Invasive Species Compendium

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Abstract

Requirement of N-3 highly unsaturated fatty acids for larval swimming crab Portunus trituberculatus.

Abstract

This experiment was conducted to investigate n-3 highly unsaturated fatty acid (n-3 HUFA) requirement of larval P. trituberculatus. Three experiments were carried out in 1-litre beakers, each holding 30 larvae. Crab larvae were fed on rotifers cultured on freshwater chlorella (Chlorella vulgaris) or fortified with corn oil, or enriched with various levels of emulsified oil (EPA28G oil) containing 25.0% eicosapentaenoic acid (EPA) and 10.1% docosahexaenoic acid (DHA) or ethyl ester of EPA (purity about 92%). Larvae fed rotifers cultured with Chlorella vulgaris or enriched with corn oil had difficulty reaching the first crab stage, indicating that perhaps both linoleic acid and linolenic acid in rotifers were not essential fatty acids for the swimming crab. On the other hand, when larvae received rotifers enriched with EPA28G oil or ethyl ester of EPA, the survival rate increased corresponding to n-3 HUFA levels in rotifers. On the basis of the feed performance and fatty acid composition of rotifers, the suitable level of n-3 HUFA, as provided in rotifers, for larval swimming crab was 0.9-1.7 g/100 g dry weight.