The component acids of lipids from marine and freshwater species with special reference to furan-containing acids†

The component acids of lipids extracted from the liver of roach, powan, brown trout, perch, pike, sea trout, salmon, ice fish, dog fish and cod, the flesh of capelin, haddock, herring and mackerel, and the digland of octopus have been examined. Differences between lipids from freshwater and marine sources and between those obtained from male and female species are noted. Particular attention is directed to a group of furan-containing acids present at low levels (up to 5%) in most of the samples. These unusual acids tend to concentrate in the cholesterol esters. In two starved cod the proportion of furanoid acids rose dramatically to 34 and 48% respectively.