What were the two strongest correlations found when assessing ASBT expression, histopathological scores, fecal BA composition, DI, serum cobalamin, and serum albumin?

• A. positive correlation between % primary BAs in the feces of CIE dogs with the fecal DI; positive correlation between log values of C. hiranonis and % secondary BAs
• B. positive correlation between % primary BAs in the feces of CIE dogs with the fecal DI; negative correlation between log values of C. hiranonis and % secondary BAs
• C. no correlations identified among these measures
• D. positive correlation between % secondary BAs and fecal DI; positive correlation between log values of C. hiranonis and % primary BAs

Answer: (A)

Relationships between gut microbiota and bile acid profiles are driven by how microbes transform primary bile acids into secondary ones. The strongest findings here show that as the fecal dysbiosis index increases (more dysbiosis), the proportion of primary bile acids in the feces also increases. This makes sense because a disrupted or imbalanced gut community often has fewer bacteria capable of converting primary bile acids into secondary ones, so primary bile acids accumulate in the stool.

The other strong relationship is that the log abundance of Clostridium hiranonis positively correlates with the percentage of secondary bile acids. Clostridium hiranonis is known to carry the enzymatic capacity to convert primary bile acids into secondary ones, so more of this organism means more transformation and a higher share of secondary bile acids in the feces.

Choice patterns that suggest a negative link between C. hiranonis and secondary bile acids, or that imply no correlations, don’t fit the biology of bile-acid metabolism by gut bacteria. Similarly, a finding that ties secondary bile acids to dysbiosis while linking primary bile acids to a different variable would misalign with the expected producer–transformer relationships in the gut microbiome.