Digestible tryptophan requirements for broilers from 22 to 42 days old

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

The objective of this experiment was to establish different criteria to evaluate the requirements of digestible tryptophan for broilers from 22 to 42 d of age, using different regression models (quadratic, exponential and Linear Response Plateau) and in case of statistical significancethecomparisonofmeansbyDuncantestat5%probabilitywasalsoadopted.Atotal of 1,920 Cobb 500 male broilers were distributed in a completely randomized experimental design, with 6 treatments (6 digestible tryptophan levels: 0.1395, 0.1610, 0.1825, 0.2040, 0.2255 and 0.2470%) and 8 replications containing 40 broilers each. Performance and carcass characteristics were evaluated. The level of 0.2255% of digestible tryptophan numerically improves feed conversion, and the 0.1919% estimated by the quadratic equation significantlyimprovescarcassyield. © 2013 Sociedade Brasileira de Zootecnia.