Microbial Ecology of the Porcine Gastrointestinal Tract in Relation to Lactobacillus Reuteri MM53 and Bacitracin Treatments

Due to concerns about antibiotic resistance and residues, there is increasing interest in the use of alternative strategies to achieve the same results as gained with the use of sub-therapeutic antibiotics. Lactobacilli are an integral part of the piglet microbiota during the weaning stage and are therefore frequently incorporated into commercial probiotic preparations. However, little research has been done at the molecular level to determine if these supplements are effectively influencing the microbiota present in the gastrointestinal tract. Therefore, changes in microbial ecology of fecal microbiota in weaning piglets was studied after introduction of an exogenous Lactobacillus reuteri strain MM53 in conjunction with bacitracin additions using molecular techniques. Denaturing gradient gel electrophoresis was used to monitor bacterial population changes and these changes were assayed based upon shifts in fecal banding patterns. Inclusion of antibiotics in the diet caused a simplification of V3-16S rDNA banding patterns and subsequently altered sample time phase alignments, which were observed to be sequential in control animals. Introduction of L. reuteri did not significantly alter the total microbial populations of the GIT, however within a sub-set of the Lactobacilli population (based upon V1-16S rDNA), there were indications that L. reuteri was able to colonize and persist in the GIT under the influence of a selective pressure. Other results indicated that the host had significant influence over the selection of bacterial species colonizing the GIT, although the actual nature of these influences are undetermined at this time. Individual piglet effects had the strongest influence on banding pattern similarities, followed closely by litter effects, which indicated that piglets of the same genetic background had bacterial populations more similar to each other, than to those of non related piglets.

Name thesis:degree_name

Ph.D.

Level thesis:degree_level

Dissertation

Discipline thesis:degree_discipline

Animal Sciences

Grantor

University of Illinois at Urbana-Champaign

Year dc:date

2015

Author dc:creator

• Simpson, Joyce Marie

Contributors dc:contributor

• Roderick Mackie

• Biology, Molecular

Language dc:language

eng

Identifier

(MiAaPQ)AAI3017207

OAI identifier oai:identifier

oai:www.ideals.illinois.edu:2142/83535