Effects of High Dietary Potassium Intake on the Metabolism of Magnesium by Sheep

Abstract
Two experiments were conducted to study the effects of a high dietary potassium intake on magnesium metabolism. In experiment 1, eight 3-day balance trials were conducted with 12 crossbred wether lambs. Rations containing equal amounts of magnesium, calcium and sodium and 0.6 or 4.9% potassium were fed. Apparent aborption of magnesium was greatly depressed (P<.01) while apparent absorption of sodium and potassium was generally increased by the addition of 100 g of potassium bicarbonate to the ration. There was a trend for higher apparent absorption of calcium by the high-potassium fed lambs. Although blood serum calcium, sodium or potassium showed no distinct trends, there was a trend toward lowered serum magnesium levels after 14 days of potassium supplementation, which disappeared after 27 days. In experiment 2, six paired yearling wethers were fed two rations identical in ingredient composition to those used in experiment 1. All wethers received an intravenous dose of 28magnesium and the magnitudes of fecal and urinary 28Mg excretion and magnesium turnover rate were determined. The high-potassium fed wethers tended to excrete smaller amounts of 28Mg in the urine and slightly greater amounts in the feces. The high-potassium fed wethers had lower magnesium turnover rates indicating that high-potassium levels interfere with magnesium absorption rather than drastically increasing its excretion into the intestine. Copyright © 1972. American Society of Animal Science . Copyright 1972 by American Society of Animal Science

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