Ideal ratio (relative to lysine) of tryptophan, threonine, isoleucine, and valine for chicks during the second and third weeks posthatch

Baker, David H.; Batal, A. B.; Parr, T. M.; Augspurger, N. R.; Parsons, C. M.

doi:10.1093/ps/81.4.485

Cited by 198 publications

(145 citation statements)

References 19 publications

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“…Feed intake and ADG evolve differently in response to Lys : NE, which explains why FCR and ADG do not necessarily reach the same optimal values. When gain and voluntary feed intake reach their highest point, gain remains constant but feed intake decreases with additional Lys (Baker et al, 2002). This shows that the Lys requirement for FCR can be higher than for ADG.…”

Section: Resultsmentioning

confidence: 94%

“…In this respect, the model may not be suitable because it does not consider the curvilinear nature of the response of a population to graded levels of a limiting nutrient. A quadratic linear-plateau model has been recommended for describing curvilinear population responses and estimating nutrient requirements (Baker et al, 2002). In this type of model, the optimum nutrient level is attributed to the intersection between the quadratic function and the plateau.…”

Section: Resultsmentioning

confidence: 99%

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Systematic comparison of the empirical and factorial methods used to estimate the nutrient requirements of growing pigs

Hauschild

Pomar

Lovatto

2010

Animal

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Empirical and factorial methods are currently used to estimate nutrient requirements for domestic animals. The purpose of this study was to estimate the nutrient requirements of a given pig population using the empirical and factorial methods; to establish the relationship between the requirements estimated with these two methods; and to study the limitations of the methods when used to determine the level of a nutrient needed to optimize individual and population responses of growing pigs. A systematic analysis was carried out on optimal lysine-to-net-energy (Lys : NE) ratios estimated by the empirical and factorial methods using a modified InraPorc R growth model. Sixty-eight pigs were individually simulated based on detailed experimental data. In the empirical method, population responses were estimated by feeding pigs with 11 diets of different Lys : NE ratios. Average daily gain and feed conversion ratio were the chosen performance criteria. These variables were combined with economic information to estimate the economic responses. In the factorial method, the Lys : NE ratio for each animal was estimated by model inversion. Optimal Lys : NE ratios estimated for growing pigs (25 to 105 kg) differed between the empirical and the factorial method. When the average pig is taken to represent a population, the factorial method does not permit estimation of the Lys : NE ratio that maximizes the response of heterogeneous populations in a given time or weight interval. Although optimal population responses are obtained by the empirical method, the estimated requirements are fixed and cannot be used for other growth periods or populations. This study demonstrates that the two methods commonly used to estimate nutrient requirements provide different nutrient recommendations and have important limitations that should be considered when the goal is to optimize the response of individuals or pig populations.

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Section: Resultsmentioning

confidence: 94%

Section: Resultsmentioning

confidence: 99%

Systematic comparison of the empirical and factorial methods used to estimate the nutrient requirements of growing pigs

Hauschild

Pomar

Lovatto

2010

Animal

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“…In the Quadratic model, these levels were obtained by equalling the first derivative of the equation to zero. The first intercept of the Quadratic model with the plateau of the Broken Line as proposed by Baker et al (2002) was obtained using the following equation:…”

Section: Methodsmentioning

confidence: 99%

Response of laying hens to methionine + cystine intake by dilution technique

et al. 2015

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-The objective of this study was to measure the response of Dekalb White laying hens to different intakes of digestible methionine + cystine (met+cys) to optimise their performance. Two hundred eighty-eight Dekalb White laying hens, ranging in age from 33 to 48 weeks, were used in the study. The birds were randomly allocated into eight treatment (levels of met+cys and the control treatment) groups with six replicates of six hens per unit. The experimental diets consisted of seven increasing levels of met+cys (1.37, 2.75, 4.14, 5.51, 6.89, 7.92 and 8.95 g kg −1 ) and were prepared using a dilution technique. A control treatment was used to confirm that the limiting response was due to met+cys intake. Egg production, feed intake, egg weight, egg mass and feed conversion per mass were measured. The data were analysed with repeated measures and regression analyses using Broken Line and Quadratic models, as well as using the combination of both models. The different met+cys intakes influenced the studied variables; all the variables except feed conversion per mass were significantly different between the periods and levels. The digestible met+cys intakes based on the association of the Broken Line and Quadratic models to optimise the birds' response to egg mass are 671 mg/bird d for 33 to 36 weeks, 728 mg/bird d for 37 to 40 weeks, 743 mg/bird d for 41 to 44 weeks, and 770 mg/bird d for 45 to 48 weeks.

