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

Abstract Antibiotics remain a critical treatment option for gastrointestinal enteropathies but are often reported to cause negative side effects such as loose stools and weight loss, in addition to negatively altering fecal microbiota. In recent years, research has demonstrated significant microbiota dysmetabolism, alterations in fermentation patterns, and prolonged dysbiosis following antibiotic treatments. Metronidazole and tylosin are the most commonly prescribed antibiotics, with metronidazole demonstrating a high ability to disrupt gastrointestinal microbiota. Targeted interventions may assist in recovery and may include dietary modification or fecal microbial transplants (FMT), which are becoming a popular treatment option for chronic enteropathies. However, research evaluating their potential effectiveness compared with dietary intervention is limited. The objective of this study was to determine how dietary fiber supplementation and FMT treatment impacted the fecal characteristics, metabolites, and microbiota of cats treated with metronidazole. All procedures were approved by the University of Illinois IACUC prior to experimentation. Twenty-five healthy adult cats were used in a randomized controlled design study and fed a commercial kibble diet for 2 wk, then administered metronidazole (20 mg/kg BW twice daily) for 2 wk. Recovery was monitored for 4 wk, then cats were allotted to 1 of 3 interventions (diet only, diet+beet pulp, diet+FMT) for 1 wk. Interventions ceased and 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 measurement of pH, dry matter, and metabolite concentrations. Fecal microbiota populations were also analyzed by 16S rRNA gene amplicon sequencing to assess alpha and beta diversity measures and to estimate relative abundances of specific taxa. All data were analyzed as repeated measures using the Mixed Models procedure of SAS 9.4, with treatment treated as a fixed effect, cat as a random effect, and significance set at P< 0.05. As anticipated, metronidazole increased fecal scores (P< 0.05), increased fecal moisture (P< 0.05), and reduced (P< 0.0001) fecal bacterial alpha diversity and short-chain fatty acid (SCFA), branched-chain fatty acid, phenol, indole, and ammonia concentrations. Few treatment effects were observed, with antibiotic recovery contributing to many of the results observed. Dietary intervention tended to increase SCFA concentrations with time, with fiber-supplemented animals tending to have higher fecal propionate concentrations immediately after intervention. Several other metabolites were influenced by recovery time. Dysbiosis was persistent throughout the study. The majority of cats recovered over time; however, 4/25 cats were noted to have mild dysbiosis. Improvements to fecal characteristics were observed, with over 50 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 research is needed to refine treatments for greater efficacy.