Reza Asadpour - Department of Clinical Sciences, Faculty of Veterinary Medicine, University of Tabriz, Tabriz, Iran
Razi Jafari - Department of Clinical Sciences, Faculty of Veterinary Medicine, University of Tabriz, Tabriz, Iran
Hossein Tayefi - Nasrabad - Department of Basic Sciences, Faculty of Veterinary Medicine, University of Tabriz, Tabriz, Iran

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 semen's were collected from ۵ bulls and diluted to a concentration of ۳۰ × ۱۰۶ sperm/mL with citrate –egg yolk (CEY) or Tris – egg yolk (TEY) extenders. The diluted semen was divided to ۵ aliquots including control and ۴ 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 ۱mM or ۲mM and vitamin E ۰.۱mM or ۰.۲mM, 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 ۱mM vitamin C and ۰.۱ mM vitamin E to CEY extender (P < ۰.۰۵). The highest sperm viability was achieved by addition of ۰.۱mM vitamin E to CEY extender. Supplementing CEY extender with ۲mM vitamin C and ۰.۱mM 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.

Antioxidant, Sperm, Lipid peroxcidation, Cryopreservation