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“…O nível de lisina correspondente à primeira intersecção da equação quadrática com o platô do LRP, proposto por Baker et al (2002), foi obtido pela expressão: (-1598,12 + (1598,12 2 -4* -715,774* (-281,998 -605,97)) 1/2 ) / ( 2*-715,774) = 1,041. Esse método de determinação das exigências mostrou-se coerente, uma vez que proporcionou estimativa intermediária (1,041%) àquelas obtidas com os modelos LRP e quadrático individualmente, contornando as críticas a esses modelos.…”

Section: Resultsunclassified

“…O nível ótimo estimado com o uso do modelo exponencial foi obtido considerando 95% da resposta assintótica por meio da expressão: (ln 0,05) / C + D, de acordo com Sakomura & Rostagno (2007). A primeira intersecção da equação quadrática com o platô do LRP, proposto por Baker et al (2002), foi obtida pela equação: L = β 0 + β 1 Lis i + β 2 Lis i 2 e o nível de lisina correspondente à intersecção, calculado pela expressão:…”

Section: Methodsunclassified

Modelos matemáticos para estimar as exigências de lisina digestível para aves de corte ISA Label

et al. 2009

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RESUMO -O objetivo neste estudo foi avaliar diferentes modelos ajustados às respostas de ganho de peso obtidas em experimento com aves da linhagem ISA Label no período de 1 a 28 dias de idade. Foram utilizados 480 pintos de ambos os sexos, distribuídos em delineamento inteiramente casualizado, em arranjo fatorial 4 × 2 (níveis de lisina × sexo), com três repetições, com 20 aves por unidade experimental. Uma ração basal foi formulada para atender às exigências das aves, exceto em lisina. Essa ração foi suplementada com L-lisina HCl em substituição ao ácido L-glutâmico, resultando em rações experimentais isonitrogênicas e isoenergéticas contendo 0,85; 0,97; 1,09 e 1,21% de lisina digestível. As respostas de ganho de peso foram ajustadas de acordo com os níveis de lisina da ração pelos modelos Linear Reponse Plateau (LRP), segmentado de duas inclinações, polinomial quadrático e exponencial. A primeira intersecção da equação quadrática com o platô do LRP também foi utilizado para estimar o nível ótimo. Os níveis de lisina digestível estimados pelos modelos LRP, segmentado e quadrático, foram 0,999; 1,010 e 1,116%, respectivamente. Na combinação do modelo quadrático com o LRP, a estimativa da exigência de lisina digestível foi de 1,041%. O modelo exponencial proporcionou estimativa de 1,066%, considerando 95% da resposta assintótica. Com base nos custos com alimentação, esse mesmo modelo gerou estimativas de 1,000 e 1,030% quando o custo do quilograma de L-lisina HCl foi R$ 8,50 e R$ 6,50, respectivamente. Considerando as limitações de cada um dos modelos propostos, o procedimento para estimar as exigências de lisina digestível pela primeira intersecção da equação quadrática com o platô do LRP foi o mais adequado para melhorar o ganho de peso das aves quando variáveis econômicas não foram consideradas.Palavras-chave: aminoácidos digestíveis, dose-resposta, frangos de corte, modelos de regressão Mathematical models to estimate digestible lysine of ISA Label broilersABSTRACT -The objective of this study was to evaluate different models in the adjustment of weight gain (WG) responses, obtained in an experiment carried out with ISA Label birds from 1 to 28 days of age. A total of 480 male and female chicks were distributed in a completely randomized design, in a 4 × 2 factorial arrangement (lysine levels × sex), with three replications of 20 birds each. The basal diet was formulated to meet the chick requirements, except for lysine.This diet was supplemented with L-lysine HCl replacing the L-glutamic acid and resulting in experimental diets containing 0.85, 0.97, 1.09 and 1.21% digestible lysine. The weight gain response was adjusted to lysine levels according to following models: Linear Response Plateau (LRP), segmented regression with two slopes, quadratic and exponential. The first interception of the quadratic model on the LRP plateau was used to estimate the optimum lysine level. The lysine levels estimated according to LRP, segmented regression and quadratic models were 0.999, 1.010 and 1.116%, respectively. The di...

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Ideal ratio (relative to lysine) of tryptophan, threonine, isoleucine, and valine for chicks during the second and third weeks posthatch

Cited by 198 publications

References 19 publications

Systematic comparison of the empirical and factorial methods used to estimate the nutrient requirements of growing pigs

Systematic comparison of the empirical and factorial methods used to estimate the nutrient requirements of growing pigs

Response of laying hens to methionine + cystine intake by dilution technique

Modelos matemáticos para estimar as exigências de lisina digestível para aves de corte ISA Label

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