Evaluation of three feeding programs for broilers based on sorghum-soybean diets with different protein percentages

Abstract

In order to evaluate performance of broiler chickens, two experiments with Ross 308 broiler chicks from 1 to 49 days of age were conducted. In both experiments six treatments and three replicates with 30 birds each, with factorial arrangement 2 x 3 were evaluated; diets with and without reduction of 2 percentile units of crude protein was one factor and the other factor was three-phase feeding programs: two phases (0-21 and 22-49 days of age), three phases (0-21, 22-42 and 43-49 days of age) and four phases (0-7, 8-21, 22-35 and 36-49 days of age). In Experiment 1, sorghum + soybean meal diets were used, and in Experiment 2, sorghum + soybean + meat meal + corn yellow gluten meal were used. In both experiments, the diets included the synthetic amino acids; in Experiment 1, lysine, methionine and threonine were administered, and in Experiment 2, lysine, methionine, tryptophan, threonine and arginine. In Experiment 1, results indicated that growth was similar (P > 0.05) between diets and feeding phases. The results of feed conversion were better in the four-phase program (P < 0.05). Carcass, breast and leg with thigh yields, as well as carcass protein and fat did not show differences (P > 0.05) between factors or interaction effect. In Experiment 2, the results on weight gain, feed conversion, carcass, breast, leg with thigh and total fat yields were similar (P > 0.05) between factors. These results indicated that broilers fed diets with and without reduction of two percentile units of crude protein in 2, 3, and 4-phase feeding obtained similar performance. The formulation of protein reduced diets, supplemented with synthetic amino acids in each phase, were efficient for performance and carcass yield.