Nutritional studies in the seed production of fish-XX. Effective components in cuttlefish meal and raw krill for improvement of quality of red seabream Pagrus major eggs.

Abstract

Red seabream broodstock were fed various diets of different nutritional quality for either 26 days or shortly before spawning to clarify the effective components in cuttlefish meal and raw krill which aid in quality egg production. The percentage of buoyant eggs was lowest in the control group receiving the white fish meal diet, and was elevated by the addition of 200mg DL-α-tocopheryl acetate. The value was also effectively improved by replacement of white fish meal with defatted or intact cuttlefish meal as a protein source. Feeding broodstock with frozen raw krill after previously being fed control diet resulted in elevation of the percentage of buoyant eggs and normal larvae. Equally good results were obtained by substitution of cuttlefish liver oil in the control diet with 2.5% krill polar lipid or 2.5% krill nonpolar lipid. However, neither defatted krill meal nor fat-soluble fraction of cut-tlefish meal showed the good effect on the egg quality. Consequently, the superior quality of cuttlefish meal to the white fish meal as a protein source for red seabream broodstock diets was reconfirmed. And the effective components in raw krill, aiding the reproduction of red seabream, are suggested to be the polar and nonpolar lipid fractions. In addition, vitamin E was also found to have the same efficiency for improvement of the egg quality.