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espanolAntecedentes: La determinacion de la suplementacion de aminoacidos en las dietas de pollos de engorde, basados solamente en el desempeno productivo no siempre refleja la maxima rentabilidad. Objetivo: Estimar los niveles optimos de treonina (Thr) y aminoacidos azufrados (SAA) en dietas para pollos de engorde basados en un analisis economico. Metodos: Se realizaron dos ensayos tipo dosis-respuesta divididos en tres fases cada uno: inicio (1-14 dias), crecimiento (15-28 dias) y finalizacion (29-42 dias). Quinientos sesenta pollos de engorde machos Cobb 500® se distribuyeron aleatoriamente en siete tratamientos con niveles crecientes de aminoacidos (SAA o Thr) y cuatro repeticiones de 20 aves cada uno. La ganancia de peso (BWG) y el consumo de alimento (FI) fueron utilizados para ajustar un modelo segmentado. El ingreso bruto (GI), costo total de la racion (TFC) y el margen bruto (GM) se calcularon tomando como referencia valores locales. Resultados: Los niveles crecientes de aminoacidos influyeron en la respuesta de BWG y FI en todas las fases evaluadas. Los estimados para maximizar la rentabilidad segun GI y TFC fueron 223, 504 y 975 mg SAA/ave/dia, y 236, 696 y 1,042 mg Thr/ave/dia para las fases de inicio, crecimiento y finalizacion, respectivamente. Conclusion: La variacion de los precios de los AA tuvo solo un ligero efecto sobre el consumo optimo de Thr y aminoacidos azufrados. A pesar de las fluctuaciones del mercado, el enfoque economico aqui expuesto demuestra ser una herramienta util para la eleccion del nivel ideal de inclusion de aminoacidos en la formulacion. EnglishBackground: The determination of amino acid supplements for broiler chicken requirements based on performance does not always reflect maximum profitability. Objective: To estimate the optimal levels of digestible threonine (Thr) and sulfur amino acids (SAA) in diets for broilers based on an economic analysis. Methods: Two dose-response assays were conducted, and each assay was divided into three phases: initial (1-14 days), grower (15-28 days), and finisher (29-42 days). Five hundred and sixty male Cobb 500® broilers were randomly distributed to seven treatments with increasing levels of the amino acid (SAA or Thr), with four replicates and 20 birds each. Bodyweight gain (BWG) and feed intake (FI) were used to fit a segmented model. Gross income (GI), total feed costs (TFC) and gross margin (GM) were calculated based on local values. Results:Increasing levels of amino acid elicited a response in BWG and FI for all evaluated phases. The estimates for maximum profit based on GI and TFC were 223, 504, and 975 mg SAA/bird/d, and 236, 696, and 1,042 mg Thr/bird/d in starter, grower and finisher phases, respectively. Conclusion: Varying the AA prices affected only slightly the economic optimal intake of Thr and sulfur amino acids. Despite market fluctuations, the economic approach presented in this study demonstrates to be a helpful tool to choose the ideal inclusion level of amino acids in the feed. portuguesAntecedentes: A determinacao da suplementacao de aminoacidos em frangos de corte baseados somente no desempenho produtivo nem sempre reflete a rentabilidade maxima. Objetivo: Estimar os niveis otimos de treonina (Thr) e aminoacidos sulfurados (SAA) em dietas para frangos de corte com base em uma analise economica. Metodos: Foram realizados dois ensaios dose-resposta, divididos em tres fases cada: inicial (1-14 dias), crescimento (15-28 dias) e final (29-42 dias). Quinhentos e sessenta frangos de corte machos Cobb 500® foram distribuidos aleatoriamente em sete tratamentos, representados por niveis crescentes de aminoacidos (SAA ou Thr), com quatro repeticoes de 20 aves cada. O ganho de peso (BWG) e o consumo de racao (FI) foram utilizados para ajustar um modelo segmentado. A receita bruta (GI), os custos totais de alimentacao (TFC) e a margem bruta (GM) foram calculados com base nos custos locais. Resultados: Os niveis dos aminoacidos influenciaram as respostas de BWG e FI para todas as fases avaliadas. A estimativa para maximo lucro com base em GI e TFC para os ensaios com SAA foram 223, 504 e 975 mg/ave/d; para Thr foram 236, 696 e 1,042 mg/ave/d para as fases inicial, crescimento e final, respectivamente. Conclusao: A variacao dos precos dos AA teve pouca influencia sobre a ingestao economica dos aminoacidos sulfurados e da Thr. Apesar do dinamismo de mercado, a abordagem economica apresentada neste estudo demonstra ser uma ferramenta util para a escolha do nivel de inclusao ideal do aminoacido na racao.

