Equine Hind Gut Dysbiosis

🦠What is it?

Dysbiosis refers to a profound imbalance in the intestinal microbiota which generates changes in the normal health and function of the gastrointestinal tract.

🦠Why is this a problem in the horse?

The equine gut microbiome represents an extremely complex microbial ecosystem that is comprised of quadrillions of microorganisms.

This ecosystem is responsible for fibre digestion producing energy for the horses body process, enhancing the horse immune system and also a myriad of chemical pathways which have a direct effect on the horses brain and thus behaviour.

The bacteria, yeast and other microorganisms digest fibre through a process known as fibre fermentation. This process provides the horse with energy, volatile fatty acids, vitamins, minerals, and amino acids necessary for good health.

Fibre fermentation is a slow process and ‘good’ bacteria only produce volatile fatty acids (see previous blog Micoriome) at the same rate as the horse can absorb them. So, acids never build up in the hindgut and the pH remains relatively neutral (close to pH of 7).

These nutrients are then assimilated through the intestinal wall for utilization in the horse’s body. A healthy intestinal wall provides a protective barrier that allows nutrients to be absorbed, but doesn’t allow toxins and microbes to enter the body.

🦠When it goes wrong

This delicate community of microbes is easily upset by changes in diet, environment, and stress. Consequently, gastrointestinal disturbance in the equine microbiota can result in alteration of fermentation patterns and, ultimately, metabolic disorders.

Basically, if the microbes are unhappy and unhealthy, and in the wrong numbers, your horse wont be able to breakdown its food efficiently.

In addition, if the microbes become disturbed and there is a decrease in good microbes and an increase in lactic acid producing microbes, resulting in a too acidic environment.

These bad bacteria love to ferment starch and sugar. Although they are obviously necessary, we never want them to take over. As starch and sugar are rapidly fermented into VFAs and lactic acid, which can accumulate in the hindgut and result in a condition known as “hindgut acidosis”.

Erosion of the epithelial cells that line the intestinal wall can also occur. An open sore or ulceration can form, accompanied by inflammation and thickening of the intestinal mucosa.

When the mucosa is compromised, the gut barrier is damaged. This is when the normally tight cell wall junctions in the hind gut begin to come loose, or permeable, meaning harmful substances can cross into the bloodstream, which can lead to infection and disease. Called Leaky Gut Syndrome.

The resulting health issues are wide ranging and can be severe. Ranging from weight loss, colic, diarrhoea, behaviour changes, FFW, to laminitis to reduced performance and reduced immunity seen in increased inflammation (both in the GI tract and other areas of the body) and recurring infections.

🦠Signs & symptoms of Hind Gut Dysbiosis

Symptoms may also differ between chronic and acute cases of dysbiosis. Possible signs of dysbiosis may include:

 Diarrhoea

 Weight loss

 Behavioural changes

 Bowel infections

 Systemic inflammation

 Laminitis

 Fatigue

 Bacterial infection of bowel

 Colic

 Colitis

Research is showing that dysbiosis is also associated with other health conditions such as equine metabolic syndrome and even dental issues.

🦠Diagnosis of hind gut dysbiosis

At present positively diagnosing dysbiosis is not easy. Tests that help identified dysbiosis, and its side effects such as intestinal inflammation and intestinal disease, may include a fecal occult blood test, biopsy of the intestine or rectum, or blood tests to screen for obvious pathogens or infection.

A fecal sample can help for assessing what types of microorganisms are present in the gastrointestinal tract of a horse suspected of having dysbiosis. As there is often a reduction in the diversity of organisms in the feces of horses with dysbiosis.

Most diagnosis will be achieved via a nutritionist services and owner keeping a health history to be able to pinpoint changes.

🦠What to do

Nutrition is the science of prevention! Have a nutritionist balance your horses individual diet programme to ensure optimum digestive health.

This will include quality and quantity of good fibre is in the diet which is critical for maintaining good numbers of health microbes.

Pre-biotics may be fed to feed and grow the numbers of beneficial bacteria that protect against toxins, combat pathogenic bacteria, stimulate immunity. These should be used strategically when competing, travelling and on medication etc.

Essential amino acids to aid in the health of the mucosal gut wall are hugely beneficial.

Feed starch levels should be kept to an amount that is easily digested in the foregut and doesn’t flow over and harm the hind gut causing a decrease in ph level and acidosis.

If grains are fed always make sure they are extruded or micronized. Access to high starch pasture should be limited for the same reasons.

Management and handling practices that keep stress to a minimum are hugely helpful. Just as if you are anxious your stomach is upset, so too is a horses stomach!