In vitro evaluation of Saanen buck semen frozen in different extenders supplemented with various antioxidants

Abstract

The aim of this present study was to investigate the effects of extenders containing different antioxidants upon the principle sperm characteristics of Saanen buck semen following freezing. In this study, four bucks were used. Semen was collected twice a week by an artificial vagina during the breeding season to obtain ten ejaculates per animal. The samples were then extended in three extenders (tris, T-, skimmed milk, M-and laiciphos 488, L-based) without (as controls) or with the two antioxidants (5 mM cysteine, C and 1000 μg/ml hyaluronic acid, H). By this way, nine experimental groups were assigned, as follows: T-C, T-H, T-O (control); M-C, M-H, M-O (control); L-C, L-H, L-O (control). For the T extender groups, the rates of motility and viability were significantly (p<0.01) higher for the T-C extender as compared to those of the T-H and T-O. However, there was no such difference (p>0.05) among the extenders based on the rates of abnormal spermatozoa, abnormal acrosome and hypoosmotic swelling (HOS) test. For the M groups, the motility was significantly (p<0.01) higher for the M-C and M-O extenders as compared to that of the M-H. However, there was no such difference (p>0.05) among the extenders based on the rates of viability, abnormal spermatozoa, abnormal acrosome and HOS test. For the L groups, the rates of motility and viability were significantly (p<0.01) higher for the L-C extender as compared to that of the L-H but not that of the L-O. Additionally, there was no such difference (p>0.05) among the extenders mentioned above based on the rates of abnormal spermatozoa, abnormal acrosome and HOS test. As a result, the present in vitro findings of semen quality parameters studied suggest that; i) both skimmed milk and laiciphos extenders were more favourable than tris, and that ii) the cysteine, as an antioxidant, provided a superior protection than the hyaluronic acid did.