Biological effects of substituting enriched 54Fe for natural iron in rats

The effect of feeding an enriched stable isotope of iron, 54Fe, to rats was examined. Weanling rats were fed semisynthetic diets in which 54Fe was substituted for all added natural iron for a period of 21 days. Growth; feed conversion; total liver, spleen, and femur iron; and hemoglobin concentrations; hematocrit; RBC and WBC volume; FEP concentration; kidney and heart aconitase activities; erythrocyte and liver catalase activities; liver microsomal oxidase activity; and pathological lesions did not differ between control and 54Fe enriched animals. Based on the biochemical and histological parameters examined in the study an isotope effect of 54Fe was not observed.