Fatty Livers in Weanling Rats Fed a Low Protein, Threonine-deficient Diet: I. Effect of Various Diet Fats

Abstract

Weanling albino rats were fed a diet containing 9% casein and 30% fat with and without supplements of threonine. The fat source in the diet was provided by corn oil, olive oil, cottonseed oil, hydrogenated vegetable oil, or corn oil hydrogenated to an iodine value of 74. Animals were maintained with their respective diets for 2 to 4 weeks. Feeding weanling rats a threonine-deficient diet containing 30% corn oil resulted in the appearance of fatty livers. Replacing the corn oil in this diet with either cottonseed oil or hydrogenated vegetable oil caused a significant reduction in liver fat concentration. Substituting olive oil for corn oil slightly increased liver fat levels. In every instance, the addition of threonine lowered liver fat levels. When hydrogenated corn oil was substituted for corn oil in threonine-deficient diets, liver fat concentrations decreased markedly after 2 weeks; this effect persisted after 4 weeks. Since all diets within a series were isocaloric and since no significant differences in food intake or growth were observed among any of the deficient groups, the “protective” action of some diet fats is apparently not mediated through a more equitable balance between the amino acid and calorie ratio.