Publicado en: BioEd Online (http://www.BioEdOnline.org)
A probiotic diet makes chickens healthier and safer to eat.
Chickens could benefit from a daily dose of friendly bacteria, researchers say.
The benefits to human health of probiotics are well known. The bacteria, found in yoghurt, are thought to out-compete other gut bacteria, including those that cause food poisoning.
Probiotics are thought to have similar benefits in animals, and are already included in some agricultural feeds. But such feeds contain a slew of bacteria, says Arjan Narbad from the Institute of Food Research, Norwich, so their effects are uncertain.
Narbad and colleagues tested a single probiotic dose in the lab. The good bacterium Lactobacillus johnsonii ousted the harmful Clostridium perfringens from chicks' guts, they report in Letters in Applied Microbiology 1 .
"We have used a single strain and shown that it can be targeted to eliminate a specific pathogen," says Narbad.
Clostridium can flare up chickens, making them sickly and thin. It's also one of the top five bacterial causes of food poisoning in humans. In the United Kingdom, the bug poisons about 200 people through undercooked chicken each year.
"We also have preliminary data suggesting that Lactobacillus may be effective against Campylobacter," Narbad says. This is a much nastier bug, causing about 63,000 UK cases of food poisoning each year. Lactobacillus also has a weak effect against the sometimes-deadly gut bacterium E. coli.
Probiotics could have other benefits too. They may also increase chicken growth rate, for example, says microbiologist Anne McCartney from the University of Reading.
The probiotic bacteria are easy to give to animals, as they can be put in animal feed or drinking water, says Narbad.
They should also help to reduce the use of antibiotics in animals. Farmers are being encouraged to cut their use of antibiotics to reduce the chance of bacteria evolving resistance.
The team is now seeking other probiotic species to help combat different pathogens. They plan to test the treatments on farms to see if results are as good as they are in the lab.
1 La Ragione, R.M., La Narbad, M.J., Gasson, M.J. & Woodward, M.J.. Letters in Applied Microbiology, 28, 197 - 205, (2004).