EFFECTS OF ANTIOXIDANTS ON MOTILITY AND MEMBRANE INTEGRITY OF CHILLED-STORED STALLION SEMEN

The use of chilled-stored stallion semen is limited by its relatively short-term fertilizing capacity. An important reason for the decrease in fertility during storage is the peroxidation of sperm membrane lipi ds. In this study, effects of the antioxidants ascorbic acid (0.45 and 0.9 g/L) and catalase (0.45 x 10(6) and 1.8 x 10(6) units/L) on chill ed-stored stallion semen were investigated. Semen was collected by art ificial vagina from 7 stallions and was diluted with skim mill: extend er or glycin extender. Sperm motility and membrane integrity were inve stigated after dilution and after 24, 48 and 72 h at 5 degrees C. Asco rbic acid significantly increased the percentage of membrane-intact sp ermatozoa at 24, 48 and 72 h at 5 degrees C when compared with that of the controls (P<0.05), irrespective of the extender. Ascorbic acid de creased the percentage of progressively motile spermatozoa (P<0.05) at a concentration of 0.9 g/L in glycin extender. Catalase decreased (P< 0.05) progressively motile spermatozoa after 24, 48 and 72 h at 5 degr ees C in skim milk extender at a concentration of 1.8 x 10(6) units/L. Catalase decreased (P<0.05) the percentage of membrane-intact spermat ozoa at 24 h. Motility and membrane integrity of spermatozoa after dil ution with glycin extender containing catalase did not differ from the controls. In conclusion, ascorbic acid has protective effects on sper m membrane integrity in diluted stallion semen. (C) 1997 by Elsevier S cience Inc.