Made available in DSpace on 2022-04-29T08:37:12Z (GMT). No. of bitstreams: 0 Previous issue date: 2022-01-01 Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Twelve dose-response trials were conducted to estimate lysine (Lys) and arginine (Arg) requirements of male and female broilers in the starter (1–14 days of age), grower (15–28 days of age), and finisher (29–42 days of age) phase. In each trial, 640 birds were randomly assigned to one of eight treatments (Lys or Arg levels) with four replicates of 20 birds. In Lys trials, for both sexes, digestible (dig) Lys concentration in feeds ranged from 8.73 to 17.5 g/kg in the starter phase, 7.80–15.7 g/kg in the grower phase, and 6.40–12.8 g/kg in the finisher phase. In Arg trials, for both sexes, the dietary dig Arg concentrations investigated ranged from 10.9 to 18.7 g/kg in the starter phase, 8.38 a 16.8 g/kg in the grower phase, and 6.85–13.7 g/kg in the finisher phase. Performance and protein gain (PG) data were fitted to linear-response plateau (LRP), curvilinear-response plateau (CRP), and quadratic polynomial (QP) regression models to estimate the dig Lys and Arg intake required to optimize the responses assessed. For each phase, average daily gain (ADG) was maximized at 0.415, 1.38, 1.79 g dig Lys/day and 0.457, 1.48, and 2.11 g dig Arg/day in male broiler chickens and 0.415, 1.21, and 1.40 g dig Lys/day and 0.446, 1.34, and 1.89 g dig Arg/day in female. For male birds, PG was maximum at 0.496, 1.63, and 1.72 g dig Lys/day, whereas for female birds, maximum values were 0.528, 1.30, and 1.80 g dig Lys/day. In Arg trials, maximum protein gain was reached at 0.518, 1.36, and 2.29 g dig Arg/day in male, and 0.474, 1.28, and 2.03 g Arg/day in female, respectively. The Lys and Arg values reported in this study may be used as a reference to formulate feeds and achieve a maximum response. Department of Animal Science Faculty of Agrarian and Veterinary Science (FCAV) São Paulo State University (Unesp), Via de acesso Prof. Paulo Donato Castellane, S/N Aquaculture Center of São Paulo State University (Unesp), Via de acesso Prof. Paulo Donato Castellane, S/N Production Systems Natural Resources Institute Finland (Luke) Department of Animal Science Faculty of Agrarian and Veterinary Science (FCAV) São Paulo State University (Unesp), Via de acesso Prof. Paulo Donato Castellane, S/N Aquaculture Center of São Paulo State University (Unesp), Via de acesso Prof. Paulo Donato Castellane, S/N CNPq: 142222/2018-6 FAPESP: 2013/25761-4

Simple Summary Achieving a close balance between amino acids provided by feeds and the estimated requirements of broilers is crucial to increase the economic and environmental efficiency in intensive poultry rearing. The utilization of factorial models to predict amino acid requirements requires previous knowledge of the efficiency with which such amino acids are utilized for growth. This study aimed to investigate broiler responses to lysine (Lys) and arginine (Arg) and, based on such responses, to estimate the efficiency with which birds utilize both amino acids for growth. Once estimated, the efficiency values were used to develop two factorial models to predict broiler intakes of Lys and Arg. Overall, the utilization efficiencies were calculated as 0.79 and 0.62 for digestible lysine and arginine intake, respectively. Based on such efficiencies, the male and female broiler requirements for digestible lysine and arginine to deposit 1 g of body protein were 94.9 and 92.9 mg, respectively. Abstract Six assays were conducted to investigate male and female broiler responses to standardized ileal digestible (SID) lysine (Lys) and arginine (Arg). Response data were modeled to estimate the efficiency of utilization (k) of both amino acids and adjust factorial models to predict bird intake for SID Lys and SID Arg. In each assay, 1280 Cobb 500® broilers (640 male and 640 female) were randomly assigned to one of sixteen dietary treatments with four replicates of 20 birds. Dietary treatments consisted of crescent levels of SID Lys or SID Arg based on the dilution technique. The values of k determined for each phase (1- to 14-, 15- to 28-, and 29- to 42-d-old) and sex were contrasted using linear regression with groups (sex and phase). The estimated efficiencies were 0.79 for Lys and 0.62 for Arg, which were unaffected by phase or sex. Factorial models based on body weight and weight gain (M1) and on body and feather protein weight and deposition (M2) were applied to estimate the SID Lys and Arg intake for growth. The amino acid intake based on M2 had a lower error of prediction. Broiler chickens require 94.9 and 92.9 mg/d of SID Lys and SID Arg to deposit 1 g of body protein.

