Chilled Storage of Stallion Semen Using Perfluorochemicals and Antioxidants

Abstract

Successful preservation of stallion spermatozoa is difficult because sperm damage occurs from lipid peroxidation during storage. We investigated the use of antioxidants with a standard skim milk extender and several gas environments during storage of stallion spermatozoa to reduce the harmful effects of oxygen while maintaining sperm metabolism. The antioxidant treatments were: ascorbic acid, reduced glutathione, tempol, quercetin, or no antioxidant. The gas environments were: perfluorochemical (PFC) charged with nitrogen, oxygen, 95% oxygen:5% carbon dioxide, or vacuum, or no PFC. Each of the five antioxidant treatments was combined with each of the five gas environment treatments for a total of 25 treatments. Sperm viability was assessed by motility rating, membrane integrity, and internal ATP concentration at 48, 96, and 144 h of storage. Antioxidant effectiveness was assessed using xanthine-xanthine oxidase challenge. Any treatment with PFC charged with oxygen resulted in lower sperm motility and a lower percentage of membrane-intact cells than any other treatment. Sperm subjected to any PFC treatment had higher internal ATP concentrations compared with sperm stored in the standard extender. Sperm stored in any quercetin treatment had higher motility, higher percentage of membrane-intact cells, and higher ATP content than sperm stored in any other antioxidant medium or standard extender. In addition, quercetin and tempol were successful in preventing lipid peroxidation while glutathione and ascorbic acid functioned as pro-oxidants in the challenge. We conclude that the viability of stallion sperm can be maintained during storage with the use of PFC charged with vacuum or nitrogen to exclude oxygen, and with the antioxidant, quercetin, in the extender to prevent peroxidative damage and improve the efficiency of energy use in the sperm.