Lactobacillus delbrueckii reduces anxiety-like behavior in zebrafish through a gut microbiome - brain crosstalk

Certain bacteria possess the ability to reduce anxiety-and stress-related behaviors through the gut microbiome-brain axis. Such bacteria are called psychobiotics, and can be used to improve mood and cognition. However, only a few bacteria have been characterized as psychobiotics, and their exact mechanism of action remains unclear. Hence, in this study we analyzed three different species under the Lactobacillacea family, namely, Lactobacillus delbrueckii, Lacticaseibacillus casei, and Lacticaseibacillus paracasei for their potential psychobiotic activities. L. delbrueckii treatment reduced anxiety-like behavior and increased brain and gut glutamic acid decarboxylase (gad) gene expression in zebrafish. It also altered zebrafish gut microbial community as deter-mined by PCR-DGGE and 16S rRNA-based metagenomics analysis. Overall, this paper showed that L. delbrueckii but not L. paracasei and L. casei, induced a consistent improvement in anxiety-like behavior in zebrafish, implicating its potential role as a psychobiotic to reduce anxiety.This article is part of the Special Issue on 'Microbiome & the Brain: Mechanisms & Maladies'.

Automated summary

Certain bacteria called psychobiotics have the ability to reduce anxiety and stress-related behaviors through the gut microbiome-brain axis. This study analyzed three species of Lactobacillacea family, finding that L. delbrueckii could reduce anxiety-like behavior in zebrafish and increase the expression of a specific gene in the brain and gut. The study also showed that L. delbrueckii altered the zebrafish gut microbial community.