Effects of COS on antioxidant status in serum. Values expressed as mean ± standard error, n = 10. a,b Different superscript letters means significant differences (p < 0.05). CON, basal diet with normal drinking water; AS, basal diet with 0.1% H2O2 in drinking water; ASC, basal diet supplemented with 200 mg/kg COS, and with 0.1% H2O2 in drinking water. MDA, malondialdehyde; SOD, superoxide dismutase; CAT, catalase; GSH-Px, glutathione peroxidase; GSH, glutathione; T-AOC, total antioxidant capacity. (A) the content of MDA; (B) the activity of SOD; (C) the activity of CAT; (D) the activity of GSH-Px; (E) the content of GSH; (F) the content of T-AOC.