Effects of Vibrio anguillarum Infection on Blood Homeostasis, Gut Microbiota and Transcriptome Profiling in Chinese Seabass (Lateolabrax maculatus)

The Chinese seabass (Lateolabrax maculatus) is one of the most popular and valuable aquaculture species in China. Recently, the disease caused by Vibrio anguillarum has brought huge economic losses in the L. maculatus industry. However, the immune response of L. maculatus after V. anguillarum infection remains unknown. In this study, the blood homeostasis, gut microbiota and transcriptomic profiling of L. maculatus after V. anguillarum infection were investigated. Our results indicated that the levels of superoxide dismutase (SOD), alanine aminotransferase (ALT) and total bilirubin (TBIL) increased, while the levels of blood glucose (BG), total protein (TP) and albumin (ALB) decreased after V. anguillarum infection. The analysis of the gut microbiota composition revealed that the dominant phyla was Firmicutes and Proteobacteria, and the relative abundance of genus Vibrio increased after V. anguillarum infection. Subsequently, the differentially expressed genes (DEGs) in the kidney and spleen after V. anguillarum infection were analyzed by transcriptome sequencing. The results indicated that immunity-related genes like TLR5, TLR8, TLR9, IL-1β, CCL3, IFNγ, CXCL11 and TNFα were affected and the NOD-like receptor signaling pathway, cytokine-cytokine receptor interaction and Toll-like receptor signaling were activated. Thus, an effective immune and pro-flammatory response can help resist V. anguillarum infection. Our results provide a theoretical support for improving the disease resistance ability of L. maculatus.