Digestible lysine requirements of male broilers from 1 to 42 days of age reassessed

Three experiments were conducted separately to estimate the digestible Lys (dig. Lys) requirements of Cobb × Cobb 500 male broilers using different statistical models. For each experiment, 1,200 chicks were housed in 48 floor pens in a completely randomized design with 6 treatments and 8 replicates. Broilers were fed diets with increasing dig. Lys levels from 1 to 12 d (Exp. 1), from 12 to 28 d (Exp. 2), and 28 to 42 d (Exp. 3). Increasing dig. Lys levels were equally spaced from 0.97 to 1.37% in Exp. 1, 0.77 to 1.17% in Exp. 2, and 0.68 to 1.07% in Exp. 3. The lowest dig. Lys diets were not supplemented with L-Lysine and all other essential AA met or exceeded recommendations. In Exp. 3, six birds per pen were randomly selected from each replication to evaluate carcass and breast yields. Digestible Lys requirements were estimated by quadratic polynomial (QP), linear broken-line (LBL), quadratic broken-line (QBL), and exponential asymptotic (EA) models. Overall, dig. Lys requirements varied among response variables and statistical models. Increasing dietary dig. Lys had a positive effect on BW, carcass and breast yields. Levels of dig. Lys that optimized performance using QP, LBL, QBL, and EA models were 1.207, 1.036, 1.113, and 1.204% for BWG and 1.190, 1.027, 1.100, and 1.172% for FCR in Exp. 1; 1.019, 0.853, 0.944; 1.025% for BWG and 1.050, 0.879, 1.032, and 1.167% for FCR in Exp. 2; and 0.960, 0.835, 0.933, and 1.077% for BWG, 0.981, 0.857, 0.963, and 1.146% for FCR in Exp. 3. The QP, LBL, QBL, and EA also estimated dig. Lys requirements as 0.941, 0.846, 0.925, and 1.070% for breast meat yield in Exp. 3. In conclusion, Lys requirements vary greatly according to the statistical analysis utilized; therefore, the origin of requirement estimation must be taken into account in order to allow adequate comparisons between references

