What do pig slurry and earthworm faeces have to do with public health? A research project funded by the German Federal Ministry of Research, Technology and Space with 3.4 million euros over five years shows this. The consortium led by Ulm University TrophicHealth is investigating how the organic fertilisation of grassland influences the spread of antibiotic resistance along the food chain.
Circular farming is one of the most sustainable forms of land management. Farm animals not only provide milk, meat and eggs, but also nitrogen-rich organic fertiliser, which provides valuable nutrients for the cultivation of plant-based food for humans and animals. The problem is: Pig manure from intensive animal fattening in particular can introduce antibiotic residues and foreign microbes into the ecosystem, which disrupt the natural microbiome in the soil. "Possible consequences include the spread of microbes that are harmful to plants, animals or humans," explains Professor of Simone Sommer. The head of the Institute of Conservation Genomics and Evolutionary Ecology at Ulm University is the coordinator of the Trophic Health consortium. Not only zoonotic pathogens that can infect both animals and humans pose a risk to public health, but also the increasing number of antibiotic-resistant pathogens that are difficult or impossible to control with medication. The Ulm scientist has been researching the interaction between the environment and health in the field of 'One Health' for many years.
Together with her Ulm University colleagues Professor Christian Riedel (Microbial Biotechnology) and Professor Bork Berghoff (Molecular Biology and Biotechnology of Prokaryotes), as well as researchers from the Universities of Regensburg and Giessen, the Robert Koch Institute and the Julius Kühn Institute of Plant Health, Sommer now wants to investigate how microbiotic changes in grassland ecosystems - triggered by organic fertilisation - affect different parts of the ecosystem along the food chain.
"Our aim is to find out how different fertiliser regimes affect soil and water pollution. To do this, we are comparing minimally fertilised grassland areas with areas on which pig manure from intensive, conventional agriculture is applied, as well as with areas that are fertilised with biogas digestate or with manure from extensive, organic farming," explain Dr Karoline Jetter and Dr Kunal Jani. The two researchers from Ulm are significantly involved in the coordination and realisation of the project.
The test areas are located in the Münster region, around Biberach and in the Swabian Alb. Farmers from these regions have agreed to make the corresponding grassland areas available. "It is important to us that we broadly involve the participating farmers in this project," emphasises Sommer. "At the end of the project, we want to develop recommendations for action for agriculture and handouts for policy-makers," says the scientist. Farmers will also be involved in this process.
The effects of different fertiliser regimes on the ecosystem are to be recorded across the entire food chain. Soils, plants and animal life below and above ground will be analysed with regard to bacteria and other microbes. "For example, we analyse the faeces of earthworms, but also of field mice and honeybees," Jetter and Jani explain. After being analysed, the animals are released back into the wild. Another focus is on the microbial contamination of surface water and wastewater in sewage treatment plants.
How can healthy soils be restored?
The methodology of the joint project is extremely sophisticated. High-throughput methods for sequencing the metagenome of the individual samples and bioinformatics approaches for the latest generation of big data analyses are being initiated. In addition to describing the current situation, ways are also being sought to restore the health of damaged soils and polluted waters. The focus here is on the resilience of natural microbial communities. Many plants, for example, live in symbiosis with beneficial microbes that help them to protect themselves against pathogens. The use of antimicrobial peptides and bacteriophages, i.e. viruses that specifically attack certain bacteria, could also help to regulate unwelcome invaders. "Our research project helps us to understand how fertilisation influences antibiotic resistance and which microbes are particularly risky - this is the only way we can take targeted countermeasures," explain Christian Riedel and Bork Berghoff.
"In the long term, we hope to find a way that makes it possible to combine intensive farming and high yields with healthy soils and a low health risk for humans and animals," says Simone Sommer, summarising the consortium's ambitious goal.
Further information:
Professor Dr Simone Sommer, Head of the Institute of Conservation Genomics and Evolutionary Ecology at Ulm University, e-mail: simone.sommer(at)uni-ulm.de
Dr Karoline Jetter, Institute of Conservation Genomics and Evolutionary Ecology, e-mail: karoline.jetter(at)uni-ulm.de
Information online:
www.gesundheitsforschung-bmftr.de/de/trophichealth-auswirkungen-von-dungung-auf-die-akkumulation-von-amr-und-zoonoseerregern-19403.php
Text and media contact: Andrea Weber-Tuckermann