Academic literature on the topic 'Poultry Eggs Calcium in animal nutrition'

Animal source foods such as eggs are often lacking in complementary foods in Ethiopia, a country with a high rate of malnutrition in under 5-year-old children. It is recommended that young children receive an egg a day, but rural households often cannot afford them or do not have experience raising chickens. The aim of this study was to conduct a poultry intervention, providing two chickens to households with a young child, stipulating that the child was the owner, and required an egg a day. This randomized, controlled, community trial was conducted in southern Ethiopia with children 6-12 mo living in selected kebeles. Chickens were gifted to families who guaranteed that eggs would be fed to the child in the Intervention, along with education on poultry production and promotion of eggs for children. Eggshell powder (ESP) was encouraged for use as a calcium supplement by children ≥ 1 y. Control kebeles continued with existing nutrition education for the 6-month trial. Baseline and end line outcome measures included child consumption of eggs, ESP, and poultry production. Other outcome measures will be reported elsewhere. Egg consumption by children was significantly improved only in the intervention group from 0.8 to 17 eggs/month (p < 0.001). ESP consumption got community acceptance with an average consumption of a child in the intervention group for 17 days/month (p < 0.001). Poultry production increased in the Intervention communities even when child-owned chickens were excluded from analysis (from 138 to 251 chickens) while in the Control communities, the number of chickens decreased (from 219 to 101). Cage construction improved in the Intervention communities, however, losses of chickens occurred. A 6-month poultry intervention that emphasized child ownership and provided education for poultry and nutrition education resulted in families increasing livestock numbers, and children eating on average more than half an egg a day.

In the present study, different eggs were collected and analyzed from five various animal species: European pond turtle (Emys orbicularis (Linnaeus, 1758)), giant African land snail (Achatina fulica (Bowdich, 1822)), common ostrich (Struthio camelus (Linnaeus, 1758)), white, light-brown, and dark-brown laying hen (Gallus gallus domesticus (Linnaeus, 1758) and European quail (Coturnix coturnix (Linnaeus, 1758). The typical mineral shell mainly composed of the calcite polymorph of CaCO3 but the eggshell consists of membranes, that composed mainly of proteins. The shell quality also could be assigned by several external and internal factors such as oviposition time, animal genotype and age, housing system (for poultry), and mineral nutrition complex. The CaCO3 content was determined by the standard titration method, coz the titration could provide a reliable method for evaluation of CaCO3 content in different types of eggshells. The structural surface characterization of eggshells was performed by scanning electron microscopy (SEM) with a field emission gun. In terms of chemical composition, ostrich eggshells generally did not differ much from those of laying hen, turtles, giant snails, or quail eggs, but the concentration of calcium carbonate was the highest. The average calcium carbonate content of various eggshells is between 84 and 98%. The thickness of the eggshell ranges from 0.08 to 1.89 mm, and it is not the same over the entire surface of the egg. At the sharp end of the egg, the shell is slightly thicker than at the blunt end. The purpose of this study was to study the quantitative content of calcium carbonate in various eggshells of different animals to draw further conclusions in which animals the eggshell contains the maximum amount of biological calcium carbonate.