Lysine requirement of male broilers using different statistical models

O objetivo desta dissertação foi estimar a exigência de lisina (Lis) para frangos de corte machos Cobb x Cobb 500 de 1 a 12 dias de idade (experimento 1), 12 a 28 dias de idade (experimento 2) e 28 a 42 dias de idade (experimento 3). Dietas basais foram formuladas para atingir ou exceder as exigências nutricionais, com exceção da Lis. Cinco níveis de Lis foram suplementados às dietas basais a partir de L-Lis HCl ou sulfato de L-Lis de modo que os níveis variaram de 0,97% a 1,37% de Lis digestível no experimento 1, 0,77% a 1,17% de Lis digestível no experimento 2 e 0,68% a 1,08% de Lis digestível no experimento 3 em incrementos de 0,08%. Os tratamentos foram distribuídos em um delineamento inteiramente casualizado com 8 repetições de 25 aves. Em cada experimento, 2200 aves foram alojadas em 88 unidades experimentais. Nos dias 1 e 12 (experimento 1), 12 e 28 (experimento 2) e 28 e 42 (experimento 3) as aves e a ração foram pesadas para determinar o ganho de peso (GP) e conversão alimentar (CA). No experimento 3, quatro aves por unidade experimental foram abatidas para determinação do rendimento de carcaça e peito. A biodisponibilidade relativa (RBV) das fontes de Lis foi avaliada através de uma regressão multivariada e comparada pelo teste t. A exigência de Lis foi estimada por três modelos de regressão: polinomial quadrática, brokenline linear e broken-line quadrática. A exigência foi representada como 95% do ponto de máxima resposta. Não houve diferença entre a RBV da Lis no sulfato de L-Lis em relação ao L-Lis HCl, portanto ambas as fontes foram utilizadas para estimar as exigências. As exigências encontradas variaram de acordo com o modelo estatístico e a variável analisada. A regressão broken-line quadrática apresentou o melhor ajustamento aos dados de desempenho, enquanto a regressão broken-line linear se ajustou melhor aos dados de rendimento de carcaça e peito. As regressões polinomial quadrática, broken-line linear e broken-line quadrática estimaram, respectivamente, as exigências como 1,190, 1,032 e 1,101% para GP e 1,226, 1,038 e 1,124% para CA no experimento 1; 1,021, 0,900 e 0,961% para GP e 1,064, 0,966 e 1,043% para CA no experimento 2; 0,949, 0,833 e 0,925% para GP, 0,978, 0,851 e 0,960% para CA, 0,933, 0,842 e 0,931% para rendimento de carcaça e 0,952, 0,839 e 0,921% para rendimento de peito no experimento 3. Os resultados demonstraram que as exigências de Lis foram consideravelmente influenciadas pelas diferentes regressões. Portanto, a escolha do modelo estatístico é crítica para a obtenção de estimativas precisas e coerentes.The objective of this thesis was to estimate lysine (Lys) requirement of male Cobb x Cobb 500 broilers from 1 to 12 days of age (experiment 1), 12 to 28 days of age (experiment 2), and 28 to 42 days of age (experiment 3). Basal diets were formulated to meet or exceed recommendations, except for Lys. Five graded levels of Lys were supplemented from L-Lys HCl or L-Lys sulfate to the basal diets. Dietary treatments ranged from 0.97% to 1.37% digestible Lys in experiment 1, 0.77% to 1.17% digestible Lys in experiment 2, and 0.68% to 1.08% digestible Lys in experiment 3 in 0.08% increments. Treatments were distributed in a completely randomized design with 8 repetitions of 25 birds each. A total of 2,200 birds per experiment were placed in 88 experimental units. At 1 and 12 days (experiment 1), 12 and 28 days (experiment 2), and 28 and 42 days (experiment 3), birds and feed were weighed to determine body weight gain (BWG) and feed conversion ratio (FCR). In experiment 3, four birds per experimental unit were processed for carcass and breast meat yield evaluation. Relative bioavailability (RBV) of Lys sources was assessed by a multivariate regression and compared by a t-test. Lysine requirement was estimated using three regression models: quadratic polynomial, linear broken-line, and quadratic broken-line. Requirements were represented as 95% of the asymptote. No difference was observed in Lys RBV in L-Lys sulfate compared to L-Lys HCl, thus both sources were used to estimate requirements. Requirement estimates varied according to statistic model and analyzed variable. Quadratic broken-line model presented the best fit to performance data (BWG and FCR), whereas linear broken-line model fitted better to carcass and breast meat yield data. Quadratic polynomial, linear broken-line, and quadratic brokenline estimates were, respectively, 1.190, 1.032, and 1.101% for BW gain and 1.226, 1.038, and 1.124% for FCR in experiment 1; 1.021, 0.900, and 0.961% for BW gain and as 1.064, 0.966, and 1.043% for FCR in experiment 2; and 0.949, 0.833, 0.925% for BW gain, 0.978, 0.851, and 0.960% for FCR, 0.933, 0.842, and 0.931% for carcass yield, and 0.952, 0.839, and 0.921% for breast meat yield in experiment 3. Results demonstrate that Lys requirements were considerably influenced by different regression models. Therefore, the choice of statistical model is crucial to obtain precise, coherent estimates

La correspondencia de Valencia : diario de noticias : eco imparcial de la opinión y de la prensa: Año XXXIII Número 11162 - 1910 Mayo 31

Copia digital. Madrid : Ministerio de Cultura. Subdirección General de Coordinación Bibliotecaria, 200

Evaluation of soybean meal, distillers dried grains with solubles, and the interactions among branched-chain amino acids in swine diets

