Authors: Emma J Gagen Pascale Mosoni Stuart E Denman Rafat Al Jassim Christopher S McSweeney Evelyne Forano
Publish Date: 2012/03/02
Volume: 64, Issue: 3, Pages: 628-640
Abstract
Reductive acetogenesis is not competitive with methanogenesis in adult ruminants whereas acetogenic bacteria are the dominant hydrogenotrophs in the early rumen microbiota The ecology of hydrogenotrophs in the developing rumen was investigated using young lambs raised in sterile isolators and conventional adult sheep Two lambs were born naturally left with their dams for 17 h and then placed into a sterile isolator and reared aseptically They were inoculated with cellulolytic bacteria and later with Methanobrevibacter sp 877 to investigate the effect of methanogen establishment on the rumen acetogen population since they lacked cultivable representatives of methanogens Putative acetogens were investigated by acetylCoA synthase and formyltetrahydrofolate synthetase gene analysis and methanogens by methyl coenzyme reductase A gene analysis Unexpectedly a low abundant but diverse population of methanogens predominantly Methanobrevibacter spp was identified in isolated lambs preinoculation with Mbb sp 877 which was similar to the community structure in conventional sheep In contrast potential acetogen diversity in isolated lambs and conventional sheep was different Potential acetogens affiliated between the Lachnospiraceae and Clostridiaceae in conventional sheep and with the Blautia genus and the Lachnospiraceae in isolated lambs The establishment of Mbb sp 877 1000fold increase in methanogens did not substantially affect acetogen diversityWe are very grateful to Gérard Vert and Christophe de Martrin Unit of Microbiology INRA ClermontFerrand/Theix for the rearing of lambs and rumen sampling and to Pascale Lepercq Rémy Roux and Gérard Andant for technical assistance This work was partly funded by the French and Australian governments through the French–Australian Science and Technology FAST program Emma Gagen was a recipient of scholarships from The University of Queensland and CSIRO Livestock Industries
Keywords: