Fatty acid metabolism in Atlantic salmon (Salmo salar L.) hepatocytes and influence of dietary vegetable oil

• Published in: Biochimica et Biophysica Acta (BBA) - Molecular and Cell Biology of Lipids
• Main Authors: Stubhaug, Ingunn, Tocher, Douglas R, Bell, J Gordon, Dick, James R, Torstensen, Bente E
• Other Authors: National Institute of Nutrition and Seafood Research (NIFES), Institute of Aquaculture, orcid:0000-0002-8603-9410
• Format: Article in Journal/Newspaper
• Language: English
• Published: Elsevier 2005
• Subjects: Atlantic salmon; Salmo salar; fish oil; vegetable oil; Hepatocytes; Lipid metabolism; Fatty acid metabolism; Fatty acids Metabolism; Fishes Food; Vegetable oils
• Online Access: http://hdl.handle.net/1893/2813; https://doi.org/10.1016/j.bbalip.2005.04.003; http://dspace.stir.ac.uk/bitstream/1893/2813/1/Stubhaug%20et%20al%20final.pdf

Isolated hepatocytes from Atlantic salmon (Salmo salar), fed diets containing either 100% fish oil or a vegetable oil blend replacing 75% of the fish oil, were incubated with a range of seven 14C-labelled fatty acids. The fatty acids were; [1-14C]16:0, [1-14C]18:1n-9, [1-14C]18:2n-6, [1-14C]18:3n-3, [1-14C]20:4n-6, [1-14C]20:5n-3, and [1-14C]22:6n-3. After 2 hours of incubation the hepatocytes and medium were analyzed for acid soluble products, incorporation into lipid classes, and hepatocytes for desaturation and elongation. Uptake into hepatocytes was highest with [1-14C]18:2n-6 and [1-14C]20:5n-3 and lowest with [1-14C]16:0. The highest recovery of radioactivity in the cells was found in triacylglycerols. Of the phospholipids the highest recovery was found in phosphatidylcholine, with [1-14C]16:0 and [1-14C]22:6n-3 being the most prominent fatty acids. The rates of β-oxidation were as follows: 20:4n-6 > 18:2n-6 = 16:0 > 18:1n-9 > 22:6n-3 = 18:3n-3 = 20:5n-3. Of the fatty acids taken up by the hepatocytes, [1-14C]16:0 and [1-14C]18:1n-9 were subsequently exported the most, with the majority of radioactivity recovered in phospholipids and triacylglycerols, respectively. The major products from desaturation and elongation were generally one cycle of elongation of the fatty acids. Diet had a clear effect on the overall lipid metabolism, with replacing 75% of the fish oil with vegetable oil resulting in decreased uptake of all fatty acids and reduced incorporation of fatty acids into cellular lipids, but increased β-oxidation activity, and higher recovery in products of desaturation and elongation of [1-14C]18:2n-6 and [1-14C]18:3n-3.