|DOWD, SCOT - Medical Biofilm Research Institute|
|BAUER, NATHAN - Food Safety Inspection Service (FSIS)|
Submitted to: Journal of Animal Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/29/2010
Publication Date: 12/1/2010
Citation: Callaway, T.R., Dowd, S.E., Edrington, T.S., Anderson, R.C., Krueger, N.A., Bauer, N., Nisbet, D.J. 2010. Evaluation of the bacterial diversity in the feces of cattle fed diets containing levels of dried distillers grains plus solubles using bacterial tag-encoded FLX amplicon pyrosequencing (bTEFAP). Journal of Animal Science. 88:3977-3983.
Interpretive Summary: Dietary composition can change the population of the gut of animals, affecting their growth efficiency. However, the effects of dietary changes on the bacteria in the gut are unknown. Distillers grains have been fed to cattle in increasing amounts because they are a byproduct of ethanol production with good nutritional value for cattle. The effects of these feeds on the bacterial population of cattle has been controversial, including increases in E. coli O157:H7 populations. This study utilizes a new molecular technique to examine changes in the microbial population of the intestinal tract and how they affect methane production and pH, markers typically used in nutritional studies. This allows us to correlate intestinal microbial populations with global changes that affect the animal directly.
Technical Abstract: Dietary components and changes cause shifts in the intestinal ecology of the gut, which can play a role in animal health and productivity. However, most information about the microbial populations in the gut of livestock species has not been quantitative. In the present study, we utilized a new molecular method, bacterial tag encoded FLX amplicon pyrosequencing (bTEFAP), that can perform diversity analyses of gastrointestinal bacterial populations. In the present study, cattle (n=6) were fed a basal feedlot ration and were subsequently randomly assigned to one of three diets (n=2 cows per diet). In each diet, 0%, 25%, or 50% of the concentrate portion of the ration was replaced with dried distillers grain (DDG). Ruminal and fecal bacterial populations were different when animals were fed DDG compared to controls; ruminal and fecal Firmicute:Bacteroidetes ratios were lower (P > 0.05) in the 25% and 50% DDG diets compared to controls. Ruminal pH was decreased (P < 0.05) and in vitro CH4 production was decreased (P < 0.08) in ruminal fluid from cattle fed diets containing the highest level of DDG. Using bTEFAP, we have examined normal microbiota of cattle using modern molecular methods to understand how diets affect the ecology of the intestinal tract and the intestinal microbiome’s contribution to animal health and production.