the environment. It was found that there was a reduction in sensitivity for the detection of these non-culturable forms (NCFs) and it was concluded that the MIPA had limited use in their detection. The lack of sensitivity of MIPA for detecting VBNC campylobacters in the environment may indicate that they are either antigenically or genetically distinct from the culturable forms. This result highlights the question of whether these VBNC forms actually represent a viable potentially infectious form of Campylobacter. This question can be answered at a molecular level; promoter activity can be monitored as a representation of viability of the bacterial cell during stress conditions. The promoter activity could be measured using a promoter probe vector. Initially we decided to construct a promoter probe vector which based on the recombinase system of the PI bacteriophage. However, the final construct was unstable and due to the constraints of time we decided to use a pre-existing promoter probe vector pSP73 constructed by Purdy and Park, (1993). This promoter probe vector contains promoterless luxAB genes which induce light emission as a reporter of gene expression. In order to investigate the genetic regulation during the conversion of C. jejuni to non-culturable forms (NCFs), we monitored gene expression during the transformation of C. jejuni into the non-culturable state. The promoterless copy of the luxAB genes was placed under the control of promoter regions of the C. jejuni flaA gene. Transformed C. jejuni was incubated under stress conditions that induce transition to NCFs (Non-culturable forms). Promoter activity, plate counts and direct microscope counts were simultaneously monitored. It was found that during the initial conversion of C. jejuni to NCFs there is an up-regulation of the flaA promoter. This regulation occurs in response to agitation and did not occur in NCFs and indicates that they are functionally non-viable.

Campylobacter are probably the most important bacterial pathogen related to food-borne illnesses; specifically, gastroenteritis and diarrheal diseases. These bacteria can be isolated from various environments, but always originate from the intestine of warm blooded animals. Particularly, Campylobacter are found in the intestinal tract of poultry, and due to contamination of poultry meat and also further contamination of other food they can cause human infections. Sometimes this results in larger outbreaks, such as during 2016-2017 in Sweden where thousands of persons got infected by a single strain of Campylobacter jejuni sequence type 918 (ST-918). The same strain was also identified amongst a large number of poultry farms and suspicions were directed towards dirty transport cages for poultry as a main route for transmitting the strain between different farms. Similar scenarios with large outbreaks related to one or two single strains (ST-50 and ST-257) had also been observed in previous years and this raised questions about certain strains being especially adapted to survive outside the intestine. The aim here was to examine whether outbreak strains and other strains of C. jejuni have different potential to resist different stress conditions that may be encountered between the poultry farm and the human intestine.

Thesis (M.S.)--West Virginia University, 1999.<br>Title from document title page. Document formatted into pages; contains xi, 77 p. : ill. Vita. Includes abstract. Includes bibliographical references.

Thesis (MScAgric)--University of Stellenbosch, 2000<br>ENGLISH ABSTRACT: A flock of 500 Hybro broiler breeders were employed to study the effect of different levels of protein and energy on production and body composition. The daily lysine intake of the birds were 900, 1050, 1200 and 1350 mg respectively, each fed in diets with a daily energy intake of 1800 and 2000 kJ ME to provide a 4 x 2 factorial design. Lysine was used as the reference amino acid in the experiment and all other amino acids were kept in a constant ratio in every experimental diet. The total production was divided into 3 periods of 13 weeks each (week 23 - 35; week 36 - 48 and week 49 - 61) to determine the effect of the treatments over time. Production was evaluated by hen day production; egg weight (g/egg); egg mass (g/day); fertility; hatchability; chicks/hen/week; feed conversion and day old chick weight. Hen day production was significantly (P < 0,05) lower at the high energy intake for period week 49 to 61. Energy and protein levels significantly increased egg weight. Effect of protein was consistent during all three periods of production. Egg mass output had a significant (P < 0,05) response to increasing levels of protein for the total period of production. The birds on the high energy diet produced a significant higher egg mass per hen during the first period of production (week 23 - 35). Hatchability was reduced (P < 0,05) by the higher energy intake for the total period of production and this effect was very significant (P < 0,01) during the final period of production. Similar to hen day production, the higher energy had a significant (P < 0,05) negative effect on the amount of chicks produced. The well-known correlation between egg weight and chick weight was confirmed with the regression equation: Chick weight = 10,5 + 1,22 x Egg weight. Both energy and protein had a significant (P < 0,01) positive effect on chick weight. The feed conversion was lower at increasing levels of amino acid intake (P < 0,01). Higher energy intake significantly (P < 0,05) increased hen weight and protein had a very significant effect during the first period of production (P < 0,01). The isotope dilution technique (tritiated water) was used to estimate the body composition of the breeders. This was done at 5 different periods (week 27, 35, 43, 52 and 61) of the production period to establish changes in requirements over time. Significant correlation were found between carcass moisture and waterspace (R2 = 0,76); fat % and carcass moisture (R2 = 0,78); protein % and waterspace (R2 = 0,35) and fat % and waterspace (R2 = 0,46). The regression equations obtained from these correlation were employed to determine excess energy and lysine consumed at different ages. Energy requirements were calculated according to the effective energy (EE) system and the conventional ME system. According to effective energy the lower energy intake was not sufficient and the maximum requirement was calculated to be 1942 kj EE/day. The metabolizable energy calculations indicated sufficient intakes at every treatment with the maximum requirement 1746 kj ME/day. The lysine requirement was found to be in excess of 1050 mg lysine per day. The recommendation for daily lysine intake is 1200 mg/day and the energy intake of breeders should be 1900 to 2000 kj ME/day from week 23 to 35 and can be reduced to 1800 kj ME/day in the final period of production.<br>AFRIKAANSE OPSOMMING: Om die effek van verskillende vlakke energie en proteïen op produksie en liggaamsamestelling te ondersoek is 'n trop van 500 Hybro braaikuiken teelouers gebruik. Die daaglikse lisien inname van die henne was onderskeidelik 900, 1050, 1200 en 1350 mg, wat elk by 'n daaglikse energie inname van 1800 en 2000 kJ ME verskaf is, in 'n 4 x 2 faktoriale ontwerp. Alle aminosure is in 'n konstante verhouding met die verwysings aminosuur lisien in die rantsoen ingesluit. Om te evalueer of daar veranderinge oor 'n tydperk plaasvind weens die verskillende behandelings is die produksie periode in drie periodes van 13 weke elk verdeel (week 23 - 35; week 36 - 48 en week 49 - 61). Die produksie standaarde wat gemeet is, is hen dag produksie, eiergewig (g/eier), eiermassa (g/dag), vrugbaarheid, uitbroeibaarheid, kuikens/hen/week, voeromset en dagoud kuikenmassa. Hen dag produksie was betekenisvol (P < 0,05) laer by die hoër energie innames in die laaste periode van 49 tot 61 weke. Energie en proteïen het eiergewig betekenisvol (P < 0,01) verhoog. Die effek van hoër vlakke proteïen was konstant in alle produksie periodes. Die daaglikse eiermassa (g/dag) het ook saam met stygende vlakke proteïen verhoog en hierdie effek was vir die totale periode van produksie. Energie het die eiermassa in die eerste periode van produksie (week 23 - 35) verhoog. Uitbroeibaarheid is verlaag (P < 0,05) vir die totale periode van produksie deur die hoër energie inname en die effek was selfs groter (P < 0,01) in die finale periode van produksie. In ooreenstemming met die hen dag produksie is die aantal kuikens geproduseer negatief beïnvloed deur die hoër energie inname (P < 0,05). Die korrelasie wat bestaan tussen eiermassa en kuikenmassa is bevestig deur die regressie: Kuikenmassa = 10,5 + 1,22 x Eiermassa. Energie en proteïen het kuikenmassa betekenisvol (P < 0,01) verhoog. Voeromset was laer by stygende vlakke van proteïen inname (P < 0,01). Die hoër energie inname het henmassa ook betekenisvol (P < 0,05) verhoog en proteïen het dieselfde effek slegs in die eerste periode van produksie gehad (P < 0,01). Die liggaamsamestelling van teelhenne is bepaal met behulp van die isotoop verdunnings tegniek (tritium water). Dit is bepaal op 5 verskillende stadiums in die produksie periode (week 27, 35, 43, 52 en 61) om die moontlike verandering in behoeftes oor tyd vas te stel. Betekenisvolle korrelasies is gevind tussen karkasvog en die waterspasie (RZ= 0,76); vet % en karkasvog (R2 = 0,78); proteïen % en waterspasie (R2 = 0,35) en vet % en waterspasie (R2 = 0,46). Die regressie vergelykings van hierdie korrelasies is gebruik om die hoevelheid surplus energie en lisien ingeneem te bepaal. Die" effective energy" sisteem en die konvensionele ME sisteem is gebruik in die bepaling van energie behoeftes. Volgens die " effective energy" was die energie inname nie voldoende by die laer energie innames nie en die maksimum behoefte is bereken as 1942 kJ EE/dag. Die maksimum energie behoefte volgens metaboliseerbare energie is bereken as 1746 kj ME/dag. Die lisien behoefte moet hoër as 1050 mg/dag wees. Die aanbeveling van die daaglikse lisien inname is 1200 mg/dag en die energie inname moet 1900 tot 2000 kj/dag wees tot 35 weke produksie en kan daarna verlaag word na 1800 kJ ME/dag.