Made available in DSpace on 2022-04-29T08:29:43Z (GMT). No. of bitstreams: 0 Previous issue date: 2021-09-01 Context: Tables of nutrient requirements assist nutritionists to formulate acceptable feeds for broilers but do not consider the objective of a business, namely, to maximise economic returns. Aims: The objective of the present study was to demonstrate that the optimum economic level of balanced protein is not static, but varies according to economic conditions. Methods: Responses of male and female broilers, reported in a companion paper, were used to calculate feed intake and weights of body, carcass, breast, leg and wing at 28, 42 and 56 days of age as functions of dietary balanced protein. Cost of feeding and revenue generated for live, dressed, and further-processed birds were calculated, from which the margin over feeding cost was generated separately for males and females at three ages and three revenue-generating scenarios. Key results: Using baseline values for the cost of protein-containing ingredients and revenue for birds sold live, dressed or further-processed, the dietary protein content that maximised margin over feed cost was always higher for males than for females, and for birds sold further-processed than for those sold dressed or live. Using digestible lysine as the reference amino acid, the optimum in the starter period for males sold live, dressed and further processed was 12.6, 13.3 and 14.2 g lysine/kg respectively. For females, the equivalent values were 11.9, 12.6 and 13.3 g/kg respectively. Where the cost of protein-containing ingredients was increased by 25% or revenue generated from the sale of product was reduced by 25%, the optimum economic level of dietary protein decreased compared with the baseline value. The opposite pertained when ingredient costs decreased, or revenues increased by 25%. Conclusions: These results demonstrated the extent to which economic factors influence the optimum economic level of dietary balanced protein to be fed to broilers. Implications: We have demonstrated that the response of broilers to dietary balanced protein may be used to maximise economic returns of a broiler enterprise under different scenarios. Departamento de Zootecnia UNESP-Universidade Estadual Paulista (Unesp) Faculdade de Ciências Agrárias e Veterinárias, Via de Acesso Professor Paulo Donato Castellane, s/n São Paulo School of Agricultural Earth and Environmental Sciences University of KwaZulu-Natal, Carbis Road, Pietermaritzburg Evonik Operations GmbH, Rodenbacher Chaussee 4 Departamento de Zootecnia UNESP-Universidade Estadual Paulista (Unesp) Faculdade de Ciências Agrárias e Veterinárias, Via de Acesso Professor Paulo Donato Castellane, s/n São Paulo

Made available in DSpace on 2021-06-25T10:57:16Z (GMT). No. of bitstreams: 0 Previous issue date: 2021-07-15 Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) The optimum levels of essential amino acids (EAAs) are required to be maintained in fish feed for obtaining normal body protein synthesis and muscle growth. This study aimed to determine the optimum dietary EAA pattern for adult pacu (Piaractus mesopotamicus) by the amino acid (AA) deletion method. A total of 165 adult fish of 1109.83 ± 14.26 g (initial body weight ± standard deviation) were equally distributed among 11 treatments in a recirculation aquaculture system. Each of the 11 treatments consisted of three randomly arranged replicates (tanks) and 5 fish were stocked per tank. During the 60-day experimental period, fish were fed with 11 diets including a control diet (CD) and 10 EAA limiting diets (LDs) two times daily until apparent satiation. The body nitrogen (N) retention and weight gain in fish fed with EAA LDs was lower (P < 0.05) than the CD. The feed efficiency in fish fed with CD was similar (P > 0.05) to most EAA LDs, except arginine and histidine LDs. The specific growth rate in fish fed with tryptophan, arginine and histidine LDs was different (P < 0.05) as compared to the CD. Based on the present N retention data obtained through the AA deletion method, the optimum pattern of dietary EAAs estimated in relation to lysine requirement (100%) was as follows: arginine 72.16%; phenylalanine 40.83%; histidine 30.15%; isoleucine 53.01%; leucine 81.71%; methionine 24.97%; threonine 58.20%; tryptophan 9.13% and valine 54.69%. Aquaculture Center São Paulo State University (UNESP) Department of Animal Science Faculty of Agricultural and Veterinary Science São Paulo State University (UNESP) Aquaculture Center São Paulo State University (UNESP) Department of Animal Science Faculty of Agricultural and Veterinary Science São Paulo State University (UNESP) CNPq: 130873/2019 FAPESP: 2019/06343-3

