Newly discovered bacteria could lead to new feed additives
Humans have little trouble digesting barley sandwiches, just as cattle have little trouble digesting dried distillers grains.
Both feedstuffs involve yeast, but intestinal bacteria ensure that the human and the bovine body can break it down and use it.
That sounds simple but it’s a tricky business for bacteria to breach the nearly impenetrable wall of complex carbohydrates, called mannan, which surround yeast cells.
Wade Abbott, an Agriculture Canada researcher in Lethbridge, was on the team of scientists who discovered a yeast-loving bacteria.
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The breakthrough has implications for future treatment of intestinal diseases in people and for prebiotic use in livestock.
Abbott said he and researchers Harry Gilbert of Newcastle University and Eric Martens of the University of Michigan began their study six years ago. They knew of enzymes they thought were breaking down mannans.
“We didn’t realize how specific that relationship was, how extensive the pathways of enzymes were, so that was not really predicted,” said Abbott.
“Sometimes you don’t know the story until you start to write it near the end, and that’s where we found ourselves. I think we realized that we were onto something pretty neat towards the end.”
The research team’s findings were recently published in the science journal Nature.
Abbott said the discovery could help develop additives that allow animals to better digest certain feeds.
It might also factor into extraction and development of more potent forms of yeast mannans that could function as growth promoters.
Ideally, the latter could replace the use of antibiotics as growth promoters, but that idea is some distance away, said Abbott.
“A lot of scientists are really motivated to find alternatives to antibiotics, and there’s a lot of funding available for doing research projects on that,” said Abbott.
“But the reason I’m excited about yeast mannans is that there is quite a bit of scientific studies that have been performed that show that they can make food safer in the sense that they prevent the binding of some pathogens,” said Abbott.
“If we can extract more potent forms from distillers grains, or if we can add enzymes to distillers grains to help the animal digest it easier, that’s another way to try and increase value for the industry.”
On the human health side, yeast sugars are known to exacerbate the symptoms of intestinal diseases and autoimmune diseases such as Crohns.
Bacteria that can break down those sugars could help alleviate those symptoms and release beneficial molecules back to the host.
Abbott summarized it in an Agriculture Canada news release: “Conversion of indigestible carbohydrates, such as yeast mannan, into beneficial molecules for their host has been associated with combating intestinal diseases, promoting correct immune responses and helping to maintain healthy tissues.”
His continuing work on bacteria and mannan meshes with a parallel project funded by the Beef Cattle Research Council, which explores potential benefits of prebiotics, probiotics and symbiotics.
That project seeks to identify and track sugars as they move through animals’ digestive systems to better understand where and how they are used.
“A lot of those mechanisms aren’t understood with prebiotics,” he said.
“We feed it, and there’s an effect, but we don’t know what’s going on.”
barb.glen@producer.com