Little is known about calcium and vitamin D intakes in Middle Eastern countries, where the prevalence of hypovitaminosis D is high. This study identifies major sources of calcium and vitamin D in the Lebanese diet, examines lifestyle factors that may influence intake of these nutrients and investigates the relationship between nutritional or lifestyle factors and parathyroid hormone (PTH). Three hundred sixteen young healthy volunteers aged 30 to 50 (men, non-veiled and veiled women) were recruited from different rural and urban Lebanese community centers. Food frequency questionnaire was used to evaluate the consumption of vitamin D and calcium-rich foods. We also measured serum PTH levels. Mean daily calcium and vitamin D intake were respectively 683.8 ± 281.2 mg and 100.6 ± 71.0 IU. Daily vitamin D sources were divided as follows: 30.4 ± 46.4 IU from milk and dairy products, 28.2 ± 26.3 IU from meat and poultry, 25.8 ± 25 IU from fish, 8.5 ± 8.6 IU from eggs, and 7.8 ± 14.3 IU from sweets (respectively 30.2%, 28%, 25.6%, 8.4% and 7.7% of the total vitamin D intake). Mean daily calcium from animal and vegetable sources were respectively 376.3 ± 233.6 mg and 307.9 ± 118.5 mg. Animal/total calcium intake ratio was 52% and was only statistically significantly higher in urban people compared to rural ones. Multivariate analysis showed that male sex and urban residence were independent predictors of both vitamin D and calcium intakes (p < 0.01 and p < 0.01 respectively). In addition, veiling was an independent predictor of low vitamin D intake (p < 0.05) and a high body mass index (BMI) was an independent predictor of low calcium intake (p < 0.05). Finally, PTH was inversely correlated with vitamin D intake and the animal/total calcium intake ratio ( r = –0.18 and r = –0.22, p < 0.01), while no significant results were achieved for the vegetable calcium. In a multivariate model, urban living, female gender, low vitamin D and calcium intakes, low animal/total calcium intake ratio, and high BMI, are independent predictors of hyperparathyroidism. The deficient nutritional status of vitamin D and calcium in Lebanon justify the implementation of dietary public health measures. People at most risk for secondary hyperparathyroidism should be advised to increase their dietary calcium (mostly animal calcium) and vitamin D, to take supplements, or to increase their sun exposure.

Abstract Objectives Adopting environmentally sustainable diets can substantially reduce anthropogenic greenhouse gas emissions (GHG). However, there remain concerns that consuming sustainable foods will increase the likelihood of nutritional deficiencies in periods of increased demand, including pregnancy. This study aimed to identify commonly consumed foods of pregnant women and determine the effect of their replacement with sustainable alternatives on nutrient intake and measures of environmental sustainability. Methods Dietary intake data from 171 pregnant women were assessed using a validated food frequency questionnaire. The food groups and food items that contributed most to energy and protein intake were identified. Of these foods, those that produce the highest GHG emissions (Poore et al. 2018) were matched with proposed sustainable alternatives for energy and protein content, and their impact on nutrient provision and sustainability measures were determined. Results Meats (bovine, poultry, fish, lamb and eggs), grains and dairy products were important sources of both energy and protein intake. With the highest GHG emissions, beef was selected as the reference food. Proposed food alternatives included lamb, chicken, eggs, fish, tofu, legumes and nuts. The most pronounced reductions in CO2 emission were from replacing beef with tofu, legumes and nuts. For example, replacing one serve of beef with an isocaloric serve of firm tofu per week during pregnancy could reduce GHG emissions by 372 kg CO2 eq, equivalent to that produced by an average passenger vehicle driving 1498 km. This replacement would not adversely impact iron (+1.1mg per serve) content, whilst providing a richer source of calcium (+294.8mg per serve), folate (+28.1µg per serve) and dietary fibre (+3.3g per serve). A once-weekly substitution of animal-derived foods for more sustainable plant-based alternatives within the context of a mixed diet has minimal effect on overall nutrient intake. Conclusions Simple dietary substitutions, as little as replacing one serve of red meat with sustainable alternatives weekly, can substantially reduce environmental impact without compromising nutrient adequacy. These sustainable food replacements should be the focus of future applied clinical research. Funding Sources No funding support for conducting this project was received.

A review work was conducted to unveil the potentials of earthworm (EW) and its by – products such as earthworm meal (EWM) and earthworm casts (EWC) in poultry nutrition and management of animal waste. Production of EW is called vermiculture and using it to decompose organic matter is vermicomposting while processing it into such product as EWM is known as vermitechnology. Being a hermaphrodite, breeding is simple and fast, requiring only two EW to come together irrespective of their sexes. Fresh EW could be fed to fish and chickens. Based on literature EWM is high in protein 62 to 65%, essential amino acids such as lysine 6 to 8%, methionine 2 to 5%, leucine 8 to 10%, isoleucine 4 to 6% and phenylalanine 4 to 6%; fat 5 to 8% and fibre< 8%. At dietary inclusion level of 0.2 to 0.6%, EWM reportedly increased feed intake, supported growth, improved carcass quality in broiler chickens, and marginally increased egg size and hen day in layers. Dry EWC could replace 5 to 10% maize in diet for finishing broiler chickens. Rich in macro plant nutrients (e.g. nitrogen 1.94%, calcium 4.4% and potassium 0.7%) EWC is nutritionally sound for growth of pasture crops especially legumes. Earthworm has cellulase, lichenase, chitinase and cellulolytic microorganisms which enable it to degrade organic waste. Cattle dung and other animal manure can be degraded by earthworm thereby reducing environmental pollution. In this era of organic farming and sustainable environment, EW could therefore have a potential place in animal nutrition and management of waste from animals.Bang. J. Anim. Sci. 2016. 45 (2): 1-9