Made available in DSpace on 2021-06-25T10:53:34Z (GMT). No. of bitstreams: 0 Previous issue date: 2021-05-30 Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) The purpose of the three trials reported here was to measure the efficiency of lysine utilization for growth and lysine requirement for maintenance of Nile tilapia (Oreochromis niloticus) during three growing stages. For the initial phase, a total of eight treatments (4.04, 6.63, 9.80, 13.3, 16.6, 20.7, 25.6 g lysine kg−1 and an additional diet containing 6.79 g lysine kg−1 called counter-proof) were randomly distributed among 36 experimental units, each containing 15 fishes of 2.35 ± 0.05 g. The grower and finisher phase consisted of seven treatments (4.13, 7.99, 11.7, 15.3, 19.4, 22.9 g lysine kg−1 and an additional diet containing 7.75 g lysine kg−1) randomly distributed among 21 experimental units of eleven (433 ± 12.49 g) and nine (733 ± 11.24 g) fishes, respectively. The counter-proof treatment confirmed that lysine was the first-limiting amino acid in all three growing stages. Overall, growth performance, feed efficiency and fillet yield were improved with lysine intake. In the grower and finisher phase, Nile tilapia fed diet containing the lower level of lysine exhibited reduction in protein weight and increase in body lipid content, indicating that the reminiscent energy, once used to deposit protein in fish consuming sufficient amount of lysine, was used for lipid deposition. The efficiency of lysine utilization of 0.60, 0.60 and 0.59 during the initial, grower and finisher phase, respectively, equating to approximately 115 mg lysine/g protein, proved to be the same (P > 0.05) and independent of the growth stage. The requirement for maintenance was estimated as 22.7, 45.1, and 56.3 mg lysine/kg0.8 body weight in the initial, grower and finisher phase, respectively, suggesting that maintenance requirements change with age or size (P < 0.05). These coefficients may be used for calculating the daily lysine requirements for maintenance and growth of Nile tilapia. Aquaculture Center São Paulo State University (UNESP), Via de Acesso Prof. Paulo Donato Castellane Department of Aquaculture Center of Agrarian Sciences Federal University of Santa Catarina (UFSC) School of Agricultural Earth and Environmental Sciences University of KwaZulu–Natal Departament of Animal Science Faculty of Agricultural and Veterinary Sciences São Paulo State University (UNESP), Via de Acesso Paulo Donato Castellane Brazil University (Univ. Brazil), Campus Fernandópolis, Est. Projetada F-1 - Fazenda 12 Santa Rita Aquaculture Center São Paulo State University (UNESP), Via de Acesso Prof. Paulo Donato Castellane Departament of Animal Science Faculty of Agricultural and Veterinary Sciences São Paulo State University (UNESP), Via de Acesso Paulo Donato Castellane CNPq: 170465/2017-9

Made available in DSpace on 2021-06-25T11:57:57Z (GMT). No. of bitstreams: 0 Previous issue date: 2021-05-07 Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) 1. Broiler breeders are subjected to qualitative or quantitative feed restrictions to prevent obesity, which causes major health and welfare problems. Diluting their feed by adding inert or low nutrient, bulky materials can reduce obesity, but the capacity of the gut needs to be determined to apply this strategy successfully. Two trials were conducted to measure the bulk capacity of Ross 308 broiler breeders prior to and after the onset of lay. The trial was completely randomised, with nine individually-caged breeders, with each cage as a replicate, totalling 189 birds per trial 2. Birds were given ad libitum access to one of 21 maize-soyabean based feeds, an undiluted control or progressive dilution (10, 20, 30 and 40%) with either cellulose fibre, rice husk, sand, vermiculite or sawdust. Feeds were analysed for density, crude-, acid detergent- and neutral detergent-fibre, water-holding capacity (WHC), cation-exchange capacity and oil-holding capacity. 