Effects of fecal microbiota transplantation on clinical outcomes and fecal microbiota of foals with diarrhea

Background Diarrhea in foals can be associated with disruption of the intestinal microbiota (dysbiosis). Effective management of intestinal dysbiosis in foals has not been demonstrated. Hypothesis/Objectives Fecal microbiota transplantation (FMT) in foals with diarrhea influences the intestinal microbiota and improves clinical and clinicopathological outcomes. Animals Twenty‐five foals <6 months of age with diarrhea and systemic inflammatory response syndrome at 3 veterinary hospitals. Methods A prospective randomized placebo‐controlled cohort study. Foals in the FMT group (n = 19) or control group (n = 9) received FMT or electrolyte solution once daily for 3 days. Fecal samples were obtained on Day 0 (D0), D1, D2, D3, and D7. Within group and between group data analyses were performed for clinical, clinicopathological, and microbiota variables. Results Treatment had no effect on survival (FMT 79%; control 100%, P = .3) or resolution of diarrhea (FMT 68%; control 55%, P = .4). On D3, the white blood cell count of the FMT group was lower than the control group (D3 FMT group median 6.4 g/L [5‐8.3 g/L]; D3 control group median 14.3 g/L [6.7‐18.9 g/L] P = .04). Heart rate reduced over time in the FMT group (D0 median 80 bpm [60‐150 bpm]; D2 median 70 bpm [52‐110 bpm] [ P = .005]; and D3 median 64, [54‐102 bpm] [ P < .001]). Phylum Verrucomicrobiota, genus Akkermansia , and family Prevotellaceae were enriched in the FMT group on D1 (linear discriminate analysis > 4). Conclusions and Clinical Importance In foals with diarrhea, FMT appears safe and can be associated with some clinical and microbiota changes suggestive of beneficial effect.