Mohd Ali Nur Shidaa, Saad Mohd Zamri, Azmai Mohammad Noor Amal, Salleh Annas, Zulperi Zarirah Mohamed, Manchanayake Tilusha, Zahaludin Muhammad Amir Danial, Basri Lukman, Mohamad Aslah, Md Yasin Ina Salwany
Laboratory of Aquatic Animal Health and Therapeutics, Institute of Bioscience, Universiti Putra Malaysia, Serdang 43400, Selangor, Malaysia.
Department of Biology, Faculty of Science, Universiti Putra Malaysia, Serdang 43400, Selangor, Malaysia.
Animals (Basel). 2023 Apr 14;13(8):1346. doi: 10.3390/ani13081346.
Streptococcosis and motile Aeromonad septicemia (MAS) are the main bacterial diseases in tilapia culture worldwide, causing significant economic losses. Vaccination is an effective method of preventing diseases and contributes to economic sustainability. This study investigated the immuno-protective efficacy of a newly developed feed-based bivalent vaccine against streptococcosis and MAS in red hybrid tilapia. The feed-based bivalent vaccine pellet was developed by incorporating the formalin-killed and antigens into a commercial feed pellet with palm oil as the adjuvant. The bivalent vaccine was subjected to feed quality analyses. For immunological analyses, 900 fish (12.94 ± 0.46 g) were divided into two treatment groups in triplicate. Fish in Group 1 were unvaccinated (control), while those in Group 2 were vaccinated with the bivalent vaccine. The bivalent vaccine was delivered orally at 5% of the fish's body weight for three consecutive days on week 0, followed by boosters on weeks 2 and 6. Lysozyme and enzyme-linked immunosorbent assays (ELISAs) on serum, gut lavage, and skin mucus were performed every week for 16 weeks. Lysozyme activity in vaccinated fish was significantly ( ≤ 0.05) higher than in unvaccinated fish following vaccination. Similarly, the IgM antibody levels of vaccinated fish were significantly ( ≤ 0.05) higher after vaccination. The bivalent vaccine provided high protective efficacy against (80.00 ± 10.00%) and (90.00 ± 10.00%) and partial cross-protective efficacy against (63.33 ± 5.77%) and (60.00 ± 10.00%). During the challenge test, fewer clinical and gross lesions were observed in vaccinated fish compared with unvaccinated fish. Histopathological assessment showed less severe pathological changes in selected organs than the unvaccinated fish. This study showed that vaccination with a feed-based bivalent vaccine improves immunological responses in red hybrid tilapia, and thus protects against streptococcosis and MAS.
链球菌病和运动性气单胞菌败血症（MAS）是全球罗非鱼养殖中主要的细菌性疾病，造成了重大经济损失。疫苗接种是预防疾病的有效方法，有助于经济可持续性发展。本研究调查了一种新开发的基于饲料的二价疫苗对红色杂交罗非鱼链球菌病和MAS的免疫保护效果。基于饲料的二价疫苗颗粒是通过将福尔马林灭活的[具体抗原未提及]抗原与以棕榈油为佐剂的商业饲料颗粒混合制成的。对该二价疫苗进行了饲料质量分析。为进行免疫学分析，将900尾鱼（12.94±0.46克）分为两个处理组，每组重复三次。第1组鱼未接种疫苗（对照组），而第2组鱼接种二价疫苗。在第0周连续三天以鱼体重的5%口服二价疫苗，随后在第2周和第6周进行加强免疫。在16周内每周对血清、肠道灌洗液和皮肤黏液进行溶菌酶和酶联免疫吸附测定（ELISA）。接种疫苗的鱼在接种后溶菌酶活性显著（P≤0.05）高于未接种疫苗的鱼。同样，接种疫苗的鱼接种后IgM抗体水平也显著（P≤0.05）升高。该二价疫苗对[具体病原体未提及]提供了高保护效力（80.00±10.00%）和对[具体病原体未提及]提供了高保护效力（90.00±10.00%），对[具体病原体未提及]提供了部分交叉保护效力（63.33±5.77%）和对[具体病原体未提及]提供了部分交叉保护效力（60.00±10.00%）。在攻毒试验期间，与未接种疫苗的鱼相比，接种疫苗的鱼观察到的临床和肉眼病变较少。组织病理学评估显示，所选器官的病理变化比未接种疫苗的鱼轻。本研究表明，用基于饲料的二价疫苗接种可改善红色杂交罗非鱼的免疫反应，从而预防链球菌病和MAS。
