Optimal in‐feed amino acid ratio for laying hens based on deletion method

Abstract

A total of 56 Hy‐line W‐36 hens from 28 to 30 weeks were used on nitrogen balance (NB) trial to estimate daily N maintenance requirements (NMR) and the genetic potential for daily N retention (NRmaxT). The treatments consisted of six graded levels of nitrogen in the diets (N1 = 8; N2 = 16; N3 = 24; N4 = 32; N5 = 40; and N6 = 48 g N/kg of feed), formulated using the dilution technique. The regression analyses between nitrogen intake and excretion were performed to fit the exponential function and to determine the NMR = 292 mg/BWkg 0.67, which was applied for further calculation of NRmaxT = 1,883 mg/BWkg 0.67. A second NB trial was conducted, and a total of 96 Hy‐line W‐36 hens were used in the same period to estimate the ideal amino acid ratio (IAAR). Twelve treatments with eight replicates and one bird per cage were used. A balanced diet (BD) was formulated to meet the IAAR and the requirement of other nutrients for pullets. The limiting diets were formulated diluting BD with cornstarch and refilled with synthetic AAs and other feed ingredients, except for the AA under study. In each trial, the data of nitrogen intake, excretion, deposition and retention were obtained in a NB trial. The IAAR determined by Goettingen approach was Lys 100, Met+Cys 88, Trp 21, Thr 69, Arg 109, Val 90, Ile 75, Leu 127, Phe+Tir 110, Gly+Ser 73 and His 29%. The IAAR determined by Louvain approach was Lys 100, Met+Cys 88, Trp 21, Thr 69, Arg 104, Val 91, Ile 78, Leu 121, Phe+Tir 119, Gly+Ser 77 and His 29%.

The Impact of Genotype and Age on Energy and Protein Utilization in Individually Housed Brown Laying Hens

“…It is intimated that the protein requirements of modern genotypes have increased because they have a higher EO [ 12 , 13 , 14 , 15 , 16 ]. Modern laying genotypes have a lower BW with a reduced EW [ 2 ].…”

“…Some comparative work on evolving broiler genotypes’ growth and nutrient requirements has been published [ 10 , 11 ], but similar studies do not appear to exist for laying hens. It is intimated that the nutrient requirements of modern genotypes have increased [ 12 , 13 , 14 , 15 ]. Kidd and Loar [ 16 ] point out that the rate of change in the egg industry is such that it exceeds the science required from research to support emerging management practices.…”

Essential amino acid recommendations for Isa Brown layers during peak and post peak production

“…To meet this increasing demand, the performance of laying hens has been improved by genetic selection breeding programs coupled with better nutritional strategies. Amino acid requirements for laying hens were published in NRC (1994) and a number of relevant investigations have been subsequently reported ( Schutte et al, 1994 ; Ishibashi et al, 1998 ; Coon and Zhang, 1999 ; Harms and Russell, 2001 ; Faria et al, 2003 ; Leeson and Summers, 2005 ; Bregendahl et al, 2008 ; Lemme, 2009 ; Soares et al, 2019 ). However, amino acid requirements for brown layers have not been updated for nearly a decade and it is important to redetermine requirements for optimal production efficiency, welfare, and health, especially during the peak production period.…”

Effects of L-valine in layer diets containing 0.72% isoleucine

“…The ideal amino acid ratio as determined by the Goettingen approach was lysine, 100; isoleucine, 75; and valine, 90. As determined by the Louvain approach, it was lysine, 100; isoleucine, 80; and valine, 91 (Soares et al, 2018) [ 22 ].…”