Oxidant/antioxidant status during foal heat in Arab mares and their relation to ovarian hormones

ObjectiveTo study the role of some oxidative stress biomarkers in conception during foal heat.MethodsUltrasound scanning was used to confirm the presence of mature ovulating follicle (>30mm) in mares exhibited foal heat on days 7 to 9 postpartum. Daily blood samples were collected from parturition till foal heat to measure equine lysozymes, nitric oxide (NO), catalase (CAT), total proteins and globulins. Lipid peroxide (MDA), reduced glutathione (GSH), ascorbic acid (AA) and zinc were measured during foal heat expression form day 7 to 10 post foaling.ResultsLysozymes were high on days 1 and 9 postpartum but low level was recorded on day 6. NO, total proteins and globulin peaked on days 5 and 6 but low level was recorded on day 9. High MDA (P<0.03), zinc (P<0.05) levels were observed on days 8 and 9. High GSH was observed on day 9. AA (P<0.03) and CAT levels were low on days 8 and 9. Non conceived mares had high MDA, low zinc, AA, CAT and GSH.ConclusionsMares during the foal heat are subjected to oxidative stress on days 8 and 9 as expressed by low AA, zinc, and GSH and high MDA and mares with sufficient antioxidant capacity can overcome this stress and conceive. Some mares need to be supplied during foal heat with antioxidants to improve their immunity and overcome oxidant/antioxidant imbalance to conceive. This study recommends the use of ascorbic acid and zinc as supplements during foal heat.