Effects of astaxanthin supplementation on the sperm quality and antioxidant capacity of ram semen during liquid storage

The aim of this study was to evaluate the effects of astaxanthin (AST) supplementation of semen extender on the quality of ram semen during storage at 4 degrees C for periods up to 72 h. Semen samples were obtained from five Small-tail Han rams by use of artificial vagina during normal reproduction season (August to October in 2014), and diluted with glucose-egg yolk buffer supplemented with 0 (control), 0.5, 1, 2, or 4 mu M AST. The results showed that supplementation of the extender with 2 mu M and 4 mu M of AST increased sperm vitality and plasma membrane integrity (P<0.05), and significantly reduced malondialdehyde and reactive oxygen species levels during the 72 h storage period (P < 0.05). Acrosome integrity did not differ among treatments. After 72 h of storage in extender, samples were analyzed with computer-assisted semen analysis. The motility of sperm in the 2 mu M and 4 mu M AST treatment groups increased significantly (P < 0.05) compared to the control treatment, while curvilinear velocity, progressive velocity, and path velocity were not affected. In conclusion, the present study demonstrated that supplementing semen extender with AST can improve ram semen preservation via protecting plasma membrane integrity. (C) 2015 Published by Elsevier B.V.