The zebrafish anxiety behaviors evaluated by the novel tank diving test. (A) Movements of the zebrafish following the transfer into the observation tank were traced for 2 min. The average speed (mm/s), average acceleration (mm/s²), total travel distance (mm), and exploration rate in the observation tank (%) of the zebrafish are presented. The error bars indicate standard error. N = 5, *p < 0.05. (B) The representative images of the traced movement of the P. sabiae-exposed and the control zebrafish.

The gut microbiome analysis of the P. sabiae-exposed zebrafish. (A) The diversity indices, Observed OTUs, Chao1, and Shannon, Faith_pd in the P. sabiae-exposed and the control zebrafish gut microbiomes. All OTUs detected by the microbiome analysis are summarized in Supplementary Table S2. (B) The phylum level and (C) genus level analyses of the zebrafish gut microbiome were conducted. The representative OTUs which increased and decreased in the P. sabiae-exposed zebrafish gut microbiomes are extracted by the LEfSe analysis. All OTUs extracted by the LEfSe analysis are summarized in Supplementary Table S3. (D) The PICRUSt2 functional analysis with METACYC database revealed that the functions of superpathway of taurine degradation (PWY-1541) was significantly reduced in the P. sabiae-exposed zebrafish gut microbiome (Supplementary Table S7). The predicted taurine metabolism pathways are represented with KEGG Mapper. Reduced functions in the taurine metabolic pathway in the P. sabiae-exposed zebrafish gut microbiome are shown as red. N = 5, *p < 0.05.

Taurine concentration and expression of taurine synthesis genes in zebrafish brains. (A) Taurine concentrations in zebrafish brains evaluated using the Taurine Assay Kit (Cell Biolabs.). N = 5, **p < 0.01. (B) Taurine biosynthesis pathways, and (C) the expression levels of taurine biosynthesis genes (ado, cdo, csad, tauT) in the zebrafish brain. N = 8, *p < 0.1.