Effects of dietary and fecal microbial transplant treatments on fecal characteristics, metabolites, and microbiota of adult cats treated with metronidazole

Antibiotics remain a critical treatment option for gastrointestinal enteropathies but in recent years has demonstrated significant microbiota dysmetabolism, alterations in fermentation patterns, and prolonged dysbiosis following treatment. The objective of this study was to determine how dietary fiber supplementation or fecal microbial transplant (FMT) treatment impacted the fecal characteristics, metabolite concentrations, and microbiota populations of cats treated with metronidazole. Twenty-five healthy adult cats (6.75 +/- 1.20 yr) were fed a commercial kibble diet for 2 wk, administered metronidazole (20 mg/kg BW twice daily) for 2 wk, then monitored for 4 wk. Cats were allotted to 1 of 3 interventions (diet only, diet+beet pulp, diet+FMT) for 1 wk, interventions ceased, then recovery was monitored for 4 wk. Fresh fecal samples were collected at the end of each phase and at the mid-points of recovery for fecal characteristics, fecal metabolites and fecal microbiota. As anticipated, metronidazole in-creased fecal scores and moisture (P<0.05), reduced fecal bacterial alpha diversity (P<0.0001) and reduced several fecal metabolite concentrations. Few treatment effects were observed, with antibiotic recovery contributing to many of the results observed. Dysbiosis was persistent throughout the study, with 4/25 cats still demonstrating mild dysbiosis after 9 wk. Improvements to fecal characteristics were observed, with several bacterial genera being affected by dietary treatment or recovery time. Overall, dietary or FMT treatments may aid in accelerated antibiotic recovery in cats but further re-search is needed to refine treatments for greater efficacy.