Effects of direct-fed Bacillus pumilus 8G-134 (NRRL B-50174) on ruminal and fecal microbial populations of pre- and postpartum Holstein cows

Westergaard, Sara A.

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https://hdl.handle.net/2142/78803 Copy

Description

Title

Effects of direct-fed Bacillus pumilus 8G-134 (NRRL B-50174) on ruminal and fecal microbial populations of pre- and postpartum Holstein cows

Author(s)

Westergaard, Sara A.

Issue Date

2015-05-05

Department of Study

Animal Sciences

Discipline

Animal Sciences

Degree Granting Institution

University of Illinois at Urbana-Champaign

Degree Name

M.S.

Degree Level

Thesis

Keyword(s)

• Bacillus
• Direct-fed microbials (DFM)
• 16s rRNA

Abstract

Direct-fed microbials (DFM) are used as feed supplements in agricultural industry to enhance animal health and performance. The effects of Bacillus pumilus 8G-134 (NRRL B-50174) as a feed supplement were investigated through 16S rRNA gene-based inferences about community structure changes, exploration of the intra-Genus taxonomic variance using oligotyping, as well as RNA-seq conducted on rumen and fecal microbial contents from lactating dairy cattle. These techniques aided in detecting changes in gastrointestinal tract microbial community populations. Phylogenetic 16S analysis identified the microbes present and bioinformatic techniques, i.e. Qiime and Oligotyping software, further elucidated the community structures. In order to further investigate the germination of B. pumilus spores in the rumen, a transcriptomic approach was employed. Oligotyping analysis revealed that certain Bacillus oligotypes were detected exclusively in DFM samples. These DFM oligotypes could be further differentiated between rumen fluid (RF) and fecal sample types. It remains unclear whether or not the spores germinated in the rumen, but the effects on the fecal microbiota are clear. The major finding in this work is a modulation of the Bacteroidetes in the fecal samples of the DFM fed cows. Previous reports have shown that an increased Firmicutes to Bacteroidetes ratio leads to increased energy harvest and an obese phenotype. In lactating dairy cows, the increased energy harvest from the colonic bacteria likely promotes enhanced milk production.

Graduation Semester

2015-05

Type of Resource

text

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http://hdl.handle.net/2142/78803

Copyright and License Information

Copyright 2015 Sara Westergaard

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