Effect of Primary Biotin Deficiency on the Skin of Germ-Free and Conventional Mice Fed a Purified Biotin-Deficient Diet without Supplementation with Egg White

Abstract

To investigate the effect of primary biotin deficiency on growth and the skin, germ-free and conventional mice were given a purified biotin-deficient diet without egg white for 57 days. The body weight was significantly reduced in germ-free mice fed the biotin-deficient diet, whereas no reduction was seen in the conventional mice. 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 also decreased significantly in the liver, kidneys, and skin of conventional and germ-free mice fed a biotin-deficient diet, and the activity in the tissues of germ-free mice was lower than that in the conventional mice. Most germ-free mice fed the biotin-deficient diet exhibited severe alopecia, whereas conventional mice on the same diet did not. The histological changes in the alopecic skin were degeneration of the medulla of hair and the cortex of hair in germ-free mice fed the deficient diet. These degenerative changes in the skin of germ-free mice fed the biotin-deficient diet induced downgrowth of the hair root.