Submitted to: Applied and Environmental Microbiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/27/2006
Publication Date: 1/20/2007
Citation: Saengkerdsub, S., Anderson, R.C., Wilkinson, H.H., Kim, W., Nisbet, D.J., Ricke, S.C. 2007. Identification and quantification of methanogenic archaea in adult chicken ceca. Applied and Environmental Microbiology. 3:353-356.
Interpretive Summary: Methane-producing bacteria are a special group of bacteria known to negatively affect the efficiency of digestion by microbial populations within the gastrointestinal tract of cattle and sheep. Because little is known about these bacteria in the gut of chickens, using molecular methods to identify and quantify the number and different types of methane-producing bacteria in the gut of an adult chicken. We found that unlike methane-producing populations in cattle and sheep, most (91%) of the methane producing bacteria identified in the chicken gut were very closely related and belonged to the same genetic group, Methanobrevibacter woesei. We also found that the chicken gut can harbour between 10,000 to 100,000,000 methane-producing bacteria per 1 gram of gut content which is quite similar to that found in the gut of cattle and sheep. These results show that chickens can harbour high numbers of methane-producing bacteria just as cattle and sheep do, although those in the chicken appear to be mostly of one type. Because large numbers of methane-producing bacteria can have an adverse affect on digestion, this research may ultimately help poultry producers more efficiently grow their chickens at less cost, thereby producing better and less expensive poultry products for the American consumer.
Technical Abstract: Methanogens, members of the domain Archaea, have been isolated from various animals but few reports exists regarding the isolation of methanogens from chicken, goose, and turkey feces. By using molecular methods for the identification and quantification of methanogenic archea in adult chicken ceca, 16S rRNA genes of 11 different phylotypes, 10 of which were 99% similar to Methanobrevibacter woesei, were found. Methanogen populations, as assessed by cultivation, and the 16S rRNA copy number were between 6.38 to 8.23 (wet weight) and 5.50 to 7.19 log10 per gram (wet weight), respectively. In conclusion, by using culture independent approaches and MPN enumeration, the results show that the methanogen community was less diverse in chicken ceca than in other animal habitats and that in chicken cecas, M. woesei was the predominant methanogen. The population levels of methanogenic archaea inhabiting this ecosystem were also similar to those in the other domestic animals.