The main objective of this study was to compare the metabolic profile (i.e. selected haematological and biochemical parameters in blood plasma) of production egg-type hybrid hens (E, MORAVIA BSL) with that of meat-type hybrid hens (M, COBB 500), and to evaluate dynamic changes occurring during the laying period from the 25th to 50th week of age. The study was prompted by both poultry farmers and veterinary practitioners since parameters defining the health of layers are absent. Selected parameters of the metabolic profile of layers were monitored regularly in 5-week intervals during egg laying. Samples of blood for haematological and biochemical examination were obtained by puncture of the vena basilica and stabilized by heparin. The study has revealed that monitored parameters of the metabolic profile significantly vary with factors such as production type, nutrition, and egg-laying intensity. Enhanced metabolism in egg-type hens was reflected in erythropoiesis which increased (in comparison with meat-type hens) highly significantly (P &le; 0.01), particularly for erythrocyte count 2.36 T/l (2.14&nbsp;T/l), haematocrit level 0.32 l/l (0.30 l/l), content of haemoglobin 94.48 g/l (84.18 g/l) and leukocyte count 17.06&nbsp;G/l (13.22&nbsp;G/l). Similarly, enhanced metabolism in egg-type hens also led to a highly significant increase (P &le; 0.01) in the levels of biochemical parameters in blood plasma, particularly the total level of protein was 57.62 g/l (50.98) g/l), glucose 14.03 mmol/l (13.36 mmol/l), cholesterol 5.34 mmol/l (3.73 mmol/l) and calcium 6.52 mmol/l (5.52 mmol/l). ) In the case of the plasma level of phosphorus, no significant difference was found between egg-type hens (1.58 mmol/l) and meat-type hens (1.59 mmol/l). The reported results are based on the total of 180 haematological and biochemical analyses performed during the laying period. The results are crucial not only for future development of avian haematology and biochemistry, but also in respect to veterinary practice. &nbsp; &nbsp;

Context The increasing demand for maize for human food and industrial uses has stimulated research interest into alternative low value crops as energy sources for poultry. Several high yielding species of aroids, commonly known as taro or cocoyam, are currently in less demand for food or industrial uses and readily available for poultry feeding. Aims To review the production, nutritional profile and antinutritional factor and current uses of cocoyam corm and the effect of processing on its utilisation in poultry feeding. Key findings The nutritional profile of cocoyam with protein content comparable or higher than maize, high starch content and starch digestibility make it a suitable energy ingredient for poultry. The major issues affecting the utilisation of cocoyam include the high moisture and low dry matter contents and the presence of antinutritional factors, mainly calcium oxalate. These constraints may preclude the utilisation of cocoyam corm in commercial diets but it could be used to reduce the cost of production on small-holder farms. Conclusion With adequate processing and proper diet formulation, cocoyam corm meal may be fed up to 280 g/kg diet but unprocessed meal may exert adverse effects on poultry performance even as low as 44 g/kg. Several animal factors including age, species and type of bird (meat or egg) affect the utilisation of cocoyam corm meal by poultry. Implications Reduction of cost of animal protein production and value addition to underutilised aroids. More research is needed into animal factors and feed processing that would allow optimum utilisation of the corm by poultry.

In the latest research relating to mineral nutrition of poultry, the interest in several nutrients is prevailing for which in ordinary diets additional sources are necessary. In mineral nutrition of layers constantly the calcium (Ca) requirements are reviewed as one of the most important factors influencing the quality of eggs and bones, in regard to adequate level, source and particle size of added Ca, as well as mutual balance with other nutrients, primarily vitamin D, phosphorus (P) and certain micro-elements. Also, efforts are directed towards possibility and justification for use of new source of vitamin D, existing recommendations related to P are reviewed as well as increase of possibility for adoption of phytine bound phosphorus in diets using enzyme phytase, as well as investigation of organic forms of certain micro-element sources. Certain researches which combine the latest studies of the mineral nutrition of poultry are especially interesting also for practical application. Contrary to layers, focus of research of mineral nutrition of broilers is on phosphorus and application of enzyme phytase. In general, researches of the mineral nutrition of modern poultry genotypes are always actual, considering that their objective is to support genetic progress with adequate nutrition, but also to solve increasing problems relating to product quality, metabolic disorders and ecology.

