Effects of magnesium-deficient diet upon puppies.

ERTAIN ASPECTS of dietary magnesium deficiency have been studied extensively in the rat and less so in the guinea pig, catf, duck, and dog. Excellent reviews of magnesium metabolism and requirement have been published by Wacker and Vallee 1 and O'Dell. 2 Magnesium deficiency results in calcification of the heart and kidney. High dietary magnesium has been shown to diminish the amount of cardiovascular lipidosis in rats fed cholesterol and cholic acid. Conversely , magnesium deficiency enhances the lipid deposition within the left ventricular valves and aorta. 3 " 5 Because magnesium deficiency produces profound changes in the myocardium and enhances cardiovascular sudanophilia, it was believed advisable to study magnesium deficiency in dogs prior to undertaking a study of feeding cholesterol to magnesium-deficient dogs. The dog, unlike the rat, develops arteriosclerosis spontaneously, and these lesions resemble in part those seen in the human. Tn addition , being relatively large, the dog lends itself to procedures such as repeated blood withdrawal, the taking of electrocardiograms, and various other physiological measurements. The present study deals with the effect of magnesium deficiency on weight gain, serum electrolytes, serum cholesterol, histopathology. and the electrocardiogram. Six male, mongrel puppies, approximately si:c to eight weeks old and weighing 3 to 5 Kg., were fed a diet of the following constituents per hundred grams of food : casein