Effect of Dietary Coenzyme Q10 on Cholesterol Metabolism in Growing Chickens

Coenzyme Q10 (CoQ10), a potent lipophilic antioxidant, is a naturally occurring compound with a ubiquitous distribution in nature and is used as a dietary supplement to combat aging. In rats, there is evidence that coenzyme Q9, major coenzyme Q homologue in rodents, suppresses hepatic cholestcrogenesis and decreases plasma total cholesterol concentration. In this study, we investigated the effect of dietary CoQ10 on cholesterol metabolism in growing chickens. The supplementation of CoQ10 in a diet significantly decreased the total cholesterol levels in the liver and plasma. Plasma very low density lipoprotein (VLDL) cholesterol concentration was significantly decreased by dietary CoQ10. The enzymatic activity of hepatic hydroxymethylglutaryl-coenzyme A reductase (HMGR), the rate-limiting enzyme of the cholesterol synthetic pathway, was significantly decreased by dietary CoQ10, whereas the mRNA level of HMGR was not affected. These findings suggest that dietary CoQ10 suppresses hepatic cholesterogenesis by the inhibition of HMGR activity at the posttranscriptional level in chickens, which in turn decreases plasma VLDL cholesterol concentration.