Fatty acids content and profile of common commercial Nile fishes in Sudan

Abstract

The muscle tissues of the Nilefishes: Lates niloticus, Bagrus bayad, Oreochromis niloticus, Synodontis schall and Tetraodon lineatus were analyzed for fatty acids compositions and profiles by gas liquid chromatography. Of the thirty-three fatty acids of different saturation levels detected, the predominant fatty acids were palmitic acid (C16:0), stearic acid (C18:0), oleic acid (C18:1ω9), docosahexaenoic acid (DHA, C22:6n3), eladic acid (C18:In9t), arachidic acid (C23:0) and palmitoleic acid (C16:1). Docosahexaenoic acid alone amounted to 37 to 77% of unsaturated fatty acids (UFAs). Eicosapentaenoic (EPA, C20:5n3), arachidonic (C20:4n6) and eicosadienoic (C20:2) acids were not detected in any of the fish studied. The range of saturated fatty acids was 31 to 65%, polyunsaturated fatty acids (PUFAs) were 4 to 53% and monounsaturated fatty acids (MUFAs) were 16 to 33%. Tetraodon lineatus contained 53% of the PUFAs and L. niloticus contained 33% of the MUFAs. The omega 3 and 6 (ω3/ω6) ratio was 0.9 to 3.6 and S. schall showed the highest ratio. The results showed that all the studied species of the Nile fish were comparable to other freshwater fish and were good sources of PUFAs, while S. schall was the best source of ω3 essential fatty acid (35% of UFAs) compared to the other four species. It was recommended that, other species of the Nile fish, especially the unused ones should be assessed for different sexes, seasons, sizes and geographical localities, because it could influence post-harvest processing and storage.   Key words: Arachidonic, decosahexaenoic, eicosapentaenoic, fatty acid profile, Nile fish, omega-3/omega-6 ratio, polyunsaturated.