Fish & shellfish immunology最新文献_第3页

Antimicrobial peptide mSshep 1 from Sebastes schlegelii combines broad-spectrum antibacterial activity, membrane-disruptive mechanism and in vivo protective efficacy schlegelii的抗菌肽mSshep 1具有广谱抗菌活性、膜破坏机制和体内保护作用。

IF 3.9 2区农林科学 Q1 FISHERIES

Fish & shellfish immunology

Pub Date : 2026-02-04 DOI: 10.1016/j.fsi.2026.111192

Hao Jing , Guang-hua Wang , Kai Yang , Zi-yue Chen , Zhi-shu Zhu , Nuo Sun , Yi-lin Du , Zi-qi Wang , Min Zhang

Hepcidins, a family of cysteine-rich antimicrobial peptides, play a pivotal role in the innate immune defense of teleosts. This study aimed to characterize the antibacterial activity, mechanism of action, and in vitro/in vivo protective efficacy of the mature peptide mSshep 1 derived from hepcidin 1 of Sebastes schlegelii (Sshepcidin 1), and to verify the functional role of Sshepcidin 1 via RNA interference (RNAi). Time-kill kinetic assay showed that mSshep 1 exhibited rapid and broad-spectrum bactericidal activity against Staphylococcus aureus, Edwardsiella piscicida, Listonella anguillarum, and Aeromonas hydrophila, with complete eradication of all tested strains within 120 min. Thermal stability analysis revealed that mSshep 1 retained significant antibacterial activity against most pathogens even after treatment at 100 °C for 30 min, and circular dichroism spectroscopy confirmed only minor conformational changes without substantial secondary structure alterations. Mechanistically, mSshep 1 exerted bactericidal effects by disrupting bacterial membrane integrity, as evidenced by increased propidium iodide penetration, elevated intracellular reactive oxygen species levels, and obvious morphological damage observed via scanning and transmission electron microscopy. In vitro, mSshep 1 showed no cytotoxicity to HEK293T, EPC, and SSI cells at concentrations up to 128 μM, and effectively eliminated intracellular E. piscicida in SSI cells while upregulating the expression of immune-related genes. In vivo experiments demonstrated that pre-injection of mSshep 1 (1, 2, 5 μg/g body weight) significantly improved the survival rate of S. schlegelii challenged with E. piscicida and reduced bacterial loads in the liver, spleen, and head kidney. RNAi analysis showed that si-Sshep1-1 (2 μg/g body weight) stably silenced Sshepcidin 1 expression in multiple tissues, and Sshepcidin 1 knockdown significantly increased bacterial loads in E. piscicida-challenged fish and disrupted the expression balance of immune-related genes. Collectively, these findings confirm that mSshep 1 is a promising candidate for the development of novel antibacterial agents in aquaculture, and Sshepcidin 1 plays a crucial role in the innate immune defense of S. schlegelii against bacterial infections.

Hepcidins是一类富含半胱氨酸的抗菌肽，在硬骨鱼的先天免疫防御中起着关键作用。本研究旨在研究schlegelii的hepcidin 1 （sshepidin 1）衍生的成熟肽msshepid1的抑菌活性、作用机制和体外/体内保护作用，并通过RNA干扰（RNAi）验证sshepidin 1的功能作用。时间杀伤动力学分析表明，msshep1对金黄色葡萄球菌、鱼酸爱德华氏菌、安氏李斯特菌和嗜水气单胞菌具有快速、广谱的杀菌活性，可在120 min内完全杀灭所有被试菌株。热稳定性分析显示，即使在100°C下处理30分钟后，mSshep 1对大多数病原体仍保持显著的抗菌活性，圆二色光谱证实只有轻微的构象变化，没有实质性的二级结构改变。从机理上讲，mSshep 1通过破坏细菌膜的完整性来发挥杀菌作用，这可以通过扫描和透射电镜观察到碘化丙啶渗透增加、细胞内活性氧水平升高以及明显的形态学损伤来证明。在体外实验中，在128 μM浓度下，mSshep 1对HEK293T、EPC和SSI细胞无细胞毒性，并能有效清除SSI细胞内的淡鱼绦虫，同时上调免疫相关基因的表达。体内实验表明，预注射msshep1（1、2、5 μg/g体重）可显著提高施勒格氏梭菌受鱼酸梭菌攻击后的存活率，降低肝脏、脾脏和头肾的细菌负荷。RNAi分析显示，si-Sshep1-1 （2 μg/g体重）在多种组织中稳定地沉默了Sshepcidin 1的表达，敲低Sshepcidin 1显著增加了piscicida侵染鱼体内的细菌负荷，破坏了免疫相关基因的表达平衡。综上所述，这些发现证实了msshepcidin 1是开发水产养殖新型抗菌药物的一个有希望的候选药物，并且Sshepcidin 1在schlegelii对细菌感染的先天免疫防御中起着至关重要的作用。

