(E36) Fecal and Intestinal Microbiota Profiles in Horses with Different Types of Surgical Colic

Abstract:

Background: Various factors influence the equine intestinal microbiota, including colic.

Objectives: To evaluate the fecal and intestinal microbiota of horses with colic undergoing exploratory celiotomy. Animals: Thirty-five horses with colic, categorized by lesion type: large colon volvulus (n = 11), displacement (n = 11), impaction (n = 6); small intestine volvulus (n = 5) and obstruction (n = 2). Twelve healthy horses from the same farms, sampled six months post-surgery, served as controls.

Methods: Fecal samples were collected at admission and on days 1, 2, 3, and 6 months post-surgery. Intestinal content was obtained from the duodenum, cecum and colon during surgery. Microbiota composition was analyzed via 16S rRNA sequencing (V4 region). ANOVA and PERMANOVA tests (p < 0.05) determined statistical significance.

Results: Fecal samples differed significantly from intestinal contents and between sampling days. Feces collected at D0 had lower richness in horses with small intestinal or strangulating lesions. Colic duration (>24 vs. ≤24 hours) also influenced fecal microbiota composition at D0. Several markers were associated with feces at D0 (e.g. Escherichia and Akkermansia) compared to healthy controls (e.g. Lachnospiraceae and Fibrobacter). By six months post-surgery, fecal microbiota composition was indistinguishable from healthy controls, indicating microbiota recovery. In intestinal contents, microbiota richness, diversity, and composition varied by intestinal segment and lesion type. Conclusions and Clinical Importance: The differences between fecal and intestinal content highlight the uniqueness of each segment during colic episodes. Future studies identifying microbial markers for specific colic types may enhance diagnosis and improve clinical decision-making.