2. In general, feed intake (scaled to body weight(0.67)) increased and then declined as the proportion of each diluent increased. Intake increased linearly when rice hulls and sand were used as diluents. 3. Water holding capacity was the most appropriate measure to define the gut capacity of broiler breeders. 4. The trial data was used to estimate the maximum-scaled feed intake (SFImax) in broiler breeders, which was 240-56.1WHC + 4.34WHC(2) g/kg(0.67)/d. Univ Estadual Paulista, Fac Ciencias Agr & Vet, Jaboticabal, Brazil Univ KwaZulu Natal, Sch Agr Earth & Environm Sci, Pietermaritzburg, South Africa Nat Resources Inst Finland Luke, Prod Syst, Jokioinen, Finland Univ Estadual Paulista, Fac Ciencias Agr & Vet, Jaboticabal, Brazil CNPq: 142192/2016-3 FAPESP: 2013/25761-4 FAPESP: 2016/11172-5

Made available in DSpace on 2021-06-25T23:35:38Z (GMT). No. of bitstreams: 0 Previous issue date: 2021-01-07 Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) Most amino acid requirement trials appear for whole-body responses, but there is little information concerning amino acid incorporation in individual tissues, which may vary according to the age. L-[N-15] threonine was used to evaluate its incorporation rate and distribution among broiler tissues in different ages. Seventy-two male broiler chickens were distributed into three different phases: starter (4 to 9 days old), grower (18 to 23 days old) and finisher phase (32 to 37 days old). L-[N-15] threonine was added on balanced diets, and birds were fed for five days in each phase. Enriched samples of breast muscle, feathers, liver, jejunum and plasma were collected at 0, 6, 12, 24, 48, 72, 96 and 120 hr after fed birds with the tracer in each phase. In the tissues were analysed dry matter, nitrogen and stable nitrogen. The N-15 isotope abundance according to the time was fitted into exponential or linear equations using a same intercept. The ratio of the steepness or slope coefficients was determined to compare the L-[N-15] threonine incorporation according to the age. In addition, L-[N-15] threonine mass balances were performed to assess the L-[N-15] threonine distribution among the evaluated tissues. Except for feathers, the L-[N-15] threonine incorporation rate decreased with ageing. Taking into account the L-[N-15] threonine distribution in the tissues, only in the jejunum was not observed an increase as the broiler grew. The L-[N-15] incorporation varied in each tissue and according to the age of the broiler chickens. These outcomes could be useful to comprehend changes in amino acid requirements tissue-specific according to age. Sao Paulo State Univ, Sch Agr & Veterinarian Sci, Jaboticabal, Brazil Sao Paulo State Univ, Stable Isotope Ctr Prof Carlos Ducatti, Botucatu, SP, Brazil Sao Paulo State Univ, Sch Agr & Veterinarian Sci, Jaboticabal, Brazil Sao Paulo State Univ, Stable Isotope Ctr Prof Carlos Ducatti, Botucatu, SP, Brazil FAPESP: 2013/25761-4 CAPES: 1318250

Made available in DSpace on 2020-12-12T01:56:43Z (GMT). No. of bitstreams: 0 Previous issue date: 2020-05-03 1. The potential growth of feathers and feather-free body and their chemical components was measured in two commercial broiler strains. 2. A total of 200 chicks of each sex x strain were fed adequate amounts of dietary protein using a four-phase feeding programme. Ten birds per genotype were sampled at 14, 28, 42, 56, 70, 84, 98 and 112 d of age. They were weighed before and after being dry-plucked to determine the weight of feathers, and the feather-free body was then minced and analysed for water, protein and lipid. 3. Body weights and chemical composition of males of the two strains were similar throughout the trial. Females of the two strains differed only in their body lipid contents, with mature Cobb females being higher than Ross (1371 vs. 1210 g). 4. Mature body weights of males and females from both strains averaged 8420 g and 6650 g; mature body protein weights averaged 1555 g and 1030 g; and mature body lipid contents averaged 908 and 1290 g, respectively. 