Effect of Lactobacilli on Urinary Indican Excretion in Gnotobiotic Rats and in Man

The effect of Lactobacillusspecies on urinary indican excretion in two types of gnotobiotic rats (GBH‐9 and GB‐5) and in man was studied. L. salivarius, L. plantarumand L. caseicolonized in the cecum and colon of both types of rats at levels of 107to 108per gram of contents following one‐dose oral administratron and caused a significant reduction in urinary indican excretion, whereas two strains of L. acidophiluswhich colonized at low levels (104to 105/g) did not reduce indican excretion. Daily feeding of Lactobacillusconcentrates caused a further significant reduction in indican excretion which was corrected by tryptophan intake, even in the case of L. acidophilus. There was a clear relationship between fecal lactobacillus counts and urinary indican. A significant reduction of indican secretion was obtained only when the fecal counts of lactobacilli exceeded 107.4/g in rats.