Effects of trehalose supplementation on semen quality and oxidative stress variables in frozen-thawed bovine semen.

The antioxidant systems of superoxide dismutase (SOD), catalase (CAT), reduced glutathione (GSH), and glutathione peroxidase (GSH-Px) are important in maintaining sperm motility and viability. The purpose of this study was to determine the effects of varying doses of trehalose on in vitro semen quality variables and antioxidant activities of frozen-thawed bovine semen. The semen samples, diluted with an extender containing trehalose (0, 25, 50, 100, and 200 mM), were evaluated. The extender supplemented with 100 mM trehalose exhibited the greatest percentages of sperm motility, acrosomal membrane integrity, and plasma membrane integrity in comparison with the control group (P < 0.05). No difference was observed for sperm motility between trehalose 50 and 100 mM groups (P > 0.05). Extender supplemented with trehalose did not affect SOD levels. Compared with the other groups, CAT was greater with the supplementation of trehalose at 100 and 200 mM (P < 0.05). The extender supplemented with trehalose had enhanced GSH-Px activity compared with the control group (P < 0.05). However, increasing the doses of trehalose (100, 200 mM) decreased GSH-Px activity, compared with 50 mM trehalose (P < 0.05). Compared with the other groups, trehalose at the concentration of 25 and 50 mM increased GSH activity (P < 0.05). The application of 200 mM trehalose produced the least amount of GSH activity among all of the groups (P < 0.05). In conclusion, extender supplemented with trehalose reduced the oxidative stress induced by freeze-thaw and improved measures of bovine semen quality. The antioxidant characteristics of trehalose may be related to its effectiveness in membrane cryopreservation. Further studies are required to obtain more concrete results on the determination of lipid peroxidation and antioxidant capacities of trehalose in cryopreserved bovine semen.