Molecular insights into dietary induced colic in the horse.
Authors: Shirazi-Beechey S P
Journal: Equine veterinary journal
Summary
# Editorial Summary Colic remains the leading cause of equine emergencies and mortality, yet our understanding of why excessive dietary carbohydrates increase colic risk has relied more on empirical observation than mechanistic knowledge. Shirazi-Beechey's 2008 review synthesises molecular and cellular research into how horses digest and absorb carbohydrates, examining both the adaptive capacity of the small intestinal epithelium and the downstream effects on large intestinal microbiology and host tissues. The evidence demonstrates that when hydrolysable carbohydrate intake exceeds the small intestine's digestive capacity, unfermented substrates reach the colon where dysbiotic shifts in microbial populations can trigger pathophysiological cascades—a mechanism that explains why high-grain diets and sudden dietary changes predispose horses to colic. For practitioners developing feeding protocols and preventive strategies, this molecular perspective underscores the critical importance of matching carbohydrate type and load to individual digestive capacity, allowing adequate adaptation time when dietary transitions occur, and considering individual variation in carbohydrate transporters and enzyme expression. Understanding these intestinal mechanisms transforms colic prevention from purely rule-based feeding protocols into evidence-informed practice tailored to each horse's digestive physiology.
Read the full abstract on PubMed
Practical Takeaways
- •Feed management focusing on appropriate carbohydrate levels and digestibility is critical for colic prevention; avoid excessive high-carbohydrate diets
- •Gradual dietary transitions allow the equine gut epithelium to adapt; abrupt feed changes increase colic risk by disrupting intestinal microbiology
- •Understanding individual horse variation in carbohydrate digestive capacity may help tailor feeding programs to reduce colic incidence in high-risk animals
Key Findings
- •Equine colic is a multifactorial disorder influenced by environmental factors, genetic predisposition, and excessive consumption of high-carbohydrate diets
- •Carbohydrate digestive and absorptive capacity of the equine small intestine has adaptive mechanisms that respond to dietary changes
- •Alterations in diet trigger changes in large intestinal microbiology and host tissue biology that contribute to colic pathology
- •Better understanding of molecular and cellular mechanisms in equine gastrointestinal carbohydrate digestion is essential for developing colic prevention strategies