Healthy age-matched control horses

Thirty clinically healthy horses of two age groups (15 young-adults [2–13 years old]; 15 geriatric horses [20–30 years old]) were selected from 5 housing facilities located in Massachusetts and Connecticut, based on the availability of phenotypically matched young and aged horses at each location, exposure to a comparable diet, and similar management. The latter selection criteria were used to determine which management and phenotypic features may contribute to differences in the fecal microbiota of healthy horses and should thus be considered in selecting a donor for fecal microbial transplantation. Prior to fecal collection, a complete diet history, medical history, and physical examination were obtained to ensure clinical health. Exclusion criteria included any recent gastrointestinal illness (colic, diarrhea), transport, medical treatment, or dietary supplementation with probiotics. Breed, age, body condition score, heart rate, respiratory rate, rectal temperature, attitude, and borborygmi were recorded prior to manure collection. Up to 10-mL of feces were collected per rectum using a clean gloved hand at two separate time-points 2 weeks apart and stored at -80°C for subsequent analysis. The experimental design and methods were approved by the Clinical Studies Review Committee and informed client consent was obtained for all horses.

A quantitative fecal egg count and Equine Diarrhea PCR panel for Coronavirus, Clostridium difficile toxins A and B, Clostridium perfringens antigens, Lawsonia intracellularis, Neorickettsia risticii and Salmonella sp. (Equine Diarrhea Panel, Research and Diagnostic Core Facility, University of California, Davis) were confirmed to be negative for 3 control horses that served as FMT donors to clinically ill geriatric patients with diarrhea. Prior to each FMT on 3 consecutive days, a 10-mL fecal sample was obtained from the donor manure pile that was subsequently processed and used as transfaunate for a single patient. All donor samples obtained on days 1–3 of transfaunation were stored and sequenced individually, thus analyzing a total of 3 FMT samples per donor obtained on consecutive days and administered to a single recipient.