Doctor of PhilosophyDepartment of Animal Sciences and IndustryMichael D. TokachThis dissertation consists of 8 chapters involving studies with branched-chain amino acids (BCAA), His requirements for nursery pigs, soybean meal (SBM) inclusion in nursery diets, and Zn source and level for grow-finish pigs. The first chapter presents a review of the literature on the interactions among branched-chain amino acids for growing pigs. Chapter 2 describes a meta-regression analysis conducted to develop prediction equations for growth performance based on BCAA, large neutral amino acids (LNAA), and their interactions. The results suggest that increasing Leu negatively impacts growth performance due to insufficient levels of other BCAA and LNAA relative to Leu. The addition of Val, Ile, and Trp, alone or in combination, has the potential to counteract the negative effects of high Leu. Chapter 3 describes two experiments that determined the His requirements of 7- to 11-kg nursery pigs. The results suggest that the His requirement is no more than 31% of Lys. Chapter 4 describes four experiments that evaluated the effects of increasing SBM in diets with or without distillers dried grains with solubles (DDGS). In general, DDGS reduced growth performance, although the magnitude was different across experiments. Increasing inclusions of SBM consistently improved G:F and caloric efficiency. Chapter 5 presents two experiments that estimated the energy value of SBM relative to corn. The results suggest that the energy value of SBM ranges from 105 and 125% of corn energy, which indicates that the NRC (2012) underestimates SBM energy. Chapter 6 describes a study that estimated the energy of high protein DDG for nursery pigs and found that it contains 97.3% of corn energy. Chapter 7 presents a Zn titration from 50 to 200 mg/kg for grow-finish pigs. There were no improvements in ADG beyond 50 mg/kg added Zn; however, providing 125 mg/kg added Zn resulted in the greatest G:F. Finally, chapter 8 evaluated Zn sources (Zn sulfate and Zn hydroxychloride) and levels (50 to 150 mg/kg) for grow-finish pigs. There were small improvements in ADG of pigs fed added Zn beyond 50 mg/kg. Zinc source did not influence growth performance, but Zn hydroxychloride improved carcass characteristics compared with Zn sulfate

Digestible lysine requirements of male broilers from 1 to 42 days of age reassessed

Three experiments were conducted separately to estimate the digestible Lys (dig. Lys) requirements of Cobb × Cobb 500 male broilers using different statistical models. For each experiment, 1,200 chicks were housed in 48 floor pens in a completely randomized design with 6 treatments and 8 replicates. Broilers were fed diets with increasing dig. Lys levels from 1 to 12 d (Exp. 1), from 12 to 28 d (Exp. 2), and 28 to 42 d (Exp. 3). Increasing dig. Lys levels were equally spaced from 0.97 to 1.37% in Exp. 1, 0.77 to 1.17% in Exp. 2, and 0.68 to 1.07% in Exp. 3. The lowest dig. Lys diets were not supplemented with L-Lysine and all other essential AA met or exceeded recommendations. In Exp. 3, six birds per pen were randomly selected from each replication to evaluate carcass and breast yields. Digestible Lys requirements were estimated by quadratic polynomial (QP), linear broken-line (LBL), quadratic broken-line (QBL), and exponential asymptotic (EA) models. Overall, dig. Lys requirements varied among response variables and statistical models. Increasing dietary dig. Lys had a positive effect on BW, carcass and breast yields. Levels of dig. Lys that optimized performance using QP, LBL, QBL, and EA models were 1.207, 1.036, 1.113, and 1.204% for BWG and 1.190, 1.027, 1.100, and 1.172% for FCR in Exp. 1; 1.019, 0.853, 0.944; 1.025% for BWG and 1.050, 0.879, 1.032, and 1.167% for FCR in Exp. 2; and 0.960, 0.835, 0.933, and 1.077% for BWG, 0.981, 0.857, 0.963, and 1.146% for FCR in Exp. 3. The QP, LBL, QBL, and EA also estimated dig. Lys requirements as 0.941, 0.846, 0.925, and 1.070% for breast meat yield in Exp. 3. In conclusion, Lys requirements vary greatly according to the statistical analysis utilized; therefore, the origin of requirement estimation must be taken into account in order to allow adequate comparisons between references