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 semen's 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.