Saleh Ahmed A, Mohamed Asmaa Z, Elnesr Shaaban S, Khafaga Asmaa F, Elwan Hamada, Abdel-Aziz Mohamed F, Khaled Asmaa A, Hafez Elsayed E
Animal and Fish Production Department, Faculty of Agriculture (Al-Shatby), Alexandria University, Alexandria 11865, Egypt.
Animal and Fish Production Department, Faculty of Agriculture (Saba Basha), Alexandria University, Alexandria 21531, Egypt.
Int J Mol Sci. 2024 Nov 28;25(23):12829. doi: 10.3390/ijms252312829.
Nile tilapia () and European sea bass () are economically significant species in Mediterranean countries, serving essential roles in the aquaculture industry due to high market demand and nutritional value. They experience substantial losses from bacterial pathogens and , particularly at the onset of the summer season. The immune mechanisms involved in fish infections by and remain poorly understood. This study investigated their impact through experiments with control and - and -infected groups for each species. Blood samples were collected at 1, 3, and 7 days post bacterial injection to assess biochemical and immunological parameters, including enzyme activities (AST and ALT), oxidative markers (SOD, GPX, CAT, and MDA), and leukocyte counts. Further analyses included phagocyte activity, lysozyme activity, IgM levels, and complement C3 and C4 levels. Muscle tissues were sampled at 1, 3, and 7 days post injection to assess mRNA expression levels of 18 immune-relevant genes. The focus was on cytokines and immune-related genes, including pro-inflammatory cytokines (, , , , , , and ), major histocompatibility complex components ( and ), cytokine receptors ( and ), antimicrobial peptides ( and ), immune regulatory peptides (, , and ), and Galectins ( and ). was used as the housekeeping gene for normalization. Significant species-specific responses were observed in N. Tilapia and E. Sea Bass when infected with and , highlighting differences in biochemical, immune, and gene expression profiles. Notably, in N. Tilapia, AST levels significantly increased by day 7 during infection, reaching 45.00 ± 3.00 ( < 0.05), indicating late-stage acute stress or tissue damage. Conversely, E. Sea Bass exhibited a significant rise in ALT levels by day 7 in the group, peaking at 33.5 ± 3.20 ( < 0.05), suggesting liver distress or a systemic inflammatory response. On the immunological front, N. Tilapia showed significant increases in respiratory burst activity on day 1 for both pathogens, with values of 0.28 ± 0.03 for and 0.25 ± 0.02 for ( < 0.05), indicating robust initial immune activation. Finally, the gene expression analysis revealed a pronounced peak of in E. Sea Bass by day 7 post infection with a fold change of 6.120, suggesting a strong species-specific pro-inflammatory response strategy. Understanding these responses provides critical insights for enhancing disease management and productivity in aquaculture operations.
尼罗罗非鱼（）和欧洲鲈鱼（）在地中海国家是具有重要经济意义的物种，由于市场需求高和营养价值高，在水产养殖业中发挥着重要作用。它们因细菌病原体和而遭受重大损失，尤其是在夏季开始时。鱼类感染和所涉及的免疫机制仍知之甚少。本研究通过对每个物种的对照组以及感染和的组进行实验，调查了它们的影响。在细菌注射后的第1、3和7天采集血样，以评估生化和免疫参数，包括酶活性（AST和ALT）、氧化标志物（SOD、GPX、CAT和MDA）以及白细胞计数。进一步的分析包括吞噬细胞活性、溶菌酶活性、IgM水平以及补体C3和C4水平。在注射后的第1、3和7天采集肌肉组织样本，以评估18个免疫相关基因的mRNA表达水平。重点是细胞因子和免疫相关基因，包括促炎细胞因子（、、、、、和）、主要组织相容性复合体成分（和）、细胞因子受体（和）、抗菌肽（和）、免疫调节肽（、和）以及半乳糖凝集素（和）。用作标准化的看家基因。在尼罗罗非鱼和欧洲鲈鱼感染和时观察到了显著的物种特异性反应，突出了生化、免疫和基因表达谱的差异。值得注意的是，在尼罗罗非鱼中，在感染期间到第7天时AST水平显著升高，达到45.00±3.00（<0.05），表明处于晚期急性应激或组织损伤状态。相反，在欧洲鲈鱼组中，到第7天时ALT水平显著升高，在33.5±3.20时达到峰值（<0.05），表明肝脏功能紊乱或全身性炎症反应。在免疫方面，尼罗罗非鱼在两种病原体感染的第1天呼吸爆发活性均显著增加，感染时的值为0.28±0.03，感染时的值为0.25±0.02（<0.05），表明初始免疫激活强烈。最后，基因表达分析显示，在欧洲鲈鱼感染后第7天，的表达有一个明显的峰值，变化倍数为6.120，表明有强烈的物种特异性促炎反应策略。了解这些反应为加强水产养殖作业中的疾病管理和提高生产力提供了关键见解。
