## 3 Results
### Turkey-Sourced LAB Vary in Their Response to Bile  
To test each isolate's ability to survive in the turkey small intestine and withstand the effects of bile, each isolate was first tested for the presence of bile salt hydrolase (BSH) activity. BSH is an enzyme that deconjugates bile salts and aids in tolerance to bile. BSH activity can be detected when unconjugated bile acid precipitates in agar and forms a powdery halo around the bacterial colonies when grown on agar containing bile salts (Figure S2). All _L. crispatus_, _L. gallinarum_, and _L. salivarius_ isolates were positive for BSH activity (Figure 3, Table S1). All _L. vaginalis_, _W. paramesenteroides_, and _P. acidilactici_ isolates were negative for BSH activity (Figure 3, Table S1). One _L. reuteri_ was positive and one was negative for BSH activity (Figure 3, Table S1). In addition to testing BSH activity, the growth of the isolates was also examined in mixed bile salts to determine whether BSH activity correlated with growth in bile. When grown in bile containing 0.03% \(w/v\) bile salts, isolate percent growth ranged from 41-104% (Table S1). There was little variability between species growth in media containing 0.03% \(w/v\) bile, with 22/24 isolates having percent growth over 80% (Table S1, Figure S3). The single _L. vaginalis_ that was tested had statistically significantly decreased growth in media containing 0.03% \(w/v\) bile, with 41% growth. When the bile concentration was increased to 0.15% \(w/v\), the percent growth range was 24-90% (Table S1). All _P. acidilactici_ isolates were numerically higher in percent growth than all the other isolates and were statistically significantly higher in percent growth than three out of seven species (Figure 4). _W. paramesenteroides_ was the second highest percent growth species numerically. Most of the other species had similar percent growth in bile to each other (Figure 4). The _L. crispatus_ group had significant variability at this concentration of bile (Figure 4). Interestingly, the two low-performing _L. crispatus_ (MOF2W6B4C10 and MOF2W6B4C8; percent growth 24.7% and 24.9%, respectively) and the three higher-performing _L. crispatus_ (SNF2W3B2M1, SNF2W6B1L3, and MOF2W3B1T2; percent growth 43%, 58%, and 60%, respectively) formed cluster sub-groupings in the phylogenetic tree (Table S1, Figure 1). When comparing percent growth in 0.3% \(w/v\), the highest bile concentration tested, the range of percent growth was 0.32-76% (Table S1). All _Lactobacillus_ and _Lactobacillus_-like isolates had percent growth  
Figure 3: Percent of isolates that were positive and negative for bile salt hydrolase activity by species (\(n=24\)). of <17%. _P. acidilactici_ had statistically significantly higher growth than all other species (Figure 4). _W. paramesenteroides_ had numerically higher growth than all species except _P. acidilactici_ and statistically significantly higher growth than five out of seven other species (Figure 4). Figure 4: Percent growth using percent area under the curve compared to matched controls by species. Growth in 0.15% \(w/v\) bile (**top**) and growth in 0.3% \(w/v\) (**bottom**), \(n=24\). Significant differences are depicted with distinct letters. Significance was set at \(p\leq 0.05\), denoted by letter differences above boxes. When comparing percent growth to BSH activity, it is interesting to note that the high-performing species _W. paramesenteroides_ and _P. acidilactici_ both had isolates that were all negative for BSH (Figures 3 and 4). In the BSH tests, the _L. reuteri_ isolate MOF2W3B1C8 was negative for BSH activity, and SNF2W3B2M2 was positive for BSH activity (Table S1). Even though these isolates had different results for BSH activity, their percent growth was very similar. MOF2W3B1C8 had a percent growth of 14% and 49% for 0.3% and 0.15% bile, respectively, and SNF2W3B2M2 had a percent growth of 16% and 53% for 0.3% and 0.15% bile, respectively (Table S1).