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United States Department of Agriculture

Agricultural Research Service

2010 Annual Report

1a.Objectives (from AD-416)
Develop fundamental knowledge concerning the microbial populations of swine manure and the swine intestinal tract. Apply this knowledge to understand the relationship between microbial populations and the production of odorous compounds. Develop improved methods to quantitate changes in bacterial populations in feces and stored manure and correlate these with emissions/odorous compounds produced.

1b.Approach (from AD-416)
Determine the identity, relative concentration, and metabolic activities of microorganisms present in stored manure. Carry out physiological, biochemical, and genetic characterization of isolated bacterial cultures; determining which organisms and processes are responsible for production of odor causing chemicals. An extension of this work will be to examine the intestinal flora of the pig and its potential impact on the properties of the manure and the concentrations of potential odor precursors. This research will be conducted using samples from representative swine farms. Evaluate potential compounds for control of specific microorganisms or the metabolic processes responsible for odors.

3.Progress Report
For FY 2010, researchers applied techniques for quantifying the levels of total gas and the odorous compound hydrogen sulfide produced from manure slurry under laboratory conditions. The effects of addition of condensed tannins from various sources were determined using a pressure meter and hydrogen sulfide analyzer. These techniques allowed the researchers to determine that only tannins from the quebracho plant were effective in reducing gas and hydrogen sulfide from the manure slurries. Researchers also applied molecular techniques to quantify the number of bacteria responsible for production of hydrogen sulfide and the effects of condensed tannins on these bacterial populations. In collaboration with the University of Leeds and the Institute of Food Research, Norwich, United Kingdom, research was also continued on targeting expression of therapeutic proteins in the human gastrointestinal tract by genetically modified bacteria. These results were communicated to the scientific community via presentations at domestic/international meetings and scientific publications.

1. Evaluation of various sources of condensed tannins on total gas and hydrogen sulfide production from in vitro swine manure slurries. Reducing overall bacterial activity in stored manure is important for lowering the production of greenhouse gases and odorous compounds such as hydrogen sulfide. Condensed tannins have been studied for their abilities to affect bacteria present in stored manure. However, for the first time Bioenergy Research Unit scientists at the National Center for Agricultural Utilization Research in Peoria, IL, have demonstrated that only tannins from the quebracho plant will reduce overall gas and hydrogen sulfide production from manure slurries studied in the laboratory when compared to other plant tannins. These results can now be applied towards reducing odors and greenhouse gas emissions in on-farm evaluations at large-scale swine facilities (patent applied for this technology).

Review Publications
Hamady, Z.Z., Scott, N., Farrar, M.D., Lodge, J.P., Holland, K.T., Whitehead, T.R., Carding, S.R. 2010. Xylan-regulated Delivery of Human Keratinocyte Growth Factor-2 to the Inflamed Colon by the Human Anaerobic Commensal Bacterium Bacteroides ovatus. Gut. 59(4):461-469.

Last Modified: 5/27/2015
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