The effect of different levels of Vitamin E in semen extender during the cooling on Caspian stallion sperm quality

The purpose of this study was to determine the effects of different concentrations of vitamin E (Vit. E) in the quality of preserved stallion semen at 5ᵒC for a period of 48 h. Semen was collected and most (≥90%) seminal plasma removed by centrifugation at 600 × g. Pooled samples divided in four equal parts and diluted with extenders that was supplemented with different concentrations of Vit. E [(0 (control، C)، 5 and 10 mM)] and DMSO positive control group [as vitamin E solvent، (DC)] to a final concentration of 50 × 106 sperm/ml. Motility، viability، plasma membrane integrity، total abnormality and lipid peroxidation were determined at 0، 6، 24 and 48h. The results showed that 5mM vitamin E resulted in higher viability and plasma membrane integrity compared to control after 48 h of storage (P<0. 05). Different concentrations of vitamin E had no significant effects on sperm motility and total abnormality compared to C and DC extender (P>0. 05). Also، 5mM Vit. E was decreased lipid peroxidation compared C and DC extenders after 48h of storage (P<0. 05). In conclusion، between above-mentioned different concentrations، 5mM Vit. E could improve Caspian stallion sperm quality during cooled-storage at 5°C.