Fig. 4

Secondary bile acids inhibit the expansion of potential pathogens in vitro. a, b In vitro growth of canine clinical isolates of E. coli or C. perfringens in the presence of varying concentrations of lithocholic acid or deoxycholic acid (mean ± sd shown). Each point in the graphs represents one replicate in the assay. As E. coli had a full growth in lithocholic acid < 0.075 mg/mL and C. perfringens had no growth in deoxycholic acid > 0.1 mg/mL, these assays were not determined below and above these concentrations, respectively. c, d Growth curves of deoxycholic acid on E. coli and C. perfringens. The in vitro inhibition tests for a and b were repeated in three independent experiments, and data shown are from a representative experiment. c and d show the mean values of three technical replicates. *P < 0.05, **P < 0.01, ***P < 0.001, ****P < 0.0001 using two-sided t test