Nilva Kazue Sakomura

Nilva Kazue Sakomura

Universidade Estadual Paulista “Júlio de Mesquita Filho”, Brazil

Title: Optimal tryptophan intake for laying hens


Nilva Kazue Sakomura has completed her PhD at Federal University of Viçosa and postdoctoral studies at University of Arkansas (USA) and University of KwaZulu-Natal (RSA). She acts as professor at the Paulista State University "Júlio de Mesquita Filho”, FCAV/UNESP and coordinates the Laboratory of Avian Sciences at same university. She participated in the elaboration of the last edition of Brazilian Tables for Poultry and Swine. Her research area is mainly foccused on modeling amino acid requirements of broilers, laying hens and broiler breeders.           



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 NRis 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).