Restricting a horse’s diet has many negative effects, as described in the following article from KAM Animal Services.  Could the diet adopted out of necessity (if not outright desperation) by owners of insulin resistant horses and easy keepers, actually be contributing to their predisposition to laminitis? 

Read the whole article here:

Here are pertinent excerpts from the lengthy article:

By: Kate McBride Puckett
November 27, 2006

Dysbiosis, also known as “Leaky Gut Syndrome” is defined as a perforated hind gut, an excessively permeable intestine or a condition of erosion and ulceration of the gastrointestinal tract.

Symbiosis is defined as the relationship between organisms in which one organism is in an intimate association with another. A pertinent example of a symbiotic relationship is the intestinal flora of a healthy species lives in harmony with its host. As such the bacteria of the intestine is often referred to as “friendly” and helps to maintain homeostasis and many “health promoting” activities including detoxification, vitamin production, and protection against pathogens.

If this relationship is out of balance, the mere overgrowth of so-called “friendly” bacteria, dys-symbiosis or dysbiosis results and inevitably leads to holes in the gut. Dysbiosis, and subsequent increased permeability of the intestinal mucosa, in general can be caused by a myriad of causes including protozoan parasites, bacteria,  yeast, excessive antibiotic or NSAID use, parasite infestation, maldigestion, stress, and an imbalanced and restricted intake diet. The most critical point to consider with dysbiosis is the extreme damage it causes the equid by permitting bacteria, pathogens, etc. to escape the intestinal lining and enter the bloodstream. With this more permeable intestinal mucosa, essentially the filtration system of the intestines is defunct/deficient and provokes three detrimental responses to “foreigners” or pathogens leaking into the blood stream:

1.)   an Immune Function System response

 2.)  a Systemic Inflammatory System response, and

 3.)  an Insulin Resistance response (which can be measured by endocrine systems tests).

Another consequence of dysbiosis is a resistance to insulin, a recently recognized syndrome labeled “Syndrome X” or Insulin Resistance syndrome. Essentially this is a metabolic syndrome characterized by an inability to transport glucose into the cell.

This resonates in the horse because an increased risk of several digestive and metabolic disorders has been associated with feeding (high carbohydrate and sugar) meals of grain and molasses.  Post eating, the pancreas produces insulin to lower blood sugar levels, however with the consequent flooding of sugar into the blood due to dysbiosis, this results in reactive “rushes” of insulin that either cause decreased future insulin levels leading to high blood sugar (diabetes), erratic insulin levels leading to low blood sugar (hypoglycemia), or Syndrome X, whereby insulin receptors in the liver, muscle and fat cells become damaged and cannot transport glucose effectively. These blood sugar conditions also cause the adrenal glands to produce increased cortisol levels catabolizing proteins and weakening and inflaming connective tissue and lamellar structures within the feet.  The cells become resistant to insulin and the glucose from the feed can no longer penetrate the cells. In turn, the horse suffers from inflammation, laminitis, and/or founder.   This metabolic syndrome also causes a general build up of lactic acid (due to stress and poor oxygenation) that interferes with muscle function, endurance,
metabolism, immunity, and hoof health, exacerbating laminitis.

Essentially the equine digestive system is a complicated system designed to process frequent small amounts of food.  By confining horses, the amount, frequency and type of feed available for them to consume is now determined by humans. Before what was a continual input from grazing, has become a once a day feeding of unvaried, unbalanced large quantities of feed. 

The causes of dysbiosis include: high starch meals, infrequent feedings and confinement during feeding times (Equine stomachs constantly produce hydrochloric acid which eats away at the mucosal lining if empty), response to chronic pain, heavy exercise (Horses contract their abdominal muscles under stress forcing the stomach’s hydrochloric acid into the upper stomach), NSAIDS and Steroidal drugs (These drugs prevent prostaglandin production, key components of the protective mucosal lining of the GI tract), and parasites.

The clinical signs of dysbiosis are varied.  Typically the horse eats grain, but will not eat hay, has a rough coat, suffers weight loss and has dificulty gaining weight, is often anxious, stressed, nervous, and objects to working or to the saddle itslef, is often sore to the touch to the bladder 21 acupunture point and is reactive to palaption along the gut sagittal line.

Once dysbiosis occurs in the equid, this essentially opens the door to many equine diseases. In addition to the aforementioned diseases founder, laminitis, inflammatory diseases i.e. arthritis, and metabolic disorders i.e. insulin resistance; dysbiosis also contributes to Cushing’s disease, endotoxemia, Diabetes mellitus, azoturia, colitis, inflammatory bowel disease, irritable bowel syndrome, infectious enterocolitis, celiac disease, bacteremia, Chronic Obstructive Pulmonary Disease (Heaves), liver disease, and colic. Most often these conditions manifest in the horse as colic, which is often recurrent and unrelated to management. Chronic weight loss and chronic diarrhea may also result from leaky gut syndrome.

Further it has a devastating effect on the liver as it is recruited to filter all “contaminated” blood from the intestine. Signs of liver dysfunction, which include tight, sore muscles, weak, easily injured tendons and ligaments, poor hoof quality, eye disorders and irritability will appear before the liver has time to increase liver detoxification enzyme production (detectable via blood tests) and thus excess free radicals are left to circulate in the blood exacerbating chronic disease i.e. laminitis.

Treatment and Prevention of dysbiosis is fairly straight forward and a simple way to avoid such grave consequences. First off, return your horse’s life to him. Permit your horse to be a horse as close to its natural state as possible. Relocate your horse “out” with ample running room, grazing, and companionship. Offer plenty of high quality grass hay and frequent small low starch meals. It is always best to prophylactically prepare/protect your horse’s gut prior to any stressful situations: deworming, vaccinations, shipping, shows etc. Maintain a well-balanced feed for your horse with appropriate Calcium/phosphorus ratios as close to 1:1 as possible. Have horses teeth checked and floated regularly and try to keep the horse’s daily regime predictable and prompt as possible. “The more boring your horses daily life, the better”.