Nippon Suisan Gakkaishi 70 (4), 573-582 (2004)

Dietary value of marine rotifer Brachionus plicatilis in different population growth stages for larval red seabream Pagrus major

TSUTOMU TOMODA,1 MASAHIKO KOISO,1 HIROSHI KUWADA,1
JAU-NENG CHERN2 AND TOSHIO TAKEUCHI2

1Notojima Station, National Center for Stock Enhancement, Fisheries Research Agency, Notojima, Ishikawa 926-0216, 2Department of Marine Biosciences, Tokyo University of Marine Science and Technology, Minato, Tokyo 108-8477, Japan

This study assessed the dietary value of rotifers at different culture stages for larvae of red seabream (Pagrus major). Cultures were prepared daily and cultured for up to eight days. Rotifers were taken out of the batch culture and equally enriched with freshwater Chlorella containing docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA). The fish larvae were reared in 500-L tanks for 20 days and supplied with enriched rotifers at the 2nd, 4th, 6th, or 8th day of batch culture. Mortality of enriched rotifers was the highest on the 8th day, and their egg production rate, which is a prime index of their physiological status, became low. The larvae fed on those rotifers showed the lowest growth at the 20th day after hatching. Despite the almost equal DHA and EPA levels in rotifers of all groups, the EPA level in fish was the lowest on the 8th day of batch culture. These results show that the dietary value of rotifers was poor during or just before the stationary growth phase of batch culture, in spite of enrichment with DHA and EPA.


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