Does age and parity affect the oxidative profile of pregnant and postpartum mares?

During gestation, there is a higher energy demand which increases oxygen requirements. As a result, there is an elevated production of reactive oxygen species. Notably, unlike in horses, the effects of maternal age and parity on women's oxidative profiles are well-documented. Thus, this study aimed to investigate oxidative changes in mares during the last third of gestation and the postpartum period, considering age and parity. Seventeen mares were categorized by age (3-7, 8-11, ≥12 years) and parity (nulliparous, 1-3, 4-6 parities). Oxidative processes were assessed using Thiobarbituric Acid Reactive Substances (TBARS), protein oxidation, total iron, and magnesium. Antioxidant defenses were measured through glutathione peroxidase, glutathione reductase, and superoxide dismutase activities. Results indicated an age and gestational duration interaction, notably with magnesium levels. Glutathione peroxidase levels were higher in older mares, with a time effect observed among groups. Conversely, glutathione reductase, superoxide dismutase, lipid and protein oxidation, and total iron showed no significant variations during the study. In conclusion, maternal age influences glutathione peroxidase and magnesium concentrations during the final trimester of gestation, parturition, and postpartum phases in mares. This research sheds light on oxidative variations in mares during pregnancy and postpartum, offering insights into the role of maternal age in antioxidant mechanisms.