Effect of Dietary Cadmium on Tissue Distribution of 109Cadmium Following a Single Oral Dose in Young Goats

Abstract

Cadmium metabolism was investigated following a single oral dose of 109Cd in four- to six-month-old male goats fed a practical diet with and without 100ppm of supplemental cadmium as CdCl2. Tissue distribution of 109Cd and total body retention were determined 14 days after dosing. Highest concentrations were found in the kidneys, liver, duodenum, and abomasum, respectively. Total body retention was 0.3 to 0.4% of the dose with about one-half of this in the liver, one-fourth in the kidneys, and a large part of the remainder in the gastrointestinal tissue and contents. Bone, muscle, blood, hair, skin, and connective tissues contained very small amounts. Feeding the high metabolic load of 100ppm of dietary cadmium significantly decreased 109Cd concentrations in the gastrointestinal tract tissues, but the effect was not sufficient to produce a detectable change in over-all body retention. 109Cadmium levels in other tissues were not materially influenced by cadmium feeding. Daily rate of 109Cd fecal excretion declined linearly and rapidly during the second week, with about 20% of the body burden eliminated on Day 8 and less than 5% on Day 14. After 21 days of cadmium feeding, kidney, duodenum, and liver concentrations of stable cadmium were 62, 28, and 18ppm of dry matter, compared to 2.7, 2.5, and 1.6ppm in comparable tissues of control animals. Ruminants do not have a homeostatic control mechanism for controlling cadmium absorption or excretion which is affected by level of dietary or tissue cadmium content. However, very low levels are absorbed.