Little is known about the effect of biochar created from poultry litter on soil properties and plant growth. Five studies were conducted using biochar made by the fast pyrolysis of poultry litter. Two were greenhouse studies and three were field studies. The greenhouse studies were conducted with a sandy loam soil and a silt loam soil. First, lettuce (Lactuca sativa L) seeds were germinated in the greenhouse across biochar incorporation rates from 0 to 100%, and secondly a trial was conducted in which green peppers (capsicum annum L) were grown in soils with up to 5% biochar by weight. Elemental analysis was completed on the biochar and the soils were analyzed for bulk density (BD), water holding capacity (WHC), pH, cation exchange capacity (CEC), soluble salts (SS) and extractable nutrients. The field studies all used the rates of 0, 4.5, and 9 Mg ha-1 biochar and the rates were applied in the early spring of 2009 and 2010. Biochar was surface applied on a tall fescue pasture [Lolium arundinaceum (Schreb.) Darbysh. (=Festuca arundinacea Schreb. subsp. arundinacea)] and tilled in on two green pepper field sites. The soils were analyzed for carbon (C) content, pH, CEC, Mehlich 1 P, and SS. No significant difference was found in yields at any of the three sites, but differences in forage quality were found. Biochar made from poultry litter showed several benefits as a soil amendment in all the studies, but application rates would be limited by soil test P and pH.<br>Master of Science

Thesis (MA. Agric. (Animal Production)) -- University of Limpopo, 2014<br>This study determined the effect of carrot meal supplementation on productivity and carcass characteristics of Arbor acres broiler chickens aged one to six weeks. Experiment I determined the effect of carrot meal supplementation on productivity of Arbor acre broiler chicks aged one to 21 days. Two hundred unsexed Arbor acre broiler chickens were randomly assigned to five treatments with five replicates, each replicate having ten birds. A completely randomized design was used in the first experiment. The treatments were 0 (UA0), 20 (AU20), 50 (AU50), 75 (AU75) or 100 (AU100) g of carrot meal supplementation per kg DM feed. Quadratic equations were used to determine levels of carrot meal supplementation for optimal feed intake, metabolisable energy intake and nitrogen retention of Arbor acre broiler chickens aged one to 21 days. Linear equations were used to determine relationships between carrot meal supplementation and productivity variables. Dietary carrot meal supplementation had no (P>0.05) effect on growth rate, live weight and feed conversion ratio of unsexed Arbor acre broiler chickens aged one to 21 days. Carrot meal supplementation, however, improved (P<0.05) metabolisable energy intake and nitrogen retention of the chickens. Dietary metabolisable energy intake and nitrogen retention of the chickens were optimized at different carrot meal supplementation levels of 40.5 and 53.57 g/kg DM feed, respectively. No chicken deaths were recorded. Experiment II determined the effect of carrot meal supplementation on productivity and carcass characteristics of female Arbor acre broiler chickens aged 22 to 42 days. The chickens were randomly allocated to five treatments with five replicates, each having 10 birds, in a completely randomized design. The supplementation levels were 0 (FA0), 20 (FA20), 50 (FA50), 75 (FA75), or 100 (FA100) g of carrot meal per kg DM feed. Quadratic equations were used to determine levels of carrot meal supplementation for optimal feed intake, feed conversion ratio, live weight, metabolisable energy intake and nitrogen retention of broiler chickens aged 22 to 42 days. Linear equations were used to determine relationships between carrot meal supplementation and production variables. Dietary carrot meal supplementation had no (P>0.05) effect on growth rate, live weight and carcass parts of female Arbor acre broiler chickens aged 22 to 42 days. Carrot meal supplementation improved (P<0.05) feed intake, feed conversion ratio, metabolisable energy intake and nitrogen retention of Arbor acre broiler chickens aged vi 22 to 42 days. Dietary feed intake, feed conversion ratio, live weight, metabolisable energy intake and nitrogen retention were optimized at different dietary carrot meal supplementation levels of 52.8, 63.8, 38.0, 42.0 and 44.3 g/kg DM feed, respectively. Dietary carrot meal supplementation had no effect (P>0.05) on tenderness and flavour of female Arbor acre broiler meat. Broiler chickens on diets supplemented with 20, 50 or 100 g of carrot meal per kg DM feed produced meat with better (P<0.05) juiciness values than those of meat from chickens not supplemented with dietary carrot meal and those supplemented with 75 g/kg DM feed. There was a positive relationship between carrot meal supplementation and chicken meat juiciness. It is concluded that carrot meal supplementation improved (P<0.05) metabolisable energy intake and nitrogen retention of unsexed Arbor acre broiler chickens aged one to 21 days. However, carrot meal supplementation had no effect (P>0.05) on growth rate, live weight and feed conversion ratio of unsexed Arbor acre broiler chickens aged one to 21 days. Carrot meal supplementation improved (P<0.05) intake, feed conversion ratio, metabolisable energy and nitrogen retention of female Arbor acre broiler chickens aged 22 to 42 days. However, carrot meal supplementation did not (P>0.05) improve growth rate and live weights of the chickens.

Orientador: Nilva Kazue Sakomura<br>Resumo: O objetivo deste estudo foi determinar a capacidade máxima de consumo, por meio da coleta de dados de consumo de ração das aves. E desta forma, ajustar equações que correlacionassem as características físicas de um alimento com a capacidade do trato gastrointestinal de frangos de corte, matrizes pesadas e poedeiras em diferentes fases de criação. Foram conduzidos 8 ensaios, sendo 4 ensaios com frango de corte, nas fases inicial, crescimento, terminação e o último para validação. Dois ensaios com matrizes pesadas e outros dois com poedeiras, nas fases de pré-postura e produção de ovo, sendo que em cada ensaio foram utilizados 225 animais. O delineamento foi inteiramente casualizado (DIC) com cinco diluentes e 5 níveis de diluição, totalizando 25 tratamentos e nove repetições contendo uma ave cada. Os tratamentos consistiram em uma dieta controle (sem inclusão de diluente) e as demais dietas com níveis graduais de cada diluente (2.5; 5; 10 e 15% para frangos de corte e poedeiras; 0; 10; 20; 30 e 40% para matrizes pesadas). Os diluentes utilizados foram a fibra de celulose, a serragem, a casca de arroz, a areia e a vermiculita. Os períodos experimentais aplicados ao estudo com frango de corte foram de 14 dias cada (1 a 14 dias; 15 a 28 dias e 29 a 45 dias), para matrizes pesadas e poedeiras foram de 28 dias cada ensaio. Nos ensaios foram mensurados o consumo diário e o peso vivo das aves. Foram realizadas análises laboratoriais que permitissem simular o comportamento físico do d... (Resumo completo, clicar acesso eletrônico abaixo)<br>Abstract: - The objective of this study was to determine the maximum food intake capacity by collecting feed intake data from birds. Thus, to fit equations that correlates the physical characteristics of a food with the capacity of the gastrointestinal tract of broilers, broiler breeders and laying hens in different rearing phases. Eight trials were conducted, four trials with broiler chicken in the initial, growth, final and last for validation. Two trials with broiler breeders and two with laying in the rearing and egg - production phases, and 225 animals were used in each test. The design was completely randomized (DIC) with five diluents and 5 dilution levels, totaling 25 treatments and nine replicates containing one bird each. The treatments consisted of a control diet (without diluent inclusion) and the other diets with gradual levels of each diluent (2.5, 5, 10 and 15% for broilers and laying hens; 0, 10, 20, 30 and 40% for broiler breeders). The diluents used were cellulose fiber, sawdust, rice husk, sand and vermiculite. The experimental periods applied to the study with broiler chicken were 14 days each (1 to 14 days; 15 to 28 days and 29 to 45 days), for broiler breeders and laying hens were 28 days each trial. In the trials the daily food intake and body weight of the birds were measured. Laboratory analyzes were performed to simulate the physical behavior of diluent and diluted diets in the gastrointestinal tract of each animal category and its phase. Therefore, using mult... (Complete abstract click electronic access below)<br>Doutor

