Researchers at the Institute of Food Research have characterised the coat of a potential poultry probiotic, giving the first clues of how it may be used to exclude pathogenic bacteria from chickens.

Lactobacillus johnsonii has previously been shown to exclude harmful Clostridium perfringens bacteria from the guts of poultry, opening the door to it being developed as a way of reducing necrotic enteritis in poultry and food poisoning in humans. Recently, researchers at IFR, found that the bacteria make coats for themselves that play important roles in colonisation in this strain.

Now, in research published in The Journal of Biological Chemistry, the researchers present the first characterisation of what makes up this coat. This will give us a better idea of the role of the coat and help in the development of these bacteria as a way of combatting C. perfringens.

Using NMR spectroscopy – a high tech means of studying the physical and chemical properties of atoms and molecules – the researchers discovered that the coat is made up of two types of exopolysaccharides (EPS), which are long sugar-containing molecules that many bacteria use to encapsulate themselves. This capsule may help the bacteria to cope with environmental stress, or aid colonisation and adhesion. Different bacterial strains have different EPS structures, and understanding this is important as they represent a key way bacteria interact with the world around them.

Reslearch leader Dr Arjan Narbad said the discovery represents the first step in attempts to harness the ability to exclude harmful bacteria. Dr Narbad added, "Characterising the EPS structures in the L. johnsonii strain is the first step to explaining how it might outcompete C. perfringens."

Further research looking into the production of EPS and the molecules' properties yielded promising results, but Enes Dertli, a Phd student at the Food Research Institute said more work is needed to fully understand them.

Even so, the strain of Lactobacillus johnsonii examined by researchers is now being taken through farm-scale trials to assess its potential to combat pathogenic infections in poultry.