Effects of n-3 HUFA levels in broodstock diet on the reproductive performance and egg and larval quality of the Japanese flounder, Paralichthys olivaceus

We investigated the effect of dietary n - 3 highly unsaturated fatty acids (n - 3 HUFA) on egg and larval quality in the Japanese flounder Paralichthys olivaceus. Diets with similar proximate composition, but different n - 3 HUFA (0.4%, 0.8%, and 2.1%) levels were fed to broodstock from 3 months before and during the spawning season. Spawning was observed from March to June. Total egg production was highest in fish fed the lowest n - 3 HUFA, and decreased with the increase of dietary n - 3 HUFA, Percentages of buoyant eggs and hatched larvae were independent of dietary treatment. In contrast, the percentage of normal larvae, survival of larvae at 3 days post hatching (DPH), and the starvation tolerance index correlated with dietary n - 3 HUFA levels. n - 3 HUFA level in eggs increased with the increase of dietary level. Higher level of arachidonic acid (AA) was also found in eggs that showed high quality, reflecting dietary fatty acids. The results of this study clearly show that n - 3 HUFA level in broodstock diet has an effect on the quality of eggs and larvae in the Japanese flounder and suggested that AA may have positive effect on the improvement in spawning quality of flounder. (C) 2000 Elsevier Science B.V, All rights reserved.