Effect of Reduced Glutathione, Water Soluble Vitamin E Analogue and Butylated Hydroxytoluene on The Post Thaw Characteristics of Boar Spermatozoa

BACKGROUND: Antioxidant in freezing extender of boar semen improved post thaw sperm function. OBJECTIVE: The study compared the effects of reduced glutathione (GSH), water soluble vitamin E analogue Trolox and butylated hydroxytoluene (BHT) on quality of cryopreserved boar spermatozoa. MATERIALS AND METHODS: Using split sample technique three different antioxidants namely, GSH (1 mM), vitamin E (0.2 mM) and BHT (0.2 mM) were added to the freezing medium of lactose–egg yolk–glycerol extender, and samples were frozen using controlled freezing rate of 40°C/min from –6 to –140°C. Samples were evaluated for sperm motility, acrosomal status, plasma membrane integrity, mitochondrial membrane potential, lipid peroxidation and sperm DNA integrity after equilibration and after freezing. RESULTS: The supplementation of GSH, vitamin E and BHT resulted in significantly higher post thaw motility, live intact acrosome and plasma membrane intact sperm. The incidence of post thaw sperm lipid peroxidation was significantly reduced after addition of antioxidants. However, antioxidants treatment neither significantly improved mitochondrial membrane potential of live sperm sub–population nor sperm DNA integrity after freezing. There was no significant difference of the post thaw sperm characteristics among three antioxidants. Protective effect of GSH, vitamin E and BHT are comparable on cryopreserved boar spermatozoa.