Oils rich in docosahexaenoic acid in livers of sharks from temperate Australian waters

Abstract

The livers from the two main commercially-targeted shark species in southern Australia (Mustelus antarcticus, gummy shark; Galeorhinus galeus, school shark), together with Squalus acanthias (white-spotted spurdog), were analysed for oil content and composition, and fatty acid composition. The yield of oil from the liver was 30-64% (wet weight) for M. antarcticus and 50-53% (wet weight) for G. galeus. Lipid classes were determined by thin-layer chromatography with flame ionization detection, with the major lipid being triacylglycerol (≥95%); other minor lipids were polar lipid, wax ester, sterol (mainly cholesterol) and free fatty acid. Long-chain ω-3 polyunsaturated fatty acids accounted for between 33% and 39% of the total fatty acids in all three species, and docosahexaenoic acid (DHA) concentrations were between 13% and 18%. The liver oils of M. antarcticus and G. galeus and other shark species may be an attractive source of w-3 fatty acids, specifically DHA, for direct use and/or for adding further value.