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.