Some Observations on Vitamin Metabolism in Germ-Free Rats

Abstract

Results from limited numbers of germ-free rats fed semisynthetic diets indicated that with an occasional exception the general metabolism of germ-free rats is very similar to that of conventional rats. Male germ-free rats do not grow as rapidly as do male conventional rats. A dietary source of biotin is required by germ-free rats. The main symptoms of biotin deficiency were retarded growth, eventual loss of weight, alopecia, dermatitis and skin ulcers. Biotin was apparently required for the biosynthesis of folic acid. A vitamin balance study in germ-free rats showed that less niacin, riboflavin and biotin were excreted and accumulated in body tissues than were fed to the rat; quantities of pantothenic acid and vitamin B₁₂ excreted are equal to the amounts fed; biosynthesis of inositol was not proven unequivocally; while “vitamin B₉” (measured as folic acid and citrovorum factor) was synthesized.