Fatty acid composition of fish feeds vended in Lagos state, Nigeria

Abstract

Fatty acid compositions of the lipids extracted from various fish feeds (Eco-float, Blue-crown, Uncle - frances, Triton, Stretting, Crown, Jik, Shaldac, Solace, Coppens, Vital, Local sinking, Local feed, Aqualis and Local floating) vended in Lagos State were determined. These feeds were designated as Feeds A to O respectively. Feed samples were procured from major fish feed markets and fish farms within Lagos metropolis and transported to the laboratory for analysis. Methylation was carried out after oil extraction to convert the fats to their methyl esters and the fatty acids methyl esters (FAME) were separated by gas chromatography. Fatty acids were analysed using a HP Agilent 5890 system gas chromatograph equipped with SP-2330 and a flame ionization detector (FID). Results revealed that the highest values for polyunsaturated fatty acid (PUFA), saturated fatty acid (SFA) and ∑n-3 unsaturated fatty acid (HUFA) were 58.26% in feed F, 38.7% in feed M and 3.59% in feed N respectively while the lowest values for PUFA (19.76%) and SFA (15.53%) were recorded in feeds M and J respectively. The results also showed that, though feed samples were high in monounsaturated fatty acid (MUFA) (55- 22%) and PUFA (58-19%), they were low in n-3 HUFA {eicosapentaenoic acids (EPA, 20:5n-3) and docosahexaenoic acids (DHA, 22:6n-3)} with the values of 0.3-3%. The shortfall in EPA and DHA of these feeds may imply that fish fed these feeds may be nutritionally deficient in these fatty acid compositions. Thus, further manipulation may be needed to improve the value of these feeds in terms of EPA and DHA.

Keywords: Fish feeds, n-3 HUFA, n-6 HUFA, Nutritional quality, aquaculture