PT  - JOURNAL ARTICLE
AU  - Milton Thomas
AU  - Megan Webb
AU  - Sudeep Ghimire
AU  - Amanda Blair
AU  - Kenneth Olson
AU  - Gavin John Fenske
AU  - Alex Thomas Fonder
AU  - Jane Christopher-Hennings
AU  - Derek Brake
AU  - Joy Scaria
TI  - Metagenomic characterization of the effect of feed additives on the gut microbiome and antibiotic resistome of feedlot cattle
AID  - 10.1101/153536
DP  - 2017 Jan 01
TA  - bioRxiv
PG  - 153536
4099  - http://biorxiv.org/content/early/2017/06/21/153536.short
4100  - http://biorxiv.org/content/early/2017/06/21/153536.full
AB  - In North America, antibiotic feed additives such as monensin and tylosin are added to the finishing diets of feedlot cattle to counter the ill-effects of feeding diets with rapidly digestible carbohydrates. While these feed additives have been proven to improve feed efficiency, and reduce liver abscess incidence, how these products impact the gastrointestinal microbiota is not completely understood. Furthermore, there are concerns that antibiotic feed additives may expand the antibiotic resistome of feedlot cattle by enriching antimicrobial resistance genes in pathogenic and nonpathogenic bacteria in the gut microbiota. In this study, we analyzed the impact of providing antibiotic feed additives to feedlot cattle using metagenome sequencing of treated and untreated animals. Our results indicate that use of antibiotic feed additives does not produce discernable changes at the phylum level however treated cattle had reduced the abundance of gram-positive bacteria at the genus level. The abundance of Ruminococcus, Erysipelotrichaceae and Lachanospira in the gut of treated steers was reduced. This may impact the ability of these animals to exclude pathogens from the gut. However, our results did not show any correlation between the presence of antimicrobial resistance genes in the gut microbiota and the administration of antibiotic feed additives.