Effects of Dietary Supplementation of Coenzyme Q10 on Growth Performance, Biochemical and Physiological Attributes of Rainbow Trout ( Oncorhynchus mykiss )

ABSTRACT Background Coenzyme Q10 (CoQ10) is a natural antioxidant and plays a vital role in the energy production of animal cells; however, its physiological and biochemical properties in fish are unclear. Objectives The current experiment was investigated to explore the effects of dietary CoQ10 on growth performance and biochemical and physiological attributes of rainbow trout ( Oncorhynchus mykiss ). Methods A 56‐day feeding trial was conducted with 5 experimental diets supplemented with CoQ10 concentrations at 0, 25, 50, 100 and 200 mg kg −1 of diet and fed to 400 rainbow trout (10 ± 0.1 g, initial body weight). Results Dietary supplementation with CoQ10, especially at the highest dietary level, significantly improved the feed conversion ratio, final body weight and lipid and protein efficiency ratio of fish ( p  < 0.05). Moreover, the fish carcass protein and lipid content significantly increased with supplementation of 200 mg CoQ10 kg −1 diet ( p  < 0.05). The blood serum levels of triglycerides (TGs), cholesterol (CHO) and uric acid significantly reduced, whereas albumin, total protein, high‐density lipoprotein and lymphocyte count increased with supplementation of 200 mg CoQ10 kg −1 diet ( p  < 0.05). Administration of 100 mg CoQ10 kg −1 diet significantly reduced the liver gene expression of sterol regulatory element‐binding protein1 (SREBP1), whereas supplementation with 200 mg CoQ10 kg −1 diet increased muscle gene expression of SREBP1 ( p  < 0.05). However, there were negative associations and correlations between blood TGs and CHO levels with liver and muscle SREBP1 gene expression. Conclusions Overall, dietary supplementation of CoQ10, particularly at the levels of 100–200 mg kg −1 of diet, can improve growth performance and health in rainbow trout by modifying blood metabolites and SREBP1 gene expression.