Their findings are expected to be significant in the ongoing fight against antimicrobial resistance, as well as promoting more sustainable farming.

 

The research team were focused on sodium butyrate, a short-chain fatty acid naturally produced by gut bacteria. Using primary chicken immune cells and cell lines, researchers sought to trace how the gut molecule acts as an immune system programmer.

 

The investigation saw them expose developing immune cells, known as macrophages, to the compound to train chickens’ natural immune defences to fight future infections.

 

It was discovered that these reprogrammed chicken immune cells had undergone a dramatic increase in their ability to kill dangerous bacteria. This included multiple strains of E. coli, Salmonella, Pseudomonas aeruginosa, and Staphylococcus aureus.

 

The study also identified a time frame when the immune reprogramming must take place.

 

The immune system ‘upgrade’ was only successful if the molecule was introduced during the early, plastic stages of the immune cells’ development. If applied to fully mature cells, the treatment did not improve their disease-fighting capabilities.

 

Traditional immune training agents can cause high levels of tissue-damaging inflammation.

 

Sodium butyrate, however, offers an alternative, cleaner route to immune training. Cells are encouraged to use a ‘two-pronged internal attack’, boosting the production of destructive oxygen molecules and accelerating autophagy.

 

Shahriar Behboudi, Professor of Immunology in the Bristol Veterinary School and senior author of the study, said: “Our findings suggest that trained immunity exists along a much wider spectrum of phenotypes than previously thought.

 

“By demonstrating that a natural gut metabolite can program immune cells through an alternative, non-inflammatory axis, we open up exciting new possibilities for enhancing animal health naturally, without the collateral damage of excessive inflammation.”

 

Dr James Adams, a Research Fellow in the School of Veterinary Medicine at the University of Surrey and the first author on the paper, added: “The increasing spread of diseases amongst chickens is of great concern. Bacterial diseases cause significant animal health and welfare issues in poultry, incurring devastating economic losses and potential disruption to our food chain. 

 

“Antimicrobial resistance is complicating the management of disease in poultry.  Therefore, it is crucial that we develop new ways of controlling bacterial infections in poultry.”

 

The full study can be found in The Journal of Immunology.