Tesis por compendio<br>[ES] La concienciación social con respecto al bienestar animal, la seguridad alimentaria, las resistencias antimicrobianas y la salud medioambiental ha incrementado en los últimos años, promoviendo la implementación de sistemas de producción que incluyan el concepto 'One Health' en su diseño. Por ello, en el sector avícola se han propuesto alternativas a nivel de campo centradas en la mejora de la bioseguridad, el uso de estirpes rústicas y de crecimiento lento y la implementación de ganadería de precisión. En este contexto, la microbiota intestinal tiene un papel importante, tanto en la salud de los animales, como en la diseminación de resistencias antimicrobianas y la transmisión de patógenos zoonósicos a lo largo de la cadena alimentaria. El bienestar animal promueve la presencia de microbiota beneficiosa y la integridad del epitelio intestinal, reduciendo las interacciones con las bacterias ambientales. Por ello, sería posible conseguir una reducción en la administración de antibióticos y reducir la presencia de patógenos en la cadena alimentaria. Salmonella spp. es la principal causa de brotes alimentarios en la Unión Europea, y la principal fuente de infección son los productos avícolas. Entre los principales serotipos se encuentra S. Infantis, actualmente muy prevalente en pollos de engorde. Por todo ello, el objetivo general de esta tesis doctoral fue evaluar el efecto de sistemas alternativos de producción avícola sobre el desarrollo y la composición de la microbiota, la evolución de las resistencias antimicrobianas y la epidemiología de Salmonella. En el primer experimento, se estudió el efecto de la estirpe genética, comparando una estirpe comercial de crecimiento rápido frente a una estirpe alternativa de crecimiento lento. Los objetivos fueron caracterizar la microbiota cecal e investigar la dinámica de las resistencias y multirresistencias antimicrobianas a lo largo del ciclo. Respecto a la composición de la microbiota, los resultados mostraron que Firmicutes fue el filo dominante y los géneros predominantes fueron Oscillospira spp., Ruminococcus spp., Coprococcus spp., Lactobacillus spp. y Bacteroides spp. Por otro lado, los resultados obtenidos en el estudio de resistencias antimicrobianas mostraron que, al inicio del ciclo, los animales de la estirpe de crecimiento rápido presentaron un mayor porcentaje de resistencia, pero al final del periodo no se encontraron diferencias. En el segundo experimento, se evaluó el efecto de las condiciones de manejo, comparando las condiciones comerciales de densidad y ventilación, frente a condiciones mejoradas. Los objetivos fueron caracterizar la microbiota cecal, evaluar la evolución de las resistencias y multirresistencias antimicrobianas, e investigar el desarrollo de S. Infantis y sus resistencias antimicrobianas a lo largo del periodo de engorde. Los resultados obtenidos en la evolución de la microbiota, mostraron un mayor nivel de diversidad en el grupo producido bajo condiciones mejoradas. Además, Firmicutes fue el filo dominante durante todo el ciclo y los géneros predominantes fueron Oscillospira spp., Ruminococcus spp., Bacteroides spp. y Coprococcus spp. Los resultados obtenidos en el estudio de resistencias antimicrobianas mostraron altas tasas de resistencia a lo largo de todo el ciclo, sin diferencias entre grupos. Por último, los recuentos más altos de excreción de Salmonella se observaron el día de sacrificio en ambos grupos. Además, el 100% de las cepas aisladas fueron multirresistentes tras la primera semana post-infección. En conclusión, los principales resultados obtenidos en esta tesis doctoral incluyen que la diversidad y la composición de la microbiota están en constante desarrollo a lo largo del periodo de engorde, viéndose afectadas por los factores de manejo estudiados. Además, las resistencias antimicrobianas están presentes en las bacterias comensales desde el día de llegada, y aumenta hasta el final del ciclo, destacando la necesidad de controlar la administración de antibióticos en todas las etapas de la producción avícola. En cuanto a la epidemiología de S. Infantis, la continua excreción durante todo el periodo de engorde y su capacidad de adquirir resistencias, independientemente de las condiciones de manejo en granja, sugieren la necesidad de realizar más estudios para poder establecer mejores programas de control de la bacteria a lo largo de la cadena alimentaria.<br>[CA] La conscienciació social amb respecte del benestar animal, la seguretat alimentaria, les resistències antimicrobianes i la salut mediambiental han incrementat en els últims anys, promovent la implementació de sistemes de producció alternatius que incloguen el concepte 'One Health'. Per aixó, en el sector avícola s'han proposat diverses alternatives en granja, centrades en la millora dels protocols de bioseguretat, l'ús d'estirps més rústiques i de creixement lent, així com la implementació de la ramaderia de precisió. En aquest context, la microbiota intestinal té un paper clau en la salut dels animals, la diseminació de resistències antimicrobianes i la transmissió de patògens zoonòsics al llarg de la cadena alimentària. El benestar animal promou la presència de microbiota intestinal beneficiosa i la integritat de l'epiteli intestinal, reduïnt les interaccions amb els bacteris ambientals. D'aquesta manera, es pot aconseguir una reducció de l'administració d'antibiòtics i la presència de patògens en la cadena alimentària. Salmonella spp. és la principal causa de brots alimentaris en la Unió Europea, i la principal font d'infecció són els products avícoles. Entre els principals serotips relacionats amb aquestos brots es troba S. Infantis, actualment molt prevalent en pollastres. Per tot açò, l'objectiu general d'aquesta tesi doctoral va ser avaluar l'efecte de sistemes alternatius de producció avícola sobre el desenvolupament i la composició de la microbiota, l'evolució de les resistències antimicrobianes i l'epidemiologia de Salmonella. En el primer experiment, es va estudiar l'efecte de l'estirp genètica, comparant una estirp comercial de creixement ràpid front a una estirp alternativa de creixement lent. Els objectius van ser caracteritzar la microbiota fecal i investigar la dinàmica de les resistències i multirresistències antimicrobianes al llarg del cicle productiu. Els resultats de la composició de la microbiota mostraren que Firmicutes va representar el fil dominant i els gèneres predominants van ser Oscillospira spp., Ruminococcus spp., Coprococcus spp., Lactobacillus spp. i Bacteroides spp. D'altra banda, els resultats obtinguts en el estudi de resistències antimicrobianes van mostrar que, a l'inici del cicle, els animals de l'estirp de creixement ràpid van presentar un major percentatge de resistència, però al final del període no es van encontrar diferències. En el segon experiment, es va avaluar l'efecte de les condicions de maneig de la granja, comparant les condicions comercials de densitat i ventilació, front a condicions millorades. Els objetius van ser caracteritzar la microbiota fecal, avaluar l'evolució de les resistències i multirresistències antimicrobianes, i investigar el desenvolupament de S. Infantis i les seues resistències antimicrobianes al llarg del cicle productiu. Els resultats obtinguts en la evolució de la microbiota van mostrar un major nivell de diversitat en el grup produït davall condicions de maneig òptimes. A més, Firmicutes va ser el fil dominant i els gèneres predominants van ser Oscillospira spp., Ruminococcus spp., Bacteroides spp. i Coprococcus spp. Els resultats obtinguts en el estudi de resistències antimicrobianes, van mostrar altes tases de resistència al llarg del període, sense diferències entre grups. Per últim, els recomptes més alts d'excreció de Salmonella es van observar en la en el dia de sacrifici en ambdós grups. A més, el 100% dels ceps aïllats van ser multirresistents després de la primera setmana post-infecció. En conclusió, els principals resultats obtinguts en aquesta tesi doctoral inclouen que la diversitat i la composició de la microbiota es troben en constant desenvolupament al llarg del període d’engreixament, veient-se afectades per els factors de maneig estudiats. A més a més, les resistències antimicrobianes es troben presents en els bacteris comensals des del dia d’arrivada, i augmenta fins al final del cicle, destacant la necessitat de controlar l’administració d’antibiòtics en totes les etapes de la producció avícola. Quant a l’epidemiologia de S. Infantis, la contínua excreció durant tot el període d’engreixament i la seua capacitat d’adquirir resistències, independentment de les condicions de maneig en granja, sugereixen la necessitat de realitzar més estudis per poder establir millors programes de control del bacteri al llargo de la cadena alimentària.<br>[EN] Social awareness regarding animal welfare, food safety, antimicrobial resistance and environmental health has increased, promoting the implementation of alternative sustainable production systems that include the 'One Health' concept. For this reason, in the poultry sector different alternatives at field level have been proposed, centred on the improvement of biosecurity protocols, the use of rustic slow-growing breeds and the implementation of precision livestock farming. In this context, intestinal microbiota play an important role in poultry health, in the spread of antimicrobial resistance and in the transmission of zoonotic pathogens throughout the poultry production chain. Animal welfare promotes the presence of beneficial microbiota and the integrity of the intestinal epithelium, reducing the interactions between environmental and intestinal bacteria. This way, it could be possible to achieve a reduction in antibiotic administration at field level, and also the presence of zoonotic pathogens in the food chain. Salmonella spp. is the main cause of human foodborne outbreaks in the European Union, and the main sources of infection are poultry products. Between the main serovars related to these outbreaks is S. Infantis, which is currently the most prevalent serovar isolated in broiler chickens. Therefore, the general objective of this doctoral thesis was to evaluate the effect of alternative production systems of poultry production on the microbiota composition development, antimicrobial resistance dynamics and Salmonella epidemiology. In the first experiment, the effect of the genetic breed was studied by comparing a commercial fast-growing breed vs. an alternative slow-growing breed. The objectives were to characterise the caecal microbiota and to investigate antimicrobial resistance and multidrug-resistance dynamics throughout the growing period. Regarding microbiota composition, results showed that Firmicutes represented the dominant phylum for both systems, and the most predominant genera were Oscillospira spp., Ruminococcus spp., Coprococcus spp., Lactobacillus spp. and Bacteroides spp. On the other hand, results obtained in the study of antimicrobial resistance showed that at the onset of the cycle, fast-growing day-old-chicks showed higher antimicrobial resistance rates. However, at the end of the period no significant differences were found. In the second experiment, the effect of the farm management conditions was evaluated by comparing commercial density and ventilation conditions vs. improved conditions. The objectives were to characterise the caecal microbiota, to evaluate antimicrobial resistance and multidrug-resistance dynamics, and to investigate the development of S. Infantis and its antimicrobial resistance throughout the growing period. Results obtained in microbiota development showed a higher level of microbiota complexity in the group reared under optimal farm conditions at the end of rearing. Moreover, Firmicutes was the dominant phylum during all the growing period, and the predominant genera were Oscillospira spp., Ruminococcus spp., Bacteroides spp. and Coprococcus spp. Results obtained in the study of antimicrobial resistance showed high antimicrobial resistance rates throughout rearing, and no statistical differences were observed between groups. Finally, Salmonella shedding showed that the highest counts were observed at slaughter day for both groups. Moreover, 100% of the isolates were multi-resistant after the first week post-infection. In conclusion, the main results obtained include that microbiota diversity and composition are in constant development throughout the growing period, and antimicrobial resistance is present as of the arrival day and increases until the end of rearing. Regarding S. Infantis epidemiology, it has been demonstrated the continuous shedding throughout the growing period and its ability to gain antimicrobial resistance.<br>Montoro Dasí, L. (2021). Effect of Farm Management on Antimicrobial Resistance and Intestinal Microbiota in Poultry Production [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/172610<br>TESIS<br>Compendio

Thesis (Ph. D. (Animal Production )) -- University of Limpopo, 2013<br>Eight experiments were conducted to determine the effect of dietary lysine to energy ratio on the productivity and carcass characteristics of indigenous Venda chickens aged one to thirteen weeks and raised in closed confinement. The eight experiments were based on four different energy levels of 11, 12, 13 and 14 MJ of ME/kg DM. Each dietary energy level had four different levels of dietary lysine (8, 9, 11 and 14 g lysine/kg DM). Thus, different dietary lysine to energy ratios were calculated. Experiments 1 to 4 determined the effect of dietary lysine to energy ratio on productivity of unsexed Venda chickens aged one to seven weeks. Each experiment commenced with 160 unsexed day-old indigenous Venda chicks with an initial live weight of 30 ± 3 g per bird and was carried out for seven weeks. In each experiment, the chicks were randomly assigned to four treatments with four replications, each having 10 chicks. A complete randomized design was used for each experiment. All data were analysed by one-way analysis of variance. Where there were significant differences, the Duncan test for multiple comparisons was used to test the significance of differences between treatment means. A quadratic regression model was used to determine the ratios for optimum productivity in each experiment while a linear model was used to determine the relationships between dietary lysine to energy ratio and optimal responses in the variables measured. Results indicated that dietary lysine to energy ratio for optimal responses depended on the variable of interest. In Experiment 1, feed intake, growth rate, live weight, ME intake and nitrogen retention were optimized at different dietary lysine to energy ratios of 0.722, 0.719, 0.719, 0.670 and 0.712, respectively. There was a positive and strong relationship (r2 = 0.950) between dietary lysine to energy ratio and feed conversion ratio (FCR). Results from Experiment 2 indicated that feed intake, growth rate, FCR, live weight, ME intake and nitrogen retention were optimized at dietary lysine to energy ratios of 0.719, 0.742, 0.788, 0.742, 0.734 and 0.789, respectively. In Experiment 3, dietary lysine to energy ratio did not have any effect (P>0.05) on all the parameters measured. However, quadratic analysis indicated that dietary lysine to energy ratios of 0.817, 0.883, 0.920, 0.898, 0.895 and 0.955 optimized feed intake, growth rate, FCR, live weight, ME intake and nitrogen retention of the chickens, respectively. Experiment 4 results showed that feed intake, growth rate, FCR, live weight ME intake and nitrogen retention were v optimized at different dietary lysine to energy ratios of 0.906, 0.964, 1.023, 0.966, 0.963 and 0.951, respectively. Experiments 5 to 8 determined the effect of dietary lysine to energy ratio on productivity, carcass characteristics, sensory attributes and haematological values of female indigenous Venda chickens aged eight to thirteen weeks. The layouts, treatments, design and execution were similar to those described for Experiments 1, 2, 3 and 4, respectively, except that Experiments 5 to 8 were for female indigenous Venda chickens aged eight to 13 weeks. These chickens were different from those used in Experiments 1 to 4. They were raised on a grower mash (16 % crude protein, 11 MJ of ME/kg DM and 180 g of lysine) prior to commencement of the study. Each experiment commenced with 120 eight weeks old female Venda chickens with an initial live weight of 412 ± 3 g per chicken. In each experiment, the chickens were randomly assigned to four treatments with five replicates, each having six chickens. Results obtained from Experiment 5 showed that feed intake, growth rate, FCR, live weight, ME intake, carcass weight, dressing percentage, breast meat, drumstick, wing weight, breast meat drip loss, juiciness, flavour, haemoglobin and pack cell volume were optimized at different dietary lysine to energy ratios of 0.672, 0.646, 0639, 0.649, 0.655, 0.656, 0.664, 0.669, 0.665, 0.663, 0.631, 0.708, 0.623, 0.556 and 0.609, respectively. In Experiment 6, the diets were formulated to have higher lysine to energy ratios than those in Experiment 5 by using a dietary lysine level of 9 g lysine/kg DM. Results from this experiment showed that feed intake, FCR, nitrogen retention, carcass weight, dressing percentage, breast meat, gizzard weights and breast meat pH at 2, 12 and 24 hours after slaughter were optimized at dietary lysine to energy ratios of 0.798, 0.613, 0.777, 0.742, 0.753, 0.729, 0.758, 0.752, 0.802 and 0.797, respectively. Red blood cell and haemoglobin values in this experiment were optimized at dietary lysine to energy ratios of 0.480 and 0.624, respectively. In Experiment 7, dietary lysine to energy ratios of 0.79, 0.85, 0.92 and 1.00 g lysine/ MJ of ME were used. Dietary treatments in this experiment had no effect (P>0.05) on all the production parameters measured except feed and apparent metabolisable energy intakes. Quadratic analysis of the results indicated that dietary lysine to energy ratios of 0.964, 0.912, 0.900, 0.890, 0.910, 1.090, 0.934 and 0.895 optimized feed intake, apparent metabolisable energy, carcass, breast meat, drumstick weights and vi breast meat drip loss, juiciness and flavour, respectively. A positive and very strong relationship (r2 =0.998) was observed between dietary lysine to energy ratio and pack cell volume. Experiment 8 diets were formulated to have higher dietary lysine to energy ratios than the other experiments. Results of this experiment indicated that all the production parameters were influenced (P<0.05) by dietary lysine to energy ratio except mortality. Feed intake, growth rate, feed conversion ratio, live weight, apparent metabolisable energy and nitrogen retention were optimized at dietary lysine to energy ratios of 0.996, 0.980, 0.991, 1.010, 0.957 and 0.993, respectively. Dietary lysine to energy ratios of 0.992, 0.974, 0.991, 0.992, 1.023, 0.981, 0.979 and 0.815 optimized carcass weight, dressing percentage, breast meat, drumstick, liver weights and breast meat tenderness, juiciness and flavour, respectively. There were variations in the optimal lysine to energy ratios for different parameters investigated. In a diet containing 8 g of lysine per kg DM, 11.13 MJ of ME/kg DM and 150 g of CP/kg DM, dietary lysine to energy ratios of 0.719 and 0.649 are recommended for optimal live weight of Venda chickens aged one to seven and eight to 13 weeks, respectively. In a diet containing 9 g of lysine per kg DM, 12.13 MJ of ME/kg DM and 180 g of CP/kg DM, dietary lysine to energy ratios of 0.742 and 0.712 are recommended for optimal live weight of Venda chickens aged one to seven and eight to 13 weeks, respectively. In a diet containing 11 g of lysine per kg DM, 12.51 MJ of ME/kg DM and 220 g of CP/kg DM, dietary lysine to energy ratios of 0.878 and 0.894 are recommended for optimal live weight of Venda chickens aged one to seven and eight to 13 weeks respectively. In a diet containing 12 g of lysine per kg DM, 12.05 MJ of ME/kg DM and 240 g of CP/kg DM, dietary lysine to energy ratios of 0.996 and 1.010 are recommended for optimal live weight of Venda chickens aged one to seven and eight to 13 weeks, respectively. The results obtained in this study showed that different production parameters of Venda chickens were optimized at different lysine to energy ratios. This implies that the nutritional requirements of these chickens are dynamic and thus, dietary lysine to energy for optimal production depends on the production parameter of interest. This has implications on ration formulation for indigenous chickens.

