Bioavailability of Trace Elements

Several reviews have been published recently on the toxicity of heavy metals, but few of these have made any reference to the influence of the nutritional state of animals upon their tolerance of heavy metals. Furthermore, the clinical and metabolic changes occurring as a consequence of increased dietary intake of heavy metals are extremely dependent on factors such as the mineral composition of the diet and nature of the protein source. These aspects will be given particular attention in this review.

https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0033583500001359

Heavy metal toxicities.

Maximum tolerable and toxicity levels of dietary copper in rainbow trout (Salmo gairdneri Richardson)

The effect of cadmium on the hematology and on the activity of δ-aminolevulinic acid dehydratase (ALA-D) in blood and hematopoietic tissues of the flounder, Pleuronectes flesus L.

Exposure of mice to 10, 20, or 40 ppm cadmium in their drinking water throughout pregnancy resulted in various degrees of fetal growth retardation. The newborn mice, as well as being smaller than normal, were severely anemic. Parenterally administered iron completely prevented the cadmium-induced fetal growth retardation and anemia. The significance of a possible relationship of small-for-date babies with cigarette smoking and cadmium intake was discussed.

Cadmium-induced fetal growth retardation in the mouse.

This study was designed to evaluate the effects of supplements of individual dietary components in altering the toxicity of dietary cadmium. Day-old coturnix (Japanese quail) were fed 75 mg Cd/kg of an adequate purified diet for 2- or 4-week periods. Cadmium produced moderate growth retardation, severe anemia, decreased ash content of the tibia, and deviations from the normal concentrations of zinc, iron, cadmium, copper, and calcium in one or more of the cells or tissues assayed (erythrocyte, liver, kidney, and tibia). Dietary supplements of zinc, iron(III), copper, and L-cysteine-HCl and injected ascorbic acid produced slight to moderate protection against cadmium-induced anemia, whereas iron(II), ascorbic acid, and D-isoascorbic acid had marked effects in preventing the anemia, growth retardation, poor bone mineralization, and perturbations in elemental concentrations of tissues. Chromium, cobalt, selenium, nickel, molybdenum, and pteroylglutamic acid had no effects. Cadmium did not affect the total ascorbate content of the liver. Removal of dietary ethoxyquin did not affect the toxicity of cadmium or the protective effects of ascorbic acid. Initiation of ascorbic acid feeding at 2 weeks was beneficial to birds fed cadmium throughout the 4-week experiment. Under the conditions of these experiments cadmium produced a functional iron deficiency and less clear-cutmore » affects on zinc function. It appears that a primary effect of cadmium was to prevent absorption of dietary iron. 33 references, 6 tables.« less

C. E. Weeks

Papers

Effect of Ascorbic Acid on Cadmium Toxicity in the Young Coturnix