THE ROLE OF INTESTINAL FLORA IN BIOTIN DEFICIENCY IN CONVENTIONAL AND GERM-FREE MICE FED A PURIFIED BIOTIN-DEFICIENT DIET WITHOUT SUPPLEMENTATION WITH EGG-WHITE

To investigate the influence of intestinal flora upon the effects of biotin deficiency, we provided germ-free and conventional mice with a purified biotin-deficient diet without egg white for 20 days. Some of the biotin-deficient germ-free mice exhibited alopecia, while conventional mice on the same diet did not. Biotin levels decreased significantly in tissues of conventional and germ-free mice fed a biotin-deficient diet except in the heart of the conventional mice. Pyruvate carboxylase activity in the liver and kidney of germ-free mice fed the deficient diet also decreased significantly, while the activity in the liver of conventional mice on the same diet showed only a slight decrease. However, no significant differences in body or tissue weights were observed between germ-free and conventional mice during the short experimental period. Thus, conventional mice fed a biotin-deficient diet showed latent biotin deficiency, while germ-free animals fed the same diet exhibited severe biotin deficiency. Enteral microbial synthesis of biotin may have made some contribution to the observed amelioration of the effects of dietary biotin deficiency.