Suplementa??o da fitase em ra??es com diferentes níveis de fósforo disponível para frangos de corte

摘要

The study was carried out with the objective of evaluating the effect of phytase supplements in feeds with different levels of available phosphorus on the performance of broilers from 22 to 42 days of age. We used 1080 Cobb-500 chickens distributed in a completely randomized design, in a 3 x 4 factorial scheme, with three levels of available phosphorus (0.30; 0.40 and 0.50%) and four levels of phytase (0; 500; 1,000 and 1,500 UF), totaling 12 treatments, each with six replications of 15 birds. The variables evaluated were: feed intake, live body weight, weight gain, feed conversion and carcass characteristics. Live body weight and weight gain were not influenced by the levels of available phosphorus or adding phytase to the diet. There was interaction between the levels of available phosphorus and phytase levels for feed intake and feed conversion. Better feed conversion was seen in birds fed on diets containing 0.30% available phosphorus at 1,500 UF kg-1. The available phosphorus levels affected the development of the thigh and the back, where the best results were from 0.30% and 0.40% respectively. The use of a diet containing 0.30% phosphorus, supplemented with 1500 UF kg -1 is recommended.