Effect of Antioxidants on Cryopreservation of Ram Semen

Antioxidants are two types in terms of mechanism of their action. In the first group, the antioxidants retard the oxidation by breaking the autoxidation chain, called primary antioxidants. Whereas, the second group are secondary antioxidants that prevent the onset of oxidation. Because some antioxidants have multiple mechanisms of action, they are called as multi-functional antioxidants. Antioxidative defence mechanisms comprise some vitamins, chemical substances and various antioxidant enzyme, such as vitamins A, E, C, β-carotene, reduced glutathione (GSH). Vitamin E shows strong antioxidant property due to the phenolic hydroxyl group in its structure. It builds the first defence line that protects from free radical damage the PUFA in membrane phospholipids by chain breaker antioxidative activity. The most important antioxidant enzymes are superoxide dismutase (SOD) that converts the superoxide anion to H2O2, glutathione peroxidase (GSH-Px) that detoxifies the organic peroxides and catalase that reduces the H2O2 to H2O. Ram semen is rather sensitive against the cryopreservation, since the unsaturated fatty acids constitute the major part of sperm membrane. During the semen cryopreservation processes, sperm membrane suffers from damage. This causes to deteriorated architecture in terms of fertilisation. Supplementation of antioxidants minimises the damages related with cryopreservation of semen.