Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 7/4/2013
Publication Date: 10/1/2013
Citation: Anderson, R.C., Epps, S.V., Edwards, H.D., Harvey, R.B., Nisbet, D.J. 2013. Nonantibiotic interventions to control pathogens and undesired microbial activities in mixed microbial populations residing in the gut of food-producing animals and their excreted wastes. 6th Annual Conference on the Challenges in Environmental Science and Engineering, Daegu, Korea. p. 6.
Technical Abstract: The intensification and industrialization of animal agriculture throughout the world has led to considerable increases in animal production efficiencies but has also led to concerns that microbial pathogens, antibiotic residues, and other chemical contaminants could be concentrated in the environment. Consequently, livestock producers are continuously looking for new nonantibiotic interventions that can be used to prevent pathogen infection and colonization and control unwanted microbial processes within their animals. In the search for nonantibiotic interventions, the application of functionally active plant compounds is perceived as an attractive alternative because these compounds may be generally recognized as safe. Essential oils extracted from a variety of plants exhibit broad-spectrum bactericidal activity against a variety of Gram-negative and Gram-positive pathogens by disrupting cell wall integrity. Plants rich in lupulones inhibit certain amino acid-fermenting bacteria, such as Clostridium and Campylobacter, presumably by perforating bacterial cells much like ionophores. Hydrolysable tannins such as tannic acid inhibit bacterial growth by binding iron, thereby reducing its bioavailability; however, the antimicrobial activity of condensed tannins is thought to result from their disruption of bacterial cell walls or by their binding of proteins, enzymes, or amino acids. Whereas results from laboratory studies have shown good efficacy, often yielding several log-fold reductions in bacterial concentrations, results from animal studies have been less conclusive, possibly because these compounds may be absorbed or degraded in the proximal alimentary tract. Additional research is required to learn how to fully exploit the bioactivity of these and other yet to be identified bioactive plant compounds.