Standardized ileal digestible lysine requirement of white commercial layers in peak egg production

Silvana Marques Pastore,Paulo Cezar Gomes,Eliane Aparecida Da Silva,Gabriel Da Silva Viana,Warley Junior Alves,Alícia Zem Fraga,Leonardo Valentino Soares Barbosa,Will Pereira De Oliveira

doi:10.14393/bj-v34n1a2018-37205

Abstract

This study was conducted to determine the standardized ileal digestible lysine (SID Lys) requirements for white commercial layers in peak egg production phase. A total of two hundred eighty-eight 24 week-old Hy-Line W-36 layers were randomly assigned to one of six treatments groups, with eight replicates of six hens each. A basal diet, SID Lys-deficient, was graded supplemented with L-Lysine HCl (78.4%) in order to produce experimental treatments (6.0, 6.6, 7.2, 7.8, 8.4 and 9.0 g SID Lys/kg diet). Throughout the 16-week-feeding trial (24 to 40 weeks of age) hens had free access to water and mash feed. Data were analyzed as one-way ANOVA and optimum SID Lys level for each dependent variable assessed were estimated using polynomial and linear broken-line regression model. Feed intake and SID Lys intake were both linearly enhanced by graded SID Lys levels. According to linear broken-line regression model, the breakpoint for egg production, egg weight, and egg mass occurred at 8.14, 8.56 and 8.35 g SID Lys/kg diet, respectively. The breakpoint for feed conversion per egg mass (kg/kg) and per dozen of eggs (kg/dozen) occurred at 8.48 and 7.80 g SID Lys/kg diet, respectively. Eggshell weight and albumen weight were unaffected by dietary SID Lys supply. Weight gain and yolk weight reached optimum values at 8.33 and 8.03 g SID Lys/kg diet, respectively, according to linear broken-line regression model. In conclusion, SID Lys requirement for white commercial layers in peak egg production phase is 8.48 g/kg diet, which corresponds to an average daily SID Lys intake of 813 mg/hen.

Highlights

Genetic evolution of commercial layer strains has markedly improved hen productive rates
standardized ileal digestible lysine (SID Lys) requirement for white commercial layers in peak egg production phase is 8.48 g/kg diet, which corresponds to an average daily SID Lys intake of 813 mg/hen
Since the SID essential amino acid requirements depend on SID Lys nutritional need, the establishment of laying hen requirements for SID Lys is crucial to warrant the adequate balance in amino acid profile and avoid impaired productivity

Summary

Introduction

Genetic evolution of commercial layer strains has markedly improved hen productive rates. In order to optimize the expression of the optimum layer performance, the nutrient content of diets must be supplied in amounts, which meetsallhen nutritional needs. Poultry diets have been formulated based on ideal protein concept to supply digestible essential amino acids based on digestible lysine requirement. The ideal protein concept became more precise the meeting of SID amino acid layer requirements. Rocha et al (2009) recommended for ideal 24-to-40-wk-old white commercial layers a daily SID Lys intake of 759 mg/hen. Higher values of ideal daily SID Lys intake for white laying hens at peak egg production phase were reported by Rostagno et al (2011) (803 mg/hen) and by the genetic line management guide (Hy-Line W-36, 2015) (805 mg/hen)

Methods

Results

Conclusion