Researchers at the University of Liverpool have shown that a bacterial infection in chickens, previously thought to be harmless to the bird, but responsible for food poisoning in humans, can in fact cause health problems in certain breeds.
Foodborne pathogen Campylobacter jejuni, which results in more than 300,000 cases of food poisoning each year in England and Wales, had previously not been considered to cause disease in chickens and the bacteria were thought to be part of the normal microbe environment of the birds.
Reader in Foodborne Zoonoses, Dr Paul Wigley, explains: “Our findings change the way we view the biology of this bacterial infection. It can cause problems in the gut, as it does in humans, but when the chickens walk through the wet excrement left in their bedding it can damage their feet and legs.”
Researchers looked at the impact of the infection in birds from four commercial breeds of broiler chickens. They found that while levels of the bacteria in the intestines did not differ by breed, immune response and inflammation did, to the extent that one breed showed damage to the gut and developed diarrhoea.
General health and welfare
Dr Wigley, from the University’s Institute of Infection and Global Health, said: “Chickens brought to slaughter age for human consumption, regardless of their breed, had similar levels of bacterial infection, but how they responded to the infection did differ. This suggests that factors such as the general health and welfare of the birds has more impact than breed on whether Campylobacter enters the food chain or not.
“Now that we know how robust the immune response to Campylobacter is, there is potential for vaccine development and breeding programmes that will help tackle the infection and improve the overall health and welfare of chickens.”
Foodborne bacterial gastroenteritis
The United States produces over eight billion broiler chickens per year and the United Kingdom produces nearly a billion. Campylobacter jejuni is the most frequent cause of foodborne bacterial gastroenteritis in the world and chicken is the most common source of infection.
The research, published in the journal mBio of the American Society for Microbiology, was funded by the Biotechnology and Biological Sciences Research Council (BBSRC) as well as a consortium of poultry producers, breeders and retailers. The research paper can be found at: http://mbio.asm.org/content/5/4/e01364-14.