Abstract

Germfree and conventional rats were used to investigate the influence of gut microflora upon vitamin B-6 deficiency. The body weights of conventional rats fed a vitamin B-6-deficient diet for more than 5 weeks plateaued, but the rats remained alive until the end of week 9 of deficiency. The body weights of germfree rats fed the same deficient diet decreased, andmost of rats were moribund around the end of week 9 of deficiency; three died. Urinary xanthurenic acid excretion following tryptophan load continued to rise at each experimental week in deficient germfree rats, while such a progressive increase in the level of the excretion was not observed in deficient conventional rats. Autopsy revealed that some of deficient germfree rats suffered from partial or toal lunficient conventional rats. The lung atelectasis was presumed to be the result of the respiratory muscle insufficiency which was closely related to the changes of the peripheral nerves innervating these muscles. The results may suggest that the presence of gut microflora made some contribution to improvement of the vitamin B-6 deficiency.