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引用次数: 0

Bivalent inactivated whole cell vaccine confers protection against Aeromonas jandaei and Edwardsiella tarda in oscar fish (Astronotus ocellatus) 双价灭活全细胞疫苗对奥斯卡鱼（astrootus ocellatus）的詹氏气单胞菌和迟缓爱德华菌具有保护作用。

IF 3.9 2区农林科学 Q1 FISHERIES

Fish & shellfish immunology

Pub Date : 2026-02-04 DOI: 10.1016/j.fsi.2026.111190

Qurat Ul Ain , Arun Sudhagar , Sagar Gorakh Satkar , Arathi Dharmaratnam , Gayatree Behera , Anutosh Paria , Mattalakkal Unnikrishnan Rekha , Thipramalai Thangappan Ajith Kumar

In recent years, multiple pathogenic organisms have been isolated from diseased fish, highlighting the need for combination vaccines to prevent infections caused by various pathogens. This study presents a comparative evaluation of heat- and formalin-inactivated bivalent vaccines targeting Aeromonas jandaei and Edwardsiella tarda tested in Oscar fish (Astronotus ocellatus). Formalin and heat-inactivated vaccines were prepared after optimizing the inactivation conditions. A concentration of 0.3% formalin applied overnight was optimal for formalin inactivation, while heating at 70 °C for 1 h was suitable for heat inactivation. After a combined bacterial challenge 12 weeks from the primary dose, the relative percentage survival (RPS) was 92.6% for the formalin-inactivated vaccine (VFI) and 82.5% for the heat-inactivated vaccine (VHI), indicating strong protective efficacy. Biochemical analysis showed that the vaccinated groups had significantly lower glutamic oxaloacetic transaminase (GOT) and glutamate pyruvic transaminase (GPT) levels post-infection, while oxidative stress assessment revealed enhanced antioxidant defence in the vaccinated fish, with catalase activity peaking on the 2nd dpc in the VFI group. Immune-related gene expression analysis (IgM-H, IL-8, MHC-IIα, and CC-1) revealed significantly higher expression levels in the vaccinated groups than in the control group. Additionally, specific serum antibody against both A. jandaei and E. tarda were significantly elevated in the vaccinated groups compared to those in the controls. The highest anti-A. jandaei antibodies occurred in week 5 after the final booster in both the VFI and VHI groups, whereas anti-E. tarda antibodies peaked in week 4 after the final booster, underscoring the vaccine's robust humoral immune response. Overall, this study demonstrated that both inactivated bivalent vaccines (VFI and VHI) effectively stimulated immune responses in Oscar fish. However, VFI exhibited a slightly superior performance compared to VHI in terms of survival, protective efficacy, and enhanced immune responses against both A. jandaei and E. tarda.

近年来，从病鱼中分离出多种致病生物，这突出表明需要联合疫苗来预防各种病原体引起的感染。本研究介绍了在奥斯卡鱼（astrootus ocellatus）中进行的针对詹氏气单胞菌和迟发爱德华菌的热灭活和福尔马林灭活二价疫苗的比较评价。优化灭活条件，制备福尔马林和热灭活疫苗。使用浓度为0.3%的福尔马林过夜可使福尔马林失活，而在70°C下加热1小时可使福尔马林失活。经首次给药后12周的联合细菌攻击，福尔马林灭活疫苗（VFI）的相对存活率（RPS）为92.6%，热灭活疫苗（VHI）的相对存活率（RPS）为82.5%，显示出较强的保护效果。生化分析显示，接种组感染后谷草酰乙酸转氨酶（GOT）和谷氨酸丙酮转氨酶（GPT）水平显著降低，而氧化应激评估显示，接种组的抗氧化防御能力增强，过氧化氢酶活性在第2天达到峰值。免疫相关基因表达分析（IgM-H、IL-8、mhc - i α和CC-1）显示，接种疫苗组的表达水平显著高于对照组。此外，与对照组相比，接种疫苗组中针对詹氏易歧杆菌和迟达易歧杆菌的特异性血清抗体显著升高。最高的反a。VFI组和VHI组在最后一次增强剂后第5周均出现jandaei抗体。Tarda抗体在最后一次加强后的第4周达到峰值，强调了疫苗强大的体液免疫反应。总之，本研究表明，两种灭活双价疫苗（VFI和VHI）都能有效刺激奥斯卡鱼的免疫反应。然而，与VHI相比，VFI在存活、保护功效和增强对詹达梭菌和迟达梭菌的免疫反应方面表现出略优于VHI的性能。

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引用次数: 0

Integrated mortality rates and transcriptome comparative analysis between wild and artificially selected ark shell (Scapharca subcrenata) populations in response to Vibrio anguillarum infection 对鳗弧菌感染的综合死亡率和人工选择方舟壳（Scapharca subcrenata）种群转录组比较分析

