OCCURRENCE OF ALL-CIS-6,9,12,15,18,21-TETRACOSAHEXAENOIC ACID IN FLATFISH LIPIDS

The component fatty acids of lipids from four species of flatfish (fla thead flounder Hippoglossoides dubius, scalyeye plaice Acanthopsetta n adeshnyi, pointhead flounder Cleisthenes pinetorum herzensteini, and K orean flounder Glyptocephalus stelleri) caught in the Sea of Japan and Funka Bay, Hokkaido were examined using open-tubular gas-liquid chrom atography. About sixty fatty acids were observed. Tetracosahexaenoic a cid, was present as an unusual fatty acid, and the structure was deter mined as all-cis-6,9,12,15,18,21-tetracosahexaenoic acid (24:6n-3) by spectrometric analyses. In the flatfish examined, the lipids of flathe ad flounder captured in the Sea of Japan were found to be particularly rich in 24:6n-3 (6-9% of total fatty acids in the flesh, 3% in the li ver, and 6% in the viscera). This acid was abundantly found in the tri acylglycerols rather than the phospholipids. The results of this study suggest that 24:6n-3 was primarily incorporated into flatfish tissues through their diets.