Location: Bioenergy Research Unit
Title: Reduction of Emissions from in Vitro Swine Manure Using Monensin Authors
Submitted to: American Society of Animal Science
Publication Type: Abstract Only
Publication Acceptance Date: July 12, 2007
Publication Date: October 1, 2007
Citation: Whitehead, T.R., Cotta, M.A. 2007. Reduction of emissions from in vitro swine manure using monensin [abstract]. Journal of Animal Science. 85(1):92. Technical Abstract: Storage of swine manure is associated with the generation of malodorous compounds and emissions. These are produced as a result of anaerobic degradation of materials present in manure and include sulfides, methane, organic acids, ammonia, and other volatile compounds. Because odor emission from livestock creates a nuisance and therefore may be regulated, there is considerable interest in devising methods to control these emissions. Previous research in our laboratories has demonstrated that the primary microbial populations in stored swine manure are low (G+C), Gram-positive anaerobic bacteria. One approach for reducing emissions production would be to target these populations. Monensin has been used to alter the bacterial population and metabolic end products in the rumen of domestic animals for improved animal performance, largely through its effect on Gram-positive bacteria. Therefore, it was decided to test the effects of monensin on stored swine manure. Fecal and manure pit slurry were collected from a local swine production facility. Manure slurry (20% final concentration) was combined with 20% (w/v) feces and buffer and mixed under gas. The mixture was aliquoted into glass bottles under gas. Monensin (10 mM) was added to three bottles, and three bottles without monensin were used as controls. Gas production was measured over time, and aliquots were removed for chemical analyses and determination of viable bacterial numbers. Gas production in the monensin samples was greatly reduced within 24 hr (<10% of controls), and this reduction was maintained over a 28-day test period. Methane production was also reduced (<5% of controls). However, no detectable hydrogen was observed in any sample. Volatile fatty acid production was only slightly decreased in the monensin samples, while butyrate production increased 3-fold. These results are quite different from those observed in the rumen. The results of this study suggest that addition of antimicrobial compounds may prove useful for reducing gaseous, odorous emissions from swine facilities. Evaluation of other microbial inhibitors in addition to monensin appears warranted.