IF 3.9 2区农林科学 Q1 FISHERIES

Fish & shellfish immunology

Pub Date : 2026-02-04 DOI: 10.1016/j.fsi.2026.111182

Peizhen Tian , Yanming Su , XingLei Wang , Feng Wang , Bo Liu , Yuming Zhao

The survival ability of artificially selected ark shells (Scapharca subcrenata) and wild populations was assessed under different combinations of temperatures (25, 27, 29, and 31 °C) and Vibrio anguillarum immersion concentrations (0, 3 × 10⁸, 6 × 10⁸, 9 × 10⁸, 12 × 10⁸, 15 × 10⁸, and 18 × 10⁸ CFU/mL). Significant differences in mortality rates between the two ark shell populations were observed across most temperature and immersion concentration combinations, with only a few exceptions. The gene expression profiles of selected and wild ark shells were analyzed through transcriptome sequencing following exposed to 1 × 10⁸ CFU/mL of V. anguillarum strain PL2. Gene Ontology (GO) functional classification of the 1558 differentially expressed genes (DEGs) common to the three comparisons revealed that ‘cellular process’, ‘membrane’ and ‘binding’ were the most enriched terms across the biological process, cellular component, and molecular function categories in the D (treated wild ark shells) _vs_C (Untreated wild ark shells were used as the control group) and KD (treated selectively bred ark shells) _vs_D groups. COG analysis reveals that the ‘Energy Production and Conversion’ category is significantly downregulated in the KD_vs_D comparison compared to the D_vs_C and C_vs_KD comparisons. Heatmap visualization of DEGs across C, D, and KD groups showed numerous genes exhibiting inverse expression trends among the groups. Among the top 10 KEGG pathways identified across the three comparison groups, no pathways were shared between the KD_vs_D group and the other two comparisons, suggesting that these pathways may be related to the resistance of ark shells to V. anguillarum. Our study indicates that ark shell populations selected under high-intensity environmental stress exhibit greater tolerance to elevated temperatures and V. anguillarum. This further demonstrates that selecting ark shells under stress conditions may enhance their survival rates in aquaculture. These findings will deepen the understanding of bivalve adaptability to environmental changes and aid in the advancement of shellfish aquaculture practices.

在不同温度（25、27、29、31℃）和鳗弧菌浸泡浓度（0、3 × 108、6 × 108、9 × 108、12 × 108、15 × 108、18 × 108 CFU/mL）组合下，对人工选择的方舟壳（Scapharca subcrenata）及其野生种群的生存能力进行了评价。在大多数温度和浸泡浓度组合中，观察到两种方舟壳种群之间的死亡率存在显著差异，只有少数例外。通过转录组测序分析了暴露于1 × 108 CFU/mL的V. anguillarum菌株PL2的方舟壳和野生方舟壳的基因表达谱。对三个比较共有的1558个差异表达基因（DEGs）的基因本体（GO）功能分类显示，在D（处理过的野生方舟壳）_vs_C（未处理的野生方舟壳作为对照组）和KD（处理过的选择性繁殖的方舟壳）_vs_D组中，“细胞过程”、“膜”和“结合”是生物过程、细胞成分和分子功能类别中最丰富的术语。COG分析显示，与D_vs_C和C_vs_KD比较相比，KD_vs_D比较中的“能量生产和转换”类别明显下调。在C、D和KD组之间的热图可视化显示，许多基因在组间表现出相反的表达趋势。在3个对照组中鉴定出的前10条KEGG通路中，KD_vs_D组与其他2个对照组之间没有共享的通路，提示这些通路可能与方舟壳对鳗鲡的抗性有关。本研究表明，在高强度环境胁迫下选择的方舟壳种群对高温和鳗鲡的耐受性更强。这进一步说明在逆境条件下选择方舟壳可以提高其在水产养殖中的存活率。这些发现将加深对双壳类对环境变化适应性的理解，并有助于推进贝类养殖实践。

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引用次数: 0

Evaluation of the immunoprotective effects of two Infectious Spleen and Kidney Necrosis Virus (ISKNV) oral vaccines on largemouth bass 两种传染性脾肾坏死病毒（ISKNV）口服疫苗对大口黑鲈免疫保护作用的评价。

IF 3.9 2区农林科学 Q1 FISHERIES

Fish & shellfish immunology

Pub Date : 2026-02-04 DOI: 10.1016/j.fsi.2026.111189

Xuan Zhang , Yunshang Ning , Zengjian Liang , Jinqiao Cao , Tao Xu , Jiayi Luo , Zemiao Zhang , Yingjing Chen , Jingguang Wei , Qiwei Qin , Sumei Xiao , Sheng Zhou