5. Rates of maturing per day of body weights of males and females of both strains averaged 0.0385 and 0.0368; feather-free body protein was 0.0316 and 0.0348 and body lipid was 0.0503 and 0.0375, respectively. The rates for body lipid differed between Cobb and Ross females (0.0352 vs. 0.0397/d). Separate equations were required for males and females to describe the allometric relationship between lipid and protein in the feather-free body. 6. The rate of maturing of feathers in females was higher than in males (0.0526 vs. 0398/d) and the mature weight was lower (205 vs. 266 g), respectively. Mature body weights of broilers in this trial were considerably higher than those measured using the same protocol 24 years ago, whereas rates of maturing remained the same. Departamento de Zootecnia da FCAV-UNESP Universidade Estadual Paulista Júlio de Mesquita Filho Faculdade de Ciências Agrárias e Veterinárias Departamento de Zootecnia da FCAV-UNESP Universidade Estadual Paulista Faculdade de Ciencias Agrarias e Veterinarias Campus de Jaboticabal Universidade Estadual Paulista Julio de Mesquita Filho Animal and Poultry Science University of KwaZulu-Natal Departamento de Zootecnia da FCAV-UNESP Universidade Estadual Paulista Júlio de Mesquita Filho Faculdade de Ciências Agrárias e Veterinárias Departamento de Zootecnia da FCAV-UNESP Universidade Estadual Paulista Faculdade de Ciencias Agrarias e Veterinarias Campus de Jaboticabal Universidade Estadual Paulista Julio de Mesquita Filho

Poultry geneticists have been highly successful in improving the egg output and feed efficiency of laying hens and, to a lesser extent, broiler breeders. As the potential output of these birds has changed so have their nutrient requirements and these are reflected in user manual guidelines, tables of requirements, and company know-how. However, the basis of these suggested changes is unlikely to be based on theoretical calculations of the updated requirements of the bird due to the lack of a robust theory describing the manner in which the nutrient requirements are calculated. Such a theory has been developed recently and is described in this article. To calculate the amino acid and energy requirements of an individual laying hen, it is necessary to be able to predict its potential body protein weight at the start of lay and its potential egg output and egg weight over time (Emmans and Fisher, 1986). From this information, and the nutritional constants that describe the rates of conversion of feed nutrients to maintenance and egg nutrients, it is possible to calculate the daily requirement of each of the amino acids and energy throughout the laying period. Once the requirements for an individual hen are correctly calculated, the same process can be followed for each bird in a simulated flock, the parameters for each bird being defined using the means and standard deviations of each parameter describing the mean individual. Calculating the daily nutrient intake required to meet the potential performance of each individual in terms of numbers of eggs produced over the production cycle would improve the possibility of optimizing the composition (and daily allocation, in the case of broiler breeders) of the feed offered to the flock. To achieve these goals, a comprehensive understanding of the factors influencing the attainment of sexual maturity in these birds, of the ovulatory cycle and how this changes during the laying cycle, and of the changes that occur in egg and body component weights over time is required. This article describes such a stochastic egg production model developed at Universidade Estadual Paulista (UNESP), Brazil. In this article, only the calculation of the nutrient requirements of flocks of laying hens and broiler breeders is described, with examples of these requirements for simulated populations having different potential outputs. No attempt has been made to use this information to predict food intake or the consequences on performance of situations where hens were unable to consume sufficient feed. The model was developed based on studies conducted at the Poultry Science Laboratory, UNESP, Brazil. One study was conducted with two strains of laying hens (Hy-Line W-36 and Isa brown) (Bendezu et al., 2018) and another with broiler breeders (Cobb) (Ferreira et al., 2016) to generate the equations and parameters used in the models described herein. An overall scheme of the egg production model is presented in Figure 1. Open in a separate window Figure 1. Flow diagram from the dynamic simulation model to estimate the nutritional requirements as a function of body protein weight and egg production.

