Influence of conditioning temperature on the postpellet recovery and efficacy of 2 microbial phytases for broiler chicks

Abstract

The effect of conditioning temperature on phytase efficacy for growth performance and bone mineralization was evaluated using 432 male Ross broilers. Birds were fed a wheat-soy-based diet that was formulated to be adequate in all nutrients with the exception of available P. Diets were conditioned at 75, 80, 85, or 90°C and fed with (1,000 phytase units/kg) or without 1 of 2 microbial phytases in a 3 × 4 factorial design. Phytase A was found to have greater thermostability than phytase B (78.3 vs. 57.5%) as an average across all conditioning temperatures. Phytase increased (P < 0.05) BW gain from d 0 to 21 and birds fed diets containing phytase A were significantly heavier than birds offered diets with phytase B. Increasing conditioning temperature decreased (P < 0.01) BW gain. Supplementing diets with phytase improved (P < 0.05) FE and birds fed diets containing phytase A were more efficient (P < 0.05) than broilers fed diets containing phytase B. Tibia ash concentrations were improved (P < 0.05) by approximately 10% with phytase A and B compared with birds fed diets without phytase. Birds fed phytase A diets had higher (P < 0.05) bone ash concentrations than birds that received the diet containing phytase B. In conclusion, the inclusion of an intrinsically thermostable exogenous phytase before pelleting would be of benefit to bird performance and bone mineralization in broilers. © 2013 Poultry Science Association, Inc.