Is Vitamin B₁₂ Malabsorption in Bile Fistula Rats due to Bacterial Overgrowth?: A Study of Bacterial Metabolic Activity in the Small Bowel

Abstract

Bergesen Ø, Schjønsby H, Schjerven L. Is vitamin B₁₂ malabsorption in bile fistula rats due to bacterial overgrowth? A study of bacterial metabolic activity in the small bowel. Scand J Gastroenterol 1988, 23, 471-476

To investigate whether vitamin B₁₂ malabsorption in rats with choledochocolic fistulae is caused by bacterial overgrowth, we studied intestinal bacterial metabolic activity in choledochocolic fistula-operated rats, self-filling blind-loop-operated rats, and sham-operated rats. Fistula-operated rats had a moderate indicanuria compared with sham-operated ones, whereas the faecal excretion of nitrogen was unchanged. There was no difference in the amounts of radioactivity recovered in sediments of intestinal contents after an oral dose of ⁵⁷CoB₁₂ indicating unaltered bacterial uptake of vitamin B₁₂ in fistula rats. The ¹⁴C-xylose breath test showed bacterial overgrowth in blind-loop rats only. Neomycin treatment of fistula rats diminished the excretion of indican but did not alter the absorption of vitamin B₁₂. The results suggest moderately increased activity of indole-producing bacteria in fistula rats, but they do not support the hypothesis that vitamin B₁₂ malabsorption is caused by bacterial overgrowth.

Key Words:

• Bacterial overgrowth
• bile fistula
• rats
• vitamin B₁₂