The Effect of Antibiotics and the Composition of Diets on Fecal Vitamin B12 and Biotin

Abstract

Adult rats were fed a basal soybean diet to which were 3 added as supplements a constant dose of Co⁶⁰Cl₂ and one of 3 the several antibiotics or a sulfa drug. The fecal matter was 3 collected, homogenized, and finally extracted with butanol. 3 The radioactivity in the organic solvent was taken as an 3 index of vitamin B₁₂. It was found that supplementation with 3 certain antibacterial agents like aureomycin caused a marked 3 and sustained rise in the butanol-soluble radioactive compounds. 3 Some antibiotics produced a temporary but sharp 3 increase and others only a slight but sustained rise. This 3 effect of antibiotics was also dependent on the composition 3 of the basal diet. Furthermore, it was found that one antibiotic 3 may enhance the synthesis of vitamin B₁₂ but may depress 3 that of biotin, and vice versa. These results were interpreted 3 in terms of the selective influence of antibiotics on 3 the intestinal flora. Discussions of the absorption of nutrients 3 synthesized in the large intestine are also presented.