Boar sperm functionality is related to α-tocopherol content after freezing-thawing.

Boar spermatozoa are sensitive to oxidative damage produced during cryopreservation. Our aim was to evaluate the participation of different antioxidants in the improvement of cryopreserved boar sperm functionality. Spermatozoa frozen with 200 μg ml(-1) α-tocopherol, 0.5 mm 17β-oestradiol or seminal plasma were used to evaluate sperm parameters and capacitation-like changes. The 17β-oestradiol and α-tocopherol concentrations were assessed by RIA and HPLC respectively. Motility was improved but lipid peroxidation and capacitation-like changes were diminished (P < 0.05) in antioxidant samples. A significant increase in 17β-oestradiol concentration was detected in 17β-oestradiol or seminal plasma samples. Alpha-tocopherol content increased in α-tocopherol, 17β-oestradiol or seminal plasma samples, obtaining the lowest level in the α-tocopherol ones. The 17β-oestradiol or seminal plasma components may be acting in the regeneration of the α-tocopherol antioxidant capacity. The α-tocopherol concentration may be conditioning the cryopreserved boar sperm functionality. The addition of antioxidants could be useful to reduce oxidative stress, thus improving the functionality of cryopreserved boar spermatozoa.