The objectives of this study were to determine the effects of microbial phytase supplementation and three levels of Non-Phytate Phosphorus (NPP) on some serum parameters in broiler chickens fed corn-soybean meal diets. The experimental diets were as follows: diet 1) 0.31% NPP during starter and 0.29% NPP during grower and finishing periods without phytase; diet 2) 0.31% NPP during starter and 0.29% NPP during grower and finishing periods plus phytase (a commercially available microbial phytase preparation, Natuphos 1000, was added at 500 phytase units/kg diet); diet 3) 0.38% NPP during starter and 0.36% NPP without phytase; diet 4) 0.38% NPP during starter and 0.36% NPP during grower and finishing periods plus phytase; diet 5) 0.45% NPP during starter and 0.43% NPP during grower and finishing periods without phytase; diet 6) 0.45% NPP during starter and 0.43% NPP during grower and finishing periods plus phytase. Serum Ca, P, Mg, Alb and total Protein were determined by Spectrophotometer. The data were analyzed using the General linear Models procedure for analysis of variance. Significant differences among treatment means were separated by Duncan’s new multiple range test with a 5% level of probability.The results of this study suggest that added phytase to diet by increasing NPP in diet increased serum P, Alb and total Protein concentrations and decreased serum Mg and did not affect Ca concentration.
