مژگان مظهری

This experiment was carried out to study the effects of Coenzyme Q10 (CoQ10) and vitamin C (VC) on growth performance and blood biochemistry in broiler chickens under heat stress conditions. One of three levels of CoQ10 (0, 20, and 40 mg/kg of diet) and one of two levels of VC (0 and 250 mg/kg of diet) were supplemented to diets of chicks (from 1-42 d of age) in a 3 × 2 factorial arrangement. Each dietary treatment had four replicate pens (10 chicks/pen). In order to create chronic heat stress, the house temperature was set at an ambient temperature of 35±2°C for 8 hrs daily (09:00 to 17:00) between 25-42 d of age. Feed intake, body weight gain (BWG), and feed to gain ratio (F:G) were recorded at d 10, 25 and 42. At the end of experiment, two chicks/pen were randomly selected to assess blood components. CoQ10 supplementation improved BWG and F:G during 11-25 days, 26-42 days, and the whole period of the experiment (P < 0.05), while VC supplementation improved BWG and F:G only during 11-25 d of age. Blood glucose, cholesterol and triglycerides concentrations were reduced (P < 0.05) by addition of CoQ10 to the diet. Both Supplementation of CoQ10 and VC together lowered heterophil (H) count but increased lymphocyte (L) count, thereby reducing H/L ratio (P < 0.05). Serum concentrations of corticosterone and T4 were positively affected by dietary supplementation of CoQ10 (P < 0.05), but no differences were obtained with addition of VC to the diet. In conclusion, our observations demonstrated that dietary supplementation of 40 mg/kg CoQ10 or 250 mg/kg VC improves the growth performance of broiler chickens under the heat stress.