Island bird links gut health and immune system
The Seychelles warbler offered a unique opportunity to study the process in the wild.
Research into a small songbird has revealed a hidden link between gut health and the immune system.
The Seychelles warbler, which is found on Cousin Island in the Seychelles, offered scientists from the University of East Anglia a unique opportunity to study life-long biological processes in the wild.
The island’s warblers are fitted with coloured leg rings so that scientists can track their behaviour, health and genetics over many years. This means conditions are similar to a laboratory population.
To examine their immunity, researchers collected the birds’ droppings to analyse their gut bacteria. Analysis revealed that their immune genes had influenced which gut microbes thrived.
The study focuses on the major histocompatibility complex (MHC). This group of genes plays a central role in immune defence for most vertebrates, including humans.
Researchers used advanced statistical and modelling approaches to examine the which regions of the MHC resulted in differences to the gut microbiome. The analysis was not limited to identifying which bacteria was present.
Dr Chuen Zhang Lee, who performed the study, said: “This work helps us better understand how immune systems and gut microbes evolve together, and we would expect to see a similar process in humans.”
He added: “We also looked at what those bacteria are actually doing. For example, whether they are involved in metabolism, nutrient processing, or defence against viruses and other infections.”
This meant that the researchers were able to go beyond a catalogue of microbes and understand how these genes shaped the microbiome for host health and survival.
The project revealed a two-way relationship between immune genes and the microbiome, with each influencing each other to inform function. There were also evolutionary trade-offs, with suggestions that immune genes balanced the benefits and costs of hosting certain microbes.
Researchers say that, while the study was carried out on birds, these biological mechanisms could be shared widely across animals. This may help inform future research into immunity, gut health and disease.
Prof David Richardson, a senior researcher at the UEA’s School of Biological Sciences, said: “In simple terms, an animal’s immune system may help determine which microbes can live in its gut, while those microbes in turn help support and train the individuals immune system.”
The full study can be found in the journal Microbiome.
Image © Shutterstock.com/COULANGES
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