بررسی اثرات سطوح مختلف چربی، شکل جیره و جنس جوجه ها بر روی عملکرد جوجه های گوشتی در شرایط تنش گرمایی

‭In order to investigate the effects of dietary added fat and feed form on productive performance and carcass traits of male and female broilers In heat stress 540, days old Arlan chicks were sexed and used on litter in an CAD design with 2x2x3 factorial arrangement. Three Isocalorlc and isonitrogenous diets with 0, 3 and 6 percent added sunflower 011, In two form (mash and pelleted) Were used from one to the end of 7th weeks of old and weight gain, feed intake, feed conversion ratio .(FC.R) .and final body weight (FBW) and so carcass. charactrlstics' were analyzed, Average max and mln room temperature along' the experimental :period respectively 31.5 and '25.7. Simple effe'cts of sex, feed form and fat level' on .6th. and 7th week body weight, effects of sex ‬ص ‭and fat level on feed intake ~nd effects of sex and feed form on FCR were significant. There were no interactions between factors. 6th FBW of chicks fed pelleted diets with 6 and.3 percent ad~ed fat was greater than mash diets without fat (P < 0.05). Pelleted diet with 3 percent fat had better FCR, different from all mash diets and pelleted diet without fat (P < 0.05). Dressing percent and abdominal fat of males and tlgh percent of females were greater. Pellets Increased breast meat yield an~ decreased giblet percent. Simple effects of feed form and fat level and so thir different combinations on dressing percent and abdominal fat were not significant. The results of this experiment showed that in m~derate heat stress, use of pelleted diet containing 6 or 3 percent added fat can ameliorate 6th FBW by 7 and 5 percent respectively In comparison with ordinary Isocaloric mash feed without fat. The use of this type of diets for female chicks ,had equal pertomance with straight .. run chicks fed mash. Keywords: Broiler, Sex, feed form, fat level, heat stress, productive performance, carcass charactrlstics.‬