Huo Jiaxin, Li Xiaowei, Zhang Kaiyang, Fu Hao, Hu Xiucai, Lv Aijun
Tianjin Key Lab of Aqua-Ecology and Aquaculture, College of Fisheries, Tianjin Agricultural University, Tianjin, China.
J Fish Dis. 2025 Mar;48(3):e14054. doi: 10.1111/jfd.14054. Epub 2024 Dec 3.
Rahnella aquatilis as an emerging pathogen can cause bacterial enteritis in cyprinid fish such as crucian carp Carassius auratus. Currently, the characterisation of immune function and gut microbiome composition in C. auratus orally challenged by R. aquatilis were yet unknown. In this study, we therefore investigated the changes of histopathology, white blood cells (i.e., LEU, NEU and LYM), serum biochemical indicators (e.g., CRE, CK and CHO) and digestive enzyme activity (e.g., LYS, AST, ALT, GSH-Px and AKP), as well as complements and immune-related genes (e.g., C3, F2, LysC, TLR3, MyD88, TGF-β, TNF-α and IL-15) that were significantly altered after the oral administration of R. aquatilis KCL-5. Moreover, the gut microbiome composition and diversity were analysed by using 16S rRNA gene high-throughput sequencing analysis. The correlation analysis showed that the high abundance of phylum Proteobacteria, Actinobacteria, Firmicutes and Fusobacteria was related to the pathogenesis of enteritis caused by oral infection. KEGG enrichment analysis indicated that fatty acid, carbon and pyruvate metabolism were significantly increased pathways (p < 0.05). To our best knowledge, this is a rare report of physicochemical properties and gut microbiome in C. auratus by R. aquatilis infection, which will provide a scientific reference for the clinical diagnosis and prevention of bacterial enteritis in cyprinid fish.
水拉恩氏菌作为一种新出现的病原体，可导致鲤科鱼类如鲫鱼患细菌性肠炎。目前，关于受水拉恩氏菌口服攻击的鲫鱼的免疫功能特征和肠道微生物群组成尚不清楚。因此，在本研究中，我们调查了口服水拉恩氏菌KCL-5后组织病理学、白细胞（即白细胞、中性粒细胞和淋巴细胞）、血清生化指标（如肌酐、肌酸激酶和胆固醇）和消化酶活性（如溶菌酶、天冬氨酸转氨酶、丙氨酸转氨酶、谷胱甘肽过氧化物酶和碱性磷酸酶）的变化，以及补体和免疫相关基因（如C3、F2、溶菌酶C、Toll样受体3、髓样分化因子88、转化生长因子-β、肿瘤坏死因子-α和白细胞介素-15）的显著改变。此外，通过16S rRNA基因高通量测序分析来分析肠道微生物群的组成和多样性。相关性分析表明，变形菌门、放线菌门、厚壁菌门和梭杆菌门的高丰度与口服感染引起的肠炎发病机制有关。京都基因与基因组百科全书（KEGG）富集分析表明，脂肪酸、碳和丙酮酸代谢是显著增加的途径（p<0.05）。据我们所知，这是关于水拉恩氏菌感染鲫鱼的理化性质和肠道微生物群的罕见报道，将为鲤科鱼类细菌性肠炎的临床诊断和预防提供科学参考。
