Single and combined effects of vitamin C and oregano essential oil in diet, on growth performance, and blood parameters of broiler chicks reared under heat stress condition.

This study was conducted to evaluate the effects of adding vitamin C (VC), oregano essential oil (OR), or their combination in diet, on growth performance, and blood parameters of broiler chicks reared under heat stress (HS) condition (38 °C). One-day-old 240 male broilers were randomly assigned to four treatment groups, six replicates of ten birds each. The birds were fed with either a basal diet or a basal diet supplemented with either 200 mg L-ascorbic acid/kg of diet, 250 mg of oregano essential oil/kg of diet, or 200 mg L-ascorbic acid plus 250 mg of oregano essential oil/kg of diet. Average daily feed intake (ADFI), average daily gain (ADG), and feed conversion ratio (FCR) were obtained for 42 days of age and at the end of the experiment (day 42); birds were bled to determine some blood parameters and weighted for final body weight (BW). Feeding birds with diets supplemented with oregano essential oil and vitamin C in a single or combined form increased ADG (P > 0.05). Also BW increased and feed efficiency decreased (P < 0.05) in the birds fed with diets including VC and OR (in a single or combined form), compared to those fed the basal diet. ADFI was not significantly influenced by dietary oregano essential oil and vitamin C (P > 0.05). Supplemental oregano essential oil and vitamin C in a combined form decreased the serum concentration of corticosterone, triglycerides, glucose, and MDA (P < 0.05) compared with other groups. An increase in the serum concentrations of vitamin C were seen in broiler chicks supplemented with vitamin C. From the results of the present experiment, it can be concluded that diet supplementation by combined oregano essential oil and vitamin C could have beneficial effects on some blood parameters of broiler chicks reared under heat stress condition.