Excretory Patterns and Bone Deposition of Zinc, Calcium and Magnesium in the Rat as Influenced by Zinc Deficiency, EDTA and Lactose

Abstract

Forty weanling male albino rats were used in a 6-week growth and balance study of the effects of temperature, dietary lactose and supplements of ethylenediaminetetraacetic acid (EDTA) and of zinc on mineral balance of rats fed a basal zinc-deficient diet. Inclusion of 25% of lactose at the expense of glucose in the isolated soy protein diet was accompanied by decreased weight gain, increased absorption, urinary excretion and balance of calcium, increased urinary excretion and decreased balance of magnesium, and increased zinc concentration in the femur. Additions of zinc stimulated weight gain, total zinc absorbed and retained (although the percentage was decreased), and increased zinc concentration in the femur. Addition of EDTA increased weight gain, zinc absorption and retention, and concentration of zinc in the femur. At an environmental temperature of 5°C the percentage retentions of calcium and of magnesium were below those obtained at a temperature of 27°C. The effect of EDTA in stimulating zinc absorption decreased as a result of an increased zinc absorption from the basal diet as animals remained on experiment longer.