Determination of digestible isoleucine: lysine ratio in diets for laying hens aged 42-58 weeks

Revista Brasileira de Zootecnia

Heloisa Helena De Carvalho Mello¹  Paulo Cezar Gomes¹  Tatiana Cristina Da Rocha¹  Juarez Lopes Donzele¹  Rodrigo Lopes De Almeida¹  Allan Reis Troni¹  Bruno Reis De Carvalho¹  Gabriel Da Silva Viana¹ 

[1] ,Universidade de Viçosa Departamento de Zootecnia Viçosa MG ,Brasil

关键词: digestible amino acids;    egg quality;    ideal protein;    white laying hens;   

DOI  :  10.1590/S1516-35982012000500032

来源: SciELO

【 摘 要 】

Two hundred and fifty-two Hy-Line W36 laying hens were allotted in a completely randomized design with 6 treatments, 7 replicates and 6 hens per experimental unit in order to determine the ideal ratio of isoleucine (Ile) in relation to lysine (Lys) to laying hens aged 42-58 weeks. Experimental diets contained digestible Ile at different levels, resulting in different Ile:Lys ratios (0.73:1; 0.78:1; 0.83:1; 0.88:1; 0.93:1 and 0.98:1). A basal diet was formulated to provide Isoleucine in levels below recommendations. This diet was supplemented with L-isoleucine to make up the 6 diets. Each diet was made isonitrogenous by varying the dietary contents of glutamic acid and isocaloric by adjusting the contents of cornstarch. All essential amino acids were provided proportionally to lysine. Egg production, egg weight, egg mass, feed conversion ratio, albumen, yolk and eggshell contents were recorded and compiled at every 28-day period. No differences were observed in the performance over a wide range of dietary isoleucine concentrations from 5.76 to 7.73 g/kg corresponding to 0.73:1 to 0.98:1 Ile:Lys ratios. The lowest Ile:Lys ratio (0.73:1) was sufficient to ensure satisfactory performance of birds, corresponding to the consumption of 534 mg of isoleucine and 731 mg of lysine/day.

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