Effects of enzymatic and non-enzymatic antioxidants in diluents on cryopreserved bull epididymal sperm

Objective:To evaluate the supplementation effects of vitamin E,vitamin C,superoxide dismutase(SOD),and catalase to diluents on bull cryopreserved epididymal sperm.Methods:Sperm were retrieved from 20 bull testes and were then supplemented with 0.1 mM vitamin E,5.0 mM vitamin C,100.0 IU/mL SOD,and 100.0μg/mL catalase alone,or in a combination.The control treatment contained no addition.After supplementation,samples were frozen and stored in liquid nitrogen.The sperm parameters including motility,progressive motility,viability,acrosome integrity,plasma membrane integrity,kinematics and DNA damage were evaluated following the thawing process.Results:Vitamin E alone significantly increased the parameters of acrosome and membrane integrity compared to the control treatment(P<0.05).While compared to the control treatment,vitamin C had no improvement effect on sperm characteristics except for membrane integrity.Treatment of vitamin E+vitamin C had a significant improvement in total motility,progressive motility,viability,membrane and acrosome integrity compared to the control and other treatments(P<0.05).Compared to the control treatment,addition of SOD or catalase alone significantly improved the percentages of total motility,progressive motility,viability,membrane and acrosome integrity(P<0.05).Furthermore,SOD+catalase significantly increased total motility,progressive motility,viability,acrosome and membrane integrity characteristics compared to the catalase treatment(P<0.05).Vitamin E alone,vitamin E+vitamin C,and SOD in diluents decreased DNA damages and thereby improved the rate of intact sperm heads.Conclusions:Addition of 100.0 IU/mL SOD alone and 0.1 mM vitamin E+5.0 mM vitamin C,and also 5.0 mM vitamin C+100μg/mL catalase in a combination improves the quality of cryopreserved bull epididymal sperm and could be used for cryopreservation.