Kanazawa, A. Tago
Phospholipids such as soybean phosphatidylcholine (PC) in the diets had been found to be indispensable for sustaining growth of larval fish and crustaceans. On the other hand, it had been demonstrated in feeding experiments that (n-3) highly unsaturated fatty acids (HUFA) such as eicosapentaenoic acid (EPA, 20:5n-3) and docosahexaenoic acid (DHA, 22:6n-3) were essential for marine fish. Two nutrients of phospholipids and (n-3) HUFA are believed to be indispensable for normal growth and survival of marine fish and crustaceans.
The present research was conducted to determine the effect of 1,2-di 20:5-PC and 1,2-di 22:6-PC on the growth and stress tolerance of larval Japanese flounder, Paralichthys olivaceus. Japanese flounder (20 days after hatching, mean total length of 9.6 +/- 1.0 mm) were fed on microparticulate diets containing 1% phospholipids (purity 99%) for 30 days at 17.2-19.5 C. After the feeding trials, their tolerance in stress factors such as changes in water temperature and salinity, and exposure to low dissolved oxygen were determined.
Results demonstrated that dietary 1,2-di 22:6-PC was more efficient than 1,2-di 20:5-PC for growth and various stress tolerance of Japanese flounder larvae.
(Faculty of Fisheries, Kagoshima University 4-50-20 Shimoarata, Kagoshima, Japan)