اثرات فيتاز ميكروبي و كلسيم جيره بر عملكرد جوجه هاي گوشتي نر

Effects of Microbial Phytase and Dietary Calcium on Performance of Male Broiler Chickens

This experiment was conducted to evaluate the effects of microbial phytase and dietary calcium levels on performance, tibia ash percentage and some blood factors in male broiler chickens. Three hundred sixty male broiler chickens from Arbor Acres plus (AA+) strain were used in a completely randomized design as a 2><3 factorial with five replicates and 12 chickens in each floor pen. Broiler chickens were fed two levels of dietary calcium (NRC recommended level and 80% of it) and three levels of microbial phytase (0, 300, and 600 FTU/kg of diet) during 7-42 days of age. Experimental diets were formulated to be isoenergetic and isonitrogenous with similar nutrients with the exception of calcium and total phosphorus. During the experiment, body weight, body weight gain, feed consumption and feed conversion ratio were measured weekly. Tibia ash percentage and blood serum factors were measured on 28 days of age. Mortality rate was recorded daily through the experiment. Low dietary calcium level had no significant effect on body weight, daily weight gain, feed intake, feed conversion ratio, serum calcium concentration and tibia ash percentage, while phosphorus concentration of blood serum decreased and activity of serum alkaline phosphatase increased (p<0.05). Phytase level, significantly improved body weight, daily weight gain, feed conversion ratio, tibia ash percentage and serum phosphorus concentration (p<0.05). Serum alkaline phosphatase activity was decreased by phytase level (p<0.05). Phytase had no significant effect on feed intake and serum calcium concentration. There was no significant difference between the effects of 300 and 600 FTU on the performance of broiler chickens