Lipid and fatty acid compositions differentiate between wild and cultured Japanese eel (Anguilla japonica)

The lipid profile and fatty acid composition of muscle, liver, and plasma lipoprotein were examined in wild and cultured Japanese eel (Anguilla japonica). Although, the muscle lipid levels of wild eels (11.6%) were less than those of cultured eels (13.1%), both eels were classified as typical fatty fish. Compared with the liver lipid composition of cultured eels, triacylglycerol (TG) level of the liver decreased in wild eels, whilst phosphatidylcholine and phosphatidylethanolamine levels of the liver increased in wild eels, reflecting the difference of liver lipid levels in both eels. Wild eels contained more cholesteryl ester (CE) and less TG, phospholipid, and free cholesterol in their plasma than cultured eels. The ratio of TG to CE decreased, whilst that of CE to total cholesterol increased in the plasma of wild eels. Different fatty acid compositions were found between wild and cultured eels. Compared with the fatty acid compositions of cultured eels, wild eels contained high percentages of 18:2, 18:3, and 20:4 and low percentages of 22:6, 20:1, and 20:5 in their muscle, liver, and plasma lipoprotein. The lipid profile and fatty acid composition seemed to be useful criteria for distinguishing between wild and cultured eels.