Effects of supplemental microbial phytase enzyme on performance and phytate phosphorus digestibility of a corn-wheat-soybean meal diet in broiler chicks

This experiment was conducted to investigate the effects of supplemental phytase in a corn-wheatsoybean meal basal diet on phosphorus (P) digestibility and performance of broiler chicks. 378 one-day old broiler chicks (Ross 308) were allocated to 3×3 factorial arrangements with three levels of phytase enzyme (0, 500 and 1000 FTU/kg) and three levels of non-phytate P (100, 80 and 60% of NRC requirements). Broiler chicks received experimental diets from 7 to 49 days of age. Phytase significantly (P < 0.05) improved body weight gain and feed intake. Tibial ash and P contents increased significantly by phytase supplementation. Ileal P digestibility increased and P excretion reduced by added phytase. The greatest response due to supplemental phytase regarding P digestibility and utilization was obtained at the lowest dietary non-phytate P (NPP) level (60% of NRC requirements). Difference between various levels of added phytase (500 and 1000 FTU/kg) regarding P excretion and utilization was not significant. The interactions between supplemental phytase and dietary NPP for P utilization, tibial ash and P contents were significant (P < 0.05). The results indicate that, supplemental microbial phytase (500 FTU/kg of diet) added to diet containing NPP lower than NRC requirements (60%) can improve growth performance, tibial ash and phytate P utilization in broiler chickens.Key words: Broiler, phytase, phosphorus digestibility, growth performance, tibia