Effect of Dietary Curcumin on the Antioxidant Status of Laying Hens under High-Temperature Conditions
ABSTRACT Heat stress induces oxidative stress, and reduces body antioxidant metabolite levels, which can affect poultry production performance. Dietary antioxidants protect birds against the adverse effects of heat stress. The effects of increasing concentrations of dietary curcumin on the antioxidant parameters of layers maintained under high-temperature conditions for nine weeks were evaluated. Roman laying hens (n = 336, 22 weeks old, 1420 g BW) were divided into three treatment groups. The first group served as a thermoneutral control (kept at 25 ± 1 °C). The second group was exposed to high temperatures (32 ± 1 °C, 6 h/d), given a basal diet. The third group was further divided into five treatment groups (100, 150, 200, 250, 300 mg/kg Curcumin) fed a basal diet (treatments H1, H2, H3, H4, H5) under high temperatures conditions (32 ± 1 °C, 6 hours/day). As a result of this study, total superoxide dismutase activity was significantly higher in H2 and H3 groups, and total antioxidant capacity was higher in H2, H3, and H5 groups. Catalase and glutathione peroxidase activity was significantly higher in the H3 group. Malondialdehyde concentration was lowered in curcumin supplemented hens compared with control groups hens. Laying hens in all curcumin treatment groups had slightly higher activities of CAT, SOD, GSH-Px, and T-AOC in the liver, heart, and lungs, compared with heat stressed control group. It was concluded that dietary curcumin given to laying hens under heat stress may enhance their antioxidant status, and alleviate the detrimental effects of stressful environmental conditions.