Selenium has been known for two centuries and its biological activities have been studied for nearly a hundred years, however the problem of Se deficit has still been persisting both in humans and animals. The cause of Se deficit in animals may be low Se level in soil. This mainly applies to cattle and sheep with their direct link to soil via roughage. The risk of Se deficit in pigs and poultry is lower due to lower dependence on soil Se level in the region and Se fortification in feed mixes. The present research focuses on the effects of Se on meat and egg quality, antioxidant activity of Se, effects on fatty acid levels, activity of glutathione-peroxidase, or the effect of Se on the immune system. Ensuring natural Se supply in human nutrition by food of animal origin, mainly poultry meat and eggs (the &ldquo;functional foods&rdquo;), is another area to which extensive attention has recently been paid. &nbsp;

Thesis (Ph. D.)--University of Adelaide, Dept. of Animal Science, 1998.
Corrigenda inserted behind title page. Copies of author's previously published articles inserted. Includes bibliographical references (leaves 193-210).

Captive insectivores may consume invertebrates as all, or part of their overall diet. The challenge with feeding captive insectivores involves the limited number of invertebrate species that are commercially available, and the lack of key nutrients provided by these insects. Among these insects, a naturally occurring low concentration of calcium and an inverse calcium to phosphorus ratio may put insectivores at the risk of developing hypocalcemia. A strategy to correct this nutrient imbalance involves supplementing the insect diet with high concentrations of targeted nutrients – a term referred to as gut-loading. Current industry guidelines recommend feeding a supplemented diet for 48 to 72 h before offering the insect to an insectivore. In the present study, the mineral profile of adult crickets (Acheta domesticus) offered a maintenance diet (1.58% Ca, DMB) are compared to crickets offered a supplemented diet (11.32% Ca, DMB) over 120 h. The supplemented diet produced a cricket with significantly higher calcium concentration compared to the maintenance diet. The calcium concentration of crickets offered the supplemented diet was highest at 48 h (0.63%), but did not achieve a 1:1 Ca:P ratio nor meet the lowest reported nutrient requirements of carnivorous reptiles, omnivorous reptiles, or an insectivorous bird at various life stages. Although the supplemented diet improved the whole body calcium concentration in feeder crickets, the crickets do not provide adequate calcium, iron, or manganese to meet the requirement of insectivores. As evidenced by the current study, the supplemented crickets are not recommended to serve as the sole source of nutrition for an insectivore.