The high pathogenicity and mortality rate of infectious spleen and kidney necrosis virus (ISKNV) have significantly threatened the development of largemouth bass aquaculture in China. Oral vaccines are urgently needed in the aquaculture industry. This study successfully constructed recombinant strains EBY100/pYD1-ISKNV and WB600/pEB03-CotC-ISKNV that can express ISKNV MCP using surface display platforms of Saccharomyces cerevisiae and Bacillus subtilis. Oral immunization of largemouth bass was conducted to evaluate the protective efficacy of both oral vaccines. Following oral immunization, the relative expression levels of IFN-γ, TNF-α, IL-1, CD8α, MHC-Ⅰ, IgM, and IgT in the spleen and head kidney tissues of largemouth bass and serum-specific antibody levels in the E-I and W-I groups were significantly higher compared to the PBS group. Following ISKNV challenge, the survival rate of the E-I group and W-I group were 53.3 % and 50.0 %, respectively, with the relative percent survival (RPS) of 30.0 % and 25.0 %. Viral load detection revealed significantly lower viral loads in the E-I and W-I groups compared to the PBS group. Histopathological examination of tissue sections revealed that no obvious lesions were observed in the liver, spleen, and head kidney of largemouth bass immunized with either oral vaccine compared to the PBS group that exhibited severe lesions in the liver, spleen, and head kidney. In summary, oral administration of EBY100/pYD1-ISKNV and WB600/pEB03-CotC-ISKNV activated both innate and adaptive immune responses in largemouth bass, demonstrating efficacy in preventing ISKNV infection. The two oral vaccines developed in this study provide novel strategies for controlling ISKNV.

传染性脾肾坏死病毒（ISKNV）的高致病性和高致死率严重威胁着中国大口黑鲈养殖业的发展。水产养殖业迫切需要口服疫苗。本研究利用酿酒酵母和枯草芽孢杆菌的表面展示平台，成功构建了表达ISKNV MCP的重组菌株EBY100/pYD1-ISKNV和WB600/pEB03-CotC-ISKNV。对大口黑鲈进行口服免疫，评价两种口服疫苗的保护效果。口服免疫后，E-I组和W-I组大口黑鲈脾脏和头肾组织中IFN-γ、TNF-α、IL-1、CD8α、MHC-Ⅰ、IgM、IgT的相对表达量和血清特异性抗体水平均显著高于PBS组。ISKNV攻毒后，E-I组和W-I组的存活率分别为53.3%和50.0%，相对存活率（RPS）分别为30.0%和25.0%。病毒载量检测显示，与PBS组相比，E-I组和W-I组的病毒载量显著降低。组织切片的组织病理学检查显示，与PBS组相比，口服疫苗免疫的大口黑鲈的肝脏、脾脏和头部肾脏均未见明显病变，而PBS组的肝脏、脾脏和头部肾脏均出现严重病变。综上所述，口服EBY100/pYD1-ISKNV和WB600/pEB03-CotC-ISKNV激活了大口黑鲈的先天和适应性免疫反应，显示出预防ISKNV感染的效果。本研究开发的两种口服疫苗为控制ISKNV提供了新的策略。

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引用次数: 0

Fish Meteorin-like factor promotes migration, proliferation and phagocytic activity of monocytes/macrophages 鱼流星蛋白样因子促进单核/巨噬细胞的迁移、增殖和吞噬活性。

IF 3.9 2区农林科学 Q1 FISHERIES

Fish & shellfish immunology

Pub Date : 2026-02-04 DOI: 10.1016/j.fsi.2026.111193

Yueshuang Ji , Yinghao Huang , Shengbin Lu , Weihua Zhao , Liwen Zhu , Wa Gao , Jianhua Feng , Gaoliang Yuan , Jun Zou , Junya Wang

Meteorin-like (Metrnl) is a cytokine known to play multifunctional roles in mammalian immunity, yet its immunoregulatory role in teleost remains largely unexplored. In the present study, we systematically investigate the effects of Metrnl on primary monocytes/macrophages (Mo/Mφ) in grass carp (Ctenopharyngodon idella). In vitro, Metrnl significantly increased the viability of primary Mo/Mφ, with increases of 12.7% on day 3 and 7.9% on day 6, as determined by flow cytometric quantification of MCSFR⁺ cells across multiple biological replicates. Furthermore, Metrnl stimulation promoted Mo/Mφ proliferation and phagocytic activity, resulting in absolute increases of 12.43% and 16.86%, respectively, calculated as the proportion of EdU⁺MCSFR⁺ or Beads⁺MCSFR⁺ cells within the total MCSFR⁺ population. Consistent with these findings, in vivo experiments using a Metrnl-expressing plasmid demonstrated enhanced Mo/Mφ proliferation and phagocytosis. Moreover, Metrnl also significantly upregulated the mRNA levels of the chemokines Cxcl8 and Cxcl11.1b, indicating its ability to recruit Mo/Mφ to target sites by activating chemokine-mediated chemotactic signaling. Importantly, neutralization of Metrnl with a specific antibody markedly impaired the enhanced Mo/Mφ recruitment, proliferation and phagocytosis, confirming that the effect is specifically mediated by Metrnl. Our results demonstrate that Metrnl acts as an important regulatory factor that activates and enhances Mo/Mφ-mediated innate immune response.

