In dogs with CIE, which bile acid proportion was significantly lower than control dogs, and is this a primary or secondary bile acid?

• A. % DCA (deoxycholic acid): secondary
• B. % LCA (lithocholic acid): secondary
• C. % CA (cholic acid): primary
• D. % UDCA (ursodeoxycholic acid): secondary

Answer: (B)

Lithocholic acid is a secondary bile acid produced when intestinal bacteria modify chenodeoxycholic acid. In dogs with inflammatory enteropathy, gut inflammation and dysbiosis reduce the bacterial activity responsible for this transformation, leading to a significantly lower proportion of lithocholic acid compared with controls. This highlights altered microbial bile-acid metabolism rather than a problem with hepatic synthesis of primary bile acids. The fact that this particular secondary bile acid drops, while primary bile acids are not necessarily reduced in the same way, points to disruption of the microbial steps that generate secondary bile acids.