ROS Induced by <i>Streptococcus agalactiae</i> Activate Inflammatory Responses via the TNF-α/NF-κB Signaling Pathway in Golden Pompano <i>Trachinotus ovatus</i> (Linnaeus, 1758)

• Main Authors: Jie Gao (Author), Mingjian Liu (Author), Huayang Guo (Author), Kecheng Zhu (Author), Bo Liu (Author), Baosuo Liu (Author), Nan Zhang (Author), Dianchang Zhang (Author)
• Format: Book
• Published: MDPI AG, 2022-09-01T00:00:00Z.
• Subjects: article
• Online Access: Connect to this object online.

Summary

<i>Streptococcus agalactiae</i> is common pathogenic bacteria in aquaculture and can cause mass mortality after fish infection. This study aimed to investigate the effects of <i>S. agalactiae</i> infection on the immune and antioxidant regulatory mechanisms of golden pompano (<i>Trachinotus ovatus</i>). Serum and liver samples were obtained at 0, 6, 12, 24, 48, 96, and 120 h after golden pompano infection with <i>S. agalactiae</i> for enzyme activity and gene expression analyses. After infection with <i>S. agalactiae</i>, the content of reactive oxygen species (ROS) in serum was significantly increased (<i>p</i> < 0.05). Serum levels of glucose (GLU), alanine aminotransferase (ALT), aspartate aminotransferase (AST), and malondialdehyde (MDA) increased and then decreased (<i>p</i> < 0.05), reaching a maximum at 6 h. Serum antioxidant enzyme (LZM) activity increased significantly (<i>p</i> < 0.05) and reached a maximum at 120 h. In addition, the mRNA expression levels of antioxidant genes (<i>SOD</i>, <i>CAT</i>, and <i>GPx</i>) in the liver increased and then decreased, reaching the maximum at 24 h, 48 h, and 24 h, respectively. During the experimental period, the mRNA expression levels of NF-κB-related genes of the inflammatory signaling pathway inhibitory κB (<i>IκB</i>) showed an overall decreasing trend (<i>p</i> < 0.05) and the lowest expression at 120 h, whereas the mRNA expression levels of tumor necrosis factor α (<i>TNF-α</i>), interleukin-1β (<i>IL-1β</i>), IκB kinase (<i>IKK</i>), and nuclear factor NF-κB increased significantly (<i>p</i> < 0.05) and the highest expression was at 120 h. In conclusion, these results showed that <i>S. agalactiae</i> could activate internal regulatory signaling in the liver of golden pompano to induce defense and immune responses. This study is expected to lay a foundation to develop the healthy aquaculture of golden pompano and promote a more comprehensive understanding of its disease resistance mechanisms.

Item Description

10.3390/antiox11091809
2076-3921