Mineral Utilization in the Rat

Abstract

Forty weanling male albino rats were used in a 28-day growth and mineral balance factorially designed experiment to investigate effects of 2 levels each of Ca (0.4 and 0.8%), Mg (142 and 420 ppm) and P (0.19 and 0.50%). Weight gain and feed intake were severely restricted by adding Ca to the low P diets irrespective of Mg supply. Obvious deficiency of Mg was produced only by addition of both Ca and P to low Mg diets; the major interference with Mg utilization was a reduction in net absorption leading to a high Ca:Mg ratio in the tissue gained. Addition of dietary Ca lowered blood serum Mg but did not affect the percentage of Mg in the bone ash. Moderate to severe kidney calcification was produced by addition of P to low Mg diets, the effect being greatest in presence of low Ca.