Mineral Balance Studies with the Baby Pig: Effects of Dietary Magnesium Level upon Calcium, Phosphorus and Magnesium Balance

Abstract

Calcium, phosphorus and magnesium balance studies were conducted with baby pigs receiving a purified casein-glucose diet containing levels of magnesium of 75, 225, 325, 425 and 825 ppm. Dietary levels of Ca and P were maintained at 0.8 and 0.6%, respectively, with a constant dietary vitamin D₃ level of 1800 IU/kg. Food intake and consequent mineral intake were reduced in animals receiving 75 ppm dietary Mg. Increasing dietary Mg level above 225 ppm did not significantly affect Ca or P balance but the maximal percentage retention of Ca and P was obtained with pigs receiving 325 ppm of dietary Mg. Urinary Ca excretion was significantly increased by increased dietary Mg. Excreta Mg and Mg balance were both positively related to Mg intake. Maximal percentage Mg retention was obtained with dietary Mg levels of 225 or 325 ppm.