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.

Land application of poultry litter has been successfully practiced for centuries to maintain and improve soil fertility, although over application may promote loss of nutrients through runoff or leaching. To decrease the potential for adverse environmental impacts of N and P in groundwater, a new approach developed in this research was to use a composted mixture of poultry litter (PL) and yard waste (YW) as a soil amendment for corn (Zea mays L.) production. Objectives of this research were to evaluate effects of pre-compost C:N substrate ratios for poultry litter-yard waste compost (PYC) on the availability of soil P, to determine the P response of corn plants to inorganic P, PL and PYC application, and to study relationships between P availability and both inorganic P and PYC application. Langmuir isotherms were used in this research to select soils with relatively high P fixation capacities. Phosphorus sorption maximum for soils evaluated were as follows: 304 and 449 micrograms of P per gram for A horizon Coastal Plain soils (Series: Kempsville and Myatt, respectively); 487 micrograms of P per gram for an A horizon Ridge and Valley soil (Series: Frederick); 918 and 603 micrograms of P per gram for A horizon Piedmont soils (Series: Elioak and Vance, respectively); 1099 microgram of P per gram for mine tailings (Series: Emporia located in the Coastal Plain); and 1524 microgram of P per gram for A and upper mixed horizon soil (Series: Starr from Piedmont region). Based on intermediate to high P sorption maxima, soil from the Vance and Starr series and mine tailing from Emporia series were selected for greenhouse research to evaluate P availability of PYC . Treatments applied to the soil in the greenhouse and field studies consisted of various levels of P as Ca(H₂PO₄)₂.H₂O, PL and PYC from 15:1, 20:1, and 25:1 C:N ratio substrates. Each P source increased dry weight of corn plants grown in the greenhouse by alleviation of P deficiency. Phosphorus uptake from PYC and PL application was either equal to or higher than P uptake from an equal level of P application as Ca(H₂PO₄)₂.H₂O. Application of 87.2 kg of P per ha increased corn grain yields in a field experiment on Vance sandy loam from 6340 kg per ha on the control to a range of 10,170 to 11,350 kg ha for PYC digested from the three C:N ratio substrates. The yields on PYC treatments were attributed to a combination of factors including slow mineralization of P with less fixation during the growing season. The low P fixing capacity results from the blockage of H₂PO₄^- sorption by competition of negative charge from organic material and from the displacement of H₂PO₄^- in soil solution by OH^- from application of the alkaline composts. It would be desirable from the standpoint of more PL utilization to prepare composts from low substrate ratio substrates. Hence, in this research composts were prepared from 15:1, 20:1, and 25:1 C:N substrates, which consisted of PL and YW. The composting process was complete after only four months for the PYC from the 20:1 and 25:1 C:N ratio substrates. Yard waste compost without PL may require somewhere between two to three years for complete composting as opposed to four months with PL addition. The composting was incomplete in four months (presence of undigested leaves and NH₃) for the PYC from the 15:1 C:N ratio substrate. The latter compost resembled poultry manure rather than a high quality compost after the 4-month composting period.<br>Ph. D.

As productive performance is improved by breed selection, amino acid requirements may change to support this higher performance in poultry. The first objective of this dissertation was to update the valine and tryptophan requirement of small-framed laying hens and the lysine requirement of young broilers using empirical dose-response methods. The tryptophan requirement was estimated as 155.8 mg/d for egg mass, 153.2 mg/d for egg production and 140.4 mg/d for feed conversion ratio using a linear broken line model. For valine, the requirement was highest for egg mass, 597.3 mg/d, followed by egg production, 591.9 mg/d and feed conversion ratio (FCR), 500.5 mg/d. The lysine requirement of young chicks was estimated by conducting four short term experiments from 1 to 3, 3 to 5, 5 to 8 and 8 to 11 days of age, respectively. The lysine requirement from 1 to 3, 3 to 5 and 5 to 8 days of age were not able to be estimated as no dose response was observed on growth performance most likely due to an overestimation of the lysine requirement. Digestible lysine requirement from 8 to 11 days of age was 1.057%, 1.050% and 1.016% based on body weight gain, FCR and pectoralis major weight using a linear broken line model, respectively. In addition to determining amino acid requirements, research was conducted to develop a new bacterial protein meal for use in laying hens diets. The data suggested that diets containing 7.5% of the bacterial protein meal was able to at least maintain egg production in laying hens, but 15% bacterial protein meal resulted in reduced performance. The second objective of this dissertation was to investigate the effects of various concentrations of dietary vitamin D3 on pullet and laying hen performance, eggshell quality and bone health in laying hens. Pullets/hens were randomly assigned to five dietary treatments containing vitamin D3 from 1,681 to 68,348 IU/kg diet from day of hatch until 68 weeks of age. These data suggested that dietary vitamin D3 fed at 68,348 IU/kg resulted in reduced egg production, but vitamin D from 8,348 to 35,014 IU/kg diet maintained egg production, increased egg vitamin D content in a dose dependent manner, and generally increased both eggshell quality and pullet and hen bone mineral status.<br>Ph. D.

Master of Science<br>Department of Animal Sciences and Industry<br>James M. Lattimer<br>Eight cecally cannulated horses were used in a replicated, 4 x 4 Latin square design conducted in 4, 14-d periods to determine effects of sodium caseinate on equine hindgut fermentation and fiber digestion. Horses were maintained on an ad libitum diet of Smooth Bromegrass hay and treatments consisted of cecal infusions of water (CON), 0.125 g sodium caseinate/kg BW (LOW), 0.25 g sodium caseinate/kg BW (MED), and 0.50 g sodium caseinate/kg BW (HI). Cecal NH3 concentrations increased (P < 0.01) as casein increased. Horses on the CON and MED treatments had greater cecal pH (P < 0.01) than horses on the LOW and HI treatments; however, there was no effect of treatment of fecal pH. Dry matter, OM, NDF, and ADF digestibility were unaffected by treatment (P > 0.10). There were no differences in dry matter intake (DMI), regardless of treatment. There was no treatment effect on cecal acetate, propionate, butyrate, total VFA concentration or acetate:propionate (A:P) ratio. Inter-horse variability and a small sample size may contribute to the lack of statistical differences amongst treatments. Results from this study may imply that medium quality, roughage based protein supplies an adequate level of nitrogen to the microflora of the hindgut. A performance study was conducted to evaluate the effect of strain and method of administration of Megasphaera elsdenii on growth performance in broiler chickens. In Experiment 1, pens were randomly assigned to 1 of 6 treatments: 0.2 mL oral gavage containing 1.97 x 10⁹ CFU/mL of M. elsdenii strain NCIMB 41125 (Lactipro, MS-Biotec, Wamego, KS; O-L), 0.2 mL of fresh culture containing 0 CFU/mL of M. elsdenii strain KS 249 (O-KS; Attempts to grow this strain were unsuccessful), 0.2 mL of a fresh culture containing 1.06 x 10⁹ CFU/mL of M. elsdenii strain B52-2083 (O-B52), aerosolized mist at rate of 15 mL per pen containing 1.97 x109 CFU/mL of M. elsdenii strain NCIMB 41125 (~1.88 mL/bird; MS-Biotec, Wamego, KS; OM), topdressing (mixture of diet and freeze dried M. elsdenii strain NCIMB 41125; TD) containing 1.18 x 10⁷ CFU/g of M. elsdenii strain NCIMB 41125 at a rate of a quarter teaspoon per bird, or negative control that had no contact with the probiotic product. Broilers across all treatment groups showed similar ADFI (P = 0.82), ADG (P = 0.89), gain:feed (P = 0.93), and mortality rates (P = 0.54). In Experiment 2, chicks were assigned to 1 of 2 treatments consisting of lyophilized M. elsdenii strain NCIMB 41125 in the form of a topdressing (TD) or a negative control that had no contact with the probiotic product (C). Average daily gain (P = 0.02) and gain:feed (P = 0.04) were both greater in birds receiving the TD when compared to the C birds. Feed intake (P = 0.70) and mortality rates (P = 0.31) were not different between treatments. Administration of lyophilized M. elsdenii strain NCIMB 41125 may be an effective means to improve growth rate and feed efficiency of broiler chicks.

