Carotenoids in the adult diet enhance egg and juvenile production in the sea urchin Lytechinus variegatus

Abstract

This study provides clear evidence of the important role of xanthophylls (lutein and zeaxanthin) over the hydrocarbon carotene (β-carotene) for reproduction of the sea urchin Lytechinus variegatus. Although carotenoids are found extensively in sea urchin eggs, limited knowledge is available on the effect of carotenoids, in the diet of adults, on the quality of the gametes produced. The present study investigated the effect of vitamins alone, vitamins and beta-carotene, and vitamins and a carotenoid mixture consisting of 60% trans-zeaxanthin, 25% trans-lutein and 15% other xanthophylls in a semi-purified diet of the adult sea urchins. Diet had a greater effect on the number of eggs spawned than on egg size. The largest numbers of eggs were produced by females fed the β-carotene diet (∼500 000/female) and those fed xanthophylls (∼2.6 million/female). Females fed vitamins alone spawned less than 400 000 eggs. Larvae from parents fed xanthophylls were larger throughout development, developed faster, had higher survival rates and attained metamorphic competence faster than those from the other two treatments. The numbers of juveniles originating from parents fed xanthophylls were significantly higher (>500/female) than those from parents fed β-carotene (15/female). No juveniles were produced by parents fed vitamins alone. This is important for sea urchin aquaculture, as a semi-purified diet containing xanthophylls would enable production of large numbers of juveniles with high survival rates. The data indicate that a defined semi-purified diet that will support normal sea urchin reproduction and development is available. Thus, the sea urchin model can be used to evaluate nutritional requirements for reproduction and development and the effects of potential toxic substances.