Scientists studying developing chicks have found that, contrary to perceived wisdom, they are not born sterile but are instead pre-infected with good gut bacteria.
University of Georgia researcher Adriana Pedroso and her colleagues incubated 300 fertilised hens eggs, cleansed them with bleach and then extracted the embryos inside using sterile tools. Using DNA analysis they were able to show that the developing chicks already contained a diverse bacterial community in their intestines.
The team suspect that the bacteria penetrate the egg shell and enter the white, which is then consumed by the chick as it grows, ferrying the bacteria to the intestines.
The result is important, says study co-author Professor John Maurer, because in recent years farmers have moved away from using antibiotics and have instead been using pro- and pre-biotics to try to make hens healthier and less likely to carry diseases like Salmonella that could be a threat to humans.
Unfortunately the results have been mixed, but this could be because the timing is wrong, Maurer suggests.