Absence of cecal secondary bile acids in gnotobiotic mice associated with two human intestinal bacteria with the ability to dehydroxylate bile acids in vitro

Germ-free mice were orally inoculated with human intestinal 7 alpha-dehydro xylating bacterial strains to evaluate their ability to transform bile acid s ill vivo, Three weeks after inoculation of the bacteria, cecal bile acids were examined, Among free-form bile acids, only beta-muricholic acid was d etected in the cecal contents of gnotobiotic mice associated with Bacteroid es distasonis strain K-5, No secondary bile acid was observed in the cecal contents of any of the gnotobiotic mice associated with 7 alpha-dehydroxyla ting bacteria, Clostridium species strain TO-931 or Eubacterium species str ain 36S.