Dietary value of marine
rotifer Brachionus plicatilis in different population growth stages
for larval red seabream Pagrus major
T. Tomoda, M. Koiso, H. Kuwada, J.-N. Chern, T.
Takeuchi-2004
Nippon Suisan Gakkaishi, 70(4): 573-582
Abstract:
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.
(Notojima Station, National Center for Stock
Enhancement, Fisheries Research Agency, Notojima, Ishikawa 926-0216, Japan)