Scholarlink

<p>Bacterial pathogens such as <i>Aeromonas hydrophila</i> and <i>Edwardsiella tarda</i> cause major economic losses in Nile tilapia (<i>Oreochromis niloticus</i>) aquaculture. In this study, we developed and evaluated a bivalent injectable vaccine (IPV) to enhance protective immunity against both pathogens using fucoidan as adjuvant. Fish were vaccinated intraperitoneally and boosted at 28&#xa0;days post-vaccination (dpv), followed by immune, biochemical, and challenge studies. The IPV group exhibited the highest survival rates, reaching 83% against <i>E. tarda</i> and 77% against <i>A. hydrophila</i>, significantly higher than other treatments and the non-vaccinated control. Vaccinated fish showed enhanced adaptive responses, with upregulation of immune-related genes (IgM, TCRβ, MHC I, MHC II, IFNγ, IL-8) in spleen and head kidney, indicating both humoral and cellular activation with tissue- and time-dependent dynamics. Serum IgM titres were significantly elevated post-vaccination and further boosted at 35 dpv, correlating with improved survival. Non-specific immune markers, including lysozyme, catalase, superoxide dismutase, and bactericidal activity, were consistently higher in the IPV group, reflecting strengthened innate defense mechanisms. Histopathological analysis of spleen and head kidney demonstrated reduced necrosis and preserved tissue architecture in vaccinated fish, confirming vaccine-mediated protection. Collectively, the bivalent IPV vaccine elicited a broad spectrum of immune responses, integrating antigen-specific and innate defenses, and conferred significant protection against two major bacterial pathogens of tilapia. These findings support the potential of bivalent injectable vaccines as a practical prophylactic strategy to reduce disease outbreaks and antibiotic reliance in commercial tilapia farming.</p>

错误：搜索内容不能为空，请输入英文关键词
错误：关键词超出字数限制，请精简
高级检索

Immunogenicity and protective efficacy of a fucoidan adjuvanted bivalent inactivated vaccine against Aeromonas hydrophila and Edwardsiella tarda infections in Nile tilapia

  • 期刊论文

  • 发表日期：

    2026年1月29日

查看全文
  • Ritam Guha,
  • Preetham Elumalai

摘要

Bacterial pathogens such as Aeromonas hydrophila and Edwardsiella tarda cause major economic losses in Nile tilapia (Oreochromis niloticus) aquaculture. In this study, we developed and evaluated a bivalent injectable vaccine (IPV) to enhance protective immunity against both pathogens using fucoidan as adjuvant. Fish were vaccinated intraperitoneally and boosted at 28 days post-vaccination (dpv), followed by immune, biochemical, and challenge studies. The IPV group exhibited the highest survival rates, reaching 83% against E. tarda and 77% against A. hydrophila, significantly higher than other treatments and the non-vaccinated control. Vaccinated fish showed enhanced adaptive responses, with upregulation of immune-related genes (IgM, TCRβ, MHC I, MHC II, IFNγ, IL-8) in spleen and head kidney, indicating both humoral and cellular activation with tissue- and time-dependent dynamics. Serum IgM titres were significantly elevated post-vaccination and further boosted at 35 dpv, correlating with improved survival. Non-specific immune markers, including lysozyme, catalase, superoxide dismutase, and bactericidal activity, were consistently higher in the IPV group, reflecting strengthened innate defense mechanisms. Histopathological analysis of spleen and head kidney demonstrated reduced necrosis and preserved tissue architecture in vaccinated fish, confirming vaccine-mediated protection. Collectively, the bivalent IPV vaccine elicited a broad spectrum of immune responses, integrating antigen-specific and innate defenses, and conferred significant protection against two major bacterial pathogens of tilapia. These findings support the potential of bivalent injectable vaccines as a practical prophylactic strategy to reduce disease outbreaks and antibiotic reliance in commercial tilapia farming.