RESUMO
BACKGROUND: The quality of frozen semen can be improved by supplementing Tris extender with antioxidant to prevent oxidation and maintain sperm motility. OBJECTIVE: To study the effects of adding combinations of suitable concentrations of butylated hydroxy toluene (BHT) and Vitamin E in Tris extender on the quality of frozen goat semen. MATERIALS AND METHODS: A total of 40 ejaculates collected from five Beetal bucks were used to study the effect on the quality of frozen semen of supplementing Tris extender with 200 µM BHT, 2 mM Vitamin E and 200 µM BHT + 2 mM Vitamin E. RESULTS: The sperm motility, live sperm, live intact acrosome and HOST-reacted sperm differed significantly (P<0.01) between stages and between antioxidants. There was no significant difference (P<0.05) in interaction between stages (equilibration, freezing) and antioxidants, except for HOST-reacted sperm. Critical difference test revealed that Tris extender containing 2 mM vitamin E showed significantly (P<0.05) higher sperm motility, live sperm, live intact acrosome and HOST-reacted sperm, and significantly (P<0.05) lower release of alanine transaminase (ALT) and aspartate transaminase (AST). CONCLUSION: Supplementation of Tris extender with 2 mM vitamin E maintained superior quality of frozen Beetal buck semen.