Comparative evaluation of the effect of antioxidants on the chilled-stored ram semen

The aim of this investigation was to assess the effect of different antioxidants on the motility and membrane integrity of the ram semen during storage at 5ºC for 0, 12, 24, 48 and 72 hrs after collection and dilution. A total of 57 ejaculates from 12 Bakhtiary rams was collected by artificial vagina and were extended 1: 3 with egg yolk-citrate buffer, which was containing one of the following antioxidants: BSA 1% (w/v), BSA 3%, BSA 1% + sucrose 10%, BSA 3% + sucrose 10%, vitamin E (1 mg), vitamin E (2 mg), ascorbic acid (0.9 mg/ml) and control group without any antioxidant. Percent of motile sperm (PMS), rate of forward movement (RFM) and membrane integrity in extenders contained vitamin E groups were significantly higher up to 48 hrs than other groups (P<0.05). Although, addition of 2 mg vitamin E was more effective than 1 mg vitamin E in sperm protection, however, the difference was not statistically significant. Likewise, addition of BSA alone or in combination with sucrose was superior to ascorbic acid in maintenance of sperm motility and membrane integrity. It seems that sucrose has not positive effect on these 3 parameters in combination with BSA. In conclusion, adding vitamin E to the extender of ram semen during dilution is superior in maintenance of sperm kinematic parameters up to 48 hrs during storage at 5ºC.