were taken down. The anterior liver lobes were brought into a special device as previously demonstrated ^[@B12]^ and a wire thermometer was placed deep into the liver parenchyma. The vascular pedicle supplying the anterior lobes was clamped using an atraumatic clip for 90 minutes, but the vascularization to the posterior lobes remained intact to prevent intestinal congestion. In the H group, topical hypothermia was induced by dropping cooled saline on the surface of the anterior lobes. To prevent liquid spillage into the abdominal cavity and body cooling, appropriate aspirators were used, and body temperature was maintained at 36.5 ± 1°C in all animals, utilizing an auxiliary heating lamp and aluminum blankets as necessary.

After 90 minutes of ischemia, liver reperfusion was accomplished, and the hypotension caused by reperfusion syndromeabsorbed in the terminal ileum and returned to the liver^[@CR16]^. Primary BAs that reach the large intestine are biotransformed by members of the gut microbiota via two enzymatic reactions, deconjugation and dehydroxylation, into secondary BAs, including MCA, hyodeoxycholate (HDCA), ursodeoxycholate, (UDCA), lithocholate (LCA), and deoxycholate (DCA)^[@CR18]^.

To date, it is poorly understood whether and to what extent intestinal bacteria are involved in the regulation of human BA homeostasis. In view of the different roles of Gram-positive and Gram-negative bacteria in intestinal BA metabolism, the modification of either of these bacteria may have distinct effects on BA homeostasis. The farnesoid X receptor (FXR, also known as NR1H4) is known to play a key role in the regulation of BA synthesis and homeostasis^[@CR19]^. We thus hypothesize that the intestinal microbiota composition