The Cryoprotective Effects of Vitamin B.

The present study aimed to investigate the effects of vitamin B supplementation on standard bovine semen quality parameters and anti-oxidative enzyme activities. Vitamin B was supplemented at concentrations of 1.25, 2.5, 3.75 and 5.0 mg/ml to bovine semen cryoprotective medium. The results indicated that the motility and straight line velocity, curvilinear velocity, mean coefficient, velocity of the average path values of sperm supplemented with 2.50 mg/ml vitamin B were significantly higher than that of other groups (p < 0.05). No significant difference was observed for linearity index, lateral head displacement values and the percentage of grade A spermatozoa between the extenders containing 2.50 and 3.75 mg/ml vitamin B (p > 0.05). The percentages of acrosome-intact and plasma membrane-intact spermatozoa were significantly improved (p < 0.05) by supplementing with 2.50 mg/ml vitamin B. The results of biochemical assay revealed that vitamin B supplementation did not cause significant changes in superoxide dismutase levels compared with control (p > 0.05). However, the catalase levels were higher in the treatment supplemented with vitamin B at 2.50 mg/ml, when compared with other groups (p < 0.05). The extender supplemented with vitamin B significantly decreased glutathione peroxidase activity compared with the control (p < 0.05). The supplementation of 3.75 mg/ml vitamin B caused the highest value of glutathione reductase activity, compared with other groups (p < 0.05). In conclusion, the extender supplemented with vitamin B could reduce the oxidative stress provoked by freezing-thawing and improve bovine semen quality. Further studies are required to obtain more concrete results on the determination of lipid peroxidation and antioxidant capacities of vitamin B in cryopreserved bovine semen. [ABSTRACT FROM AUTHOR]