Doctor of Philosophy<br>Food Science Institute<br>Kelly J. K. Getty<br>Salt is used as a preservative in food. Reducing sodium in food, due to its link to hypertension, and replacing NaCl with other types of salt could have an effect on food safety. The main objective was to determine differences in salts and salt substitutes on growth of Listeria monocytogenes in broth and meat and poultry systems. Salts (NaCl, KCl, CaCl2, MgCl2, sea salt, and replacement salt) were added (0.5, 1, and 2.5%) to Listeria monocytogenes (five-strain cocktail) inoculated Listeria enrichment broth at 25 °C and sampled at 0, 24, and 48 h. Results showed that MgCl2, regardless of concentration, caused Listeria monocytogenes populations to grow approximately 0.6 log CFU/mL more (P < 0.05) than the other salts. Fresh ground beef, pork, and turkey with NaCl, KCl, CaCl2, MgCl2, sea salt, and replacement salt (2.0%) were inoculated with Listeria monocytogenes (five-strain cocktail) to determine growth/survival during 5 d at 4 °C to simulate a pre-blend process. Listeria monocytogenes populations significantly decreased (0.41 log CFU/g) during the storage time in beef, however no differences (P > 0.05) were observed over time in pork or turkey. Salt type did not affect (P > 0.05) Listeria monocytogenes populations during pre-blend storage. However, salts (MgCl2 and NaCl) allowed growth (P < 0.05) of aerobic populations during storage. Emulsified beef and pork products were processed with NaCl, KCl, sea salt and a NaCl/KCl blend (2%) and post-processed surface inoculated with Listeria monocytogenes (five-strain cocktail) to determine growth/survival at 4 °C for 28 d. Pork products showed greater (P < 0.05) Listeria monocytogenes population growth at all sampling times (0, 7, 14, 21, and 28 d) than beef products; whereas salt type had no effect on Listeria monocytogenes populations with sampling times pooled for data analysis. Although salt types were not shown to have an impact on Listeria monocytogenes growth/survival in pre-blend and emulsified post-processed surface inoculated meat products, pork and turkey pre-blends and emulsified pork had greater Listeria monocytogenes populations compared to beef products. These studies demonstrate that sodium reduction or replacement may not affect safety of pre-blends and emulsified meat and poultry products.

The load wetting is a widely practice used in poultry production during the pre-slaughter loading and carrying operations. According to most producers, the practice of wetting is a way to release the stress of the chickens and minimize production losses. Several studies developed in the ambience of the area have focused their attention on pre-slaughter fasting operations, capture, loading, transportation and waiting. The wetting, however, is only mentioned as a widespread practice and it was not found, however, any analysis that proves its benefit. Thus, the aim of this study was to evaluate the efficiency of cargo wetting to reduce thermal stress. For this aim, they were measured the temperature and the relative humidity, with the help of meteorological mini-stations (Data Logger), and it was calculated the enthalpy of Comfort Index (IEC), to characterize the environments where there were pre-slaughter operations. For the bioclimatic characterization (microclimate) of the load, it was carried out the analysis of the temperature distribution of the boxes located in the outer parts (right, left, top and back) by thermography (thermal imagers). Concerning the boxes located in the center of the load, where it was not possible to use the Imager, they were used eighteen data loggers, thus distributed in strategic boxes, as a record, at every minute, of the temperature and relative humidity for subsequent calculation of the IEC. It as also performed, with the help of geostatistical techniques (kriging maps), the spatial determination of temperature, relative humidity and IEC during observations with and without load wetting. There was also an attempt to determine the thermal sensation of the load during the trip of the chickens located on the right side, on the left side and on the top of the load, with the help of three thermoanemometers to record, at every minute, the temperature and wind speed and, to calculate the real comfort sensation, we used the equation of equivalent temperature Wind Chill. The approach of this work emphasizes the use of IEC and enthalpy tables, and the use of the t hypothesis testing to verify the claim that there would be no difference between the means of the IEC load of wet and dry cargo in the region with the worst heat dissipation situation (central row) during transport. The results have shown that the load wetting was not effective in alleviating the thermal stress during transportation. It can also be perceived that the use of thermography as a thermal diagnostic tool, as well as studies for modeling an equation that might represent the wind chill of the chickens, depending on the temperature and wind speed, is of great importance for the design of vehicles to transport live load.<br>O molhamento da carga à uma prÃtica muito utilizada na avicultura de corte, durante as operaÃÃes prÃ-abate de carregamento e transporte. Segundo a maioria dos produtores, a prÃtica do molhamento à uma forma de amenizar o estresse das aves e minimizar as perdas produtivas. VÃrios trabalhos desenvolvidos na Ãrea de ambiÃncia focaram suas atenÃÃes nas operaÃÃes prÃ-abate de jejum, captura, carregamento, transporte e espera. O molhamento, porÃm, à apenas citado como uma prÃtica muito difundida, nÃo constando, no entanto, nenhuma anÃlise que comprove o seu benefÃcio. Sendo assim, o objetivo deste trabalho foi avaliar a eficiÃncia do molhamento da carga na reduÃÃo do estresse tÃrmico. Para isso, foram medidas a temperatura e a umidade relativa, com o auxÃlio de miniestaÃÃes meteorolÃgicas (Data Logger), e calculado o Ãndice Entalpia de Conforto (IEC), para a caracterizaÃÃo dos ambientes onde ocorreram as operaÃÃes prÃ-abate. Para a caracterizaÃÃo bioclimÃtica (microclima) da carga, foi realizada a anÃlise da distribuiÃÃo da temperatura das caixas localizadas nas partes externas (lateral direita, esquerda, topo e traseira) atravÃs da termografia (termovisores). As caixas localizadas no centro da carga, onde nÃo foi possÃvel o usar o termovisor, foram utilizados dezoito Data Loggers, distribuÃdos em caixas estratÃgicas para o registro, a cada minuto, da temperatura e umidade relativa, para posterior cÃlculo do IEC. Procedeu-se, ainda, com a ajuda de tÃcnicas de geoestatÃstica (mapas de Krigagem), a determinaÃÃo espacial da temperatura, umidade relativa e IEC durante as observaÃÃes com e sem o molhamento da carga. TambÃm se tentou determinar a sensaÃÃo tÃrmica durante a viagem dos frangos localizados nas laterais direita, esquerda e topo da carga, com a ajuda de trÃs termoanemÃmetros para registro, a cada minuto, da temperatura e velocidade do vento e, para o cÃlculo da real sensaÃÃo de conforto, foi utilizada a equaÃÃo da temperatura equivalente de Wind Chill. A abordagem deste trabalho dà Ãnfase ao uso do IEC e das tabelas de Entalpia, alÃm do uso do teste de hipÃteses t para verificar a afirmaÃÃo de que nÃo haveria diferenÃa entre as mÃdias do IEC da carga molhada e da carga seca, na regiÃo que apresenta a pior situaÃÃo de dissipaÃÃo do calor (fileira central) durante o transporte. Os resultados mostraram que o molhamento da carga nÃo se mostrou eficiente em amenizar o estresse tÃrmico durante o transporte. Pode-se ainda constatar que o uso da termografia como ferramenta de diagnÃstico tÃrmico, assim como estudos para a modelagem de uma equaÃÃo que retrate a sensaÃÃo tÃrmica da ave em funÃÃo da temperatura e velocidade do vento, à de suma importÃncia para o projeto de veÃculos de transporte de carga viva.

Thesis (MPhil)--Stellenbosch University, 2003.<br>ENGLISH ABSTRACT: A farm in Zimbabwe (Farm A) obtains its water for tbe poultry operations from tbe Makavusi River that is heavily contaminated with bacteria and performance results are thereby reduced. Anolyte is a Russian invention that claims to have bactericidal effects that could be beneficial to broilers. The aim of this research is to investigate the effect of Anolyte on production profits of broilers given water of poor quality by carrying out a number of trials. Trials that were conducted are basic in vitro tests on Anolyte within the laboratory, water analysis on water supply to the broiler section (both chemical and bacteriological), and a detailed trial within an experimental trial site comparing broiler performance results with different chemical water treatments and different dilutions of Anolyte. Broiler chicks from different hatcheries (Hatchery A and Hatchery B) were also compared. Performance results were based on growtb rate, mortality, feed conversion ratios (FCR), performance efficiency factors (PEF) and profit margin comparisons. Results showed that in tbe laboratory, Anolyte had an antibacterial activity. In the broiler performance trial on Hatchery B broilers, the live weights at forty two days of age in broilers given 15% Anolyte differed from other treatments (P<0.05) other than 10% Anolyte (P > 0.05). However, the FCR and mortalities did not differ (P > 0.05) between treatments. In the trial on Hatchery A broilers to 42 days of age, growth rates in broilers given 15% Anolyte differed from tbe control, Chematron and 20% Anolyte (P < 0.05). However, the FCR and mortalities did not differ between (P>0.05) treatments. In comparing chicks from different hatcheries, Hatchery B broilers differed (P < 0.05) from Hatchery A broilers in live weights at 42 days on 10% Anolyte, 15% Anolyte and on Chematron treatments. However, tbe cumulative mortalities and FCR did not differ (P > 0.05) between the Hatchery B and Hatchery A on any treatment. When comparing profitability, tbe treatment that had the greatest margin in comparison to tbe control (untreated drinking water) was 15% Anolyte for both tbe Hatchery B and Hatchery A trials.<br>AFRIKAANSE OPSOMMING: 'n Plaas in Zimbabwe, (Plaas A) verkry water, vir hul pluimvee bedryf vannuit die Makavusi rivier. Die rivier is swaar besmet met bakterië en as gevolg daarvan verhoed dit dat hulle hul volle opbrengs potential bereik. Anolyte is 'n Russiese uitvindsel wat aanspraak maak daarop dat dit bakteriëdodende effekte besit wat tot die bevordering van slaghoenders kan lei. Die doel van die navorsing is om Anolyte op proef te stel aangaande produksie profyt op slaghoenders waaraan swak kwaliteit water verskaf is. Verskeie toetse is uitgevoer n1. 'n basiese 'in vitro' toets in samewerking met die laboratorium, water ontleding op water wat aan die slaghoender seksies verskaf is (beide chemikalies and bakterieologies) asook 'n intensiewe proefnemeing waarin die verskeie obrengs resultate, van chemikaliese behandelde water en verskillende verdunnings van Anolyte, met mekaar vergely is, in 'n experimetele navorsings eenheid. Slaghoender kuikens van twee verskillende broeihuise (n1. Broeihuis A en Broeihuis B) is ook met mekaar vergelyk. Die resultate is gabasseer op groei tempo, sterftes, voer omsettings verhouding, opbrengs geskikthied faktore asook vergelykings op wins. Laboratorium navorsing het bevestig dat Anolyte wel antibakteriese aktiviteit getoon het. Terwyl in die proefneming op Broeihuis B slaghoenders, het die lewende gewig van hoenders, op 42 dae van ouderdom, waaraan 15% Anolyte verskaf is, verskil van ander behandelings (P<0.05) met die uitsondering van 10% Annolyte (P>0.05). Alhoewel die voer omsetting verhoudings en sterftes nie in die verskillende behandelings verskil het nie. In die proefnemeing op Broeihuis A slaghoenders tot 42 dae van ouderdom, het die ontwikkeling van slaghoenders, waaraan 15% Anolyte verskaf is, verskil van die kontiole, Chematron en 20% Anolyte. Die voer omsettings verhoudings en sterftes het egter geen verskil getoon tussen die verskeie behandelings nie. Resultate van die vergelyking tussen die kuikens uit die twee verskillende broeihuise, het getoon dat die Broeihuis A en Broeihuis B lewensgewigte, op 42 dae van ouderdom, wel met mekaar verskil het met 10% Anolyte, 15% Anolyte sowel as die Chematron behandelings. Daar was egter geen verskil, (P>O.05) tussen die twee tipes aangaande elke tipe se saamgestelde sterftes en die voer omsettings verhoudings, in welke behandeling nie. Die vergelykings op wins het getoon dat die behandeling met die grootste brulo marge, die was van 15% Anolyte in vergelyking met die kontiole (onbehandelde drinkwater) vir beide die Broeihuis A en die Broeihuis B proefnemings.

