In vitro evaluation of the potential for select bacteria and yeast as probiotics in poultry production
This project focused on the characteristics of selected microbes for use as probiotics in poultry production. The three experimental microbes were B. longum, L. plantarum and S. boulardii. First, the ability of the microbes to tolerate and survive varying pH levels and bile concentrations was assessed. The microbes were tested in PBS at pH 7, 6, 5, 4, 3 and 2 for 5hrs; and in bile concentrations of 3%, 2%, 1.5%, 1% and control with just media for 6hrs. Samples were taken each hour in order to evaluate growth or decline in CFU/ml. It was found that B. longum did significantly (p>0.05) well at a pH range of 5 - 7; L. plantarum showed significant ability to tolerate pH 4 - 7; and S. boulardii pH 2 - 7. The bile assessment resulted in B. longum showing no significant difference in tolerance levels at any of the bile concentrations. Nonetheless, L. plantarum and S. boulardii were able to tolerate the various bile concentrations. Next, the microbes' ability to attach to chicken GIT mucosa was studied. Duodenal tissue was inoculated with either of the experimental microbes for an hour at 37oC in 10% CO2 and later assessed for attachment using SEM. B. longum and L. plantarum showed remarkable ability to attach by obvious changes in the cell surface and cytoskeleton where they were anchored. S. boulardii was also present on the cell surface, but no changes were observed on the epithelial cell surface. Lastly, the microbes were used to challenge pathogenic microbes. An agar spot test method was employed where B. longum, L. plantarum or S. boulardii were spotted and grown on their respective agar. Then the pour plate method was used to add the pathogenic microbes. The plates were read for positive inhibition (ZOI > 5mm). B. longum and L. plantarum showed the ability to positively inhibit all pathogenic microbes with the exception of B. longum falling short of inhibiting E. faecium by 0.5mm. S. boulardii only showed positive inhibition towards C. lari and C. jejuni. Overall, the results of this project indicate that these microbes have a strong potential for use in the poultry industry.
Beverly R.E.A Dixon,
"In vitro evaluation of the potential for select bacteria and yeast as probiotics in poultry production"
ETD Collection for Tennessee State University.