Abstract

This research was conducted to study the efficacy of different growth promoter’s on the productive performance and carcass yield of broiler chickens. 840 male ROSS and 308 hybrid chickens were used according to completely randomize the design in six treatments and one control (Five growth promoters and control). Thus, there were six groups of chickens: group 1; control diet (without any promoter’s), group 2; control diet + antibiotic, group 3; control diet + probiotic, group 4; control diet + prebiotic, group 5; control diet + phytobiotic and group 6; control diet + symbiotic. The productive indicators evaluated were: feed intake, weight gain, feed conversion ratio (FCR). The carcass yield and the main portions (breast, thigh and abdominal fat) was also determined. In all current studies, there wasn’t any significant difference between treatments in body weight gain (P > 0.05) but all of them had beneficial effect compared to control. Lowest feed conversion ratio was observed in probiotic group and caused more efficient feed intake. Treatments vs. control increased carcass yield significantly but the difference between treatments was not significant. Breast and thigh was not affected by treatments and there wasn’t any significant difference between treatments and control group. Lowest abdominal fat were seen in antibiotic group. According to our results, probiotic and symbiotic appeared to be superior compared to other growth promoters.

Key words: Growth promoters, performance, carcass, broiler.