Research
| Title： | Comparative analysis on antioxidant capacity, immunity and histopathological changes of largemouth bass (Micropterus salmoides) in response to mono-or co-infection with Aeromonas veronii and Nocardia seriolae |
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| First author： | Cheng, Gaofeng; Zhu, Nengbin; Xu, Ruiping; Wangkahart, Eakapol; Zhang, Lin; Liu, Lihe; Wang, Rui; Xu, Zhen; Kong, Weiguang; Xu, Hongsen |
| Journal： | FISH & SHELLFISH IMMUNOLOGY |
| Years： | 2025 |
| DOI： | 10.1016/j.fsi.2025.110886 |
| Abstract： | Previous research has found that largemouth bass co-infected with Aeromonas veronii and Nocardia seriolae caused quicker and higher mortality than those infected by one single bacteria. Whereas, the pathogenic mechanism of co-infection with A. veronii and N. seriolae is still unclear. To explore this reason, the bacterial load in liver, spleen and head kidney, as well as the antioxidant capacity, non-specific immunity, histopathological changes and gene expression profiles of largemouth bass were both investigated and comparatively analyzed following mono- and co-infections. The results revealed that the total amount of A. veronii and N. seriolae in liver, spleen and head kidney of co-infected fish was significantly (P < 0.05) higher than that of every single infected fish at 7(th) and 14(th) days post-infection (dpi). Meanwhile, the activities of SOD, GSH-Px, AKP and LZM were remarkably (P < 0.05) decreased in infected fish, whereas the CAT and ACP capacities were increased. Moreover, the expression levels of immune-related genes in the spleen and head kidney increased initially and then decreased during 96 h after infection, whereas apoptosis-related genes showed a continuous rise. Especially, the mRNA profile of genes from co-infected fish was higher than that of each single infected fish at the time when the maximum expression appeared. In addition, the liver, spleen, head kidney and intestine of largemouth bass exhibited severe tissue lesions after infection. Particularly, the degree of damage in co-infected fish was more serious than that of each single infected fish. The results will advance our knowledge on the interaction between pathogenic bacteria and host immune system during mono- or co-infection with A. veronii and N. seriolae, and then help to develop management strategies to mitigate the impact of bacterial infection on largemouth bass production. |
