Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Study reveals livestock gut microbes contributing to greenhouse gas emissions

18.06.2014

“Increased to levels unprecedented” is how the Intergovernmental Panel on Climate Change (IPCC) described the rise of carbon dioxide, methane and nitrous oxide emissions in their report on the physical science basis of climate change in 2013.

According to the US Environmental Protection Agency (EPA), the atmospheric concentration of methane, a greenhouse gas some 28 times more potent than carbon dioxide has been steadily growing since the 18th century and has now increased by 50 percent compared to pre-industrial levels, exceeding 1,800 parts per billion.


Ruminant livestock are the single largest source of methane emissions, but they are not all equal when it comes to greenhouse gas emissions. (Sheep image courtesy of AgResearch – Gerry le Roux, Sciencelens. Art by Wayne Keefe, Berkeley Lab Creative Services.)

The EPA attributes one-fifth of methane emissions to livestock such as cattle, sheep and other ruminants. In fact, ruminant livestock are the single largest source of methane emissions, and in a country like New Zealand (NZ), where the sheep outnumber people 7 to 1, that’s a big deal. However, not all ruminants are equal when it comes to greenhouse gas emissions.

 It turns out that the amount of methane produced varies substantially across individual animals of the same ruminant species.  To find out why this is so, a team of researchers led by the US Department of Energy Joint Genome Institute (DOE JGI) deployed high throughput DNA sequencing and specialized analysis techniques to explore the contents of the rumens of sheep in collaboration with NZ’s AgResearch Limited to see what role ruminant “microbiomes” (the microbes living in the rumen) play in this process.

The study was published online June 6, 2014 in Genome Research.“We wanted to understand why some sheep produce a lot and some produce little methane,” said DOE JGI Director Eddy Rubin.  “The study shows that it is purely the microbiota responsible for the difference.”To learn why the amount of methane that ruminants produce varies, the researchers took advantage of a large sheep screening and breeding program in NZ that aims to breed low methane-emitting ruminants without impacting other traits such as reproduction and wool and meat quality.The team measured the methane yields from a cohort of 22 sheep, and from this group, they selected four sheep with the lowest methane emissions, four sheep with the highest emissions and two sheep with intermediate emission levels. Rumen metagenome DNA samples collected on two occasions from the 10 sheep were sequenced at the DOE JGI, generating 50 billion bases of data each.“

The deep sequencing study contributes to this breeding program by defining the microbial contribution to the methane trait, which can be used in addition to methane measurements to assist in animal selection,” said senior scientist Graeme Attwood of AgResearch Limited, a senior author on the paper.The team then checked to see if there was a correlation between the proportions of methanogens in the eight sheep with the highest and lowest recorded methane emissions.

In sheep with low methane emissions, they found elevated levels of one particular species of methanogen (Methanosphaera) while sheep with high methane emissions had elevated levels of another group of methanogens (Methanobrevibacter gottschalkii). Exploring further, the team then identified a methane-producing pathway and three variants of a gene encoding an important methane-forming reaction that were involved in elevated methane yields.While the overall changes to the methane-producing microbial community structure and methanogen abundance across sheep were rather subtle, the team reported that the expression levels of genes involved in methane production varied more substantially across sheep, suggesting differential gene regulation, perhaps controlled by hydrogen concentration in the rumen or by variations in the dwell time of their feed.

“It’s not so much the actual composition of the microbiome that determines emission—which conventional wisdom would suggest—but mostly transcriptional regulation within the existing microbes that makes the difference, which is a concept that is relatively new in metagenomic studies,” Rubin said.  The team’s findings suggest new possible targets for mitigating methane emissions at the microbiome level.Screening and breeding for low-methane producing sheep is still underway, and importantly, low-methane lines then need to be tested for stability of the trait, as well as the absence of any impacts on fertility or meat or wool production.

Moreover, as Attwood notes, “there needs to be an incentive for farmers to incorporate low methane animals into their flocks, that is, achieving better performance with the low methane animals or being able to claim carbon credits. If everything went well you could expect introduction of the low methane trait to begin in three years, and for there to be slow but incremental changes to the sheep industry in subsequent years.”The DOE Office of Science supported the sheep rumen research at the DOE JGI.

