Systematic review and meta-analysis of the effect of fecal microbiota transplantation on behavior in animals

• Published in: Neuroscience and biobehavioral reviews Vol. 153; p. 105316
• Main Authors: Keubler, Lydia M., Talbot, Steven R., Bleich, André, Boyle, Erin C.
• Format: Journal Article
• Language: English
• Published: United States Elsevier Ltd 01.10.2023
• Subjects: Animal studies; Behavior; Fecal microbiota transplantation; FMT; Gut microbiota-brain axis; Meta-analysis; Reproducibility; Risk of bias; Systematic review; Gut microbiota-brain axis; Fecal microbiota transplantation; PRISMA; Systematic review; SMD; FMT; Meta-analysis; Animal studies; REML; Risk of bias; Reproducibility; Behavior; SyRF; SYRCLE
• ISSN: 0149-7634; 1873-7528
• DOI: 10.1016/j.neubiorev.2023.105316

The bi-directional interaction between gut microbiota and the central nervous system has been coined the gut microbiota-brain axis. Fecal microbiota transplantation (FMT) is the administration of a solution of fecal matter from a donor into the intestinal tract of a recipient. Preclinical FMT experiments are essential to prove causality in the context of the gut microbiota-brain axis. In this systematic review, we assess the body of evidence related to the ability of FMT to modulate an animal’s behavior. Accordingly, we provide a detailed summary of the use of FMT in behavior-related animal studies, an extensive risk of bias analysis, and a meta-analysis of the overall effect of FMT on behavioral outcome measures in 64 studies, representing 4889 animals. The resulting meta-analysis revealed FMT was effective at changing animal behavior, thereby substantiating evidence for the gut microbiota-brain axis. However, our study also highlights an urgent need for methodological safeguards within this research field to reduce the risk of bias and improve the internal validity of future studies. •We evaluated the evidence for the ability of FMT to modulate an animal’s behavior.•FMT was effective at changing animal behavior (effect size 0.82; 95% CI 0.68–0.97).•FMT had the largest effect on outcomes related to mood, cognition, pain, and motor function.•Inadequate methodological reporting and study design flaws were prevalent.•Our findings emphasize the need for methodological safeguards in FMT study design.