|Wang, Jaw Kai|
|Nisbet, David - Dave|
Submitted to: Bioresource Technology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/1/2008
Publication Date: 5/13/2009
Publication URL: http://hdl.handle.net/10113/29907
Citation: Bozic, A.K., Anderson, R.C., Carstens, G.E., Ricke, S.C., Callaway, T.R., Yokoyama, M.T., Wang, J., Nisbet, D.J. 2009. Effects of the methane-inhibitors nitrate, nitroethane, lauric acid, Lauricidin**R and the Hawaiian marine algae, Chaetoceros, on ruminal fermentation in vitro. Bioresource Technology. 100:4017-4025. Interpretive Summary: The gastrointestinal tract of cattle can harbor food poisoning bacteria such as E. coli O157:H7, Salmonella, Listeria, and Campylobacter; bacterial pathogens estimated to cause greater than 3.9 million human infections in the U.S. each year. Methane production by bacteria in the gastrointestinal tract of cattle is a digestive inefficiency that costs the United States cattle feeding industry up to $900,000 per day. In order to develop affordable technologies that can help cattle ranchers reduce the presence of food poisoning bacteria in cattle, we tested the effects of certain chemical compounds known to inhibit the growth of one or more of these food poisoning bacteria for their ability to reduce methane production. We found that sodium laurate, Lauricidin**R, and a finely-ground product of the marine algae, Chaetoceros, ingedients known to inhibit Listeria, all reduced methane production by a cow’s gastrointestinal bacteria by greater than 90%. Another compound, nitroethane, known to inhibit Salmonella Typhimurium, and Listeria was also tested and found to reduce methane production by greater than 98%. These results suggest that the potential preharvest food safety benefits of supplementing cattle diets with nitroethane, lauric acid, Lauricidin**R, or the marine algae Chaetoceros may also reduce economic losses associated with methane production by cattle. These results may ultimately help cattle producers implement economically feasable strategies that will help them continue to produce safe and wholesome products for the American consumer.
Technical Abstract: The effects of several methane-inhibitors on rumen fermentation were compared during three 24 h consecutive batch cultures of ruminal microbes in the presence of nonlimiting amounts of hydrogen. After the initial incubation series, methane production was reduced greater than 92% from that of nontreated controls (25.8 +/- 8.1 umol ml-1 incubation fluid) in cultures treated with nitroethane, sodium laurate, Lauricidin**R, or a finely-ground product of the marine algae, Chaetoceros (added at 1, 5, 5 and 10 mg ml-1, respectively), but not in cultures treated with sodium nitrate (1 mg m1-1). Methane production during two successive incubations was reduced greater than 98% from controls (22.5 +/- 3.2 and 23.5 +/- 7.9 umol ml-1, respectively) by all treatments. Reductions in amounts of volatile fatty acids and ammonia produced and amounts of hexose fermented, when observed, were most severe in sodium laurate-treated cultures. These results demonstrate differential effects of the inhibitors on fermentation by rumen bacterial populations.