Inhibitory effect of intestinal bacteria on spontaneous multiple polyps in the small intestine of gnotobiotic BALB/c mice.

The incidence of multiple polyps and number of polyps per mouse were significantly lower in conventionalized (CVz), and chloroform-resistant bacteria (CRB)- or fusiform bacteria (FB)-associated mice than in germfree (GF) BALB/c mice. The concentration of fecal fatty acids was also higher in mice associated with either CRB or FB than in GF mice. The incidence of multiple polyps and number of polyps per mouse were significantly correlated with the concentration of fatty acids in the feces of CVz and CRB-GB mice. This study demonstrated that inhibition of multiple polyps in the small intestine of BALB/c mice was affected by the production of intestinal fatty acids.