OLEIC ACID TRANS-MEMBRANE UPTAKE IN HEPATOCYTES OF ATLANTIC SALMON (SALMO SALAR L.) AND EFFECT OF REPLACING DIETARY FISH OIL WITH VEGETABLE OIL

Taking 1-14C OA (oleic acid;18:1n-9) as the indicator, the uptake of OA in Atlantic salmon (Salmo salar L.) hepatocyte with different membrane fatty acid composition induced by dietary fish oil (FO) and vegetable oil (VO) diets was determined to investigate the effect of replacing dietary fish oil with vegetable oil on fatty acid uptake and to provide the probability of replacing dietary fish oil with vegetable oil in Atlantic salmon diet. Atlantic salmon post smolt was fed diets containing either 100% FO or VO for 5 months to produce hepatocytes with typical FO and VO fatty acid composition, then OA uptake in isolated hepatocytes were studied by incubating with 1-14C OA and 37.5 mol/L OA (1/30, mol/mol, 0.3 Ci/flask) for 2h and by calculating the radioactivity in the cells. Meanwhile total RNA of the other same batch of FO and VO hepatocytes were extracted and the relative expression of FATP (fatty acid transport protein) and FAT/CD36 (fatty acid translocase) were determined by RT-PCR. The result showed that OA uptake in FO and VO was (0.9240.258) nmol/(hmillion cells) cells and (0.8880.179) nmol/(hmillion cells) respectively and there was no significant different between them (P0.05). The relative expression of FATP and FAT/CD36 were not significantly different between FO and VO hepatocytes too. The results indicate that by the same OA uptake between FO and VO hepatocytes, replacing dietary FO with VO was available in Atlantic salmon diet.