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December 23, 2019

Prebiotics and Probiotics: It’s All About the Bugs

by Dr. Cayla Iske, PhD

With all of the hype over the last few years, you’ve likely heard the terms probiotics and/or prebiotics at least a few times. Whether related to animals or humans, pre- and probiotics have recently garnered a great deal of attention. But what exactly are these “magical bugs” and what do they do? Are they simply two words meaning the same thing? All great questions that deserve some answers.

For Starters: Understanding The Microbiome

You cannot define pre- or probiotics without first understanding something we’ve referenced a few times in previous blogs: the microbiome. The microbiome refers to billions and billions of microscopic living organisms (e.g. bacteria, protozoa, fungi, etc.) which reside throughout the entire gastrointestinal tract, but the largest diversity and abundance are located in the large intestine and cecum. The microbiome also varies widely between species; for example, the population compared between rabbits and cats looks very different. In recent years, scientists have been heavily focused on this topic which as led to more and more discoveries of the processes, functions, and pathways that the microbiome plays a role in and influences. Processes including fiber digestion, immune system health, pathogen colonization, inflammation, mood regulation, and many others have all been linked to the microbiome. Research in humans, dogs, and cats continues to highlight ways in which the microbiome contributes to numerous physiological pathways. Unfortunately, microbiome research is far less bountiful in exotic species.

What Are Prebiotics and Probiotics?

Prebiotics and probiotics can be supplemented to an animal via many different routes, diet being one of the more common. These products are generally added to the diet with the intent of strengthening the healthy microbiome to provide a health benefit to your animal. A prebiotic is an ingredient that is not digested until it reaches the large intestine/cecum where a majority of the microbiome lives. Once it reaches the large intestine or cecum, the good bacteria feed on the prebiotics, which in turn promotes the growth of more beneficial bacteria. Probiotics, on the other hand, are the actual good living bacteria themselves. These microorganisms are added directly to food (or via other routes such as capsules, etc.) and should be capable of withstanding most digestive barriers of the target host species until reaching the large intestine, where they help repopulate the healthy microbiome.

Pre- And Probiotics: Miracle Ingredients?

While it may sound like pre- and probiotics could be the cure for any and all ailments, and while they certainly have the potential of offering many health benefits, those benefits are often overstated and not all are created equally. Furthermore, what is good for one species may not be good for all. For probiotics to be beneficial, you must first understand the population and function of the animal’s natural microbiome. As mentioned earlier, the microbiome has been fairly well established in humans, dogs, cats, rats, and even some livestock species. However, for hindgut fermenting species such as rabbits and guinea pigs, this has not been well-defined. We do know from preliminary research that significant differences do exist in our species as compared to those species more routinely studied. For example, the rabbit microbiome does not appear to include Lactobacillus species, a prominent good bacterium in the human microbiome and a very commonly marketed probiotic across many species. For this reason, not all probiotics are applicable nor appropriate for all species, as the introduction of a bacteria not native to an animal’s microbiome could have serious negative consequences.

When selecting a probiotic for a specific species, there are numerous characteristics the probiotic needs to possess to be effective and viable.  They should:  

  • Be native to that animals’ microbiome.
  • Provide beneficial effects in the target species.
  • Be proven to survive the manufacturing and storage process and be stable in the product.
  • Resist the acidic gastric environment of the animal consuming them to reach the intended location for colonization (many times this is the large intestine/cecum).
  • Contain the species and listed label number of live organisms. Unfortunately, many probiotics on the market do not abide by this and, in many cases, the type of probiotics offered lack published data supporting clinical benefits in the targeted animals.
  • Probiotics are also not a one and done fix.  To sustain benefits once the appropriate probiotic is identified, the animal must consume the probiotic regularly.

Prebiotics - A Better Bet For Today

Because so little research exists in our species and there is the potential of negatively disrupting the healthy microbiome with inappropriate probiotics, it is currently safer to utilize prebiotics versus probiotics in the diet. Common examples of prebiotics found on pet food labels include inulin (chicory root), hydrolyzed yeast, yeast culture, and brewer’s dried yeast. You may have also heard the terms fructooligosaccharides (FOS) and mannan-oligosaccharides (MOS). These are general terms used to describe classes of prebiotics. The FOS category describes prebiotics that naturally occur in plants, such as inulin, and MOS are composed of complex carbohydrates such as yeast cell walls. The advantages of prebiotics are they aren’t species-specific and can be utilized by the animal’s natural microbiome to promote the good bacteria without introducing new bugs. They are also not live microorganisms and thus don’t have to “survive” the food processing, storage, and digestion in the animal to be beneficial.

Future Benefits of Prebiotics and Probiotics

To recap, prebiotics are food for the healthy microbiome to feed on and probiotics are the living microbial organisms themselves. While there is more and more research taking place, currently prebiotic usage has been more studied and universally applies across a large range of species. There is no doubt the potential to influence and strengthen the microbiome through probiotics in Oxbow’s core species is tremendous. But we must first understand what is naturally occurring in their specialized GI tract and what beneficial changes should look like. The talk and research behind pre- and probiotics are only gaining momentum.  So, while we don’t have all of the answers for our little guys yet, more is sure to come.