EFFECT OF BETA,BETA-CAROTENE, BETA-ECHINENONE, ASTAXANTHIN, FUCOXANTHIN, VITAMIN-A AND VITAMIN-E ON THE BIOLOGICAL DEFENSE OF THE SEA-URCHIN PSEUDOCENTROTUS-DEPRESSUS

A disease characterized by spine loss was frequently observed among se a urchins fed a carotenoid-free diet during a feeding experiment. Furt hermore, the gonads of most of them were underdeveloped. We think that the symptoms were due to decreasing of biological defense caused by c arotenoid deficiency. Therefore, as a screening study for the biologic al defense reactions, we examined the effects of beta,beta-carotene, b eta-echinenone and astaxanthin on the phagocytic activities of the sea urchin Pseudocentrotus depressus and compared them with the effects o f well-known immunoenhancers, vitamin A and vitamin E. It was found th at carotenoids facilitated the engorgement of phagocytes in sea urchin s. The phagocytic index of beta-echinenone was the highest among them and was approximately 7.4 times stronger than that of the control. On the other hand, we also investigated the effects of fucoxanthin, which is a major carotenoid in the brown algae fed to sea urchins, beta,bet a-carotene and beta-echinenone on the phagocytic activities and develo pment of the sea urchin P. depressus. Fucoxanthin did not accumulate i n the gonad, but had statistically significant effects on phagocytic a ctivities and ovulated eggs. Furthermore, it was very interesting that the number of eggs ovulated was higher when the diet contained fucoxa nthin than when it contained beta,beta-carotene related to growth and reproduction. The present experiment would indicate that fucoxanthin a s well as beta,beta-carotene and beta-echinenone may play an important role in the biological defense and reproduction of sea urchins. (C) 1 998 Elsevier Science B.V.