July 14, 2016

Methane matters: an interpretive summary

By Lucy Schroeder, ASAS Science Communications Intern

Southwest Semi-Arid Steppe Dairy Cow BlendJuly 14, 2016 – The growing concerns posed by climate change have fueled animal science research into reducing methane emissions from livestock. Currently, some studies report that emissions from ruminant livestock are estimated to be as great as 20 percent of global annual methane emissions. Considering the demand for milk and meat, (estimated to increase by 60 percent within the next 35 years) experts believe it is vital that approaches be taken to manage ruminant livestock emissions.

Kangur.rudy.drsA key factor in understanding methane emissions comes from studying the gut microbiome. Ph.D. candidate Emily Hoedt of the University of Queensland and colleagues have examined the prevalence of the lesser studied genus, Methanosphaera, and the resulting methane emissions in species across the animal kingdom. From studies of dairy cows to kangaroos to human beings, the presence of Methanosphaera was consistent with animals considered to be low emitters. Hoedt and colleagues Dr. Páraic Ó Cuív and Professor Mark Morrison discuss this research in the July 2016 issue of Animal Frontiers.

For example, they isolated a type of Methanosphaera from samples of cattle rumen contents and found that this strain had reduced capability of methane production based on the chemicals present in its environment. This could have implications for developing solutions specifically for suppressing methane-producing microbes in ruminants.

Their studies also included kangaroos, which are known to depend on the microbiota of their gut for digestion, yet have relatively low methane emissions. Samples of Methanosphaera Hoedt isolated from kangaroo gut have indicated that these bacteria are able to thrive in gut environments by breaking down molecules of alcohols like methanol and ethanol into methane, more efficiently than in hydrogen-rich environments.

Methane-producing bacteria can have implications for human health as well. In studies of patients with irritable bowel syndrome (IBS), increased methane presence has been correlated with slower intestinal tract transit times. However, it is still unknown whether the methane causes or is a product of IBS. Hoedt and colleagues examined blood samples taken after healthy subjects were introduced to different species of methane-producing bacteria and found that some strains for gut bacteria have the ability to stimulate the immune systems of animals and humans.

The authors imply that studying the gut microbial community of both humans and ruminant livestock can be mutually beneficial in improving health and reducing environmental impact.

Read more about this research in the July 2016 issue of Animal Frontiers.