Evaluation of the effect of dietary zinc, iron, and manganese supplementation on growth and survival of the sea urchin Lytechinus variegatus

摘要

The dietary requirement for trace minerals in sea urchin feeds is not known. Isocaloric semi-purified feeds were supplemented with one of three levels of dietary zinc (0, 0.03, or 0.15% ZnSO4, as fed), iron (0, 0.1 or 0.25% FeSO4, as fed), or manganese (0, 0.01, or 0.05% MnSO4, as fed). Small sea urchins (ca. 15 g wet weight, 31 mm diameter) were held individually in semi-recirculated systems and fed ad libitum for 12 weeks. Water quality was acceptable as survival was 100% and growth rates exceeded those reported in the field. Sea urchins fed the 0.15% ZnSO4 had significantly larger diameters than those fed 0.03%. Total wet weights did not differ among dietary zinc treatments; however, sea urchins fed 0.25% FeSO4 weighed significantly less than those fed 0.1%. There were no significant differences in wet weights or diameters among the sea urchins fed supplemental manganese. These data suggest that sea urchins 1) require dietary supplementation of zinc 2) may not require supplementation of dietary iron 3) have reduced growth with high concentrations of iron, and 4) may not require supplementation of dietary manganese.