Comparison between eicosapentaenoic and docosahexaenoic acids in terms of essential fatty acid efficacy in larval red seabream.

Abstract

Efficacy of EPA and DHA as the EFA for larval red seabream was evaluated by feeding them rotifers enriched with respectively methyl oleate, EPA, DHA and n-3 HUFA mixture for 8 days in 100l tanks.The larvae fed on rotifers containing a low percentage of n-3 HUFA showed low growth and survival rates together with a high incidence of the so-called hydrops. These larvae also showed poor vitality and all of them died in the both vitality tests. The growth and survival rates were effectively improved by the incorporation of EPA and DHA or n-3 HUFA mixture into the rotifers. However, the incidence of hydrops was not completely prevented by EPA and the n-3 HUFA mixture, but was almost totally prevented by DHA. The growth and the survival rate after vitality test were also highest in the larvae fed the DHA-rotifer.The fatty acid analysis on the total lipids of larvae has shown that the level of assimilation of DHA was much higher than EPA, although EPA may partly be converted to 22:5n-3 and that no retroconversion of DHA may be available. Thus DHA is found to be superior to EPA as EFA for larval red seabream.