Scientists ponder what will replace animal antibiotics

Prebiotics, probiotics, organic acid and essential oils are not perfect substitutes for antibiotics now being used

A combination of products may be needed to replace the antibiotics that are used to treat livestock.

Research into essential oils, probiotics, prebiotics, enzymes and short chain fatty acids shows these compounds might work to some degree, but none are likely as effective as a good antibiotic, said a group of scientists during an international webinar on antimicrobial replacements.

“It will be quite difficult to solve the problems by just taking out the antibiotics and replacing them with probiotics,” said Loek de Lange of Scothorst Feed Research in the Netherlands.

“We should try to find other ways. I believe in a concept, not just taking one thing out and putting another thing in.”

Scientists do not entirely know what happens in an animal’s gastrointestinal system. They need to identify the good and bad gut mic-robes before developing products that could potentially replace antibiotics.

“We understand that antibiotics have had a major effect on gut microflora, but we really haven’t in the past, had a good handle on being able to really identify the specific species,” said poultry researcher Doug Korver from the University of Alberta.

Probiotics have received considerable attention, but they are not a perfect substitute, and effective products could be five to seven years away, said Todd Callaway, a U.S. Department of Agriculture microbiologist.

“I think they are a great tool that we can use. You are not going to find a silver bullet, at least not in my opinion, where probiotics one to one will replace antibiotics,” he said.

“They have a role along with prebiotics, and these other mechanisms like organic acid and essential oils.”

Theo Niewold, a professor of nutrition and health at the University of Leuven in Belgium, said treatment plans start by reducing bacterial overloads. Some of that starts with good farm management and taking better care of livestock, whether it is a chicken or a pig.

“Immunity starts with the mothers,” he said.

“We need to look at broiler breeders to see what we can do to give them a more stronger, healthy and better offspring.”

Organic acids have been used to stimulate pigs’ early immune system but were less successful in chickens because the birds’ gizzards reduce the pH in the gastrointestinal system.

De Lange said protein can have antibacterial and anti-inflammatory attributes.

“Try to choose those feed ingredients that have a very high stability of protein,” he said.

Egg yolk antibiotics that bind to pathogenic bacteria are another alternative. The bacteria are not necessarily killed but cannot establish in the gut and are washed away.

Enzyme treatments for feed grains may work. Wheat is a common feedstuff for poultry in Canada, but corn is used in the United State. Each grain requires a different enzyme.

Research on all products needs to continue because of growing pressure from government and consumers in North America to push antibiotics out of livestock production.

“For the past 15 years, I thought we would lose antibiotics from animal production in the U.S., but it has not moved along any further,” Callaway said.

Europe has already moved to alternative treatments following government pressure, although antibiotics are still used with a veterinary prescription.

“I think that the EU model has been through legislation, and so far in North America, industry has been leading the charge, if not to eliminate antibiotics, certainly change the way they are used,” Korver said.

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