Supplementation of Enzymatic and Non-enzymatic Antioxidants to the Extender improves Sperm Functionality during Storage at 4°C in Labrador Dog

Several extenders to preserve fertilizing capacity of preserved canine semen have been successfully tested, but further studies are requisite to improve its quality. Effect of supplementation of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPX) and glutathione (GSH) to Tris-citric acid-fructose-egg yolk extender on Labrador dog sperm survival during storage at 4° was evaluated. Different concentrations per antioxidant i.e. SOD (50-300 IU/ml), GPX (1.5-2.5 IU/ml), CAT (100-400 μg/ml) and GSH (2.5-10 μM/ml) were evaluated to look for an optimum dose. Semen was analyzed for motility, viability and plasma membrane integrity (PMI) after every 24 hrs till 72 hrs of preservation. Semen was also analyzed for acrosome integrity (AI) at 0, 72 hrs and lipid peroxidation at 72 hrs of storage. Values for motility, viability, PMI, AI were significantly (p<0.05) higher in the presence of 200IU/ml SOD, 2 IU/ml GPX, 200 μg/ml CAT and 7.5 μM/ml GSH compared to control and other tested doses. MDA concentration was non-significantly (p>0.05) less in the presence of all doses of SOD and 2.0 IU GPX compared to control at 72 hrs of preservation. MDA concentration in the presence of 200 μg/ml catalase and 7.5 μM/ml GSH was non-significantly (p>0.05) higher than control. It was concluded that SOD, catalase, GPX and GSH at a concentration of 200 IU, 2.0 IU, 200μg and 7.5 μM per ml were optimum concentrations to be supplemented to the extender for positive effect. Supplementation of antioxidants could improve sperm attributes by maintaining proportionate level of oxidative stress during preservation of Labrador dog semen at 4° for 72 hrs.

• Effect of supplementation of different doses of antioxidants was observed on semen during preservation at 4°C.

• SOD, catalase, GPX and GSH at a concentration of 200 IU, 2.0 IU, 200μg and 7.5 μM per ml were optimum concentrations to be supplemented to the extender for positive effect.