The Maintenance of Adult Rats on Diets Low in Certain B Vitamins

Abstract

Rats were raised from weaning to 12 weeks of age on synthetic diets containing 0.1% choline and low, medium, or high amounts of nicotinic acid, thiamine, riboflavin, pantothenic acid, and pyridoxine. They were then maintained for periods up to a year on a diet containing all of these vitamins or on diets from which one of them had been omitted. On the diet free of thiamine the rats lost weight and died in 3 to 7 weeks. Most of the adults on the other deficient diets survived for many months. Those deprived of nicotinic acid and choline for a year were comparable in appearance, growth, and survival to rats receiving these vitamins. The rats on the diet free of riboflavin lived 7 to 12 months. They soon ceased to grow but appeared normal for about 4 months on the deficient diet, after which characteristic symptoms of deficiency developed. Half of the rats on the diet free of pantothenic acid survived for 5 months. These rats stopped growing in 1 month and lacked muscle tonus in 2 to 3 months. On autopsy hemorrhagic areas were found in the intestinal tract. Rats grown on a diet containing 60 μg. of pyridoxine per 10 gm. of ration subsequently survived for at least 12 months of maintenance on a diet deficient in this vitamin. Those grown on lesser amounts of pyridoxine lived for an average of 8 months. Growth ceased in 1 month and a general atony developed after 3 months more. It is concluded that adult rats can survive in a reasonably healthy state on very low amounts of certain critical vitamins, and that experiments on the therapeutic value of tolerable nutritional deficiencies are feasible.