Effect of Dietary Cadmium on Growth, Survival, and Tissue Concentrations of Cadmium, Zinc, Copper, and Silver in Juvenile American Lobster (Homarus americanus)

Abstract

The addition of as much as 45 mg Cd/kg to a crab-based diet did not significantly affect growth or survival of juvenile American lobster (Homarus americanus) fed for 17 wk. The addition of Cd to the crab-based diet destroyed the highly significant relationship observed in nature between Cu and Ag concentrations in the digestive gland. Cd, Zn, and Cu in the crab-based diet were taken up by the digestive gland more efficiently than these metals added to the casein-based diet. Cu, Zn, and Ag concentrations in tail muscle were not affected by dietary Cd. Tissue mean molar ratios of metals (normalized to Cu and Ag) and dietary Cd ic crab-based diets showed a significant (p < 0.05) logarithmic relationship between dietary Cd levels and Cu/Ag (or Ag/Cu) ratios in both the tail muscle and digestive gland and Cd/Cu and Cd/Ag ratios in the digestive gland. A linear relationship was observed between Cd levels in crab-based diets and Cd/Cu, Cd/Ag, and Zn/Ag ratios in tail muscle. The absence of ascorbic acid (vitamin C) in the diet increased the uptake of Cd by the digestive gland and had an interactive effect on mean molar ratios of Cd, Cu, and Ag in the digestive gland.