Nilva Kazue Sakomura
Universidade Estadual Paulista “Júlio de Mesquita Filhoâ€, Brazil
Title: Optimal tryptophan intake for laying hens
Biography
Biography: Nilva Kazue Sakomura
Abstract
The research was conducted to re-evaluate the assumptions of ideal ratios (IAAR) of the essential amino acids for Hy-line W-36 laying hens, using the amino acid deletion and nitrogen balance methods. The nitrogen balance trial was performed from 28 to 32 weeks of age, 12 treatments with 8 replicates and 1 bird per cage were used. A balanced diet (BD) was formulated to meet the IAAR and the requirement of other nutrients. The limiting diets were formulated diluting BD with corn starch and refilled with synthetic amino acids (AA) and other feed ingredients, except for the AA studied. The trial lasted 25 d, being the first 5 d for adaptation and the other 20 d for total collection of excreta and eggs. Diets, excreta and eggs samples were analyzed for nitrogen content to quantify nitrogen intake and excretion. From these data, nitrogen retention (NR) was calculated. The estimated requirement of each AA (AAR) was calculated as AAR= 100 x (1-NRi/NRcontrol) where NRi is the NR associated with each limiting diet calculated and NRcontrol is the NR associated with the balanced control diet. The estimated optimum ratio between each AA and Lys [(AA/Lys) * 100] and the optimum level of each AA (values in parentheses) were: Lys = 100 (0.673), Met+Cys = 82 (0.552), Thr = 69 (0.464), Trp = 21 (0.141), Arg = 104 (0.700), Val = 91 (0.612), Ile = 78 (0.525), Leu = 121 (0.814), Phe+Tyr = 119 (0.801), Gly+Ser = 77 (0.518) and His = 29 (0.195).