The Equine Practice Inc, Travels With Doc T

Gut Microbes – Decomplexicating Equine Nutrition Part 3 of 12

So far we have covered the definition of grazers as an animal that eats cellulose. We have discussed the similarities between carbohydrates (glucose, starch, cellulose, glycogen), fats (triglycerides, short chain fatty acids, ketones) and amino acids (the building blocks of protein). Each of these have the atoms Carbon, Hydrogen and Oxygen and the way they are put together into molecules determines whether they become a carbohydrate, fat or protein. In this article we will be looking at the microbes in our gut and their relationship to the different molecule construction.

Who Eats Our Food?

The concept of gut microbes will either mesmerize you or will completely turn you off to further discussions on feeding anything. It took me a bit of convincing but now that my paradigm has shifted, I live by this concept. Simply put, we do NOT feed us or our horses. We feed the bacteria living inside the gastrointestinal tract and THEY feed us and our horses. This is the part that has been missing in so many discussions on nutrition and has lead to more confusion. It is the missing link. Feeding the body is a two step process involving the gut microbes.

Now the concept of comfort food is not the food that comforts us but the food that comforts the gut microbes that in turn makes our horses healthy and happy. And grains are NOT comfort foods.

The words to describe the colonies of microbes that inhabit the gut are the “microbiome” and the “microbiota.” There are also microbes on the skin (this causes the arm pit odor and skin infections when wounded) as well as a cloud of microbes around us (our breath). This total collection is called the holo-biome and the number of total bacteria inside us, on us and around us is 8 times larger than the number of cells of our body. 90% of our genetic make up is from this holo-biome.

Advancing science has enabled us to look at the bacteria in our feces and in our mouth identifying the individuals by name. Swabbing the mouth has identified 700 individual species of bacteria. Think of it as a neighborhood with the Smith family, the Jones family, the Adams family and many others. Within one family there are many individuals like Papa Smith, Mama Smith, Little Smith 1, Little Smith 2, Uncle Smith, Aunt Smith and all of their children. In a study done recently at the Texas A&M vet school it was found that one dose of a non-steroidal anti-inflammatory drug commonly given to horses wiped out an entire family of bacteria. Same is true with antibiotics, anti-ulcer medication and anti-parasite medications. After they are killed, either opportunistic bacteria take over or if the drugs are stopped the original family returns.

There is a company now asking for a pea sized sample of feces and it will tell you what diseases your horse is prone to. No one has been able to sample gut material from specific sites in living beings yet, but I will tell you a fascinating story. When potent antibiotics first came out in humans back in the 1970’s many patients developed life threatening colitis (inflammation of the colon). To save these patients a “honey pot” was passed around to healthy medical students collecting their normal feces. This was mixed with water and the patients were given an enema of this fresh feces mix. It stopped the colitis instantly and saved lives because in essence, they were given a good gut microbe transfusion.

The importance of the normal gut bacteria cannot be overemphasized. Feces from fat mice were fed to thin mice who then became fat. Feces from thin mice were fed to fat mice who then became thin. It is the neighborhood of gut bacteria that feeds the body. Once the neighborhood goes bad there is not much to stop the disease processes that come from it nor the fat that develops. But with healthy gut bacteria, the body becomes healthy. This is being proven over and over again in human medicine but in the horse world we are very slow to realize this relationship.

In the first article I stated that stopping what we are feeding the horse is more important than adding something new to gain an effect. This is because when a horse feeds on what it has fed on for millions of years the good gut bacteria thrive and they feed the horse correctly. In 1973 horses were still fed a lot of pasture and given hay to survive the winter. Now the number of different types of grains and supplements is staggering. Anecdotal stories of various seeds (grains) and oils and herbs abound without even a tip of the hat to what the horse really should be eating. If we all realized that the horse can produce everything that it needs to survive and thrive when the gut bacteria are fed what they need to survive and thrive then feeding the horse becomes very simple. This includes vitamins produced by the good bacteria.

