Impact of an environmentally-realistic intake of cadmium on calcium, magnesium, and phosphate metabolism in bank voles, Clethrionomys glareolus.

Oral intake of cadmium can disrupt calcium metabolism in laboratory rodents. If this occurs in free-living wild rodents, reproductive potential, growth, and survival could be adversely affected. This study investigated whether an environmentally-realistic intake of cadmium (1.5-1.7 mg/kg BW/24h) by bank voles, Clethrionomys glareolus, affected uptake and assimilation of calcium and also that of magnesium and phosphorus, two elements metabolized in close association with calcium. Mineral metabolism was monitored in bank voles fed four different diets; two diets were relatively low (0.12%) in calcium and also contained either no cadmium (HC) or cadmium (LCCd), while the remainder were relatively high (0.74%) in calcium and also contained either no cadmium (HC) or cadmium (HCCd). Dietary calcium levels were varied because calcium can affect gut absorption of cadmium, and calcium levels in natural forage vary with habitat soil type. Cadmium had a significant effect on voles fed a low calcium diet. Animals given LCCd diet had significantly poorer calcium net gut absorption efficiency than animals fed the corresponding control (LC) diet and were in negative calcium balance, losing approximately 0.5-1% of body calcium reserves each day. In contrast, calcium inputs matched total outputs in animals fed the LC diet. Cadmium had no effect on net gut absorption of magnesium and phosphorus, but renal reabsorption and subsequent assimilation of these elements was greater in animals fed the LCCd diet than in those given the LC diet. Cadmium had no clear effect on macroelement metabolism in bank voles fed a diet relatively high in calcium.(ABSTRACT TRUNCATED AT 250 WORDS)