Fatty acid profile of Brachionus plicatilis for sea bream (Sparus aurata) larviculture

Carnivorous marine fishes have limited biosynthesis capacity of n-3 series highly unsaturated fatty acids (HUFAs). Thus, the content in living feeds of essential fatty acids, such as 20:5n-3 (eicosapentanoic acid) and 22:6n-3 (docosahexaenoic acid), is one of the principal factors in their dietary value for larviculture. In the present work, the fatty acid profile of Brachionus plicatilis was modified during an 18 h enrichment. Tests were made with Chlorella sp. and three commercial enrichment products: Algal Rotifero (microparticles), Frippak Booster (microcapsules) and Selco (emulsion). Larval feeding experiments were carried out during a 24 d period after hatching. The efficiency of transfer of fatty acids to rotifers was extremely variable, depending on the biochemical profile of the products and also on their physical properties. B. plicatilis revealed biosynthesis capacity of docosahexaenoic acid. Comparison of the prey’s lipid content with that of the sea bream eggs and larvae showed a lower value of HUFA n-3 in B. plicatilis. Similar results were found concerning the HUFA n- 3/HUFA n-6 ratio. As for the 20:5n-3/22:6n-3 ratio, the eicosapentanoic acid was dominant in rotifers, contrary to that of sea bream eggs and larvae. These discrepancies may be responsible for the low survival and growth of sea bream larvae.Description not yet available.