Pre- and Probiotics - Know the Difference

Apr 23

4/23/20

“Many products list pre- & probiotics as ingredients. It’s important to know the difference and what these items target.”

Let's start with a few basic definitions:

Probiotics - also referred to as direct fed microbials, these are LIVE naturally occurring microorganisms. They are measured in CFUs (colony forming units) and are fed to horses in an effort to increase the number of beneficial microbes in the gut. When fed, these microbes are intended to make it to the hindgut, which is about 70 feet down the digestive tract, where the reservoir of these active microbes predominantly reside. Once there, the intention is that they enhance the existing population of beneficial gut microbes and ultimately improve digestive health.

Prebiotics - these are non-digestible ingredients (ex. fiber, yeast fermentate, fructo-oligosaccharides, etc.) which can be fermented by hindgut microbes resulting in energy for the good "bugs" to thrive (bugs = bacteria, microorganisms). Most simply stated, prebiotics are intended to provide "food" for the healthy gut microbial population and promote increases in their numbers. The desired result includes increased performance of the good bugs' beneficial tasks including improved immune function, strengthening of the intestinal lining reducing the chance of invasion of pathogens, and a role in attenuation of inflammation.

What we all want to know... do they actually work? Here is where things get muddy...

When it comes to probiotics, many obstacles present themselves. First, challenges arise in getting these to the hindgut alive! If they're put into a commercial feed as an additive, it is highly variable as to whether or not they've survived the feed production process (which involves intense heating, cooling, etc. to form a pellet, you know, all the things that live microorganisms don't love). One study in particular evaluated probiotic products to see if the probiotics guaranteed on the tag were actually in the product at those levels... sadly only 2 out of 13 products matched their label claims for live cultures. This can be assumed to be true for feed as well.

The next challenge is surviving the highly acidic and harsh environment of the digestive tract to make it to the hindgut. Those microorganisms have about 70 feet to travel! That's a long journey for a little bug.

So now let's say these probiotics make it to the hindgut. There is limited evidence to support that they colonize here and benefit digestive health. Adding to this great mystery, we as a scientific community don't know exactly what a healthy hindgut looks like. In a sea of millions of microbes we have just only begun to scratch the surface on what actually resides there. Currently, we are relying on data from other species to suggest what strains may benefit horses. There is research in horses but it is not concrete and sometimes conflicting. We also find that what works for one horse as a probiotic may have no effect on another horse. We have also learned that even horses on the same property, eating the same diet can have differences in their microbiome (the word which encompasses all the microbes I've been discussing). Further adding to the challenge, the dose at which they may be beneficial is mostly unknown.

So, if you asked me, do these work or not? - here is my answer....

There is still a lot of mystery surrounding the equine microbiome... equine scientists are working on solving this puzzle and identifying which organisms are beneficial to hindgut health and how to get them to the hindgut intact at the correct level. However, even with many unknowns, some horses do seem to respond favorably to supplemented probiotics. If you have a horse that responds favorably, by all means, continue feeding them. The good news is these are generally not harmful if added to the diet. The bad news... many of us horse owners are throwing away money on these. The jury is still out. I am personally very skeptical of probiotics, especially as a feed ingredient. I do believe someday we will find beneficial probiotics to support digestive health in all horses, although I do not believe we are there yet. We also need to be careful not to extrapolate human probiotic data to our horses. Our digestive tract and diet is a lot different. Because it works for you does not mean it will work for them!

Prebiotics... my PhD work is focused on prebiotics so it is hard for me to not show any bias here! But the data on prebiotics, particularly yeast fermentates, in the horse have shown some very exciting results in aged horses. In their senior horse products, Purina has a yeast fermentate called "ActivAge" which has been scientifically proven to boost immune response and decrease systemic inflammation. Because not all prebiotics are created equal, this data does not support this function in all prebiotics, but it is quite an interesting finding by Purina! Data in humans is also finding similar benefits of prebiotics in growth of populations of beneficial bacteria including Lactobacillus and Bifidobacteria, in some cases followed by stronger immune function and other health benefits. Take home message, eat more fiber!!

A big difference between pre and probiotics is that these are fibrous in nature, so we know they will make it to the hindgut intact. This takes away a major battle that we have with probiotics. The challenge with prebiotics is that (much like probiotics), they are not all created equal and the science does not support all of them having a benefit. If you want to try these, check with the company about data to support the efficacy of the prebiotic and make sure you feed it at the recommended level.

If your horse has a healthy, functioning digestive tract, access to plentiful high quality forage, normal consistent manure, and is overall healthy, odds are they do not need a pre- or probiotic. You have the current information I provided that indicates the science is still lacking in the efficacy of most of these products. Although if you want to try pre- or probiotics, go ahead! They are highly unlikely to have any negative effects and it is possible (huge maybe...) that your horse will respond favorably to them!