Assessment of the oxidant-antioxidant blood balance in a field exercise test in Standardbred and eventing horses

The aim of this study was to determüie which oxidant-antioxidant blood markers are of interest for a field exercise test (ET) performed on a racetrack. Healthy Standardbred herses (S: n = 12) and healthy eventing horses (E: n = 12) were investigated. Exercice was monitored by measuring velocity (V), heart rate (HR), and plasma lactate (LA). Whilst maximal LA did sot Biffer (11.8 ± 0.88 mmoll-1), maximal V (S: 12.3 ± 0.17ms-1 versus E: 11.1 ±0.24ms-1, P < 0,05) and final HR (S: 222 ±1 versus E: 203 ± 8 beats min-1, P < 0.03) were significantly différent between groups. Venous was collected at rest (R) prior to ET and The following oxidant-antioxidant markers were detennitted: uric acid (UA), ascorbic acid (AA), alpha-tocopherol (Vit E). vitamin A (Vit A), superoxide cüsmutase (SOB), glutaYhione peroxidase (GPx), glutathione (reduced: GSH and oxidized: GSS(r), glutathione redox ratio (GRR), copper (Cu), zinc (Zn) and sélénium (Se), uxidized proteins (Protox), lipid prrosides (Pool), antioxidant capacity of water-soluble comporteras (ACW) and antioxidant capacity of lipid-soluble components (ACW). The following markers were further determined 15 min (E15) after the ET:UA, ACW; AA, GSH, Proton, Pool, ACL. Standardbreds had significantly higher concentrations of ACW, GSH, ACL and Protox, whilst Se, Zn and SOI) were significantly lover than in eventing horses. Exercice induced a significant increase in ACW and UA. GSH decreaced in eventing horses and Pool significantly decreased in both horse groups. This study describes a field ET of high intensity for Standardbred and eventing horses, which could be performed by all animals tested. By sampling blond al rest and at E15, changes of thé hydrophilic antioxidant defence were partially assessed, whereas no interpretable changes of the lipophilic antioxidants and of oxidation markers (Protox, Pool) could be detected