Meteorin-like （Metrnl）是一种已知在哺乳动物免疫中发挥多功能作用的细胞因子，但其在硬骨鱼中的免疫调节作用仍未被充分研究。在本研究中，我们系统地研究了Metrnl对草鱼原代单核/巨噬细胞（Mo/Mφ）的影响。在体外，通过对MCSFR+细胞进行多个生物重复的流式细胞术定量检测，Metrnl显著提高了原代Mo/Mφ的活力，第3天提高了12.7%，第6天提高了7.9%。此外，以EdU+MCSFR+或Beads+MCSFR+细胞占MCSFR+总细胞群的比例计算，Metrnl刺激可促进Mo/Mφ增殖和吞噬活性，绝对增幅分别为12.43%和16.86%。与这些发现一致，使用表达metrnl的质粒进行的体内实验表明，Mo/Mφ的增殖和吞噬作用增强。此外，Metrnl还显著上调趋化因子Cxcl8和Cxcl11.1b的mRNA水平，表明其能够通过激活趋化因子介导的趋化信号通路将Mo/Mφ募集到靶点。重要的是，用一种特异性抗体中和Metrnl可显著削弱增强的Mo/Mφ募集、增殖和吞噬作用，证实了这种作用是由Metrnl特异性介导的。我们的研究结果表明，Metrnl是激活和增强Mo/ m φ介导的先天免疫应答的重要调控因子。

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引用次数: 0

IL-7 enhances the protective efficacy of inactivated grass carp reovirus vaccine as adjuvant in grass carp (Ctenopharyngodon idella) IL-7增强了草鱼呼肠孤病毒灭活苗佐剂对草鱼的保护作用。

IF 3.9 2区农林科学 Q1 FISHERIES

Fish & shellfish immunology

Pub Date : 2026-02-03 DOI: 10.1016/j.fsi.2026.111183

Shijie Wang , Yizhong Lu , Yuezong Xu , Guanyu Chen , Jingjing Zhang , Jianguo Su , Chunrong Yang

Grass carp reovirus (GCRV) causes severe hemorrhagic disease and significant threat to grass carp (Ctenopharyngodon idella) aquaculture. Although inactivated vaccines are commonly used, their limited protective efficacy necessitates effective adjuvants. In this study, recombinant grass carp interleukin-7 (rIL-7) and its enterokinase-cleaved form (EK rIL-7), obtained by removing the fusion tag using enterokinase, were successfully expressed, purified, and evaluated as adjuvants for an inactivated GCRV vaccine. Following GCRV challenge, both rIL-7 adjuvanted and EK rIL-7 adjuvanted vaccines significantly increased the survival of grass carp and effectively suppressed viral replication in the head kidney and spleen. Histopathological examination further confirmed that fish in the IL-7 adjuvant exhibited significantly reduced tissue damage compared to other treatments. Additionally, IL-7 enhanced both innate and adaptive immune responses in grass carp. The activities of serum enzymes (SOD, LDH and LZM) in the groups receiving IL-7 in combination with the vaccine increased significantly, reflecting the enhancement of antioxidant capacity and non-specific immune defense ability. In parallel, IL-7 treatment promoted IgM synthesis at both the transcriptional and serum antibody levels and increased the expression of immune-related genes such as CD4(-1, −2), MHCII (α, β), IFN-γ2, and IL-1β, indicating the activation of both humoral and cellular immune pathways. However, the difference between EK rIl-7 and rIl-7 is not significant. Collectively, these findings demonstrate that IL-7 acts as a potent adjuvant to enhance the protective efficacy of inactivated GCRV vaccines, and provide valuable insights for exploring other cytokines as immune adjuvants in the prevention of viral diseases in aquaculture.

草鱼呼肠孤病毒（GCRV）对草鱼养殖业造成严重的出血性疾病和重大威胁。虽然通常使用灭活疫苗，但其有限的保护功效需要有效的佐剂。在本研究中，利用肠激酶去除融合标签获得重组草鱼白细胞介素-7 （il -7）及其肠激酶裂解形式（EK il -7），成功表达、纯化并评估其作为GCRV灭活疫苗的佐剂。在GCRV攻毒后，il -7佐剂疫苗和EK il -7佐剂疫苗均能显著提高草鱼的存活率，并有效抑制病毒在头肾和脾脏中的复制。组织病理学检查进一步证实，与其他处理相比，IL-7佐剂对鱼的组织损伤明显减轻。此外，IL-7还能增强草鱼的先天免疫和适应性免疫反应。IL-7联合疫苗组血清SOD、LDH和LZM酶活性显著升高，反映了抗氧化能力和非特异性免疫防御能力的增强。与此同时，IL-7处理在转录和血清抗体水平上促进了IgM的合成，并增加了免疫相关基因如CD4（-1, -2）、MHCII （α, β）、IFN-γ2和IL-1β的表达，表明激活了体液和细胞免疫途径。然而，EK il-7和il-7之间的差异不显著。总之，这些研究结果表明，IL-7作为一种有效的佐剂可以增强灭活GCRV疫苗的保护效果，并为探索其他细胞因子作为免疫佐剂预防水产养殖业病毒性疾病提供了有价值的见解。

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引用次数: 0

Effects of dietary fermented sugar kelp (Saccharina latissima) on intestinal histology, antioxidant capacity, and immune-related biomarkers of post-smolt Atlantic salmon (Salmo salar ). 饲粮中添加发酵海带对大西洋鲑鱼肠道组织学、抗氧化能力和免疫相关生物标志物的影响

