Dietary magnesium, manganese and boron affect the response of rats to high dietary aluminum.

Abstract

Studies were done to ascertain whether dietary magnesium, manganese and boron affect the response of the rat to high dietary aluminum. Four factorially arranged experiments of 7 weeks duration were performed with weanling Sprague-Dawley male rats. The variables were the following supplements (microgram/g fresh diet): boron as boric acid, 0 and 3; aluminum as aluminum chloride, 0 and 1,000; and magnesium as magnesium acetate, 100 and 400 (experiments 1 and 4) or 100, 200 and 400 (experiments 2 and 3). In experiments 1 and 2, the diet was supplemented with 20 micrograms manganese/g as manganese acetate, in experiments 3 and 4 the supplement was 50 micrograms/g. High dietary aluminum seemed most toxic when dietary magnesium was low enough to cause a marked growth depression (100 micrograms/g). High dietary aluminum elevated the spleen weight/body weight and liver weight/body weight ratios in magnesium-deficient, but not in magnesium-adequate rats. High dietary aluminum depressed the concentrations of magnesium in bone more markedly in magnesium-deficient than adequate rats. On the other hand, aluminum seemed most toxic when dietary boron was not low. Aluminum more markedly depressed growth in boron-supplemented than boron-deprived rats. In the boron-deprived rats fed 400 micrograms magnesium/g of diet, high dietary aluminum (1,000 micrograms/g) apparently was beneficial, in experiments 2 and 3, hematocrit, and hemoglobin were actually normalized by high dietary aluminum. Plasma magnesium was significantly depressed by high dietary aluminum when the manganese supplement was 50 micrograms/g diet but not when it was 20 micrograms/g diet. On the other hand, growth was more markedly depressed by high dietary aluminum in boron-supplemented rats when the manganese supplement was 20 rather than 50 micrograms/g diet. The findings indicate that the response of rats to high dietary aluminum is influenced by magnesium, boron, and manganese nutriture.