Dietary fructan carbohydrate increases amine production in the equine large intestine: implications for pasture-associated laminitis.

The research explores the link between dietary fructan intake in horses and the increase in harmful amine production in their intestines, which is believed to contribute to a horse disease known as laminitis. The study found that amine levels in ponies rise when they switch from a hay-based diet to consuming fructan carbohydrates, suggesting fructan can significantly impact the health conditions of ponies, regardless of their predisposition to laminitis.

Introduction to the Research

The research was designed to study the implications of feed changes from a hay diet to a lush spring-summer pasture diet rich in carbohydrates, such as fructan (inulin), on horses’ gut function. The specific emphasis was on the production of amines, which are suggested as potential trigger factors for laminitis, a painful and often crippling disease in horses linked to overconsumption of fermentable carbohydrates.

• The study involved two groups of ponies – five normal and six predisposed to laminitis.
• All ponies were initially fed a basal hay diet, after which inulin and chopped dried grass were introduced to their meals.
• Throughout the study, the research team periodically collected blood samples, fecal samples, and foot temperature measurements from all ponies.

Key Findings

As the ponies transitioned from a hay diet to an inulin-enriched feed, the team observed changes in their gut function.

• The fecal pH, a measure of acidity, dropped from 6.89 to a minimum of 6.18, indicating an increase in gut acidity with the addition of inulin.
• Fecal concentrations of several amines, including tryptamine and tyramine, significantly increased. Tryptamine showed a 2.5-fold increase and tyramine a 2-fold increase.

Interestingly, no changes were found in plasma amine concentrations or plasma D- or L-lactate levels, suggesting a threshold of hindgut pH change before damage to the mucosal layer can release these factors into circulation.

Implications and Conclusion

There were no differences observed between the normal ponies and those prone to laminitis, implying that variations in intestinal microflora do not account for this predisposition.

The research concludes that moderate increases in dietary fructan carbohydrate intake can lead to surges in bacterial fermentation products and other compounds in the large intestine. These alterations are significant as they may be relevant to the pathogenesis of acute laminitis in ponies on pasture. Therefore, dietary management may be a significant key to preventing laminitis episodes in horses.