Jesuí Vergílio Visentainer

The influence of feed supply time on the fatty acid profile of Nile tilapia (Oreochromis niloticus) fed on a diet enriched with n-3 fatty acids

Abstract The purpose of the study was to examine the fatty acid profiles of Nile tilapia ( Oreochromis niloticus ) submitted to different feeding times (0, 10, 20 and 30 days) on a diet enriched with n-3 fatty acids, by addition of flaxseed oil in substitution for sunflower oil. The main fatty acids detected were palmitic (C16:0), stearic (C18:0), oleic (C18:1n9), linoleic (C18:2n6) and α-linolenic (C18:3n3) in all the treatments. The 30 day-fed fish presented the best values for total n-3 fatty acids, with a prominence of α-linolenic acids, showing that the flaxseed oil as well as the feed supply time influenced the fatty acid profiles.

Chapter 11 – Incorporation and Bioconversion of Omega-3 Fatty Acids for Obtention of Enriched Fish

Farm-raised fish present low concentrations of polyunsaturated omega-3 fatty acids ( n −3 PUFA). As the series of omega-6 ( n −6) and omega-3 ( n −3) fatty acids share the same enzymes, elongases, and desaturases, during bioconversion of the precursors alpha-linolenic acid (ALA, 18:3 n −3) and linoleic acid (LA, 18:2 n −6), the incorporation of ALA from diet favors the biosynthesis of eicosapentaenoic (EPA, 20:5 n −3) and docosahexaenoic acids (DHA, 22:6 n −3) in muscle tissue of freshwater fish and leads to an ideal n −6/ n −3 ratio. The understanding of this metabolism has been essential to science, because while n −3 series possesses antiinflammatory functions, the excess of n −6 fatty acids affects proinflammatory processes. In this way, the incorporation of different vegetable sources of n −3 fatty acids in the diet of farm-raised fish, targeting the biosynthesis of long-chain n −3 fatty acids ( n −3 LC-PUFA), becomes a viable alternative to exploit the technological and functional benefits of enriched fish meat for human consumption.