The PhD project was focused on the study of the poultry welfare conditions and improvements. The project work was divided into 3 main research activities. A) Field evaluation of chicken meat rearing conditions kept in intensive farms. Considering the lack of published reports concerning the overall Italian rearing conditions of broiler chickens, a survey was carried out to assess the welfare conditions of broiler reared in the most important poultry companies in Italy to verify if they are in accordance with the advices given in the European proposal COM (2005) 221 final. Chicken farm conditions, carcass lesions and meat quality were investigated. 1. The densities currently used in Italy are in accordance with the European proposal COM 221 final (2005) which suggests to keep broilers at a density lower than 30-32 kg live weight/m2 and to not exceed 38-40 kg live weight/m2. 2. The mortality rates in summer and winter agree with the mortality score calculated following the formula reported in the EU Proposal COM 221 final (2005). 3. The incidence of damaged carcasses was very low and did not seem related to the stocking density. 4. The FPD scores were generally above the maximum limit advised by the EU proposal COM 221 final (2005), although the stocking densities were lower than 30-32 kg live weight per m2. 5. It can be stated that the control of the environmental conditions, particularly litter quality, appears a key issue to control the onset of foot dermatitis. B) Manipulation of several farm parameters, such litter material and depth, stocking density and light regimen to improve the chicken welfare conditions, in winter season. 1. Even though 2 different stocking densities were established in this study, the performances achieved from the chickens were almost identical among groups. 2. The FCR was significantly better in Standard conditions contrarily to birds reared in Welfare conditions with lower stocking density, more litter material and with a light program of 16 hours light and 8 hours dark. 3. In our trial, in Standard groups we observed a higher content of moisture, nitrogen and ammonia released from the litter. Therefore it can be assumed that the environmental characteristics have been positively changed by the improvements of the rearing conditions adopted for Welfare groups. 4. In Welfare groups the exhausted litters of the pens were dryer and broilers showed a lower occurrence of FPD. 5. The prevalence of hock burn lesions, like FPD, is high with poor litter quality conditions. 6. The combined effect of a lower stocking density, a greater amount of litter material and a photoperiod similar to the natural one, have positively influenced the chickens welfare status, as a matter of fact the occurrence of FPD in Welfare groups was the lowest keeping the score under the European threshold of the proposal COM 221 final(2005). C) The purpose of the third research was to study the effect of high or low stocking density of broiler chickens, different types of litter and the adoption of short or long lighting regimen on broiler welfare through the evaluation of their productivity and incidence of foot pad dermatitis during the hot season. 1. The feed efficiency was better for the Low Density than for High Density broilers. 2. The appearance of FPD was not influenced by stocking density. 3. The foot examination revealed that the lesions occurred more in birds maintained on chopped wheat straw than on wood shaving. 4. In conclusion, the adoptions of a short light regimen similar to that occurring in nature during summer reduces the feed intake without modify the growth rate thus improving the feed efficiency. Foot pad lesion were not affected neither by stocking densities nor by light regimens whereas wood shavings exerted a favourable effect in preserving foot pad in good condition. D) A study was carried out to investigate more widely the possible role of 25-hydroxycholecalciferol supplemented in the diet of a laying hen commercial strain (Lohmann brown) in comparison of diets supplemented with D3 or with D3 + 25- hydroxycholecalciferol. Egg traits during a productive cycle as well as the bone characteristics of the layers have been as well evaluated to determine if there the vitamin D3 may enhance the welfare status of the birds. 1. The weight of the egg and of its components is often greater in hens fed a diet enriched with 25-hydroxycholecalciferol. 2. Since eggs of treated groups are heavier and a larger amount of shell is needed, a direct effect on shell strength is observed. 3. At 30 and at 50 wk of age hens fed 25 hydroxycholecalciferol exhibited greater values of bone breaking force. 4. Radiographic density values obtained in the trial are always higher in hens fed with 25-hydroxycholecalciferol of both treatments: supplemented for the whole laying cycle (25D3) or from 40 weeks of age onward (D3+25D3).

Mestrado em Ecologia, Biodiversidade e Gestão de Ecossistemas<br>A utilização dos compostos de uso veterinário e seus efeitos nos diferentes compartimentos ambientais têm sido alvo de grande atenção nos anos recentes. Produtos medicinais veterinários tais como os antibióticos são utilizados no combate aos parasitas e na prevenção de doenças em animais. Esses compostos são largamente utilizados como aditivos alimentares na indústria de criação de galináceos como aceleradores de crescimento. As conseqüências e efeitos ainda não conhecidos desses fármacos no ambiente matéria de estudo de muitos trabalhos. Os compostos fármacos veterinários podem entrar no ambiente por inúmeras formas, incluído a via direta, onde esses compostos são aplicados nas águas superficiais tal como nos tratamentos de aquacultura através da lixiviação oriunda dos tratamentos e das excretas das excretas dos animais. O propósito deste estudo era de avaliar o impacto de dois compostos de uso veterinário (nicarbazin e monensin) utilizados como aditivos alimentares na indústria de criação de galináceos em organismos não alvos e duas espécies de plantas. Ensaios ecotoxicológicos foram realizados para avaliar a toxicidade aguda e crônica em minhocas (Eisenia andrei), colêmbolos (Folsomia candida) e as duas espécies de plantas (Brassica rapa e Triticum aestivum). As medidas analíticas dos químicos no solo estiveram de acordo com as concentrações nominais utilizadas. Os resultados obtidos demonstraram que não houve efeito significativo na exposição ao nicarbazin a todos os organismos testados, enquanto que a exposição ao monensin apresentou uma dose-resposta de efeito observado. A sensibilidade das espécies decresceu na seguinte ordem: Brassica rapa < Eisenia andrei < Triticum aestivum < Folsomia candida, com os valores de EC50 variando entre aproximadamente 10 e 100mg/kg. Esse estudo demonstrou a importância da utilização de uma bateria de testes para avaliar os efeitos ecotoxicológicos, principalmente pela utilização de diferentes parâmetros de avaliação de resposta e/ou espécies de diferentes níveis tróficos. ABSTRACT: The usage of veterinary pharmaceutical (VP) compounds and their effects in the different environmental compartments have received a special attention in recent years. Veterinary medicinal products such as antibiotics are used to combat parasites and prevent diseases in the animals. They are widely used as food additives in the poultry industry and also in other farm animals to promote growth. The unknown consequences of these VPs into the environment are a matter of concern and many works have been made to analyze the effects of these compounds. The VP compounds may enter into the environment via a number of different pathways, this include direct via, when it’s applied in the surface waters as in the aquaculture treatments by wash-off from topical treatments and the excreta of animals. The purpose of this study was to examine the direct impact of two veterinary pharmaceuticals (nicarbazin and monensin) used in the poultry industry on non-target organisms and two plant species. Ecotoxicological tests were used to evaluate the acute and chronic toxicity in earthworms (Eisenia andrei), collembolans (Folsomia candida) and two species of plants (Brassica rapa and Triticum aestivum). Analytical measurements of the chemicals were in good agreement with the nominal concentrations used. The results obtained showed no effect of nicarbazin for all the tested organisms, while in exposures with monensin, there was a dose-response pattern. Species sensitivity decreased in the following order: Brassica rapa > Eisenia andrei > Triticum aestivum > Folsomia candida, with EC50 ranging between approximately 10 and 100mg/kg. This study showed the importance of the test battery when assessing ecotoxicological effects, mainly by using different endpoints and/or species from different trophic levels.

