U.S. flagAn official website of the United States government
                    Here's how you know **Official websites use .gov**
                            
                            A **.gov** website belongs to an official government organization in the United States.
 **Secure .gov websites use HTTPS**
                            
                            A **lock** (                            
                              A locked padlock                                                      
                            
                            ) or **https://** means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.


Menu Agricultural Research Service
						
                    U.S. DEPARTMENT OF AGRICULTURE
 Food and Feed Safety Research: College Station, TX
 close



    Research

                    Research Projects
                                    Publications
                                    Collaborations
                                    News
                People

                    Staff Listing
                                    CareersSearch small
                    Search
            
            ARS Home
                                About ARS
                                Contact Us




ARS Home Plains Area College Station, Texas Southern Plains Agricultural Research Center Food and Feed Safety Research Research Publications at this Location





- ARS National Programs
- Search for a scientific manuscript
- Search for a research project
- ARS Software
- Programs and Projects
- Collaborations
- Subjects of Investigation
- Publications

Title:   Author  item
                                            Anderson, Robinitem
                                            RICKE, STEVEN - UNIVERSITY OF ARKANSASitem
                                            Krueger, Nathanitem
                                            Nisbet, David
  Submitted to: Book Chapter
                                    Publication Type: Book / Chapter
                                    Publication Acceptance Date: 1/25/2009
                                    Publication  Date: 4/20/2009
                                    Citation: Anderson, R.C., Ricke, S.C., Krueger, N.A., Nisbet, D.J. 2009. Targeting physiological activities to modify the ecology and functionality of rumen and gastrointestinal ecosystems, prototypical anaerobic digesters. In: Biswas, S., Kaushik, N., Pandey, A., editors. Bioprocess and Bioproducts: Technology Trends and Opportunities. New Delhi, India: Asiatech Publishers Inc. p. 50-65.Interpretive Summary: In the biotechnology industry, anaerobic fermentation of animal and municipal wastes provides an opportunity to transform low value biomass into higher value products such as ethanol, organic acids, or methane.  However, because pathogenic bacteria can reside in animal and municipal wastes, the biotechnology industry is interested in learning how to minimize the potential contamination of end, or byproducts produced during their anaerobic digestion.  Additionally, in order to optimize the biochemical conversions that take place in these ecosystems, the biotechnology industry is looking to learn from studies conducted with other microbial ecosystems.  Of particular interest is the microbial population inhabiting the cow’s stomach because it also can harbor pathogenic bacteria and is highly regarded for its ability to digest and transform low quality plant material into chemical forms of value for the host animal.  In this review, we summarize the development of strategies targeting unique biochemical pathways of pathogenic Salmonella, Escherichia coli, and Campylobacter that have been proven successful in reducing the survivability of these pathogens in the cow’s gut.  We also summarize the use of a certain type of chemical known as a nitrocompound to inhibit the energetically wasteful process of methane production that occurs in the cow’s stomach.  Another undesirable reaction that occurs within the cow’s stomach is the conversion of beneficial fats to unhealthy fats, and we present results from experiments that show how we can minimize this process.  This review will help the biotechnology industry produce safer products at less cost, with the ultimate products derived from these processes being more affordable for the American consumer.
                                Technical Abstract: The rumen microbial ecosystem is highly regarded for its ability to digest and transform low quality plant material into chemical forms of use by the host.  However, less than 35% of the dietary energy consumed by the ruminant is conserved by the host.  Methane production within the rumen contributes the loss of up to 15% of the animal’s gross energy intake and, as in certain other anaerobic digesters, contributes significantly to the carbon footprint of this industry.  Certain short chain nitrocompounds, such as nitroethane, 2-nitroethanol, and the phytotoxins, 3-nitro-1-propionic acid, and 3-nitro-1-propanol, markedly inhibit ruminal methane production by inhibiting the oxidation of hydrogen and formate, the primary reducing substrates for methanogenesis within the rumen.  An attractive aspect of nitro-caused inhibition of methanogenesis is that these inhibitors also consume electrons via their reduction to amines or amino acids, and thus provide the ecosystem an alternative mechanism for the disposal of reducing equivalents generated during glycolysis.  Lipolysis within the rumen liberates free fatty acids from dietary lipids thereby making unsaturated fatty acids available for biohydrogenation.  Consequently, ruminant-derived foods contain high proportions of saturated fats which are associated with negative-health effects such as coronary heart disease.  High concentrations of free long-chain fatty acids also negatively impact digestion via inhibition of cellulolytic bacteria.  Addition of glycerol to rumen incubations inhibits rumen lipolysis by as much as 80% suggesting that supplementation of ruminant diets with this common byproduct of biofuel production would exert endproduct inhibition of microbial fat hydrolysis.  The ruminant gastrointestinal tract can be a reservoir for certain pathogenic bacteria, thus requiring exporters of ruminant-derived products to implement food security standards.  Strategies targeting nitrate respiration of Salmonella and enterohemorrhagic Escherichia coli and targeting amino acid metabolism of Campylobacter, have been proven successful in reducing the survivability of these pathogens in the ruminant gut.  Strategies targeting specific physiological activities have successfully modified the ecology and functionality of the rumen ecosystem and may have application in other anaerobic fermentations as well.


Return to top


Connect with ARS Sign up


ARS Home
                            USDA.gov
                            Plain Writing
                            Policies & Links
                            Civil Rights Statements
                            FOIA
                            Accessibility Statement
                            Privacy Policy
                            Non-Discrimination Statement
                            Quality of Information
                            USA.gov
                            WhiteHouse.gov