ARS | Publication request: DETECTION OF METHANE AND QUANTIFICATION OF METHANOGENIC ARCHAEA IN FAECES FROM YOUNG BROILER CHICKENS USING REAL-TIME PCR

Submitted to: Letters in Applied Microbiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: July 16, 2007
Publication Date: December 20, 2007
Citation: Saengkerdsub, S., Herrera, P., Woodward, C.L., Anderson, R.C., Nisbet, D.J., Ricke, S.C. 2007. Detection of methane and quantification of methanogenic archaea in faeces from young broiler chickens using real-time PCR. Letters in Applied Microbiology. 45:629-634.

Interpretive Summary: Methane-producing bacteria that live in the gut of food producing animals such as cows and sheep can decrease the efficiency by which these animals can digest and obtain energy from feeds they eat. Adult chickens are also known to contain methane-producing bacteria in their gut but it is not known how soon chickens acquire these bacteria or what impact they may have on digestion and health in these animals. Therefore, we conducted the following study to determine when chicks first start to become colonized by methane-producing bacteria and to see if we could find sources that may contribute to their colonization. Using sensitive methods that detect the DNA from methane-producing bacteria, we found that chicks have these bacteria in their gut as early as 3-days after they are hatched. Using traditional microbiological methods for growing methane-producing bacteria in special growth cultures, we were able to recover methane-producing bacteria from the gut of chicks as young as 5 days of age thus confirming that these bacteria do become established very early in the chicken’s life. We found that methane-producing bacterial DNA was present in house flies and manure collected from the chicks’ living space thus indicating that chicks may first become exposed to methane-producing bacteria from these sources. These results help us learn just how and when chickens become colonized by methane-producing bacteria. Ultimately, this research will help scientists and farmers understand how to grow more efficient and healthier chickens thus providing less expensive and more wholesome poultry products for the American consumer.

Technical Abstract: Succession of methanogenic archaea colonization of the chick ceca was assessed by traditional culture methodology and real-time PCR. Quantitative PCR of pooled fecal samples collected from 12 separate groups (10 chicks per group) of similar aged chicks revealed that methanogenic 16S rDNA gene was present at 4.19 to 5.05 log10 copies per gram wet weight in broilers 3, 4, 5, 9, and 12 days of age. Traditional bacteriological cultivation revealed that methane-producing bacteria were present in 25, 67, and 100 % of cultures inoculated with separate pooled fecal samples collected from each of the 12 groups of chicks at 5, 9, and 12 days of age, respectively. The presence of methanogen DNA in litter and house flies collected in the bird house was 4.94 ± 0.10 and 5.51 ± 0.11 log10 16S rDNA copy number per gram wet weight, respectively, and methanogenesis was observed in viable cultures inoculated with litter and house fly samples. Results suggest that methanogens colonization begins in chicken ceca soon after hatch and that litter and house flies likely contribute to the dissemination of methanogens during colonization in broiler chicks.