Fecal bile acid excretion and taurine status in cats fed canned and dry diets.

Cats conjugate their bile acids with taurine but are unable to synthesize sufficient quantities of this amino acid to meet their needs. To maintain the same blood taurine level, canned foods must contain more taurine than dry foods. In the present study we examined the effect of soluble fiber on fecal bile acid excretion and taurine status and compared the quantity and profile of fecal bile acids in cats fed canned and dry diets. In a cross-over design, 10 adult cats were fed a typical canned diet containing 0.25% kappa carrageenan with or without the addition of 0.5% guar gum (2.5% on a dry matter basis) for 6 wk. All cats were then transferred to a dry diet. The addition of guar gum to the canned diet had no significant effect on taurine status, but the dry diet, which contained less taurine than the canned diet, resulted in an increase in plasma taurine. With the dry diet, total bile acid excretion was reduced by approximately 65%. The profile of bile acids in feces was also radically different with a marked decrease in secondary bile acids. This work suggests that when canned rather than dry diets are fed, the conversion of primary to secondary bile acids is greater and is indicative of an alteration in the activity of the gut flora that may lead to an increase in taurine degradation.