Bile acid metabolism, bacterial bowel flora and intestinal function following ileal pouch-anal anastomosis in dogs, with reference to the influence of administration of ursodeoxycholic acid.

The pathophysiology following a total colectomy with ileal pouch-anal anastomosis (IPAA) has not been sufficiently clarified yet. We investigated bile acid metabolism, bacterial bowel flora and transit of the alimentary tract after IPAA, with reference to administration of ursodeoxycholic acid (UDCA) in dogs undergoing IPAA. Ten adult beagle dogs underwent IPAA at one stage, and were observed for 12 months. UDCA (100 mg/day) was administered orally to five dogs, and the other five did not. In the UDCA(+) group, UDCA replaced other bile acids, especially cholic acid, accounting for 16.5% of gallbladder bile at 12 months after surgery. Both plasma levels and postprandial increase of total bile acids remained unchanged in the UDCA(+) group, but decreased in the UDCA(-) group at 12 months. Fecal excretion of bile acids tended to be smaller in the UDCA(+) group, and the ratio of secondary to primary bile acids was larger in the UDCA(-) group. Almost all the bile acids were in free form in stool, and UDCA constituted 19% in the UDCA(+) group. The transit time of the whole alimentary tract was elongated by administering UDCA, especially at an early period after IPAA. Although both anaerobic and aerobic bacteria decreased after IPAA, the latter decreased more in stool, resulting in an increase in the ratio of total anaerobes/total aerobes, especially in the UDCA(-) group. The decrease in Bacteroidaceae and Lactobacillus after IPAA was slightly smaller in the UDCA(+) group. Administration of UDCA following IPAA was efficient to induce rapid intestinal adaptation and also to keep the bile acid fraction in the ileal pouch less harmful.