Results from the Global Rumen Census project show global solutions to reduce methane emissions from ruminants are feasible. The same bacteria and methanogens (microbes producing methane) appear to dominate in nearly all rumens across the world, for a wide variety of ruminant species and ruminant diets. This means that new technologies that seek to reduce methane emission by influencing rumen microbes can have global application. Surprisingly, there were few strong co-occurrence patterns between microbes. Such functional redundancy among the microbes means that multiple microbial species can fulfil the same function within the foregut. The “Global Rumen Census” project was a New Zealand-led project and analysed the rumen and camelid foregut microbial community composition, involving 140 researchers from 73 institutions, including Wageningen UR.
The results of the Global Rumen Census have been released on 9 October 2015 in the open-access journal Scientific Reports. The main part of the study was funded by the New Zealand Government via the Ministry for Primary Industries as part of its support for the Global Research Alliance on Agricultural Greenhouse Gases.
Contribution by Wageningen UR’s Animal Nutrition Group
From Wageningen UR, Jan Dijkstra, André Bannink and Kasper Dieho submitted samples and data from dry period and early lactation dairy cows that were collected in their project focusses on the adaptive capacity of the rumen to nutritional changes. The collaboration was advantageous for both groups, as the Global Rumen Census provided the composition of the populations of protozoa and archaea in their samples of rumen content. These data are complementary to the data on the composition of the bacterial population, generated in cooperation with the Microbiology Group. This collaboration of the Animal Nutrition Group with AgResearch’s Global Rumen Census has already led to a follow-up project involving a much larger set of rumen samples from a second experiment, which will also be analysed for microbial composition.
Flexible foregut microbial community
There was a wide variety of foregut samples from more than 30 animal species and 35 countries. The microbial survey involved extracting DNA from all the samples and sequencing diagnostic marker genes that allow the identification of different protozoa, bacteria and methanogens. The rumen microbes ended up being much more similar than expected. Differences in microbial community compositions were predominantly attributable to diet, with the host being less influential. The relatively few co-occurrence patterns between microbes suggest that microbial interactions do not rely on exclusive associations, with different combinations of microbes being co-selected depending on the diet. This flexibility of the rumen microbial community structure would confer on the ruminant host the ability to exploit a variety of different plant feeds.
Read the complete press release at the NZAGRC.