Australian fish-An excellent source of both arachidonic acid and ω-3 polyunsaturated fatty acids

The fatty acid methyl esters obtained by the esterification of total lipids extracted from 24 species of fin fish and 4 species of invertebrates caught in the rivers and coastal waters of southern Australia were analyzed by gas chromatography. The lipids of most species contained significant levels of arachidonic acid (0.7-15.8%) as well as the more common marine polyunsaturate, eicosapentaenoic acid (0.7-15.9%). The major ω6 fatty acid present in most species was 20:4; however, other fatty acids of this series, including 18:2, 22:4 and 22:5, were present. The level of total ω6 fatty acids ranged from 3.9 to 22.3% of the total lipid. In general, the level of total ω3 polyunsaturates was higher than the total ω6 fatty acids with levels of ω3 fatty acids ranging from 9.6 to 48.2%. Only 2 fish (barramundi and gurnard perch) had ω6/ω3 ratios greater than 1.0. Most of the Australian species examined contained low levels of fat (0.5-7.8% of fresh weight). Two species examined, callop (freshwater) and blue groper (marine) contained sufficient quantities of both fat (7.7 and 7.8%) and arachidonic acid (4.8 and 9.3%) to warrant consideration for commercial exploitation.