Scientists at the Institute of Food Research (IFR) found that the probiotic Lactobacillus johnsonii clears the pathogenic bacterium Clostridium perfringens from the gut of chicks. A bacterium can cause lesions in chicks as well as causing food poisoning in humans.
"Some poultry feed already contains probiotic bacteria, but an undefined mixture that gives inconsistent results. This research is exciting because we have used a single strain and shown that it can be targeted to eliminate a specific pathogen," said Dr Arjan Narbad, research scientist at the Institute of Food Research (IFR).
The probiotic also reduced colonisation of the small intestine by E. coli, but did not clear it completely, report the scientists.
The scientists screened thousands of 'commensal' bacteria from the adult chicken gut to identify strains that might competitively exclude 'bad' bacteria. Lactobacillus johnsonii showed particular promise, and the IFR teamed up with the Veterinary Laboratories Agency to test its potential.
"For decades we have known that naturally-occurring bacteria in adult chickens can prevent pathogens from colonising in younger birds, whose gut flora is not yet well developed. But we have not known which bacteria are most effective," said Dr Narbad. "We are particularly pleased to have identified a strain to combat Clostridium perfringens because it can not only cause food poisoning in humans, but can cause illness in chicks."
Clostridium perfringens is naturally present in the chicken gut, normally without causing disease. Sometimes the bacteria produce toxins, and scientists believe these are what cause the disease necrotic enteritis. Necrotic enteritis has a number of symptoms in poultry, including poor weight gain and ulcers. In humans it causes intense abdominal cramps and diarrhoea, sometimes accompanied by vomiting.
British and European farmers are being encouraged to reduce their use of antibiotics in animal feed, and this research provides one viable alternative. Probiotic bacteria could have additional health benefits for poultry, such as stimulating the immune system and improving the rate of growth.
Market leaders supplying probiotics in Europe include Chr Hansen and Danisco through its recent acquisition of the food ingredients arm of Rhodia.
Valued at around €10.2m in 2003, the total market for probiotic ingredients in applications for human consumption is currently growing at an estimated rate of 14 per cent.
Increased consumer awareness of probiotics and their possible health benefits has been a primary market driver. Large marketing spends of companies such as Danone and Yakult were seen by suppliers as having played a crucial role in enhancing consumer knowledge. Wider consumer choice and growing media interest in probiotics and gut health also helped to improve awareness levels.
There are also new application areas with potential to grow the market further. Probiotics have largely been confined to dairy applications so far, owing to the low stability of the bacteria, with major probiotics applications for human consumption in yoghurts and fermented milk drinks. The European supplements market, although less developed than that in the United States, is however a prospective area of growth, predicts the Frost report.
The latest findings on feed certainly indicate that this could be a further source for growth for probiotics.