T. Takeuchi, N. Ohkuma, S. Ishida, W. Ishizuka, M. Tomita, H. Hayasawa, H. Miyakawa
For several years fish nutritionists have attempted to develop micro-particle diet (MD) for larval fish. Among the MD currently available, some of them can partly replace Artemia, but still the initial phase of larval rearing, i.e., 10-15 days after hatching, require rotifer as food. For perfecting the seed production cycle, it is important to develop suitable MD that could relieve the dependence on live foods.
In this direction, we have developed a new MD. It contains the combination of peptide and fatty acid Ca which has a high amount of docosahexaenoic acid. Using this MD Japanese flounder Paralichthys olivaceus, red sea bream Pagrus major etc. were among the larvae successfully cultured.
Ten days after hatching Japanese flounder was weaned using MD without any combination of live foods. On the other hand, red sea bream accepted the MD even from the 3rd day and was cultured for 26 days only on it. Final feeding results for red sea bream are as follows; fish fed live foods, 10.9 mm TL and 90% survival rate; fish fed MD, 8.5 mm and 58%, respectively. Analytical results of body amino acid and fatty acid compositions, confirmed that nutrients in the MD are well absorbed.
These results clearly demonstrate that larval fish accept and utilize this new MD quite well.
(Tokyo University of Fisheries)