Effects of dietary lipids, fatty acids, and phospholipids on growth and survival of prawn ( Penaeus japonicus) larvae

Abstract

The effects of lipids, fatty acids, and phospholipids on growth and survival of larvae of the prawn, Penaeus japonicus, were examined using purified diets containing carrageenan as a binder. P. japonicus larvae did not metamorphose to post-larvae and died in 7 days when fed the diets containing no phospholipid. Growth and survival rate of the prawn larvae were improved by the addition of soybean phosphatidylcholine (PC) to the diets containing 18:1ω9 and essential fatty acids (EFA), or pollack liver oil (PLO) as lipid sources. These results suggest that P. japonicus larvae probably require dietary sources of some phospholipids for growth and survival. The efficacy of phospholipids in improving growth and survival varied with the kinds and sources of phospholipids. Bonito-egg PC, soybean PC, and soybean phosphatidylinositol (PI) had a high efficacy, whereas chicken-egg PC was ineffective. Ovine-brain phosphatidylserine, bonito-egg phosphatidylethanol-amine (PE), and ovine-brain PE improved slightly growth and survival of P. japonicus larvae. The PC and PI containing high proportions of ω6- and ω3-fatty acids as constituents were thought to be effective in improving growth and survival of the prawn larvae. The optimum level of soybean PC for P. japonicus larvae varied with the kinds of coexistent dietary lipids. The best growth and survival were attained on the diets containing 6.0% soybean PC when 18:1ω9 and 1.0% highly unsaturated fatty acids were used as basal lipids. But the inclusion of 3.5% soybean PC was enough to attain optimum growth and survival when PLO was used as the lipid source. The present study did not give a clear picture of the EFA requirements of P. japonicus larvae, although they seemed to vary with dietary phospholipid levels.