Investigation of the physiological effects of uridine on Nile Tilapia (Oreochromis niloticus)

Abstract

Uridine, an essential nucleoside involved in various physiological and biochemical processes, has been shown to influence hepatic fat accumulation. However, its broader physiological roles in aquaculture species like Nile tilapia remain underexplored. This study aimed to systematically assess the effects of uridine on Nile tilapia physiology. Nile tilapia (3.58 ± 0.02 g) were fed with different levels (0, 1, and 4 g/kg) of uridine for 10 weeks. The supplementation with 4 g/kg uridine significantly increased the carcass ratio and total protein of whole fish by 4.18 % and 4.08 %, respectively, and reduced the viscerosomatic index and total lipid of whole fish by 12.76 % and 20.48 %, respectively. Supplementation with 4 g/kg uridine increased the expression of protein synthesis genes. The supplementation of uridine suppressed the expression of fatty acid synthesis genes and promoted the expression of lipolysis-related genes by the activation of AMP-activated protein kinase (AMPK). This activation led to a significant decrease in both liver and serum triglyceride levels. The administration of 4 g/kg uridine significantly reduced hepatic cholesterol levels by inhibiting the expression of cholesterol synthesis-related genes. Additionally, 4 g/kg uridine notably augmented the liver's antioxidant capacity, thereby promoting the hepatic health. Furthermore, addition of uridine elevated the intestinal villi height, improved intestinal barrier integrity, and reduced intestinal inflammation response. Therefore, this study suggested that dietary supplementation of uridine can promote protein deposition and improve hepatic and intestinal health in Nile tilapia.