Influence of Added Vitamin C and Vitamin E on Frozen-Thawed Bovine Sperm Cryopreserved in Citrate and Tris-Based Extenders

The objective of this study was to evaluate quality of frozen-thawed bull semen processed with extenders containing vitamin C and E as antioxidants. Pooled semenʹs were collected from 5 bulls and diluted to a concentration of 30 × 106 sperm/mL with citrate –egg yolk (CEY) or Tris – egg yolk (TEY) extenders. The diluted semen was divided to 5 aliquots including control and 4 experimental groups. Each aliquot was further diluted with an equal volume of CEY or a Tris (hydroxymethyl) aminomethane (TRIS) - based extender without (control) or containing vitamin C 1mM or 2mM and vitamin E 0.1mM or 0.2mM, and routine semen evaluations like sperm motility, viability and measurement of lipid peroxidation (LPO) were conducted. Significant reductions of LPO were achieved by addition of 1mM vitamin C and 0.1 mM vitamin E to CEY extender (P < 0.05). The highest sperm viability was achieved by addition of 0.1mM vitamin E to CEY extender. Supplementing CEY extender with 2mM vitamin C and 0.1mM vitamin E improved the sperm motility compared with the control group. On the basis of the present results it is concluded that vitamin C and E are very efficient antioxidants in CEY extender.