With the worldwide increase in consumption of poultry meat in recent years, the production of hatchable eggs from broiler breeding stock has become a critically important component of the poultry industry. Surprisingly, a perusal of the literature pertaining to broiler breeder nutrition leads to the conclusion that research nutritionists have neglected these birds. It has been assumed in many cases that the research on laying hens is applicable to broiler breeders. However, fundamental differences are apparent between the two strains that should be investigated more comprehensively if the potential of broiler breeder hens is to be achieved. Commercial laying hens have been selected predominantly for increased egg production whereas broilers have been selected for early rapid growth rate. By selecting for improved growth rate, both food consumption and mature weight of these birds has increased (Reddy, 1996), but because of the negative genetic correlation between body weight and egg production (Robinson et al, 1993) reproductive performance has not been improved. Broiler breeder hens differ from commercial laying hens, by their non-normal frequency distribution of egg outputs, their considerable lipid reserves, and by the fact that many do not lay in closed cycle. The practice of restricting feed intake during both the rearing and laying periods has become a standard management procedure in commercial broiler breeder operations and this differs from the manner in which commercial hens are fed. This raises important issues regarding the requirements of these birds for energy, amino acids and other essential nutrients, as the birds do not have the opportunity of meeting their nutrient requirements by adjusting food intake upwards when one or more of these nutrients is deficient in the feed. It is the duty of the nutritionist to provide the correct daily allowance of each nutrient in order to achieve maximum egg output by the flock, but given the variation between hens within a flock, such decisions need to be made on both biological and economic grounds. Improved strains are continually being produced by breeder companies, which exhibit better growth, feed efficiency and productivity. The way in which broiler breeder hens were fed in the past might not be the most effective way to feed the latest strains. Getting the right amount of feed with the right nutrient levels at the right time is the most important part of feeding broiler breeders, and to succeed their daily nutrient requirements need to be known. Information concerning the nutritional requirements of broiler breeder hens is limited in comparison to other types of domesticated poultry. However, enough information is available concerning energy and amino acid nutrition of this type of poultry to enable one to develop models useful for constructing accurate feeding programmes. The most appropriate way of estimating the nutrient requirement of broiler breeder hens during the laying period, or of optimising a feeding strategy, is by the use of simulation models. Emmans and Fisher (1986) suggested that a better approach to the problem of describing requirements and of expressing them quantitatively can be achieved by considering: firstly, the bird’s characteristics, secondly by defining resource scales carefully and thirdly by considering the quantities of each resource needed per unit of function. This approach has a greater chance of success than attempting to measure requirements by direct experimentation. Energy and amino acids are required for growth of tissues, egg production, maintaining normal body temperature, vital life functions and activity. For development of feeding programmes, we are most concerned with the three primary components, maintenance, growth and egg output. There are a number of factors that impact on the total nutrient requirement of the breeder. The maintenance component is affected by body size, environmental temperature, level of activity (housed in floor pens vs. cages) and possibly breed. Regarding the growth component, in the case of broiler breeders during lay the composition of growth needs to be addressed: whether this is only lipid gain or also includes protein gain. Lastly, the egg component is influenced by egg mass and hen age. In order to calculate energy and amino acid requirements, one must have knowledge of the requirements per unit of body protein weight, growth rate and egg mass. By continually monitoring the environmental conditions in the broiler breeder house, as well as body weight, egg weight and egg number, it is possible to estimate the state of the hens at any time and hence the optimum nutrient concentrations that should be fed the next day of the laying period by using the Breeder Model presented in this thesis. Optimising the feeding of broiler breeders during the laying period is made difficult because of the many interacting factors influencing their performance All the hens are not the same, they are not housed in the same environments, and the costs of feeding and the revenue derived from the sale of the product differs from one locality to another. The solution to this problem lies in the use of simulation models to describe the causal relationship between inputs and the predicted responses. This thesis explored new concepts and components for a simulation model to predict the nutrient requirement and performance of broiler breeders after sexual maturity.
Thesis (Ph.D.)-University of KwaZulu-Natal, Pietermaritzburg, 2007.

This study was designed to devise a method by which the optimum combination of dietary energy and protein could be found that maximises the margin over feeding cost in an egg production enterprise. It was necessary to be able to predict feeding costs and revenue associated with the use of a wide range of feeds varying in protein and energy. To this end, two experiments were conducted using 256 Lohmann (128 White and 128 Brown) in the first, and 1296 Hy-line Brown laying birds in the second trial, that were 33 and 38 weeks old at the beginning of the two trials. Using the WinFeed 1.1 (1996) feed formulation programme, four basal (corner) feeds were formulated in both experiments, from which four protein and four energy contents (16 feeds) were produced in the first experiment, and six protein and three energy contents ( 18 feeds) were used in the second. Each feed was given to three replicates of 16 birds in the first trial, and to three replicates of 24 birds in the second. The trials each lasted ten weeks, and the data collected included food intake, change in body weight, egg weight and rate of laying. Using the results from these two experiments and from previously published research, the effects of dietary protein and energy on food intake were predicted independently, and these predictions were then used to determine the cost of feeding. Similarly, egg weight and rate of lay were predicted independently for changes in dietary protein and energy, from which the revenue could be calculated over the range of energy and protein contents. It is understood that a more integrated approach would be more accurate for this purpose, but such an approach was beyond the scope of this investigation. The use of contour plots based on regression analyses of the estimated income-minus-feeding cost on changes in dietary protein and energy enabled evaluations to be made of the effect on profitability of changes in egg price and maize price. And it was deduced that under conditions in which the maize price is high, maximum profitability is achieved with high energy and high protein content, irrespective of the price paid for eggs. When the maize price is reduced, the combination of protein and energy that yields the highest return over feed cost changes to low protein and low energy feeds. This change is defensible on the grounds that the price of high-density feeds does not change as much as that of low-density feeds when the maize price is lowered, whereas production, and hence returns, remains the same, hence the low density feeds yield higher returns under such circumstances. The method applied in this study appears to be a useful tool for decision-making by egg producers and nutritionists.
Thesis (M.Sc.)-University of KwaZulu-Natal, Pietermaritzburg, 2005.

