Addition of antioxidants improves quality of ram spermatozoa during preservation at 4 °C

The aim of this study was to investigate the effects of different antioxidants on the quality of ram spermatozoa. For this purpose, ejaculates were collected from six adult healthy rams and extended with Tris egg yolk fructose extender without (Control) or with different antioxidants like ascorbic acid (4.5 mg/ml), butylated hydroxytoluene (BHT, 1 mM) and taurine (25 mM) and stored up to 72 h at 4 °C. The quality of spermatozoa on the basis of percentage of sperm motility, live sperm, morphological abnormalities, intact acrosome and hypoosmotic swelling test (HOST) reacted spermatozoa was evaluated at 0, 24, 48 and 72 h of preservation at 4 °C. The percent sperm motility was significantly (P < 0.01) higher in BHT and taurine and significantly (P < 0.01) lower in ascorbic acid than the control at 72 h of preservation. The percent live sperm did not differ significantly (P > 0.05) amongst the extenders containing different antioxidants and the control. The morphological abnormalities were significantly (P < 0.01) lower in BHT and taurine than ascorbic acid and control during preservation up to 72 h at 4 °C. The percent HOST reacted spermatozoa was significantly (P < 0.01) higher for BHT and significantly lower (P < 0.01) for ascorbic acid than control. The percent intact acrosome was significantly (P < 0.01) higher in all the extenders containing antioxidants than control. In conclusion, BHT and Taurine were found to improve the quality of ejaculated ram spermatozoa during preservation for 72 h at 4 °C.