Campylobacter is the main cause of human bacterial gastroenteritis worldwide. Within the EU reported cases are rising each year. Epidemiological studies have identified that chicken meat is one of the major sources of human infection. However, it is poorly understood whether differences in chickens’ rearing and production methods impact on the contamination levels of Campylobacter on chicken meat and therefore the risk of entry into the food chain. To investigate the role of production system, flocks from diverse broiler commercial production systems with differences in welfare standards, bird type and stocking densities were investigated during the whole rearing period and at slaughter. Caecal samples were collected to estimate the flock prevalence. In order to assess the level of carcass contamination during processing, neck skin samples were collected at different production stages. Breast meat samples were also investigated to estimate the risk that chicken meat poses to human health. The objective was to link the flock Campylobacter status to the risk of contamination on the consumer’s plate. All samples were cultured for the presence of Campylobacter species. A quantitative method based on ISO 10272-2:2006, was used to determine the level of flock colonisation and Campylobacter contamination on broiler carcasses and final products. Results show that birds reared indoors under higher welfare standards with decreased stocking density with a slower growing breed (Hubbard JA57) had a reduced prevalence of Campylobacter, compared to the standard fast growing breed (Ross 308) when grown at the same stocking density. The production system with the higher Campylobacter prevalence and the higher Campylobacter count in the caecal contents, also reported a greater Campylobacter prevalence and counts on carcasses. The bacterial numbers on the final product appeared to be strongly associated with the intestinal colonisation of the slaughter batch. Consequently it is crucial to prevent flock colonisation during the rearing period, to ensure negative flocks are entering into the processing plant. The significance of the aforementioned point was also highlighted by the fact that production stages such as final washing and chilling have little impact in the reduction of contamination of the final product. The high level of contaminated carcasses showed clearly that the chicken meat is putting the UK consumers’ health at risk. An increased incidence of welfare issues, such as pododermatitis and hock lesions, was observed among the production system with the higher level of colonisation, which bring to light a link between Campylobacter colonisation and welfare issues. Furthermore, this study emphasised that stressful events such as thinning and transport were followed by an increase in Campylobacter prevalence. This highlights the importance of animal health and welfare interactions with Campylobacter spp colonisation. Multi Locus Sequence Typing (MLST) was used to determine how diverse and distinct the genetic Campylobacter population structure was among the different commercial production systems investigated. Results showed that all production systems could be potential sources of Campylobacter infection in humans with common clonal complexes found. Changes in the prevalence of genotypes associated with the final product compared to those genotypes found in birds arriving from farms were observed. This may reflect the enhanced ability of certain genotypes to resist environmental stressors, such as carcass washing, chilling, chlorine dioxide treatment and oxygen that occur during processing. In this data set, isolates belonging to the ST-257 complex showed a higher tendency to survive in the slaughterhouse environment. Internal contamination of the breast muscle was also reported in our study, hence posing a further public health threat, as the bacteria contained within the muscle are better able to survive cooking. These studies have demonstrated that this pathogen was highly prevalent among the broiler population investigated. Due to the common extent of this pathogen in food and its impact on human health, it is necessary for the Government bodies, food producers and retailers, to raise consumers’ awareness of the Campylobacter issue. Particularly the consumers must be made aware of how to manage the risk appropriately during food preparation.

Submitted by Nathália Faria da Silva (nathaliafsilva.ufv@gmail.com) on 2017-07-28T13:57:52Z No. of bitstreams: 1 texto completo.PDF: 1092273 bytes, checksum: 61189e2f9ff1c859ecd3bbb9a9959c9a (MD5)<br>Made available in DSpace on 2017-07-28T13:57:52Z (GMT). No. of bitstreams: 1 texto completo.PDF: 1092273 bytes, checksum: 61189e2f9ff1c859ecd3bbb9a9959c9a (MD5) Previous issue date: 2002-02-28<br>Coordenação de Aperfeiçoamento de Pessoal de Nível Superior<br>Um sistema de medição e controle foi desenvolvido para o estudo de respostas fisiológicas de aves sujeitas a mudanças térmicas como meio de alívio de estresse térmico. O sistema faz o controle automático da temperatura (t a,SP ±0,2 oC) e da umidade relativa do ar (RH SP ±2 %); sendo que a velocidade do ar foi controlada manualmente (V SP ±0,1 m· s -1 ); e contínuo armazenamento das termografias (ex., temperatura superficial, t surf ) e da temperatura corporais (t b ) dos animais. As condições térmicas controladas na zona de ocupação animal (AZO) são atingidas pela operação de um pequeno túnel de vento (V = 0 to 1,5 m· s -1 ) colocado no interior de uma sala ambiental com t a e RH controlados (5,0 m comprimento × 3,5 m largura × 3,0 m altura). Os valores desejados de t a e RH foram alcançados por meio de aquecedores e umidificadores controlados em dois estágios via um módulo de controle e medição programável, e periféricos. Termografias (discernabilidade de 0.06°C) são adquiridas com uma camera infravermelho cuja operação é controlada remotamente por um PC. t b (±0.1°C) é armazenado em uma unidade de telemetria, sem a necessidade de intervenção cirurgica, que também é conectado a um PC. Em adição, um sistema de video tem sido usado para observar e arquivar os comportamentos do animal. A instrumentação desenvolvida foi usada em um experimento para ajustar equações empíricas para descrever as necessidades de molhamento parcial da superfície em galinhas poedeiras (Hy-Line W98, com 34 ± 1 semanas) sujeitas a condições de estresse térmico. A água necessária para limitar o aumento da temperatura superficial das galinhas foi expressada em termos de intervalo de aspersão (SI 10 , min) para uma dosagem constante (10 ml· aspersão -1 ) ou para uma taxa de evaporação (ER, ml.min -1 ) de água aspergida. As exposições térmicas consistiram de uma combinação fatorial de 3 temperaturas de bulbo seco (t db ) (35, 38 e 41 °C) x 2 temperaturas de ponto de orvalho (t dp ) (21,1 e 26,7 °C) x 3 velocidades do ar (V) (0,2, 0,7 e 1,2 m· s -1 ). As condições ambientais foram expressas como 18 combinações de déficit de vapor de pressão do ar (VPD air ) x V. ER foi diretamente proporcional ao produto VPD air · V . As relações podem servir como a base para a otimizar o sistema de resfriamento superficial intermitente para alívio de estresse térmico em galinhas criadas em gaiolas. Ademais, um índice de desconforto térmico (TDI) foi derivado com base nas respostas fisiológicas, temperatura superficial (t surf ) e temperatura corporal (t b ), de galinhas sujeitas a exposições térmicas. Com base no aumento da t b aos 50 min de exposição térmica (Δt b,50 ), um TDI foi relacionado ao VPD air e a V da seguinte forma: TDI = -15.17 + 18.62 (t db ) n – 0.92 · (VPD air · V ) n . Usando TDI, quatro zonas de desconforto térmico (segura, alerta, perigo e fatal) foram definidas para as várias combinações de condições térmicas. Um modelo teórico de transferência de calor e massa em regime transiente também foi proposto para predizer Δt b,50 em função das condições ambientais, das condições fisiológicas das aves e do nível de molhamento (β). O modelo proporciona uma ferramenta conveniente e interativa para determinar Δt b,50 nas galinhas submetidas ou não ao molhamento superficial para t db variando de 35 a 38 °C.<br>A control and measurement system was developed for studying physiological responses of poultry to thermal challenges and means of thermal stress relief. The system features automatic control of air temperature (t a,SP ±0.2 oC) and relative humidity (RH SP ± 2 %); manual setting of air velocity (V SP ± 0.1 m· s -1 ); and continuous recording of thermographs (i.e., core body temperature (t b ) of the animal. surface temperature, t surf ) and The controlled thermal conditions in the animal-occupied zone (AOZ) are achieved through operation of a small wind tunnel (V = 0 to 1.5 m· s -1 ) inside a t a - and RH-controlled environmental room (5 m L × 3.5 m W × 3.0 m H). Target t a and RH values are achieved by controlling auxiliary heaters and humidifiers in two stages via a programmable measurement and control module and peripherals. Thermographs (0.06°C discernability) are acquired with an infrared (IR) imager whose operation is remotely controlled by a PC. Core body temperature (t b , ±0.1°C) is recorded with a surgery-free telemetric sensing unit that is also interfaced with a PC. In addition, a video monitoring system is used to observe and archive animal behaviors. The instrumentation developed was used in an experiment to establish empirical equations to describe the need of partial surface wetting for cooling laying hens (Hy-Line W-98, 34 ±1 wk old) subjected to a range of thermal stress conditions. The thermal exposures consisted of a factorial combination of 3 dry bulb temperatures (t db ) (35, 38 and 41 °C) × 2 dew point temperatures (t dp ) (21.1 and 26.7 ° C) × 3 air velocities (V) (0.2, 0.7 and 1.2 m· s - ). The environmental conditions were expressed as 18 combinations of air vapor pressure deficit (VPD air ) × V. The water necessary to limit hen surface temperature from rising was expressed in terms of sprinkle interval (SI 10 , min) for a constant spray dosage (10 ml· spray -1 ) or evaporation rate (ER, ml· min -1 ) of the sprayed water. ER was directly proportional to VPD air · V . The relationships may serve as the basis for optimizing an intermittent partial surface cooling system for thermal stress relief of caged layers. Also from the study, a thermal discomfort index (TDI) was derived based on physiological responses, surface temperature (t surf ) and core body temperature (t b ) of the control (non-cooled) hens. Based on t b rise after 50 min of thermal exposure (Δt b,50 ), TDI related to VPD air and V as: TDI = -15.17 + 18.62 (t db ) n – 0.92· (VPD air · was V ) n . Using TDI, four zones of thermal discomfort (safe, alert, danger, and fatal) were defined for various combinations of thermal conditions. Furthermore, theoretical transient heat and mass transfer model was proposed to predict Δt b,50 as a function of environmental conditions, physiological responses of the hens and surface wetness level (β). The model provides a convenient, interactive tool for determining Δt b,50 on wetted and non-wetted hens for t db ranging from 35 to 38 °C.

Thesis (M.S.)--West Virginia University, 2008.<br>Title from document title page. Document formatted into pages; contains iii, 50 p. : ill. Includes abstract. Includes bibliographical references (p. 43-50).

