The horse’s digestive tract houses a unique and diverse microbial population, each species in careful balance with the others to serve specific purposes. Diet, age, and disease status, however, can all negatively affect the microbiota (the microbial population residing in the digestive tract). In humans, researchers know that metabolic syndrome can be associated with changes in the intestinal microbiota. So what happens in the gut when horses have equine metabolic syndrome (EMS)?

Sarah Elzinga, a graduate student working under Amanda Adams, PhD, at the University of Kentucky’s Gluck Equine Research Center, in Lexington, set out to answer this question. Her team studied 20 horses of varying breeds and genders consuming free-choice mixed-grass hay for at least two months prior to sampling. They classified the horses based on the presence or absence of insulin dysregulation, regional or general adiposity (body fat), previous history of or predisposition for the hoof disease laminitis as EMS or as control (not affected) horses.

After grouping the horses, the team extracted DNA from fecal samples for examination and microbial classification. As expected, EMS-affected horses had greater insulin concentrations, both while fasting and 60 minutes after oral sugar administration (a standard protocol used to diagnose insulin dysregulation), than control horses. They also had higher body condition and cresty neck scores than controls.

Regarding fecal microbiota, while the EMS group did not have different quantities of bacteria in the intestinal tract, they did have less microbial diversity. Other disparities between the two groups’ bacteria populations included:

• An abundance of phylum Verrucomicrobia in EMS-affected horses. In humans, abundance of this phylum has been described as a potential marker of glucose intolerance, and researchers found increased numbers of Verrucomicrobia in obese mini-pigs compared to lean ones;

• Control Horses had More Fibrobacter than EMS horses—an integral part of the horse’s microbiota contributing to the breakdown of fiber. Both Fibrobacter and Ruminococcaceae tend to be intolerant of acidic conditions in the hindgut and decrease in number as lactic acid bacteria increase, usually due to large quantities of starch spilling over into the hindgut or to intestinal disease;

• Greater Lactobacillus concentrations in EMS-affected horses, which Elzinga said could be a representation of the lower Fibrobacter numbers;

• Greater Ruminococcaceae (which produce the volatile fatty acid butyrate) concentrations in control horses. The researchers noted that lower microbial diversity seen in EMS-affected horses has also been seen in horses receiving antibiotics or in response to dietary change.

Take-Home Message

Horses with EMS appear to have different microbiota numbers and diversity than healthy horses, potentially impairing gut health and affecting metabolism. Adams added, “The future goals are to develop therapeutic tools that target the gut microbiota that have the potential to modulate disease states, including insulin resistance in EMS horses.”



Article taken from source=Newsletter&utm_medium=health-news&utm_campaign=05-23-2017

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