ZFIN ID: ZDB-PUB-170120-2
Systemic regulation of L-carnitine in nutritional metabolism in zebrafish, Danio rerio
Li, J.M., Li, L.Y., Qin, X., Ning, L.J., Lu, D.L., Li, D.L., Zhang, M.L., Wang, X., Du, Z.Y.
Date: 2017
Source: Scientific Reports   7: 40815 (Journal)
Registered Authors: Du, Zhen-Yu, Li, Dong-Liang, Li, Jia-Min, Lu, Dong-Liang, Wang, Xin, Zhang, Mei-Ling
Keywords: Animal physiology, Fat metabolism
MeSH Terms:
  • Animals
  • Carnitine/metabolism
  • Carnitine/pharmacology*
  • Carnitine O-Palmitoyltransferase/genetics
  • Carnitine O-Palmitoyltransferase/metabolism
  • Dietary Supplements
  • Gluconeogenesis/genetics
  • Glycogen/metabolism
  • Glycolysis/genetics
  • Lipid Metabolism/drug effects*
  • Lipid Peroxidation/drug effects
  • Liver/metabolism
  • Mitochondria/metabolism
  • Muscles/metabolism
  • TOR Serine-Threonine Kinases/metabolism
  • Zebrafish/metabolism*
PubMed: 28102299 Full text @ Sci. Rep.
Excess fat accumulation has been observed widely in farmed fish; therefore, efficient lipid-lowering factors have obtained high attention in the current fish nutrition studies. Dietary L-carnitine can increase fatty acid β-oxidation in mammals, but has produced contradictory results in different fish species. To date, the mechanisms of metabolic regulation of L-carnitine in fish have not been fully determined. The present study used zebrafish to investigate the systemic regulation of nutrient metabolism by dietary L-carnitine supplementation. L-carnitine significantly decreased the lipid content in liver and muscle, accompanied by increased concentrations of total and free carnitine in tissues. Meanwhile, L-carnitine enhanced mitochondrial β-oxidation activities and the expression of carnitine palmitoyltransferase 1 mRNA significantly, whereas it depressed the mRNA expression of adipogenesis-related genes. In addition, L-carnitine caused higher glycogen deposition in the fasting state, and increased and decreased the mRNA expressions of gluconeogenesis-related and glycolysis-related genes, respectively. L-carnitine also increased the hepatic expression of mTOR in the feeding state. Taken together, dietary L-carnitine supplementation decreased lipid deposition by increasing mitochondrial fatty acid β-oxidation, and is likely to promote protein synthesis. However, the L-carnitine-enhanced lipid catabolism would cause a decrease in glucose utilization. Therefore, L-carnitine has comprehensive effects on nutrient metabolism in fish.