LCFA Uptake and FAT/CD36: molecular cloning, tissue expression and mRNA expression responses to dietary oil sources in grass carp (Ctenopharyngodon idellus)

The fatty acid translocase (FAT/CD36) plays an important role in trans-membrane uptake of long-chain fatty acids (LCFA) and has been identified and described in many organisms, while little is known about this gene in freshwater fish, and especially in the grass carp (Ctenopharyngodon idellus). In this study, the uptake of LCFA in hepatocytes of C. idellus was firstly determined and then FAT/CD36 gene was cloned; then the gene was sequenced and mRNA levels from different tissues and the effect of dietary oils on its expression were determined. Present data showed that trans-membrane absorption of LCFA was related to the type and concentration of fatty acids (FAs) and it could be inhibited by specific membrane uptake inhibitors. The FAT/CD36 isolated from grass carp contained 1422 bp and the open reading frame was predicted to have 1403 bp (GenBank access number: KU361231.1). FAT/ CD36 was highly expressed in the brain and its lowest expression was in the gills. FAT/CD36 expression in white muscle was up-regulated when fish were fed with groundnut oil, whereas it was downregulated in fish fed fish and linseed oils, respectively. These results indicated n-3 PUFA might inhibit the FAT/CD36 mRNA expression and therefore the oxidation of FAs.