Dietary phytase supplementation on nutrient metabolism in initial and growth stages of broilers under heat stress

Abstract

The experiments were conducted to evaluate the effect of different inclusion levels of phytase in diets on the apparent metabolizable energy corrected for nitrogen balance, metabolization coefficient of dry matter, intake, excretion and coefficient of apparent retention of nitrogen, calcium and phosphorus in broilers under heat stress in initial and growth stages. Birds were distributed in a randomized block design and treated with five levels of phytase (0, 1000, 2000, 3000 and 4000 FTU/kg diet) and five replicates. Isonutrient diets based on corn and soybean meal, fed on chickens were formulated to meet nutritional requirements, except for available phosphorus, which was reduced in 20 % of requirement. Each experimental period lasted eight days, four for adaptation of poultry cages and diets and four for collection of excreta. Diet supplemented with phytase reduced apparent metabolizable energy corrected for nitrogen balance and decrease phosphorus excretion of birds under heat stress, initial and growth stages.