INFLUENCE OF THE DIFFERENT FEEDING SCHEDULE OF FOOD ORGANISMS FOR LARVAL SWIMMING CRAB PORTUNUS TRITUBERCULATUS

T. Takeuchi, N. Satoh, S. Sekiya, T. Shimizu, T. Watanabe-1999

Nippon Suisan Gakkaishi, 65 (5): 804-809 (from Current Contents)

Abstract:

This experiment was conducted to investigate the suitable feeding schedule for different larval stages of swimming crab Portunus trituberculatus when fed rotifer and/or Artemia nauplii enriched with n-3 highly unsaturated fatty acids (n-3HUFA) at zoea 3 and zoea 4 stages. Two feeding experiments were carried out in 1 l beakers with duplicate lots, each holding 30 larvae. The molting rate and the inter-molt period in days to reach each larval stage were measured. These biodata were compared with n-3HUFA contents in live foods (rotifer and Artemia). When the zoea 3 stage larval crabs were introduced to the live foods containing n-3HUFA, especially Artemia, the molting rate of the megalopa and the inter-molt period were much improved compared with the zoea 3 stage fed unenriched live foods or when live foods were initiated at the latter zoea 4 stage. It was also found that the incorporation of n-3HUFA content in Artemia (2.7%) was higher than that in rotifer (1.6%), even though both were enriched with the same amount of emulsified oil (EPA28G: 25.0% eicosapentaenoic acid and 10.1% docosahexaenoic acid). Therefore, the enriched Artemia appears to be a better vehicle for fatty acid delivery to the crab larvae. These results suggest that larval crab should be fed Artemia containing n-3HUFA from the zoea 3 stage in order to get a high survival rate for the first swimming crab.

(Tokyo Univ Fisheries, Dept Aquat Biosci, Tokyo 1088477, Japan)

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