Effect of Gynostemma Pentaphyllum polysaccharide on boar spermatozoa quality following freezing-thawing

Gynostemma Pentaphyllum Polysaccharide (GPP) was added at concentrations of 0.25, 0.5, 1.0, 1.5 and 2.0 mg/ml to the extenders used to freeze boar semen and its effects on the quality of frozen-thawed sperm were assessed. The sperm motility was significantly higher in the extenders containing 0.25 and 0.5 mg/ml GPP, as compared to other groups (P<0.05). The extender supplemented with 0.5 mg/ml GPP favored the highest intact membrane and intact acrosome percentages in comparison with other groups (P<0.05), respectively. The mitochondrial activity was significantly higher at the concentrations of 0.25, 0.5 and 1.0 mg/ml GPP than that of other treatments, and the control group (P<0.05). In biochemical assays, the extender supplemented with 0.25 and 0.5 mg/ml GPP significantly improved SOD levels, compared to other groups (P>0.05). However, the extenders supplemented with GPP did not cause significant differences in levels of CAT and GSH-Px, compared to the control (P>0.05). In summary, GPP exhibited a dose-related response and the lower concentration produced greater protective effect. According to the standard semen quality parameters and antioxidant activities measured in this study, the concentration of 0.5 mg/ml GPP caused a beneficial cryoprotective effects on the quality of frozen-thawed boar semen. It is proposed that an extender containing 0.5 mg/ml GPP could be used as cryoprotective medium of better efficiency.