Successive in vitro studies have shown up to 100% reduction in the emissions of the potent greenhouse gas from grass digestion.
A new study by Australian-based researchers shows that adding freeze-dried Asparagopsis taxiformis to test tubes replicating the fermentation process at work in a ruminant’s gut “completely inhibited the production of CH4” (methane).
The study led by James Cook University academic Matthew Vucko looked into various post-harvest treatments of the tropical red algae and found that “frozen and subsequently freeze-dried was the most effective processing method to maintain antimethanogenic activity”. It links the methane-inhibiting effect of the seaweed to the presence of the chemical compound bromoform.
Seaweed not only helped improve the cows’ health and growth, but also reduced their methane production
It builds upon research published last year, in which scientists added various types of seaweed to the fluid extracted from cattle’s rumen and observed gas emissions from the digestion of Rhodes grass. At the time, they found that adding 2% of asparagopsis taxiformis to the organic matter fed into the digestion process reduced methane emissions by at least 70% and up to 99%.
The latest study refined earlier findings to identify the treatment of seaweed most efficient at stopping methane formation.
According to Michael Battaglia of the Australian-based Commonwealth Scientific and Industrial Research Organisation, which supports the research, investigations started after a Canadian farmer noted the benefits of cattle grazing seaweed in 2005.
“Canadian researchers Rob Kinley and Alan Fredeen have since found that seaweed not only helped improve the cows’ health and growth, but also reduced their methane production by about 20%,” Battaglia wrote.
Climate change targets
The findings made since then are promising as agriculture represents one third of Ireland’s greenhouse gas emissions, most of these under the form of methane from ruminants. EU targetsimpose cuts on these emissions to combat climate change.
Further research is needed to confirm the potential of seaweed in controlling methane emissions from live animals as opposed to laboratory apparatus.
Side effects may be an issue as bromoform “is toxic to aquatic life with long lasting effects, is harmful if swallowed, causes serious eye irritation and causes skin irritation,” according to the European Chemicals Agency. The US National Library of Medicine adds that “chronic (long-term) animal studies indicate effects on the liver, kidney, and central nervous system (CNS) from oral exposure to bromoform,” which is also a “probable human carcinogen”.