Coenzyme Q10 in Equine Serum: Response to Supplementation

Although the importance of coenzyme Q10 (CoQ10) in health and disease and its critical role in cellular bioenergetics have been well established in various species, there is a total lack of information on the role of CoQ10 in horses. Therefore, the present study was undertaken first to ascertain the occurrence of CoQ10 and/or possibly other homologs of coenzyme Q (CoQ) in horse serum, and then to examine the response to CoQ10 supplementation on serum CoQ10 concentration. The study was carried out with 2-year-old Thoroughbred horses. Total CoQ (reduced and oxidized forms) in serum was assayed by high-performance liquid chromatography. The data show that horse serum contains CoQ as CoQ10, at a much lower concentration as compared with that of humans and several other species. There is no evidence for the presence of coenzyme Q9 or other homologs of CoQ. On supplementation with CoQ10 at 800 mg a day (1.47 mg/kg body weight), there was a significant increase in serum CoQ10 concentration, approximately 2.7-fold at 60 days. CoQ10 supplementation at this dosage was found to be safe and well tolerated. Additional studies are needed to examine whether maintaining higher serum CoQ10 concentrations is of potential health benefit to the horses, as assessed by selected biochemical markers and also in terms of performance.