The microbial metabolism of tryptophan in rats fed a diet containing 7.5% saccharin in a two-generation protocol

Sodium saccharin was fed at 7.5% in the diet to rats in a two-generation protocol. Saccharin-treated animals in both generations showed increased urinary excretion of indican. During lactation, the pups of saccharin-fed dams were exposed to elevated levels of indican via the milk. Establishment of the gut flora in pups at weaning in the presence of saccharin was associated with increased caecal size and caecal protein, decreased caecal tryptophanase activity, and increased urine volume and urinary indican excretion. Pups from dams fed saccharin from birth only, showed more-variable responses during the first weeks of life than pups from dams fed saccharin from before conception, due to variations in tryptophanase activity. The various biochemical and physiological changes were detected soon after the pups were weaned, and were found equally in both males and females. After adjustment for body weight, the changes detected were greatest during the first month after weaning.