The NZ Fund for Global Partnerships in Livestock Emissions Research funded the work done in NZ to support the objectives of the Livestock Research Group of the Global Research Alliance on Agricultural Greenhouse Gases, and the NZ Agricultural Greenhouse Gas Research Centre and the NZ Pastoral Greenhouse Gas Research Consortium made the methane screening data and animal resources available. 

The data from the study complement the genomic sequences being generated from the Hungate1000 project, which seeks to produce a reference set of rumen microbial genomes from cultivated rumen bacteria and archaea, together with representative cultures of rumen anaerobic fungi and ciliate protozoa.The U.S. Department of Energy Joint Genome Institute, supported by the DOE Office of Science, is committed to advancing genomics in support of DOE missions related to clean energy generation and environmental characterization and cleanup.

DOE JGI, headquartered in Walnut Creek, Calif., provides integrated high-throughput sequencing and computational analysis that enable systems-based scientific approaches to these challenges. Follow @doe_jgi on Twitter.DOE’s Office of Science is the largest supporter of basic research in the physical sciences in the United States, and is working to address some of the most pressing challenges of our time. For more information, please visit science.energy.gov.

David Gilbert | Eurek Alert!

Further reports about: Genome breeding emissions greenhouse livestock microbes microbial sheep species

More articles from Life Sciences:

nachricht New technology helps ID aggressive early breast cancer
01.07.2016 | University of Michigan Health System

nachricht In times of great famine, microalgae digest themselves
01.07.2016 | Alfred-Wegener-Institut, Helmholtz-Zentrum für Polar- und Meeresforschung

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Mainz-based physicists find missing link between glass formation and crystallization

Densified regions with drastically reduced internal motion either act as crystal precursors or cluster and frustrate all further dynamics

Glasses are neither fluids nor crystals. They are amorphous solids and one of the big puzzles in condensed matter physics. For decades, the question of how...

Im Focus: Thousands on one chip: New Method to study Proteins

Since the completion of the human genome an important goal has been to elucidate the function of the now known proteins: a new molecular method enables the investigation of the function for thousands of proteins in parallel. Applying this new method, an international team of researchers with leading participation of the Technical University of Munich (TUM) was able to identify hundreds of previously unknown interactions among proteins.

The human genome and those of most common crops have been decoded for many years. Soon it will be possible to sequence your personal genome for less than 1000...

Im Focus: Optical lenses, hardly larger than a human hair

3D printing enables the smalles complex micro-objectives

3D printing revolutionized the manufacturing of complex shapes in the last few years. Using additive depositing of materials, where individual dots or lines...

Im Focus: Flexible OLED applications arrive

R2D2, a joint project to analyze and development high-TRL processes and technologies for manufacture of flexible organic light-emitting diodes (OLEDs) funded by the German Federal Ministry of Education and Research (BMBF) has been successfully completed.

In contrast to point light sources like LEDs made of inorganic semiconductor crystals, organic light-emitting diodes (OLEDs) are light-emitting surfaces. Their...

Im Focus: Unexpected flexibility found in odorant molecules

High resolution rotational spectroscopy reveals an unprecedented number of conformations of an odorant molecule – a new world record!

In a recent publication in the journal Physical Chemistry Chemical Physics, researchers from the Max Planck Institute for the Structure and Dynamics of Matter...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Quantum technologies to revolutionise 21st century - Nobel Laureates discuss at Lindau

30.06.2016 | Event News

International Conference ‘GEO BON’ Wants to Close Knowledge Gaps in Global Biodiversity

28.06.2016 | Event News

ERES 2016: The largest conference in the European real estate industry

09.06.2016 | Event News

 
Latest News

Mainz-based physicists find missing link between glass formation and crystallization

01.07.2016 | Physics and Astronomy

Scientists observe first signs of healing in the Antarctic ozone layer

01.07.2016 | Earth Sciences

MRI technique induces strong, enduring visual association

01.07.2016 | Medical Engineering

VideoLinks
B2B-VideoLinks
More VideoLinks >>>