اثر سطوح مختلف پروتئين و پروبيوتيك بر صفات توليدي و برخي از فاكتورهاي خوني درجوجه هاي گوشتي

Effects of different Protein and Probiotic levels on production and some blood metabolites of broilers

In order to study the effects of different protein and probiotic levels on production and some blood parameters of broiler chickens, a 2 x 3 factorial experiments in a completely randomized design with 360 male chicks for 42 days was used. Factors were two protein levels (NRC, 1994, recommended level and 90 percent of recommended levels) and three probiotic levels (without probiotic, recommended level and 120 percent of reeommended level). All diets were isocalloric and had the minimum nutrient requirements reeommended by NRC (1994) except for protein. The results showed that, supplementing of probiotic to the diets had sufficient quantity of protein significantly improved chicks daily gain. Also, chicks fed with 120 percent of recommended probiotic level had more daily gains compared to other groups (P<0.05). Feed conversions of the chicks fed with 120 percent probiotic were significantly better than control group (P<0.05). The lowest and the highest feed conversion ratio were for the balanced protein with 120 percent recommended probiotic level and control groups, respectively (1.851 vs 2.038). Decrease of dietary protein level resulted in lower protein consumption and higher protein efficiency ratio (P<0.05). Supplementing of probiotic to the basal diet did not affect protein consumption but significantly increased protein efficiency ratio (P<0.05). Generally, this experiment indicated that supplementing of probiotic to basal diets resulted in better production performance, decrease nitrogen excretion, litter pH and decline in uric acid, cholesterol and triglyceride levels.