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EQUINE HEALTH
different strains of these, and some are better than others, though all of them seem to be beneficial,” he says.
“There are also a number of beneficial Lac- tobacillus and Bacillus bacteria for which there is some evidence-based research supporting their effects. The proven probiotic yeasts (which are fungi) and bacteria have beneficial effects on the horse’s microbiome, which is the entire living community inside the intestinal system. We are trying to maintain a high proportion of beneficial resident microbes compared to the number of pathogenic microbes,” he explains.
There are always some nasty pathogens in the GI tract, and they are necessary to keep stimulating the body to maintain a highly-func- tioning immune system, but everything needs to be in balance. “Studies on disease-free mice (raised in an environment with no pathogens) show that when animals are completely patho- gen-free they don’t thrive as well as a normal animal that has everything in healthy balance.” Without some “bad” bacteria to stimulate immune response, the animal has reduced intes- tinal function and immunity and may become more vulnerable to infection or disease.
Providing probiotics is a very natural way to fine-tune and restore the balance between the beneficial and detrimental microbiome throughout the GI tract. “We see the start
of a significant microbiome in the ilium and definitely through the cecum and large intes- tine. All the way through the cecum and large intestine there is a lot of microbial activity,” says Lindinger. These beneficial “gut bugs” are crucial to digestion of forages as well as to the health of the gut.
“In horses and ruminants these microbes break down the otherwise non-digestible starches and fiber that come in through the diet. These microbes use non-digestible starches as substrate and do the actual digestion, producing a lot of beneficial molecules in that process,” he says.
“The beneficial bacteria and yeasts can also provide substrate for other beneficial bacteria (playing a prebiotic role) and some can actually produce butyrate, which is a very important molecule involved in maintaining the tight junctions between each of the intestinal epithelial cells. Studies in many species of
The best prevention against Leaky Gut Syndrome is to reduce stress and promote a healthy gut by providing hay and high quality clean water.
animals, except horses, have shown that when we provide something like butyrate, we see an almost immediate tightening of these junctions and the gut becomes less leaky,” he says.
In the hindgut, the “good” bacteria also produce volatile fatty acids that serve as nutrients which are taken in through the intestinal wall and utilized by all the cells in the body. “Throughout the intestinal system, some bacteria also help the intestine’s epithe- lial cells produce and maintain a mucus layer which serves as the first line of defense inside the intestine itself.” The mucus lies over the top of the epithelial cells and acts as a protective shield and buffer against irritants and harmful substances and pathogens.
“The mucus also possesses bactericides
to kill the pathogens but not the beneficial bacteria. Thus, it provides both a physical and chemical barrier against pathogens yet allows the diffusion of nutrient molecules to get into and go through the epithelial cells,” he says. Anything that disrupts and disturbs that mucus layer can put the horse at risk for leaky gut syndrome.
“While some pathogens are able to directly disturb the mucus layer; mainly it is mechanical disturbances from ingested for- eign materials such as sand, wood fragments/ splinters, straw, etc., that erodes the mucous barrier. Abrasive feeds or foreign material in the gut can actually pierce the intestinal wall occasionally, but this wall is capable of very rapid healing and repair. There is actually an ongoing cycle of breaking down and repair-
ing,” says Lindinger. Even gastric ulcers can rapidly come and go as the stomach wall heals itself.
“In the intestinal system this healing is even faster, with replacement of damaged cells and repair of leaks within 3 to 6 hours, with turnover of cells in a matter of 2 to 3 hours.
It is a very dynamic system, but energetically expensive to maintain. It is only one cell layer thick, so it is easy to patch and repair as well as damage,” he says.
Use of non-steroidal anti-inflammatory medications should be minimized. “All of the NSAIDs are known to have detrimental effects on horses, whether within the joints themselves (degrading the joints) and also known to cause pockets or areas of insufficient blood flow within the GI tract, causing dead zones. Then we get an area of inflammation and leaky gut, colic and possibly ulcers. There is a very strong association between use of NSAIDs (when used for longer than 3 days) and the incidence of colonic ulcers.”
PROBIOTICS AND PREBIOTICS
Prebiotics serve as nutrients for beneficial bacteria. “The idea behind providing prebiot- ics is that we don’t want to have nutrients for detrimental bacteria in the gut, so we want to help the beneficial bacteria to grow and develop at a normal rate and maintain a healthy balance in the GI tract. The prebiotics don’t directly contribute to producing beneficial molecules, but they serve as food for the good bacteria,” explains Lindinger.
“The idea behind providing prebiotics is that we don’t want to have nutrients for detrimental bacteria in the gut, so we want to help the beneficial bacteria to grow and develop at a normal rate and maintain a healthy balance in the GI tract.”
58 SPEEDHORSE May 2020