Made available in DSpace on 2019-10-04T11:56:24Z (GMT). No. of bitstreams: 0 Previous issue date: 2019-01-14 Ensminger Endowment, State of Iowa USDA-NIFAAFRI Climate Change Award Hatch funding Extreme environmental conditions are a major challenge in livestock production. Changes in climate, particularly those that contribute to weather extremes like drought or excessive humidity, may result in reduced performance and reproduction and could compromise the animal's immune function. Animal survival within extreme environmental conditions could be in response to natural selection and to artificial selection for production traits that over time together may leave selection signatures in the genome. The aim of this study was to identify selection signatures that may be involved in the adaptation of indigenous chickens from two different climatic regions (Sri Lanka = Tropical; Egypt = Arid) and in non-indigenous chickens that derived from human migration events to the generally tropical State of Sao Paulo, Brazil. To do so, analyses were conducted using fixation index (Fst) and hapFLK analyses. Chickens from Brazil (n = 156), Sri Lanka (n = 92), and Egypt (n = 96) were genotyped using the Affymetrix AxiomR (R) 600k Chicken Genotyping Array. Pairwise Fst analyses among countries did not detect major regions of divergence between chickens from Sri Lanka and Brazil, with ecotypes/breeds from Brazil appearing to be genetically related to Asian-Indian (Sri Lanka) ecotypes. However, several differences were detected in comparisons of Egyptian with either Sri Lankan or Brazilian populations, and common regions of difference on chromosomes 2, 3 and 8 were detected. The hapFLK analyses for the three separate countries suggested unique regions that are potentially under selection on chromosome 1 for all three countries, on chromosome 4 for Sri Lankan, and on chromosomes 3, 5, and 11 for the Egyptian populations. Some of identified regions under selection with hapFLK analyses contained genes such as TLR3, SOCS2, EOMES, and NFAT5 whose biological functions could provide insights in understanding adaptation mechanisms in response to arid and tropical environments. Iowa State Univ, Dept Anim Sci, Ames, IA 50011 USA Univ Peradeniya, Dept Anim Sci, Fac Agr, Kandy, Sri Lanka Sao Paulo State Univ, Dept Anim Sci, Coll Agr & Vet Sci, Jaboticabal, Brazil Anim Prod Res Inst, Dept Anim Biotechnol, Giza, Egypt Univ Delaware, Anim & Food Sci, Newark, DE USA Sao Paulo State Univ, Dept Anim Sci, Coll Agr & Vet Sci, Jaboticabal, Brazil USDA-NIFAAFRI Climate Change Award: 2011-67003-30228

Made available in DSpace on 2019-10-06T16:57:47Z (GMT). No. of bitstreams: 0 Previous issue date: 2018-12-01 Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Determining the efficiency of amino acid (AA) utilization in growing animals is crucial to estimate their requirement accurately. In broiler chickens, the composition of AA in feather is different from feather-free body and the proportion of feathers will change along broiler’s growth, which may impact the efficiency of utilization on AA consumed. Therefore, in order to establish a method that predicts the efficiency of utilization for feather-free body and feather, two approaches were evaluated: a multiple linear regression and a multivariate analysis. Additionally, a new factorial model was proposed to predict AA requirements in broiler chickens. Data from 13 trials that evaluated the requirements for lysine (Lys), sulphur AA (SAA), threonine (Thr), and valine (Val) in male broilers were used for the analyses. Both methods of analysis were consistent in showing that the efficiency of utilization in feather-free body and feather were different. Using multiple linear regression, the values of efficiency of utilization estimated in feather-free body were 0.68, 0.72, 0.81, 0.79 (mg of amino acid deposited / mg of amino acid consumed above maintenance) and in feather were 0.58, 0.77, 0.78, and 1.57 (mg/mg) for Lys, SAA, Thr, and Val, respectively. Applying the multivariate approach, the corresponding predicted values were 0.68, 0.67, 4.23, 0.27 (mg/mg) in feather-free body and 1.16, 0.86, 0.16, and 1.10 (mg/mg) in feather, respectively. According to the results, efficiency of utilization may be related, to some extent, on the concentration determined in each tissue. The uncertainty around the amount of AA consumed for gain directed to feather-free body or feather deposition could be a limitation for multivariate analyses. The results indicated that multiple linear regression predictions may be better estimates of utilization efficiency. However, more studies are needed to elucidate the effect of age on deposition and partitioning of dietary AA in different parts of the broiler. Universidade Estadual Paulista (Unesp) Faculdade de Ciências Agrárias e Veterinárias Department of Animal Science University of California Universidade Estadual Paulista (Unesp) Faculdade de Ciências Agrárias e Veterinárias FAPESP: 2013/25761-4 FAPESP: 2015/50444-8 FAPESP: 2016/ 11172-5