عنوان مقاله [English]
نویسندگان [English]چکیده [English]
This experiment was performed to investigate the effects of propolis and chromium picolinate on performance and immune response of broiler chicken under heat stress conditions. Treatments included different levels of propolis (500, 1000, and 1500 mg/kg) and chromium picolinate (1500 µg/ kg) along with a control group. A completely randomized design was taken into account with 4 replicates of 10 Ross (308) male broiler chicks per treatment under heat stress conditions (34 ±2°C, 5 hours/day). The chicks received treatments from 1 to 42 days. Birds fed 1500 mg/kg propolis had significantly higher feed intakes (p<0.01). Weight gain (p<0.01) and feed conversion ratios (p<0.05) were significantly more pronounced than the control for different levels of propolis and chromium picolinate. Experimental diets did not show any significant effect on blood glucose and insulin levels. Chicken fed 1500 mg/kg propolis had more lymphocytes than control did (p<0.05). There were not any significant differences observed in weights of different organs, except for edible carcass and bursa of Fabricius relative weights that were recorded higher than those of control for different levels of propolis and chromium picolinate (p<0.01).