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

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

Westergaard, Sara A

关键词: Bacillus;    Direct-fed microbials (DFM);    16s rRNA;   

Others  :  https://www.ideals.illinois.edu/bitstream/handle/2142/78803/WESTERGAARD-THESIS-2015.pdf?sequence=1&isAllowed=y

美国|英语

来源: The Illinois Digital Environment for Access to Learning and Scholarship

【 摘 要 】

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.