Effect of a-tocopherol acetate and ascorbic acid in extender on quality of zebu bull spermatozoa

The experiments were designed to determine the effect of a-tocopherol acetate and ascorbic acid in extender on post-thaw motility,plasmalemma functionality,viability and chromatin damage of zebu bull spermatozoa. semen collected from three bulls of sahiwal breed (bos indicus) was diluted with tris-citric acid extender either containing a-tocopherol acetate or ascorbic acid at 0.5,1.5,2.5 and 3.5 mm or without any supplement (control) and cryopreserved. for each extender,thawing of three semen straws was performed at 37°c for 30 seconds for the assessment of sperm quality parameters. sperm motility (%) remained similar in extenders containing a-tocopherol at 0.5. 1.5,2.5 mm and control. sperm plasmalemma functionality (%) was recorded higher (p < 0.05) in extender containing 0.5,1.5 and 2.5 mm a-tocopherol acetate than control. sperm viability (%) was observed higher (p<0.05) in extender containing 0.5 mm a-tocopherol acetate. sperm chromatin damage was similar (p > 0.05) in all experimental extenders containing a-tocopherol acetate and control. extenders containing ascorbic acid 0.5,1.5,2.5,3.5 mm did not improve sperm motility,plasmalemma functionality,viability and chromatin integrity. in conclusion,a-tocopherol acetate (0.5 mm) in extender improved the plasmalemma functionality and viability of frozen-thawed zebu bull spermatozoa. copyright © 2012 zoological society of pakistan.