Effect of Antioxidant Supplementation on Systemic Oxidative Status in Breeding Stallions During Intensive Semen Collection

Breeding stallions are subjected to increased metabolic and physiological demands during the reproductive season, which may lead to enhanced production of reactive oxygen species and disruption of redox balance. The present study evaluated the effects of dietary antioxidant supplementation on oxidative status, metabolic profile, and hindgut fermentation in stallions undergoing intensive semen collection activity. Ten adult breeding stallions were assigned either to a control group or to a treatment group receiving a commercial antioxidant supplement (Oxyliver^®) for 60 days, followed by a 60-day post-supplementation period. Blood and fecal samples were collected at regular intervals to assess hematological, biochemical, oxidative, and fermentation parameters. Hematological and biochemical variables remained within physiological ranges throughout the study, with no significant treatment-related effects, indicating that the supplementation was safe and well-tolerated. In contrast, during the supplementation period, oxidative status was significantly influenced by the antioxidant treatment, as demonstrated by reduced lipid peroxidation and increased total antioxidant capacity (TAC) and ferric reducing antioxidant power (FRAP). These findings indicate an enhancement of systemic antioxidant defenses. In conclusion, dietary antioxidant supplementation effectively improved oxidative balance in breeding stallions without adversely affecting metabolic health, supporting its potential use as a nutritional strategy to mitigate oxidative stress associated with intensive reproductive activity.