As an independent equine nutritionist, I come across many horse owners that supplement their horses with some type of gut support product. This article is going to dive into some of the science behind probiotics!

Let’s start today’s blog post with some definitions ->

Probiotics: microbials that deliver live bacteria to the horse’s gastrointestinal tract and provide benefit to the host.

Prebiotics: used as “food” for the probiotics. They are soluble plant fibres that cannot be digested in the foregut and therefore when they reach the hindgut, they are able to be broken down by the microbes. Prebiotics do not introduce new bacteria to the gut.

Now that we’ve got some simple definitions, let’s get into the science!!

Horses are hindgut fermenters; this means that they have a large cecum and colon where microbes play an important role in digestion. Research has shown that horses with colitis have a different composition of fecal microbiota than healthy horses. Additionally, differences in fecal microbial population have also been shown when horses are fed differing diets. A general hypothesis when colic or gastrointestinal disorders are present is that the microbial population must have shifted – but unfortunately, there is limited research on the hindgut and microbiome of horses.

A recent study looked at the fecal microbial composition of horses over the course of 1 year. The horses experienced minimal changes in management over the 12-month period. The researchers were able to show that season, supplementary forage, and weather conditions were closely associated with changes in the composition of the microbial population in the feces. These findings simply highlight that there is so much more we need to know about the equine hindgut as using the simple explanation of a changing microbiome in gastro-intestinal health disorders is too simplistic.

For a probiotic to be effective it must:

1)      Contain live mircoorganisms that remain viable at the intended site

2)      Remain viable in sufficient quantities

3)      Be a correct strain of bacteria

There is positive research on probiotics out there. The probiotic yeast Saccharomyces cerevisiae has been shown to provide benefits such as improved fiber digestibility when supplemented in feed. Probiotic supplementation has also been shown to be effective in reducing the duration of hospitalization for horses with colitis.

Unfortunately, the research has not fully elucidated ideal strains to supplement in horses or ideal dosing. The suggested minimum dosage is 10 billion CFU/d and commonly fed probiotics are Saccharomyces, Bifidobacterium, Enterococcus and Lactobacillus. I have mentioned this in previous blog posts – but the equine supplement industry is not well-regulated. This is evident in the research on probiotic supplements as various studies have investigated tag claims compared to content of the product and found many discrepancies.

Therefore, I encourage horse owners to reach out to your supplement companies and ask for the research! I make a conscious effort to recommend supplements from companies that invest in research on their products…because if not you’re simply using your own horse for research. I also look for supplement companies that are transparent in providing you with all of the necessary information on their products. For example, if you are looking for a probiotic supplement you should be able to find out the actual content of live bacteria they guarantee in the supplement – this should not be a secret.

If you have any questions please email me at balancedbaynutrition@gmail.com 

Written by: Madeline Boast, MSc. Equine Nutrition

About the author: Madeline Boast completed her master’s in Equine Nutrition at the University of Guelph and started an independent nutrition company known as Balanced Bay. She has worked with a variety of equids – from miniature ponies to competing thoroughbreds. Through Balanced Bay she designs customized balanced nutrition plans that prioritize equine well-being. This includes diets for optimal performance as well as solving complex nutritional issues and everything in between. For additional information see www.balancedbay.ca