Effect of Satureja khuzistanica essential oils on antioxidative potential and postmortem pH of breast muscle in heat stressed broiler chicken

BACKGROUND: Inclusion of antioxidant sources in feed or water reduces the detrimental effects of free radicals and increases the antioxidative potential and stability of lipids in heat stressed broiler chicken. OBJECTIVES: This study was conducted to examine the effect of Satureja khuzistanica essential oils (SkEO) on early postmortem and ultimate pH as well as antioxidative potential of breast muscle in broiler chicken. METHODS: A total number of 720,1-d-old Arian broiler chicks were used in a 42-d trial to examine the effects of six experimental treatments consisting inclusion of 0 (control-), 200, 300, 400, 500 mg/L SkEO and 500 mg/L Polysorbate-80 (control+) in drinking water in six replicates of 20 birds each in a completely randomized blocks design. Catalase enzyme activity (by kinetic method) and glutathione peroxidase as well as superoxide dismutase activities (via Randox® kits) were measured spectrophotometerically. Lipid peroxidation also was measured in breast muscle by a chemical method with thiobarbituric acid. RESULTS: The breast percentage and early as well as ultimate pH of breast muscle was not differ for the birds received SkEO-treated water compared to the control birds (p>0.05). Addition of SkEO in drinking water at doses greater than 200 mg/L significantly decreased the thiobarbituric acid reactive substances values in breast muscle of the birds in comparison with the control birds (p<0.05). Catalase activity was significantly higher in breast muscle of the SkEO-treated groups than the control groups (p<0.05). Activity of glutathione peroxidase was significantly greater in the birds given 400 and 500 mg/L SkEO. Addition of SkEO into water up to 400 mg/L increased superoxide dismutase activity in breast muscle of the treated birds compared to the control birds. CONCLUSIONS: It was concluded that supplementation of drinking water with SkEO elevates the antioxidative potential and increases the lipid stability of breast muscle in heat stressed male broiler chicken.