Unfortunately the horse owner has been blasted with misinformation on what a horse should be fed and these ingredients are causing destruction of the good bacteria and the overpopulation of the bad bacteria. Additionally most horses are limited in what they can eat due to confinement and overgrazing. This in turn is affecting the gut lining (leakage with invasion of foreign proteins, immune system compromise, ulceration, hormonal disruption and an overall unthriftiness and structural demise).

An emu at a horse farm in FL -  Just a break in the dialog to rest your brain 🙂

In my discussions with horse owners I ask what they are feeding the horse. The starting point for almost everyone is describing the grains and supplements rather than the amount of pasture and amount and types of hay. Digging deeper, the answers given include the name of a product but when asked for the ingredients of the feed, the owner doesn’t know. Worse, after reading the ingredients the owner still is unsure of what they mean. Almost every horse feed I look at now includes byproducts of the grain industry such as wheat middlings, oat hulls, soybean hulls, distillers grain byproducts, rice bran and sugar beet pulp. All of these at the minimum are inflammatory due to plant defense proteins built into them. And if there are whole grains such as corn, oats, barley and such, these are also sources of starch. There is nothing that will cause fat production and inflammation more rapidly in horses or humans than starches fed year round coupled with inflammatory plant proteins (more on these later.)

Remember the last article where I described the constant feeding of sugar taxes the insulin system, burdens the mitochondria, adds body fat and prevents the use of body fat as a fuel source of the preferred fuel called ketones. This is bad enough but remember that the bacteria are also living things requiring food. This is the definition of prebiotics which is the foods that feed these good bacteria. Unfortunately when fed incorrectly the “good” bacteria needed for cellulose digestion die while the smaller colonies of sugar eating bacteria expand and overgrow in the horse’s gut. This in turn causes inflammation and even ulceration of the colon leading to behavioral issues including bucking and girthiness. It also contributes to many if not all colonic causes of colic.

Many horse owners have described the benefits of removing grain and other sources of added sugar (sugar cubes, carrots, apples, red mineral salt licks and other minor sources). These include ease of grooming and saddling the horse, calmer energy, quieter and more productive rides, elimination of colic and anhydrosis (non-sweating) among other things.

There often is a complaint in older horses that they look worse after elimination of grain. Like taking the clothes off and seeing what a person really looks like, once the fat comes off the horse the owner now sees how much muscle has been lost. This is from the gluconeogenesis where existing muscle protein is turned into glucose for survival. Why does the horse need glucose from muscle when he is being fed starch in the grains? Simply put, the cells are becoming insulin resistant and the glucose isn’t getting to the cells. The brain sees a lack of glucose and orders gluconeogenesis because he thinks he is starving to death even though he has abundant body fat. Additionally any gut microbes digesting the cellulose to make the alternative fuel called ketones have been greatly reduced in numbers while the neighborhood is being overrun with sugar eating microbes. (The solution to this will be discussed in another blog but in the meantime, read )

Add to this nutritional mess any non steroidal anti-inflammatory, anti-ulcer medicine, anthelmintic, or anti-biotic and the microbiome balance just gets worse.


1) Feeding our horses is a two step process. We feed the microbes living in the gastrointestinal tract and they in turn feed the horse.

2) If the good microbes are fed correctly the way they have been fed for millions of years then they will feed the horse with everything they need to live a healthy life.

3) If the good microbes are fed incorrectly then they will starve and other opportunistic bad gut microbes take over feeding the horse things it can not remain healthy on.

4) The dead bacteria create inflammation of the gut lining and along with plant proteins, the gut starts to leak bad things into the body disrupting hormone communication (insulin resistance for example) and immune function (autoimmune disease for example).

5) Year round intake of glucose laden food bypasses the normal lean time of the year causing mitochondrial fatigue and destruction, insulin resistance and muscle resorption (gluconeogenesis).

These last two points are teasers of what will be coming in the next few articles. I hope you will return for more.

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