Sheryl Haitana
There is an old story of farmers, who, if they were bringing new stock on to their property, would take the cud out of their cows and put it in the mouth of the new animals to help them adjust to their new environment.
This is an example of a beneficial use of sharing bacteria between animals, Lincoln University Professor of Animal Science Craig Bunt says.
The World Health Organization defines probiotics as “live microorganisms which when administered in adequate amounts confer a health benefit on the host”.
These microbes perform a number of helpful functions, including the production of beneficial compounds such as organic acids that help modify the gut to protect it against inflammation and help fight off other bacteria.
Scientists only know a fraction of the bacteria that exist, and for every bacterial species there are multiple strains that can change what they’re doing.
“You can have a bacteria that produces this wonderfully beneficial compound that’s great for our gut, but it might suddenly stop doing it, or it might produce something else.
“Science is looking at these more and more and realising how complicated it is. Science is often looking for the magic bullet, but probiotic bacteria are little bioreactor powerhouses that can respond to different situations. They aren’t just a small range of arrows in their quiver.”
This is one of the attractive things about probiotics, that if the bacteria find what it is producing isn’t working, it is losing the war, it can switch to producing something else.
“It’s not then surprising that if we introduce probiotics into an animal’s diet it’s going to provide some benefit.”
All bacteria including probiotic bacteria produce their own antibiotics and similar compounds and are where scientists think they might find new antibiotics to use.
“That’s where we know we will find new antibiotics most likely. But there is always the risk that whatever we find we overuse and use in a way nature doesn’t.”
Probiotic bacteria in our guts are essential for us to survive. It is the same for cows and they are essential to support the complicated microbial population that breaks down their feed, he says.
“Ruminants don’t eat grass, they process grass. If they don’t have the right population in the rumen, they can’t process the grass and eat the bacterial products that come off that.”
Just a small amount of probiotic bacteria can be significant in a cow’s rumen.
An example of probiotic bacteria all farmers can relate to is silage inoculant, which is a lactic acid producing bacteria that break down the plant material.
The history of silage started with a Norwegian researcher in the 1920s working out by putting hydrochloric acid with grass it got the pH down and made the feed last longer. It was in the 1950s when the acid got replaced with these inoculant products using bacteria.
“An agricultural scientist won a Nobel prize for silage, because it suddenly made all this feed available over winter. That’s amazing.”
At Lincoln, they have been looking at the best way probiotics can be formulated and kept alive so they can be given to animals, such as a freeze-dried capsule or a liquid live fermentation products.
“A probiotic is not just the bacteria, it’s the compounds they make. The advantage of the fresh probiotic is it’s already got it there, it’s rearing to go. Whereas the freeze dried has to get up to speed.”
The use of probiotics by farmers is becoming more common and accepted. But the industry is unregulated, with no legal definition of probiotic.
Craig advises farmers to stay away from products that state they have ‘fragments of probiotics’ because the bacteria and the compounds they produce are probably dead. He also suggests avoiding products based on spore-forming (bacillus) microbes as these tend to cease activity and form a spore when the going gets tough in the gut, an option not available to non-spore-former probiotic microbes like lactobacilli.
“Products that have live bacteria, that have a labelled number of bacteria, stating how much in the capsule or bottle now, are the products I have more faith in.”
Craig has been working with company BioBrew for the last 10 years to study their probiotics. CalfBrew is a fresh probiotic product from BioBrew, developed through Callaghan Innovation-funded research at Lincoln University.
One study using CalfBrew on the short and longterm effects of using a probiotic on calves has shown an increase in calf growth by up to 10%.
- Read more about this study and CalfBrew in our next issue.
