Helminth extracellular vesicles - the key to reducing methane emissions from farmed livestock?

Food production is a major source of greenhouse gas (GHG) emissions. Presently, there is an unprecedented demand for high quality, nutritious food to support the growing human population. Recent estimates indicate that global food consumption alone may contribute to global warming by as much as 1C by the year 2100 - 75% of which is driven by significant sources of methane such as ruminant livestock. Whilst the link between animal health and GHG emissions is clear, there have been few studies to quantify potential reductions in GHG emissions that may be achieved through animal health improvements. Addressing this gap would enable animal health interventions to be properly incorporated into mitigation pathways aimed at decarbonising the agri-food sector and achieving the UK government's wider net zero targets by 2050.

Parasitic worm (helminth) infections are responsible for >55% of livestock diseases and are a major concern for producers worldwide. Whilst it is well known that helminths release molecules that can modulate or dampen the host immune response to ensure their long-term survival and reproduction, we are just beginning to explore how helminths interact with, and influence, the collection of friendly microbes (i.e. the microbiome) that live in the host gut. Towards this, we recently showed that molecules secreted by the rumen fluke Calicophoron daubneyi (an emerging infection of livestock in the UK/Ireland) that are packaged into tiny membrane-bound sacs called extracellular vesicles (EVs), display antimicrobial activity and can shape rumen microbial communities in vitro. Furthermore, we found that sheep infected with rumen fluke, may produce more methane per kg of bodyweight than non-infected animals. We thus hypothesise that rumen fluke increase methane production from livestock by directly influencing the microbial population within the rumen.

Therefore, this project aims to target EV production by C. daubneyi and investigate their impact on host rumen microbiome diversity and function.

We envisage that determining the molecular interactions between helminth-microbiome-host will have broad implications for animal health, immunity, production efficiency and greenhouse gas emissions.