IF 3.9 2区农林科学 Q1 FISHERIES

Fish & shellfish immunology

Pub Date : 2026-02-03 DOI: 10.1016/j.fsi.2026.111179

Sahar Sartipiyarahmadi, Ingvild Lunderød Øverbø, Benjamin Costas, Lourenço Ramos-Pinto, Nina S Liland, Harald Sveier, Silje Steinsund, Tom Johnny Hansen, Øivind Strand, Jan Vidar Jakobsen, Antony J Prabhu Philip, Sofie C Remø

Brown seaweeds such as sugar kelp (Saccharina latissima) are rich in bioactive compounds with potential health benefits for fish. This study evaluated the effects of dietary fermented sugar kelp (FSK) on mid-intestinal histology, antioxidant biomarkers, and immune response in post-smolts Atlantic salmon (Salmo salar). A total of 975 fish (204 ± 37 g) were allocated across 15 tanks and fed one of five isonitrogenous (≈45% crude protein) diets containing 0-4% FSK for 10 weeks. Plasma, liver, muscle, and mid-intestine samples were analyzed for histological and biochemical parameters at the end of the trial. FSK inclusion up to 4% had no adverse effects on mid-intestinal morphology or signs of inflammation. Liver antioxidant capacity was modulated, with significantly higher glutathione (GSH) concentrations and lower malondialdehyde (MDA) levels in FSK 4%-fed groups compared to the control. However, no changes were observed in muscle or intestinal antioxidant levels. Immune-related parameters were also modulated: plasma lysozyme activity doubled at 1% and 3% FSK, and plasma bactericidal activity more than doubled at 3% FSK compared to the control group. Antiprotease activity increased dose-dependently, although plasma peroxidase activity and IgM levels declined slightly. Overall, dietary FSK up to 4% does not alter mid-intestine morphology or induce inflammation. Additionally, it shows potential functional effects in fish, including the modulation of hepatic antioxidant capacity and innate-immune mechanisms, particularly antibacterial effects. These findings support further investigation into the functional use of seaweed-derived ingredients in aquafeeds. The study design and main findings are provided in a graphical abstract (Figure 1).

褐海藻，如糖海带（Saccharina latissima）富含生物活性化合物，对鱼类有潜在的健康益处。本研究评估了饲粮中添加发酵糖海带（FSK）对大西洋鲑鱼（Salmo salar）幼鱼中肠组织学、抗氧化生物标志物和免疫反应的影响。共975尾鱼（204±37 g）分配在15个水族箱中，分别饲喂含0-4% FSK的5种等氮（≈45%粗蛋白质）饲料中的一种，为期10周。在试验结束时，对血浆、肝脏、肌肉和中肠样本进行组织学和生化参数分析。FSK掺入高达4%对中肠形态或炎症症状没有不良影响。肝脏抗氧化能力受到调节，与对照组相比，4% FSK饲喂组的谷胱甘肽（GSH）浓度显著升高，丙二醛（MDA）水平显著降低。然而，肌肉或肠道抗氧化剂水平没有变化。免疫相关参数也得到了调节：与对照组相比，血浆溶菌酶活性在1%和3% FSK下翻了一番，血浆杀菌活性在3% FSK下翻了一番以上。抗蛋白酶活性呈剂量依赖性增加，血浆过氧化物酶活性和IgM水平略有下降。总的来说，饮食中FSK高达4%不会改变中肠形态或诱导炎症。此外，它在鱼类中显示出潜在的功能作用，包括调节肝脏抗氧化能力和先天免疫机制，特别是抗菌作用。这些发现支持进一步研究海藻衍生成分在水产饲料中的功能用途。研究设计和主要发现以图形摘要形式提供（图1）。

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引用次数: 0

The role of VxrB in Vibrio harveyi and evaluation of a VxrB knock-out as a vaccine candidate VxrB在哈维弧菌中的作用及VxrB敲除作为候选疫苗的评价

IF 3.9 2区农林科学 Q1 FISHERIES

Fish & shellfish immunology

Pub Date : 2026-02-03 DOI: 10.1016/j.fsi.2026.111186

Yinhui Peng , Xin Lu , Ming Liu , Shuo Hu , Lulu Liu , Renjie Li , LuJia Yang , Xiaohui Cai , Shuanghu Cai

Vibrio harveyi is a major bacterial pathogen in marine aquaculture and can cause serious disease outbreaks in fish and invertebrates. Two-component systems help bacteria sense environmental change and adjust gene expression, including genes linked to virulence. VxrB is a response regulator that has been connected to virulence control in other Vibrio species, but its role in V. harveyi is not well defined. In this study, we deleted VxrB in a virulent V. harveyi strain and named the mutant VHΔVxrB. We compared it with the wild-type strain (W-VH) using in vitro assays, gene expression analysis, and infection and vaccination tests in pearl gentian grouper. Deleting VxrB did not change cell morphology by Gram staining or scanning electron microscopy. However, VHΔVxrB grew more slowly and showed reduced hemolytic activity, while swarming motility increased. RT-qPCR showed that VxrB deletion reduced expression of several virulence-associated genes and lowered expression of the type VI secretion system (T6SS) genes hcp and vgrG. In fish, VHΔVxrB was less virulent than W-VH, with an LD50 of 1.45 × 10⁸ CFU/mL compared with 4.88 × 10⁷ CFU/mL for the wild type. We also tested VHΔVxrB as a live attenuated vaccine. Vaccinated fish had higher survival after homologous challenge, with an RPS of 68.75%, and showed no obvious histopathological lesions. Vaccination increased spleen expression of mhc-Iα, myd88, and il-10. Together, these results show that VxrB supports virulence-related programs in V. harveyi and that VHΔVxrB is a promising attenuated vaccine candidate for pearl gentian grouper.

