The methionine and choline status of rat diets and their effects on nutrition and myocardial lesions.

This study evaluated for rats the nutritional adequacy of casein-based diets routinely used to test the cardiopathogenicity of vegetable oils. Diets were formulated containing 20% by weight casein, 20% soybean oil and graded levels of choline with and without methionine and were fed to male Sprague-Dawley rats for 16 weeks. Rats fed methionine-supplemented diets had improved growth and food consumption, increased liver lipids mainly in the form of triglycerides and normal amino acid metabolism. On the other hand, choline supplementation reduced liver lipids but had no effect on growth and feed consumption. The results would indicate that diets including 20% casein and 20% oil require methionine supplementation to assure the nutritional adequacy of this high caloric diet. However, in this study there was no evidence to indicate that choline or methionine supplementation affected the heart lesion incidence in male rats. It was therefore concluded that the amount and type of fat in the diet, not the choline and methionine status of the diet, is related to heart lesions in male rats.