Effects of Resveratrol and Epicatechin on Oxidative Damage and Bacterial Contamination in Boar Semen Following Short-Term Storage

The aim of this study was to evaluate the impact of natural polyphenols, resveratrol (RES) and epicatechin (EPI), on the oxidative balance, bacterial contamination and functionality of boar spermatozoa during short-term storage at 4 °C. Both biomolecules exhibit strong antioxidant and antimicrobial effects. Semen samples were collected from 15 adult Duroc boars and diluted in the Androhep Plus extender enriched with varying concentrations of RES or EPI (10, 25 and 50 µM). Selected parameters, including motility, mitochondrial activity, DNA fragmentation, protein oxidation (PO), lipid peroxidation (LPO) as well as the generation of reactive oxygen species (ROS) were analyzed after 24, 48 and 72 h. Exposure to 10 and 25 µM of RES significantly preserved motility (P<0.0001), increased mitochondrial function (P<0.0001), acrosome integrity (P<0.0001), and reduced the generation of ROS (P<0.0001), superoxide radicals (P<0.001, P<0.01) and LPO (P<0.001) after 24-72 h compared to the untreated control. In contrast, 50 µM of RES significantly decreased sperm motility (P<0.0001), membrane integrity (P<0.001), acrosome integrity (P<0.0001) as well as microbial growth (P<0.01). Following EPI treatment, 25 and 50 µM concentrations significantly preserved motility (P<0.0001), reduced ROS (P<0.0001; P<0.001), LPO (P<0.001) and superoxide production (P<0.001; P<0.01) compared to the control. Mitochondrial activity (P<0.0001), acrosome integrity (P<0.0001; P<0.001) and membrane integrity (P<0.0001) significantly increased in the groups enriched with 25 or 50 µM of EPI after 24-72 h. Furthermore, a significant decline (P<0.05) in microbial growth was observed in the group with the highest dose of EPI compared to the untreated group. Our findings suggest that RES and EPI may improve the quality of extended boar spermatozoa and exhibit antioxidant and antimicrobial properties. However, the application of both biomolecules depends on the dose and the duration of exposure.