Submitted to: Bioresource Technology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/1/2005
Publication Date: 12/1/2006
Citation: Anderson, R.C., Carstens, G.E., Miller, R.K., Callaway, T.R., Schultz, C.L., Edrington, T.S., Harvey, R.B., Nisbet, D.J. 2006. Effect of oral nitroethane and 2-nitropropanol administration on methane-producing activity and volatile fatty acid production in the ovine rumen. Bioresource Technology. 97:2421-2426.
Interpretive Summary: The production of methane in the forestomach (also called the rumen) of cattle and sheep is an inefficient process resulting in the loss of up to 15% of the dietary energy consumed by the animal. This inefficiency has been calculated to cost the U.S. cattle feeding industry up to $900,000 per day. Nitroethane and 2-nitropropanol are chemicals that have been shown to kill foodborne pathogens such as Salmonella and Campylobacter and to inhibit methane production in test tube experiments in the laboratory. In the present study, we evaluated the effect of nitroethane or 2-nitropropanol on methane-producing activity and volatile fatty acid production, both measures of microbial digestion, in the rumen of mature sheep. Oral administration of nitroethane and 2-nitropropanol significantly reduced methane-producing activity by as much 69% when compared to control animals given no nitroethane. Oral administration of nitroethane or 2-nitropropanol had little or no effect on amounts or proportions of volatile fatty acids produced in the rumen of these sheep, indicating that the digestive efficiency was not adversely affected. These results demonstrate that nitroethane and 2-nitropropanol safely reduced methane production in the live animal. Our findings lead us closer to the development of practical strategies that can reduce the digestive inefficiency as well as any negative environmental impacts of methane production in cattle and sheep. Ultimately, the development of such strategies will help farmers safely and more efficiently produce meat and milk at less cost for the American consumer.
Technical Abstract: Strategies are sought to reduce economic and environmental costs associated with ruminant methane emissions. The effect of oral nitroethane or 2-nitropropanol administration on ruminal methane-producing activity and volatile fatty acid production was evaluated in mature ewes. Daily administration of 24 and 72 mg nitroethane/kg body weight reduced (P < 0.05) methane-producing activity by as much as 45 and 69% respectively, when compared to control animals given no nitroethane. A daily dose of 120 mg 2-nitropropanol/kg body weight was needed to reduce (P < 0.05) methane-producing activity by 37% from that of untreated control animals. Reductions in the methane-producing activity may have been diminished by the last day (day 5) of treatment, presumably due to ruminal adaptation. Oral administration of nitroethane or 2-nitropropanol had little or no effect on accumulations or molar proportions of volatile fatty acids in rumen contents collected from the sheep. These results demonstrate that nitroethane was superior to 2-nitropropanol as a methane inhibitor and that both nitrocompounds reduced ruminal methanogenesis in vivo without redirecting the flow of reductant generated during fermentation to propionate and butyrate.