The effectiveness of microbial phytase on performance and bone tissue characteristics of broilers

The possibilities to use microbial phytase in maize/soybean meal diets for broilers with different dietary total and available phosphorus (TP and AP) levels were investigated. A 21-day experiment was carried out on 300 Arbor Acres broilers of both sexes divided into six groups. The broilers were fed diets with 0.46%, 0.25% or 0.10% AP, with or without phytase supplementation. During the experiment, health status and mortality, performance and physical, chemical and morphological bone tissue characteristics were investigated. Total exclusion of a mineral source of P from the diet increased mortality and health problems. Addition of phytase decreased mortality and alleviated negative effects of dicalcium phosphate exclusion. Reduction of dietary TP and AP level induced lower body mass and daily gain and feed consumption, as well as higher feed conversion. However, by introducing phytase into diets negative effects of P reduction were, to some extent, alleviated. Physical, chemical and histological analysis of broiler tibia indicates that the extent and significance of changes depend on P deficiency and phytase addition. Phytase efficacy was greater in diets with a reduced level of dicalcium phosphate.