哈韦氏弧菌是海洋水产养殖中的一种主要细菌病原体，可引起鱼类和无脊椎动物的严重疾病暴发。双组分系统帮助细菌感知环境变化并调节基因表达，包括与毒力相关的基因。VxrB是一种反应调节因子，与其他弧菌物种的毒力控制有关，但其在哈维弧菌中的作用尚不明确。在这项研究中，我们在一株强毒的哈维氏V.菌株中删除了VxrB，并将其命名为VHΔVxrB。我们将其与野生型菌株（W-VH）进行了体外实验、基因表达分析、感染和接种试验。通过革兰氏染色和扫描电镜观察，删除VxrB未改变细胞形态。然而，VHΔVxrB生长较慢，溶血活性降低，而蜂群运动性增加。RT-qPCR结果显示，VxrB缺失降低了多个毒力相关基因的表达，降低了VI型分泌系统（T6SS）基因hcp和vgrG的表达。在鱼类中，VHΔVxrB的毒性低于W-VH，其LD50为1.45×108 CFU/mL，而野生型为4.88×107 CFU/mL。我们还测试了VHΔVxrB作为减毒活疫苗。免疫后的鱼在同源攻毒后存活率较高，RPS为68.75%，且未出现明显的组织病理学病变。接种疫苗可增加脾脏mhc-Iα、myd88和il-10的表达。总之，这些结果表明VxrB支持V. harveyi的毒力相关程序，并且VHΔVxrB是一种有希望的珍珠龙胆石斑鱼减毒候选疫苗。

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引用次数: 0

Mechanisms underlying differential utilization of carbohydrates from diverse structures and sources in Nile tilapia (Oreochromis niloticus): Insights from glycolipid metabolism, protein deposition and liver health 尼罗罗非鱼（Oreochromis niloticus）对不同结构和来源的碳水化合物的差异利用机制：来自糖脂代谢、蛋白质沉积和肝脏健康的见解。

IF 3.9 2区农林科学 Q1 FISHERIES

Fish & shellfish immunology

Pub Date : 2026-02-03 DOI: 10.1016/j.fsi.2026.111187

Meng-Ting Liu , Chen-Chen Wu , Si-Miao Pan , Samwel Mchele Limbu , Yu-Yang Liang , Ying-Man Yu , Fang Qiao , Mei-Ling Zhang , Zhen-Yu Du , Yuan Luo

The proper structure and source of dietary carbohydrates are vital for farmed fish health, yet their metabolic responses to varied carbohydrates are not clear. To explore fish metabolic responses to varied carbohydrates, Nile tilapia was fed with five different carbohydrate diets for eight weeks. The results showed that polysaccharides significantly enhanced the growth performance of fish (P < 0.05). The fish fed with polysaccharides showed lower serum glucose, pyruvate and lactate, while their liver glucose uptake and catabolic capacity were significantly enhanced (P < 0.05). Furthermore, the PDK4-PDHE1α axis, which linked glycolysis to the TCA cycle, exhibited a stronger response to polysaccharides, particularly in the corn starch group. The total lipid of the whole fish, as well as the TG in the liver and serum, were significantly elevated in the fish fed with wheat and tapioca starch (P < 0.05). Additionally, the fish fed with wheat and tapioca starch exhibited a significant higher expression of PPARγ, DGAT and FAS (P < 0.05). The serum levels of AST and ALT, as well as the liver MDA content, significantly decreased in the fish fed with polysaccharides (P < 0.05). Meanwhile, the expression levels of pro-inflammatory (TNFα and IL12) and apoptosis (caspase8 and caspase9) -related genes in the liver were significantly downregulated, while the antioxidant capacity markedly increased (P < 0.05). The total protein of the whole fish, muscle protein content, and muscle fiber diameter of fish fed polysaccharides were significantly increased, particularly in the corn starch group (P < 0.05). Furthermore, the fish fed with polysaccharides exhibited stronger mTOR signaling response and higher protein synthesis capacity in the muscle, particularly in the corn starch group (P < 0.05). This study demonstrated that the PDK4-PDHE1α axis and mTOR exhibit a stronger response to polysaccharides, boosting carbohydrate breakdown and protein synthesis for growth. PPARγ responds more robustly to wheat and tapioca starch, facilitating the esterification of free fatty acids into TG, which reduced lipid toxicity and maintained liver health.