Thesis (MSc. (Animal Production)) -- University of Limpopo, 2016<br>This study was conducted to determine the effect of supplementing diets with antimicrobials and effective microorganisms on productivity and carcass characteristics of Ross 308 broiler chickens. The study consisted of two parts. The first part determined the effect of antimicrobial and effective microorganism (EM) supplementations on growth performance of unsexed Ross 308 broiler chickens aged one to 21 days. A complete randomized design was used and 150 unsexed day-old chicks with an initial weight of 42 ± 2g were randomly assigned to five different treatments which were replicated 3 times with each replicate having 10 chicks. The five grower diets had the same nutrients (20% CP and 12MJ/kg) but different supplementation levels of 0g oxytetracycline and 0ml EMs/l of water (UAM0EM0), 0.01g oxytetracycline (UAM0.01EM0), 30ml EMs/l of water (UAM0EM30), 50ml EMs/l of water (UAM0EM50) and 100ml EMs/l of water (UAM0EM100). A quadratic regression model was used to determine dietary effective microorganism supplementation levels for optimal feed intake and live weight of Ross 308 broiler chickens. A linear model was used to determine the relationship between dietary effective microorganism supplementation levels and metabolisable energy intakes. Antimicrobial and effective microorganism supplementations did not have any effect (P>0.05) on growth rate, feed conversion ratio and mortality. Antimicrobial supplementation improved (P<0.05) feed intake and live weight of the chickens. Supplementation with 50ml of EMs/l of water improved (P<0.05) feed intake. Supplementation with 50 or 100ml of EMs per litre of water increased (P<0.05) ME intake of the chickens. Effective microorganism supplementation levels of 72.25 and 48.29ml of drinking water optimized feed intake and live weight, respectively. The second part of the experiment determined the effect of antimicrobials and effective microorganisms on productivity, blood, carcass characteristics and meat quality of male Ross 308 broiler chickens aged 22 to 42 days. The chickens were randomly allocated to five treatments with three replications, each having six chickens. A total of 90 male chickens, with the initial live weight of 452 ± 3g were allocated to the treatments in a complete randomized design. The chickens were fed a grower diet supplemented with 0g oxytetracycline and 0ml EMs/l of water (MAM0EM0), 0.01g oxytetracycline (MAM0.01EM0), 30ml EMs/l of water (MAM0EM30), v 50ml EMs/l of water (MAM0EM50) and 100ml EMs/l of water (MAM0EM100). Antimicrobial and effective microorganism supplementation did not have effect (P>0.05) on feed intake, growth rate, live weight, ME intake, blood glucose and mortality. Poorer (P<0.05) feed conversion ratio was observed with the supplementation of antimicrobial. Blood glucose levels were optimized at an effective microorganism supplementation level of 29.00ml of EM/l of drinking water (Figure 4.05). Supplementing diets with antimicrobials and effective microorganisms did not have effect (P>0.05) on crop, gizzard, proventriculus and large intestine pH values of male chickens. However, supplementation with of 100ml of EMs per litre of drinking water reduced (P<.0.05) the pH of ileum. Effective microorganism supplementation level of 85.00ml per litre of drinking water optimized the crop pH value. Antimicrobial and effective microorganism supplementations did not have influence (P>0.05) on gizzard, proventriculus, small intestine, caecum, large intestine, liver and heart weights of male chickens at 42 days. Effective microorganism supplementation level of 50ml per litre of drinking water reduced (P<.0.05) crop weight. Antimicrobial and effective microorganism supplementations did not have effect (P>0.05) on whole gastro-intestinal tract (GIT), small intestine and caecum length of the chickens. Antimicrobial supplementation reduced (P<0.05) the length of large intestine. Effective microorganism supplementation levels of 41.00, 45.50 and 85.00ml per litre of drinking water optimized crop weights and caecum and large intestine lengths, respectively. Antimicrobial and effective microorganism supplementations did not have any influence (P>0.05) on live weight, carcass weight, breast weight, drumstick weight ad thigh weight. Similarly, antimicrobial and effective microorganism supplementations did not have influence on meat tenderness, juiciness and flavour. There were no antibiotic and effective microbe residues in the meat. It is, therefore, concluded that effective microorganism supplementation did not have much effect on production parameters, carcass characteristics and meat quality of Ross 308 broiler chickens.

Four studies were conducted to evaluate the effects of different feeding programs during rearing and production on broiler breeder male growth, fertility, and progeny performance. In Experiment I, the effects of two levels (High and Low) of cumulative nutrient intake during the rearing period to photostimulation at 21 wk of age through different dietary formulations or feeding programs were evaluated. The High cumulative nutrition program supplied 33.5 Mcal ME and 1,730 g CP, while the Low cumulative nutrition program supplied 29.6 Mcal ME and 1,470 g CP. At 21 wk of age in Experiment I-2, males were classified into Heavy or Light BW groups. A cumulative nutrient intake during the rearing period of 29.6 Mcal ME and 1,470 g CP, regardless of diet or feeding program resulted in a male of adequate BW that was able to maintain good fertility throughout the production period and produce broilers with increased 42-d BW. In Experiment III, two levels of dietary CP (12% and 17%) and two feeding programs (Concave and Sigmoid) were evaluated during the rearing period to 26 wk of age. The Concave or 17% CP treatments were unable to sustain fertility after 40 wk of age without an increased allocation of feed. In Experiments II, two antioxidant levels and different source of selenium were evaluated during the production period. In Experiment IV different feeding programs from 16 to 26 wk of age and during the production period were evaluated. The data showed that feed allocation relative to BW affected fertility more than did antioxidant inclusion. Furthermore, slow and consistently increasing feed increments from 16 to 26 wk of age and during the production period improved fertility and favorably impacted progeny performance. In conclusion, when males failed in accumulate adequate nutrients during the rearing period or gain adequate BW, as an indication of ME allocation, after photostimulation fertility declined and significant negative effects were observed in progeny performance.

The effect of X-ray irradiation on Campylobacter jejuni, Campylobacter coli, Arcobacter butzleri and Salmonella Typhimurium was examined by measuring the recovery on ifferent media. Irradiation doses (1.0-7.0 kGy) caused a significant reduction in icrobial counts irrespective of the media used for recovery. Recovery was highest on Blood Mueller Hinton Agar (D-value being 3.30,3.32,3.56 and 6.86 kGy for C jejuni, C. coli, A. butzleri and S. Typhimurium respectively) and lowest on selective media (Dvalue being 3.20, 3.08, 3.36 and 3.20 kGy for C. jejuni, C. coli, A. butzleri, and S. lurium respectively).

While food recalls are receiving growing attention amongst consumers, they are also of great importance from a company perspective. By applying an event study method, we examine the impact of recalls on the stock price of affected companies. Our paper contributes to the existing literature in three ways. First, our study shows that the average reduction in firm value after twenty days is approximately $304 million. Second, we identify two explanatory variables not identified by previous literature. These variables assist in explaining the stock price fluctuations related to recalls. Third, we present a comprehensive model of all the explanatory variables, consisting of our findings compiled with explanatory variables identified by previous literature. Our findings extend to the general body of knowledge on food recalls‘ impact on stock price by identifying two explanatory variables. Additionally, we provide three practical recommendations that are beneficial when developing and evaluating risk-management strategies.

Thesis (MA.Agricultural Management (Animal Production)) -- University of Limpopo, 2013<br>The objectives of the study were to evaluate the productivity of the Vhembe egg production project and determine the management and socio-economic factors affecting productivity. The data were collected from 2005 to 2007. Thirty-two farmers from four municipalities were randomly selected. Each household received a once-off unit consisting of a cage with eighteen point of lay chickens 4x50 bags of laying mesh, feeding and drinking troughs. Production records from sampled farmers were used in the analysis. Data included monthly egg production, eggs consumed, eggs sold, income from eggs, production costs, monthly feed utilization and mortality. Primary data on educational standards, socio-economic characteristics (age and gender of the household head, farming size, level of education and alternative income, were collected using a questionnaire. The study revealed that sex, age and educational level had impact on production as low production was associated with older farmers and low level of education. These factors should be considered when planning community projects. Chicken rearing and ownership is often shared among the family members, in this study, the management was predominantly by women (63%) and children (18%). This may be an indication that if assistance efforts are targeted towards women, village poverty could be significantly reduced. It is concluded that the low income accrued from the project explains the reason for high abandonment or neglect of the project. The income received from the project is smaller than the government grants and as such not attractive. It is not surprising that presently most farmers have abandoned the project. It is noted that if labour costs had been taken into consideration, the project would be running at a serious loss and the resultant output would discourage even the most enthusiastic farmers.

Nutrient availability from poultry manures can be affected by soil types and manure processing. Estimates of nutrient release from manures are important when recommending their use. Three separate laboratory experiments were conducted to evaluate N and P availability, and liming value of poultry layer manures (fresh, composted, and pelleted) with surfaces samples of three NC soils: Belhaven (loamy, mixed, dysic, thermic Terric Haplosaprists), Cecil (fine, kaolinitic, thermic Typic Kanhapludults), and Lynchburg (fine-loamy, siliceous, semiactive, thermic Aeric Paleaquults). The N incubation compared N mineralization from poultry manures and urea, applied at a rate of 133 µg N cm-3 soil (200 kg ha-1) and incubated for 90 days. Net N mineralized from the manures was described by a single pool first order kinetic model. Potential available N, estimated as the proportion of applied N, was greater for the fresh and composted manures than for the pelleted source in the three soils investigated. Nitrogen availability in fresh, composted, and pelleted manures for the Belhaven soil was 57, 53, and 46 % of total N applied, respectively; 83, 73, and 61 % of total N applied in the Lynchburg soil; and 41, 33, and 25 % for the same order of manure sources in the Cecil soil. The 21 day lime incubation compared poultry manure rates of 1333 and 2667 µg cm-3 of soil (2 and 4 t ha-1) with multiple rates of CaCO3. Liming materials in all the manures were just as effective in neutralizing soil acidity as equivalent amounts of CaCO3. Nitrification of manure N, however, can reduce the net liming effect by the release of H+. The 21 day P incubation experiment compared available P from the manures applied at rates of 1333 and 2667 µg cm-3 of soil (2 and 4 t ha-1) with multiple rates of Ca(H2PO4)2. A linear relationship across all P sources and rates was the best estimator of the increase in Mehlich-3 extractable P per unit of P added. These results suggested that P from the manures behaved similar to inorganic P fertilizer. Treatments in a subsequent greenhouse experiment were designed to evaluate millet [Urochloa ramosa (L.) T. Q. Nguyen] response to N, P and lime supplied in manures. Plant available N from the manures, estimated from the urea-N fertilizer equivalence of plant N accumulation, followed the decreasing order of fresh > composted > pelleted. This ranking among manures is similar to that obtained in the N incubation study. Millet dry matter and nutrient accumulation at targeted levels of N supply and soil values of Mehlich-3 P and pH were similar between treatments of manure supplemented with P fertilizer and lime, and treatments receiving only inorganic fertilizers and lime. These results indicate that optimum plant growth in manure amended systems requires the appropriate identification and correction of soil N, P and/or acidity constraints. Type of manure processing affects total N availability, and soil properties such as texture and buffer capacity can influence N mineralization and soil available P.

The use of ethanol produced from lignocellulosic biomass for transportation fuel offers solutions in reducing environmental emission and the use of non-renewable fuels. However, lignocellulosic ethanol production is still hampered by economic and technical obstacles. For instance, the inhibitory effect of toxic compounds produced during biomass pretreatment was reported to inhibit the fermenting microorganisms, hence there was a decrease in ethanol yield and productivity. Thus, there is a need to improve the bioconversion of lignocellulosic biomass to ethanol in order to promote its commercialization. The research reported here investigated the use of poultry litter biochar to improve the ethanol production from steam-exploded poplar and corn stover. The effect of poultry litter biochar was first studied on Saccharomyces cerevisiae ATCC 204508/S288C growth, and second on the enzyme hydrolysis and fermentation of two steam-exploded biomasses: (poplar and corn stover). The third part of the study investigated optimal process parameters (biochar loading, biomass loading, and enzyme loading) on the reducing sugars production, and ethanol yield from steam-exploded corn stover. In this study, it has been shown that poultry litter biochar improved the S. cerevisiae growth and ethanol productivity; therefore poultry litter biochar could potentially be used to improve the ethanol production from steam-exploded lignocellulosic biomass.