Protective effects of ascorbic acid and vitamin E on antioxidant enzyme activity of freeze-thawed semen of Qinchuan bulls.

The aim of this study was to determine the protective effects of the combination of ascorbic acid (Vc) and vitamin E (VE) on antioxidant enzyme activity, sperm motility, viability, and acrosome integrity of Qinchuan bulls after freeze-thaw. In this study, we determined the effects of Vc and VE on the activity of the antioxidant enzyme defense system comprising glutathione peroxidase (GSH-Px), glutathione reductase (GR), catalase (CAT), and superoxide dismutase (SOD). The combination of Vc and VE had protective effects on sperm motility and viability. With respect to acrosome integrity and the activity of GR and SOD, differences were observed between the experimental groups with added Vc (7 mg/mL) and VE (0.12 IU/mL) and the control group. The activity of GSH-Px in the experimental group (1400 IU/mL Vc and 0.12 IU/mL VE) was not different (P > 0.05) compared with that in the control group, while the activity of CAT showed a significant difference between the 2 groups (P < 0.05). Therefore, we inferred that the combination of Vc (1400 IU/mL) and VE (0.12 IU/mL) protected the sperm quality in the freeze-thaw process.