Impact of Lactobacillus casei BL23 on the Host Transcriptome, Growth and Disease Resistance in Larval Zebrafish

Abstract

In this study, zebrafish were treated with Lactobacillus strains as probiotics from hatching to puberty, and the effect of treatment with L. casei BL23 on the development and immunity response of the host was investigated. Genes that were differentially expressed (DEGs) in the overall body and intestine were detected at 14 days post fertilization (dpf) and 35 dpf, respectively, using whole transcriptome sequencing (mRNAseq). We showed that zebrafish raised by continuous immersion with L. casei BL23 showed a higher final body weight at 14 dpf (P < 0.05), and 35 dpf (P < 0.01). DEGs between L. casei BL23 treatment and control group at 14 dpf were involved in myogenesis, cell adhesion, transcription regulation and DNA-binding and activator. At 35 dpf, 369 genes were DEGs in the intestine after treatment with L. casei BL23, which were involved in such categories as signaling, secretion, motor proteins, oxidoreductase and iron, tight junctions, lipid metabolism, growth regulation, proteases, and humoral and cellular effectors. KEGG analysis showed DEGs to be involved in such pathways as those associated with tight junctions and the PPAR signal pathway. RT-qPCR analysis showed that expression of insulin-like growth factors-I (igf1), peroxisome proliferator activated receptors-α (ppar-α) and -β (ppar-β), Vitamin D receptor-α (vdr-α), and retinoic acid receptor-γ (rar-γ) was up-regulated in fish treated with L. casei BL23 at 35 dpf. After 35 days of treatment, the mortality rate in L. casei BL23 treated group was lower than the control after challenge with A. hydrophila (P < 0.05), and the pro-inflammatory cytokine il-1β, anti-inflammatory cytokine il-10 and complement component 3a (c3a) showed more expression in L. casei BL23 group at 8h after challenge, 24 h after challenge, or both.. Together, these data suggest that specific Lactobacillus probiotic strains can accelerate the development profile and enhance immunity in zebrafish, which supports the rationale of early administration of probiotics in aquaculture.

The Responses of Germ-Free Zebrafish (Danio rerio) to Varying Bacterial Concentrations, Colonization Time Points, and Exposure Duration

“…However, another previous study indicated that, microbial colonization upregulated the expression level of myd88 gene (van der Sar et al, 2006). Additionally, Qin et al (2018) found that Lactobacillus casei BL23 increased the expression of stress-related genes compared to GF zebrafish, suggesting the expression of these genes might be a self-protection mechanism of the host, which is consistent with our results on stress related genes.…”

“…The microbiota residing within the animal gastrointestinal tract play important roles in various physiological processes, including modulation of immune system (Koch et al, 2018), enhancement of intestinal barrier (Takiishi et al, 2017), absorption or digestion of nutrients (Delzenne and Singer, 2016), inhibition of pathogens (Qin et al, 2018) and host behavior and neurodevelopment (Diaz Heijtz et al, 2011; Davis et al, 2016; Phelps et al, 2017). Therefore, studies on the relationships between the host and intestinal microbiota have received more attentions in recent years (Zhao, 2013).…”

Feed, Microbiota, and Gut Immunity: Using the Zebrafish Model to Understand Fish Health

“…Zebrafish immersed with Lactobacillus casei BL23 from 3-25 dpf displayed an increased survival compared to controls after an immersion challenge with Aeromonas hydrophila. Gut gene expression of il-1β, C3a, and il-10 was upregulated after 8 and 24 h after A. hydrophila challenge compared to controls (71). Interestingly, potential probiotics from the genera Lactobacillus modulated gene regulation in a strain-specific fashion.…”

Novel Insights into the Potential Diagnostic Value of Circulating Exosomal IncRNA-Related Networks in Large Artery Atherosclerotic Stroke

“…RNA purity was checked using a NanoPhotometer ® spectrophotometer (IMPLEN, CA, United States). RNA concentration was measured using a Qubit ® RNA Assay Kit in a Qubit ® 2.0 Fluorometer (Life Technologies, CA, United States) (Qin et al, 2018). RNA integrity was assessed using the RNA Nano 6000 Assay Kit of the Bioanalyzer 2,100 system (Agilent Technologies, CA, United States).…”