The effects of dietary vitamin D3 on lipid metabolism in turbot (Scophthalmus maximus. L)

Vitamin D 3 (VD 3 ) plays a crucial role in multiple physiological processes. This research examined the impact of VD 3 on lipid metabolism in turbot ( Scophthalmus maximus . L). Juvenile turbot (initial weight: 13 ± 0.08 g) were fed diets containing 0, 400, or 1600 IU/kg VD 3 over an 8-week period. Results showed a reduction in hepatic lipid content in fish fed VD 3 . Additionally, VD 3 inhibited the expression of genes associated with lipid synthesis and breakdown, leading to lower triglyceride accumulation in the liver. Cholesterol-related gene expression ( srebf1 , srebf2 , hmg-coar ) was also suppressed, resulting in decreased total cholesterol levels. Furthermore, lipid droplet synthesis was minimized due to the downregulation of plin2 gene expression, accompanied by reduced activity of AST and ALT enzymes and decreased apoptosis-related gene expression ( fadd , caspase3 , bax ). In summary, dietary VD 3 significantly alleviated hepatic triglyceride and cholesterol accumulation, modulated lipid metabolism processes, and supported liver health in turbot, thereby underscoring its significance in optimizing fish nutrition and aquaculture practices. • Vitamin D 3 (VD 3 ) supplementation significantly reduced lipid metabolism pathways in the liver of turbot. • VD 3 lowered serum and hepatic triglyceride levels by inhibiting key genes involved in hepatic lipid metabolism. • VD 3 suppressed genes involved in cholesterol synthesis, lowering total cholesterol levels in both serum and liver. • VD 3 decreased the content of lipid droplets in the liver and mitigated liver injury associated with lipid accumulation.