ABSTRACT
Exogenous phytase enhances the utilization of plant phytate phosphorus in poultry. In the present study the effects of exogenous phytase was investigated on tibia bone characteristics of white quail. In a 2x2 factorial arrangement, eighty, 11-day old unsexed chicks were randomly divided into 4 treatments of 20 replicates. All birds received one of four experimental diets with two levels of aP [5.2 or 3.9 g kg-1] and two levels of phytase [0 or 500 FTU kg-1]. On day 25, all birds were weighed, sacrificed, and blood samples were obtained for the determination of blood phosphorus. Both tibiae were excised for the determination of ash, calcium and phosphorus content, bone length and thickness, and breaking strength. Birds which had received lower aP diets showed lower levels of blood phosphorus as well as tibia bone weight, ash, calcium, phosphorus, bone thickness and strength when compared with the higher aP fed birds. Adding phytase to the lower aPdiet was able to restore the above-mentioned variables. Phytase increases rigidity and strength of tibia by enhancing the availability of phytate phosphorus to the quail. This is important, particularly when the bird is grown for flight and hunting