Effect of polar and nonpolar lipids from krill on quality of eggs of red seabream Pagrus major

Red seabream broodstock were fed on various diets shortly before spawning to reexamine the effectiveness of phospholipid and astaxanthins for the improvement of egg quality in comparison to frozen raw krill or vitamin E. The rate of buoyant eggs was lowest in the broodstock fed the control diet, and the value was elevated by supplementation of 200mg α-tocopherol, 2.5% krill polar lipids and 2.5% krill non-polar lipids or by feeding frozen raw krill. The rate of hatching was also improved by inclusion of one of these substances into the control diet. These results suggested that the effective components in raw krill for improving the quality of red seabream eggs are both phosphatidyl choline of the polar lipid fraction and astaxanthins of the polar lipid fraction. Therefore, the principal factors aiding the reproduction of red seabream are the common factors between these substances, probably free radical scavengers.