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

Nutrition is the key driver of animal health, welfare and production. In agriculture, nutrition is crucial to meet increasing global demands for animal protein and consumer demands for cheaper meat, milk and eggs and higher standards of animal welfare. For companion animals, good nutrition is essential for quality and length of life. Animal Nutrition examines the science behind the nutrition and feeding of the major domesticated animal species: sheep, beef cattle, dairy cattle, deer, goats, pigs, poultry, camelids, horses, dogs and cats. It includes introductory chapters on digestion and feeding standards, followed by chapters on each animal, containing information on digestive anatomy and physiology, evidence-based nutrition and feeding requirements, and common nutritional and metabolic diseases. Clear diagrams, tables and breakout boxes make this text readily understandable and it will be of value to tertiary students and to practising veterinarians, livestock consultants, producers and nutritionists.

AbstractBoth poultry meat and eggs provide high-quality animal protein [containing sufficient amounts and proper ratios of amino acids (AAs)] for human consumption and, therefore, play an important role in the growth, development, and health of all individuals. Because there are growing concerns about the suboptimal efficiencies of poultry production and its impact on environmental sustainability, much attention has been paid to the formulation of low-protein diets and precision nutrition through the addition of low-cost crystalline AAs or alternative sources of animal-protein feedstuffs. This necessitates a better understanding of AA nutrition and metabolism in chickens. Although historic nutrition research has focused on nutritionally essential amino acids (EAAs) that are not synthesized or are inadequately synthesized in the body, increasing evidence shows that the traditionally classified nutritionally nonessential amino acids (NEAAs), such as glutamine and glutamate, have physiological and regulatory roles other than protein synthesis in chicken growth and egg production. In addition, like other avian species, chickens do not synthesize adequately glycine or proline (the most abundant AAs in the body but present in plant-source feedstuffs at low content) relative to their nutritional and physiological needs. Therefore, these two AAs must be sufficient in poultry diets. Animal proteins (including ruminant meat & bone meal and hydrolyzed feather meal) are abundant sources of both glycine and proline in chicken nutrition. Clearly, chickens (including broilers and laying hens) have dietary requirements for all proteinogenic AAs to achieve their maximum productivity and maintain optimum health particularly under adverse conditions such as heat stress and disease. This is a paradigm shift in poultry nutrition from the 70-year-old “ideal protein” concept that concerned only about EAAs to the focus of functional AAs that include both EAAs and NEAAs.

The SAAs are limiting in the major poultry feed ingredients, ranking first and fifth in soya bean meal and maize, respectively. Feed ingredients rich in protein, in particular and other nutrients, enhance Energy supply and protein accretion. Modern commercial broilers have reduced maintenance needs and high amino acid requirements, and are more responsive to protein (amino acids) than energy. Cysteine is a semi-essential amino acid belonging to the SAAs. It plays essential roles in protein synthesis, structure and function, causing growth depressing effects in broiler chicks when there is methionine:cysteine imbalance. Genetically predetermined amino acid sequences in proteins are essential for production of adequate quantities of meat, milk and eggs. Therefore, ideal amino acid ratios which conform to the requirements of broilers should be utilized. In nutrition, amino acids are equivalent to proteins, hence the shift in focus from proteins to individual amino acids, expressed as ideal ratios to lysine. The SAAs are practically relevant and have critical nutritional roles in animal nutrition with over 90% production being used to fortify animal (particularly poultry) diets. A balance in the methionine:cysteine ratio is necessary to ensure efficient utilization of the SAAs for proper growth and development in broiler poultry.