Evaluation of the oxidative status of periparturient mares supplemented with high amount of α-tocopherol

Aim of the study was to investigate the oxidative status during peripartum period in mares fed high amount of dietary alfa-tocopherol. Alfa-Tocopherol, ferric reducing ability of plasma (FRAP) and reactive oxygen metabolites (d-ROMs) levels were measured in blood samples from 17 Thoroughbred mares at three intervals: (1) 20 days before the expected foaling date; (2) 12h following parturition; (3) 7 days post-partum. The levels of alfa-tocopherol, d-ROMs and FRAP were retrospectively analysed in relation to the number of insemination services (Ins) after foaling performed per conception. The parameters alfa-tocopherol and d-ROMs evidenced minimal fluctuations during peripartum period while FRAP levels showed a linear decrease. The alfa-tocopherol did not show significant variations and was numerically higher in mares >10 years old while FRAP levels were significantly higher in older mares in the post-partum. Mares receiving three natural insemination services showed higher levels of FRAP in the pre-partum period (p=.009) and lower values of alfa-tocopherol (p=.015) in the postpartum compared to mares receiving one service. No d-ROMs level differences appeared among service classes. Oxidative stress is not present in periparturient mares fed 2.750IU of supplementary alfa-tocopherol. Differences in redox metabolism are detectable between young and old mares. Plasma antioxidant potential is higher in older mares particularly in the post-partum period.