Getting to Know the Microbiome

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Dr. Robert Jacobs and Wrangler at the Equine Research Unit at the Purina Animal Nutrition Center - Picture by Robbie McCord

Purina Animal Nutrition is on a decades-long mission to define the equine microbiome to help horse owners support their horses’ health, performance, comfort, and wellbeing while including and educating horse owners along the journey

BY April Bilodeau

As horse lovers, we know so much about our horses. Their routines, what they like, what they dislike, what tack suits them best, and so much more. 

While all of these factors are important in the overall picture of keeping our horses happy, very few people understand exactly what goes on inside the horse to keep them healthy. This is where the experts at Purina Animal Nutrition are there to help.

While the respiratory, cardiovascular, musculoskeletal, gastro-intestinal, and nervous systems are all critical to maintaining the health of your horses, there is one thing that connects all of them in ways that we are just scratching the surface on understanding. 

The Microbiome.

What Is The Microbiome?

Morghan Bowman, MS, works in the Emerging Technology Lab at the Purina Animal Nutrition Center – Picture by Robbie McCord

The microbiome is defined as a community of microorganisms which includes protozoa, bacteria, fungi, and viruses. Every living thing has a unique and purposeful microbiome. In the horse, the key responsibility of this community is the digestion of fibers that the horse cannot digest themselves (think of the hay and forage that we feed our horses every day). The bacteria (predominantly) ferment these fibers to produce volatile fatty acids that the horse uses as an energy source, along with key vitamins and other factors required by the horse. But, in addition to this primary function, we know that the microbiome plays a major role in regulating immune function, inflammatory health, and overall gastrointestinal function. 

Each section of the horse’s GI tract has its own unique microbiome with a distinct purpose and function. From the horse’s mouth through the end of its large intestine, the microbial inhabitants work hard to support your horse’s health. Researchers continue to investigate the microbiome in all areas of the horse’s GI tract, but special focus has been placed on the microbial community in the hindgut (cecum and large intestine). 

What makes a horse unique is also what makes their individual microbiome unique. Different breeds, sexes, diets, lifestyles, and even geographic locations play a role in the diversity of the microbes that make up the microbiome of the horse. 

“What’s really fascinating is the microbiome of a specific horse is optimized to the needs of that unique individual,” Robert Jacobs, Ph.D., Equine Innovation Manager at Purina Animal Nutrition tells The Plaid Horse. “For example, horses consuming primarily pasture have a more diverse microbiome than those that consume larger quantities of feed. Neither one is better or worse, rather the community is optimized to meet the needs of the horse.”

Exploring the Microbiome

Dr. Jacobs and Morghan work together to extract DNA from samples submitted by horse owners around the country – Picture by Robbie McCord

The microbiome is made up of trillions of microorganisms that live all throughout the horse’s body. It is so large and diverse that the number of bacteria in the GI tract of the horse actually outnumbers the cells that make up the horse itself. Not only is the microbiome different throughout the GI tract of the horse, but when taken as a whole, the microbial community of one horse is rarely the same as that of a different horse. In fact, a horse’s microbiome is as unique to them as your fingerprints are to you. For example, two horses living at the same facility may have totally different microbiome characteristics.

While experts are still learning more about the microbiome as a whole, one thing that everyone can agree upon is that it’s an integral part of the horse’s health and performance. The bacteria that make up the largest portion of the microbiome can interact directly with the horse, affecting the immune function, exercise performance, and even the behavior of the horse. These bacteria are typically classified as either good (probiotic), or potentially bad (pathogenic). The balance of good bacteria to bad bacteria may be responsible for whether or not a horse stays healthy during times of stress. 

For example, when horses undergo stressful exercise, they often experience a decrease in immune function. Horses with more beneficial bacteria in their GI tract may be less susceptible to illness or disease than those with an imbalance of good and bad bacteria. 

What We Know

Dr. Jacobs and Morghan work together to extract DNA from samples submitted by horse owners around the country – Picture by Robbie McCord

Even as research in this area progresses, there are more questions than there are answers when it comes to the microbiome of the horse, but there are some things that experts know for sure. 

Consistent feeding practices that prioritize high-quality forage are critical to the maintenance of a healthy microbiome. There are many probiotics marketed to horse owners with wide-ranging claims of efficacy. However, the research into these specific products is often inconclusive. “Identifying not only the right bacteria, one that will provide a benefit to the horse, but also ensuring that it is delivered to the horse alive are key factors in the development of efficacious probiotics for horses” says Dr. Jacobs. 

Just like other supplements that we feed to our horses, it is important that probiotic products are evaluated to ensure they are backed by equine research and provide the correct amount of a specific bacterial strain. “Not all probiotics are created equally. By definition, probiotics need to be delivered to the horse while they are still alive, which is often a challenge with typical supplement manufacturing processes” says Dr. Jacobs. “Research in this area is moving quickly, but the marketing is moving even quicker” adds Jacobs. 

What’s Left to Learn 

Dr. Jacobs and Morghan discuss research findings – Picture by Robbie McCord

“Everything is a chicken and egg type of question with the microbiome”, says Morghan Bowman, M.S., Equine Microbiome Scientist at Purina Animal Nutrition. Attempting to alter the microbiome of the horse without first understanding it’s full complexity may result in decreased horse health and performance, which is why the research that is ongoing at Purina Animal Nutrition is so important. “We still have a lot to figure out and explore,” adds Bowman.

Microbiome research is an exciting science, and one that offers up researchers, nutritionists, and veterinarians unique tools and insights into the health of our equine companions. Purina Animal Nutrition is at the forefront of this research with dedicated facilities, equipment, and people that are working hard to evaluate the effect of the microbiome on equine health and performance. “Through our research, we are striving to develop science-backed supplements to help owners support the overall health of their horses”, says Dr. Jacobs. 

Until then, Jacobs and Bowman advise horse owners to carefully consider what they are feeding their horses and work with a veterinarian and a nutritionist to optimize the diet of their horses. “We are learning so much every day about the equine microbiome that is helping us make unique recommendations to horse owners around the country,” says Morghan. And most importantly, they urge everyone to keep an eye on the great research coming out of Purina Animal Nutrition so you can learn in real time more about the microbiome!