Effect of antioxidants resveratrol and quercetin on in vitro evaluation of frozen ram sperm

The objective was to assess the effects of the antioxidants resveratrol and quercetin on frozen-thawed ram sperm. Semen samples (which exceeded minimum standards) from four mature crossbreed Santa Inês rams were pooled and aliquots of each pool were diluted in Tris-egg yolk-glycerol, with the addition of 0, 5, 10, 15, and 20 μg/mL of resveratrol and quercetin in Experiment 1 and Experiment 2, respectively. In Experiment 1, the proportion of sperm with a high mitochondrial membrane potential was greater (P < 0.02) in the control group than in resveratrol 20 μg/mL group. In Experiment 2, the proportion of sperm with high mitochondrial membrane potential was greater in the control group (P < 0.0001) than in the other experimental groups, and greater in the quercetin 5 μg/mL group (P < 0.05) than in the other quercetin-treated groups. Thus, addition of 5 to 20 μg/mL of either resveratrol or quercetin to the Tris-egg yolk-glycerol extender reduced sperm mitochondrial membrane potential.