Effect of suplemental microbial phytase on the utilization of phosphorus phytate in broiler chickens fed corn-soybean diets

To determine the effect exogenous phytases incorporated to a corn-soybean diet for growing and finishing broilers, 520 one day-old birds of the commercial hybrid CobbxCobb were used. A factorial arrangements (3 x 4) with four repetitions of 10 birds each was used. Increasing levels of Aspergillus niger synthetic phytases (0, 300, 400 y 500 U/Kg), and total phosphorous (0,45, 0,55 y 0,65%) were added to a corn-soybean diet. Phytase supplementation increased weight gain, feed intake, and bone ash, when compared to phytase-free diets. The results indicate that the liberation of one g of phytic phosphorous varied with the content of available phosphorous (aP) in the diet (540 U/Kg and 1290 U/Kg for 0,25% y 0,35% aP, respectively).