膳食碳水化合物的适当结构和来源对养殖鱼类的健康至关重要，但它们对不同碳水化合物的代谢反应尚不清楚。为了探索鱼类对不同碳水化合物的代谢反应，研究人员用5种不同的碳水化合物饲料喂养尼罗罗非鱼8周。结果表明，多糖显著提高了鱼的生长性能（P < 0.05）。饲粮中添加多糖显著降低了血清葡萄糖、丙酮酸和乳酸含量，显著提高了肝脏葡萄糖摄取和分解代谢能力（P < 0.05）。此外，连接糖酵解与TCA循环的PDK4-PDHE1α轴对多糖表现出更强的响应，特别是在玉米淀粉组。小麦淀粉和木薯淀粉显著提高了全鱼的总脂质、肝脏和血清中的TG （P < 0.05）。此外，小麦和木薯淀粉饲料显著提高了PPARγ、DGAT和FAS的表达量（P < 0.05）。添加多糖显著降低了血清AST、ALT水平和肝脏MDA含量（P < 0.05）。肝脏促炎基因（TNFα、il - 12）和凋亡基因（caspase8、caspase9）表达水平显著下调，抗氧化能力显著增强（P < 0.05）。全鱼总蛋白、肌肉蛋白含量和肌纤维直径均显著提高，以玉米淀粉组显著提高（P < 0.05）。此外，以玉米淀粉组的mTOR信号响应更强，肌肉蛋白质合成能力更高（P < 0.05）。该研究表明，PDK4-PDHE1α轴和mTOR对多糖的反应更强，促进了碳水化合物的分解和蛋白质的合成。PPARγ对小麦和木薯淀粉反应更强，促进游离脂肪酸酯化成TG，从而减少脂质毒性并维持肝脏健康。

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引用次数: 0

Single-cell RNA-seq reveals cellular dynamics and emergency hematopoiesis in banana shrimp Penaeus merguiensis hemocytes upon Yellow Head Virus infection 单细胞RNA-seq揭示了黄头病毒感染后香蕉对虾血细胞的细胞动力学和紧急造血功能。

IF 3.9 2区农林科学 Q1 FISHERIES

Fish & shellfish immunology

Pub Date : 2026-02-02 DOI: 10.1016/j.fsi.2026.111178

Keiichiro Koiwai , Phattarunda Jaree , Kanjanaporn Nanthajak , Masachika Harada , Hiroki Kusaka , Ammara Sinprasertporn , Hajime Yuasa , Kayo Konishi , Reiko Nozaki , Hidehiro Kondo , Jumroensri Thawonsuwan , Kunlaya Somboonwiwat , Ikuo Hirono

As global aquaculture of penaeid shrimp expands, the banana shrimp (Penaeus merguiensis) has gained attention as a promising sustainable alternative to the non-native P. vannamei. However, its cellular immune response to major pathogens like yellow head virus (YHV) remains poorly understood, limiting effective disease management. In this study, we established a comprehensive reference transcriptome for P. merguiensis by integrating data from 13 major tissues and conducted single-cell RNA sequencing (scRNA-seq) on hemocytes under normal and YHV-infected conditions. We identified eight distinct hemocyte clusters (cluster 0–7) and demonstrated that YHV infection triggers a massive turnover of the hemocyte landscape. Specifically, mature immune-active clusters expressing anti-lipopolysaccharide factors (ALFs) and lysozymes were significantly depleted, likely due to virus-induced apoptosis. Conversely, a marked expansion of an immature hemocyte progenitor cluster (cluster 4) was observed, indicating a host-driven emergency hematopoiesis response. Our analysis further revealed that global transcriptional changes are heavily biased by these composition shifts: 30.7% of the total 114 globally regulated genes were identified as cluster-specific markers. These findings provide a high-resolution model of crustacean immune dynamics and highlight the necessity of single-cell analysis for accurately deciphering host-pathogen interactions.

随着全球对虾养殖规模的扩大，香蕉对虾（Penaeus merguiensis）作为一种有前途的可持续替代非本土南美对虾（P. vannamei）受到了关注。然而，其对黄头病毒（YHV）等主要病原体的细胞免疫反应仍然知之甚少，限制了有效的疾病管理。在本研究中，我们整合了13个主要组织的数据，建立了merguiensis的综合参考转录组，并对正常和yhv感染条件下的血细胞进行了单细胞RNA测序（scRNA-seq）。我们确定了8个不同的血细胞簇（簇0-7），并证明YHV感染引发了血细胞景观的大量周转。具体来说，表达抗脂多糖因子（ALFs）和溶菌酶的成熟免疫活性簇明显减少，可能是由于病毒诱导的细胞凋亡。相反，观察到未成熟血细胞祖细胞集群（集群4）的显著扩增，表明宿主驱动的紧急造血反应。我们的分析进一步表明，全球转录变化受到这些组成变化的严重偏倚：114个全球调控基因中有30.7%被确定为集群特异性标记。这些发现提供了甲壳类动物免疫动力学的高分辨率模型，并强调了准确破译宿主-病原体相互作用的单细胞分析的必要性。

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引用次数: 0