Antioxidant status of the lower oviduct in the chicken varies with age and dietary vitamin E supplementation

Protection of sperm membranes against lipid peroxidation is a pre-requisite to prolonged sperm storage, both in vivo and in vitro. As females from avian species can store spermatozoa in the utero-vaginal junction (UVJ) for prolonged periods, we investigated the mechanisms involved in antioxidative protection of the plasma membrane of chicken sperm in this region. Comparisons of concentrations in nonenzymatic (alpha-tocopherol, ascorbic acid, and GSH) and enzymatic (GSH-Px, SOD) antioxidants among the vagina, UVJ and uterus of sexually mature chicken hens revealed tissue-specific profiles, with higher ascorbic acid content and increased GSH-Px and SOD activity in the UVJ compared to other regions of the lower oviduct (vagina, uterus). Deterioration of the antioxidant profile in the UVJ was observed in aging hens, but it was partially compensated by dietary supplementation with vitamin E (130 ppm). It is concluded that the chicken UVJ provides a complex defense barrier against lipid peroxidation of the sperm membrane during in vivo storage, which can be partially improved by dietary supplementation with vitamin E. The protective effects of this barrier decline over time during the reproductive season.