Influence of Dietary Ca and P Levels on the Mg Requirement of the Chick

Abstract
The effect of the levels of calcium and phosphorus in the diet upon the magnesium requirement of young chicks was studied. When either the calcium or phosphorus content of the diet was increased, the quantity of magnesium required in the diet for maximal weight gain increased. When the levels of supplemental calcium and phosphorus in the diets were 0.6% Ca and 0.3% P, 0.6% Ca and 0.6% P, 0.6% Ca and 0.9% P, 1.2% Ca and 0.3% P, 1.2% Ca and 0.6% P, and 1.2% Ca and 0.9% P, the magnesium requirement for maximal growth was 461, 524, 562, 517, 577 and 594 ppm magnesium in the diet, respectively. A toxicity study was conducted and a level of 6400 ppm of magnesium in the diet caused a decrease in growth rate and an increase in mortality.