EFFECTS OF CONCENTRATION AND DURATION OF ENRICHMENT OF ROTIFER BRACH IONUS PLICATILIS WITH COD OIL EMULSION WITH EMPHASIS ON FATTY ACIDS

In this study, effects of concentration and length of enrichment of rotifer Brachionus plicatilis fatty acid composition and its population profile by cod liver-oil emulsion were tested. Rotifers pre-fed on yeast (Saccharomyces cerevisiae) were enriched with cod liver oil emulsion at three different concentrations (4, 8 and 12%). Rotifers were sampled after 0, 3, 6, 12 and 24 hours of enrichment. Considering total lipid present in rotifers as a function of the enrichment period, the increase was significant for 3 hours treatment while the same was not observed when raising the oil concentration (P<0. 05). Increasing the enrichment period rather than the amount of oil present in the medium was found to be more efficient in increasing the n-3 highly unsaturated fatty acids (n-3 HUFA) level in rotifers. Rotifers showed a better incorporation of Eicosapentaenoic acid (EPA, 20:5n3) than Docosahexaenoic acid (DHA, 22:6n-3), regardless of the ratio between the two fatty acids in the emulsion.