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Optimization of dietary levels of isoleucine, valine and tryptophan for the maintence and production of eggs for commercial laying hens.

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Author(s):
Vinicius Duarte de Oliveira
Total Authors: 1
Document type: Master's Dissertation
Press: Jaboticabal. 2018-04-02.
Institution: Universidade Estadual Paulista (Unesp). Faculdade de Ciências Agrárias e Veterinárias. Jaboticabal
Defense date:
Advisor: Euclides Braga Malheiros; Nilva Kazue Sakomura; Edney Pereira da Silva
Abstract

Determination of optimal intakes of isoleucine (Ile), valine (val), tryptophan (Trp) of commercial laying hens may allow further reductions in the supply of dietary crude protein. To achieve this goal, the optimal economic intakes of isoleucine (Ile), valine (Val) and tryptophan (Trp) for commercial laying hens were evaluated in three trials, using 70 hens of Hisex White strain at 29 weeks of age for each assay. The experimental design was completely randomized, with six treatments and ten replications of one bird each. The experimental diets were formulated using the dilution technique, resulting in increasing dietary levels of Ile (2.80; 3.64; 5.11; 6.34; 6.95; 7.80 g.Kg-1), Val (3.56; 4.58; 6.35; 7.83; 8.58; 9.60 g.kg-1) and Trp (0.81; 1.06; 1.50; 1.86; 2.05; 2.30 g.kg-1). In addition, a seventh diet was formulated for each trial, in order to confirm if the amino acid test was the first-limiting. After a six-weeks adaptation period, the data collection were carried out for four weeks, thus each trial lasted ten weeks. The variables of amino acid intake, egg mass and feed conversion were submitted to analysis of variance and regression with significance level of α = 5. Then, two mathematical models were fitted: linear plateau (LP) and quadratic polynomial (PQ). It was also estimated the optimal intake obtained by the 1st intersection of the PQ with the LP plateau. To obtain the coefficients for the Reading Model, the data were analyzed by the EFG program (2006). Levels of Ile, Val and Trp significantly influenced all variables studied (p <0.01). The optimal levels of Ile, Val and Trp estimated by LP were 376, 679 and 150 mg / bird / day, respectively. Considering the intakes estimated by the PQ, 633 mg / bird / day were obtained for Ile, 931 mg / bird / day for Val and 218 mg / bird / day for Trp. Based on the combination of the two models (LP + PQ), Ile, Val and Trp intakes were 531, 771 and 184 mg / bird / day, respectively. The estimated coefficients of production (a) were 7.23; 9.83 and 2.28 mg / g egg for Ile, Val and Trp, respectively. The efficiency of use was 82% for Ile, 75% for Val and 85% for Trp. The maintenance coefficients (b) for Ile, Val and Trp were 13.20; 0.03 and 7.48 mg / kg body weight. Considering the current economic scenario, the optimal economic intakes of Val and Trp recommended by the Reading Model were 852 and 195 mg / bird / day, for commercial laying hens from 29 to 39 weeks (AU)

FAPESP's process: 16/14754-5 - Use of isoleucine , valine and tryptophan for maintenance and egg production in order to optimize the dietary levels for commercial laying hens
Grantee:Vinícius Duarte de Oliveira
Support Opportunities: Scholarships in Brazil - Master