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United States Department of Agriculture

Agricultural Research Service

2008 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 2008, researchers developed new techniques for quantifying the levels of sulfate-reducing bacteria in swine manure samples, which are responsible for production of the odorous compound hydrogen sulfide. These techniques involve the use of quantitative real-time polymerase chain reaction (qRT-PCR) and allow the researchers to assay the effects of potential additives to manure storage pits on the levels of these bacterial populations. The qRT-PCR approach was also used to determine levels of sulfate-reducing bacteria in the gastrointestinal tract of swine under different diet conditions in a joint study with the Agricultural Research Service (ARS)-Swine Odor and Manure Management Research Unit, Ames, Iowa. Researchers also identified and named a new bacterial genera and species after former ARS scientist Isadore Robinson. Collaborative research was also carried out targeting carbohydrate metabolism in bifidobacteria, beneficial bacteria present in the human gastrointestinal tract. These results were communicated to the scientific community via presentations at domestic/international meetings and scientific publications. This research addresses NP 206, Component I.

1. DEVELOPMENT OF QUANTITATIVE REAL-TIME POLYMERASE CHAIN REACTION (PCR) ASSAYS FOR SULFATE-REDUCING BACTERIA. Determining the levels of bacteria responsible for producing hydrogen sulfide is critical for determining the effects of management practices on stored swine manure. Real-time PCR techniques were developed to quantitate the levels of sulfate-reducing bacteria which produce hydrogen sulfide. These techniques were used to assess the effects of addition of condensed tannins to manure on the populations of sulfate-reducing bacteria. This research addresses NP 206, Component I, Problem Areas 1 and 3.

5.Significant Activities that Support Special Target Populations

6.Technology Transfer

Number of Invention Disclosures Submitted1
Number of Non-Peer Reviewed Presentations and Proceedings3
Number of Newspaper Articles and Other Presentations for Non-Science Audiences1

Review Publications
Whitehead, T.R., Price, N.P., Drake, H.L., Cotta, M.A. 2008. Catabolic pathway for the production of skatole and indoleacetic acid by the acetogen Clostridium drakei, Clostridium scatologenes, and swine manure. Applied and Environmental Microbiology. 74(6):1950-1953.

Cook, K.L., Whitehead, T.R., Spence, C., Cotta, M.A. 2008. Evaluation of the sulfate-reducing bacterial population associated with stored swine slurry. Anaerobe. 14:172-180.

Last Modified: 5/27/2015
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