Plasma Coenzyme Q10 and Tocopherols in Thoroughbred Race Horses: Effect of Coenzyme Q10 Supplementation and Exercise

The fundamental role of coenzyme Q10 (CoQ10) in cellular bioenergetics is well established in humans and several other species, yet there is no information about its role in horses. In continuation of our study of serum CoQ10 in Thoroughbred race horses, we examined the effect of CoQ10 supplementation and exercise on changes in plasma CoQ10 and α- and γ-tocopherol concentrations. Two groups of horses, five per group, were used. One group received 1.9 g of CoQ10 daily and the second group 3.4 g as a dietary supplement. Both groups were subjected to graduated training sessions that involved low-intensity exercise (gallop) followed by high-intensity exercise (breeze). CoQ10 supplementation resulted in a significant increase in plasma CoQ10 during low-intensity exercise, whereas the increase following high-intensity exercise was markedly attenuated in both groups (P < .05). There were no changes in plasma α- and γ-tocopherol concentrations following the two exercise sessions. γ-Tocopherol constituted approximately 5% of α-tocopherol; this is the first report of plasma γ-tocopherol in horses. The attenuated response of plasma CoQ10 in horses receiving CoQ10 supplementation following high-intensity exercise may be attributed to its consumption during severe oxidative stress. This finding indicates that in horses not receiving any CoQ10 supplementation, high-intensity exercise would result in a marked depletion of endogenous CoQ10 in plasma, which could compromise their health and physical performance. This documents the importance of CoQ10 in horses. The study also establishes the safety and tolerability of high-dose CoQ10 in Thoroughbred race horses.