The effects of melatonin, glutathione and vitamin E on semen cryopreservation of Mediterranean buffalo.

The aim of this study was to investigate the effects of melatonin (MLT), reduced glutathione (GSH) and vitamin E (Vit. E) or their combinations on semen cryopreservation of Mediterranean buffalo. The quality parameters such as viability, abnormality rate, motility, structural integrity and the antioxidant capacity of frozen-thawed sperm were evaluated. The efficiency of frozen-thawed sperms in performing their functions was further analyzed by in vitro fertilization (IVF). In those separately supplemented groups, 0.2 mg/mL MLT, 0.2 mM GSH and 0.4 mg/mL Vit. E had the best effect on antioxidant capacity, kinetics and morphology, respectively. In addition, the cleavage, blastocyst and hatching blastocyst rates of IVF embryos were higher in 0.2 mg/mL MLT, 0.2 mM GSH, 0.2 and 0.4 mg/mL Vit. E groups than the blank control. Among the three combination groups, the kinetics and structure integrity of frozen-thawed sperms, cleavage, blastocyst and hatching blastocyst rates of IVF embryos were higher in 0.4 mg/mL Vit. E plus 0.2 mg/mL MLT group than the blank control group, revealed that this combination had comprehensive protection on frozen-thawed sperm of Mediterranean buffalo. These results support to develop special semen freezing extender containing an optimal choice of MLT, GSH and Vit. E, and to enhance the efficiency of frozen-thawed sperm of Mediterranean buffalo for IVF.