Alpha – Tocopheryl Succinate in Extender Improves The Post Thaw Quality of Water Buffalo Spermatozoa

BACKGROUND: Alpha – tocopheryl succinate, a major chain-splitting antioxidant, is the most effective form of vitamin E and may be used in the semen extender for the cryopreservation of buffalo spermatozoa. OBJECTIVE: To use different concentrations of alpha – tocopheryl succinate (T1, 0.3 mM, T2, 0.6 mM, and T3, 0.9 mM) and control (0.0 mM) in extender for dose optimization and hence improve the frozen – thawed quality of water buffalo spermatozoa. MATERIALS AND METHODS: Semen samples were collected from three mature buffalo bulls with an artificial vagina (42°C) and this study was replicated five times. Semen was cryopreserved by a conventional method, which included placing semen into 0.5 mL French straws, sealing with polyvinyl alcohol powder, holding 5 cm above the liquid nitrogen vapours for 12 min and then storing in liquid nitrogen. Frozen-thawed semen was also processed for total antioxidant capacity content (TAC) and lipid peroxidation (LPO) level by thiobarbituric acid (TBA). Computer-assisted semen analysis (CASA) and other assays were also performed. RESULTS: TAC levels were higher (P<0.05) with T2 and T3 as compared to T1 and control. LPO levels were lower (P<0.05) with T2 and T3 as compared to T1 and control. Sperm progressive motility (%) and rapid velocity (%) were higher (P<0.05) with T2 and T3 as compared to control. The extender containing T3 had higher (P<0.05) sperm average path velocity ( μm/s) and straight line velocity ( μm/s) as compared to control. At 1 and 2 h incubation period (37 °C) T2 and T3 in extenders had higher (P<0.05) progressive motility and rapid velocity compared to the control. Sperm supra vital plasma membrane integrity (%), mitochondrial transmembrane potential (%), viable and intact acrosome (%) and DNA integrity (%) were higher (P<0.05) with T2 and T3 as compared to T1 and the control, respectively. CONCLUSION: The supplementation of alpha – tocopheryl succinate in extender, either at 0.6 (T2) or 0.9 (T3) mM concentration improves the post thaw quality of water buffalo spermatozoa by sustaining the TAC levels and keeping the LPO levels lower as compared to the control. It is suggested that future studies should explore the influence of these optimal concentrations of alpha – tocopheryl succinate on the in vivo fertility of buffalo bull spermatozoa.