en fish disease fish disease پژوهشي Orginal research papers <span lang="TR" style="font-size:10.5pt"><span calibri="" style="font-family:"><span style="color:black">Co-infection with <i>Streptococcus</i> <i>iniae</i> and <i>Vibrio harveyi </i>is the major health challenge in Asian sea bass (<i>Lates calcarifer</i>) farms. Vaccination is the most effective means of preventing these diseases, therefore, this study presents an efficacious bivalent vaccine against <i>S. iniae </i><span style="letter-spacing:1.35pt">and</span><i> </i><i>Vibrio harveyi</i> infections in Asian sea bass. 420 juvenile sea bass (weighing</span></span></span><span lang="TR" style="font-size:10.5pt"><span calibri="" style="font-family:"><span style="color:black"> 20.35 &plusmn; 0.37 g</span></span></span><span lang="TR" style="font-size:10.5pt"><span calibri="" style="font-family:"><span style="color:black">) were </span></span></span><span lang="TR" style="font-size:10.5pt"><span style="background:white"><span calibri="" style="font-family:"><span style="color:black">separated</span></span></span></span><span lang="TR" style="font-size:10.5pt"><span calibri="" style="font-family:"><span style="color:black"> into seven equal groups in triplicates: group A: received Phosphate-buffered saline as a control group, groups B and E: immunized with </span></span></span><i><span lang="TR" style="font-size:10.5pt"><span calibri="" style="font-family:"><span style="color:black">S. iniae</span></span></span></i><span lang="TR" style="font-size:10.5pt"><span calibri="" style="font-family:"><span style="color:black"> vaccine via injection (<i>S.i</i>-Inj) and immersion (<i>S.i</i>-Im) routes, groups C and D: immunized with <i>V. harveyi</i> vaccine via immersion (<i>V.h</i>-Im) and injection (<i>V.h</i>-Inj) routes, and groups F and G: immunized with bivalent <i>S. iniae</i>+<i>V. harveyi</i> vaccine via immersion (Bi-im) and injection (Bi-inj) routes. The blood, serum, and gene samples were taken on 0, 30, and 60 days of the experiment and to measure specific and non-specific immune parameters, hematological and immune-related gene expression. The bacterial challenge test was used as a protective immunity measure at the end of the experiment. The results showed that the injection bivalent vaccine (<i>S. iniae+V. harveyi</i>) route was more effective than monovalent vaccines in enhancing the specific (antibody titer) and non-specific (lysozyme and complement activity, Nitro Blue Tetrazolium (NBT) reduction, protein, and globulin level) immune responses. Meanwhile, the vaccine efficacy and expression of <i>IL-10</i> and <i>GM-CFC</i> genes in the bivalent vaccine were significantly higher (<i>P<0.05</i>) than monovalent vaccines. <span style="background:white">These results indicate that the high immunogenicity and protective immunity provided by the bivalent vaccine (<i>S. iniae+V. harveyi</i>) strongly support its use as a general preventive measure against streptococosis and vibriosis in Asian sea bass farms.</span></span></span></span> Asian sea bass, Lates calcarifer, Bivalent vaccine, Streptococcus iniae, Vibrio harveyi, Immunogenicity 863 885 http://jifro.ir/browse.php?a_code=A-10-792-9&slc_lang=en&sid=1 M. Kahkesh mahboube.kahkesh@gmail.com 100319475328460056915 100319475328460056915 No Department of Clinical Sciences Faculty of Veterinary Medicine, Shiraz University, Shiraz, Iran M. Alishahi alishahim@scu.ac.ir 100319475328460056916 100319475328460056916 Yes Department of Livestock, Poultry and Aquatic Animals Health, Faculty of Veterinary Medicine, Shahid Chamran University of Ahvaz, Ahvaz, Iran S. Soltanian soltanian@shirazu.ac.ir 100319475328460056917 100319475328460056917 No Department of Clinical Sciences Faculty of Veterinary Medicine, Shiraz University, Shiraz, Iran A. Gholamhoseini ghorbanpoor2000@yahoo.com 100319475328460056918 100319475328460056918 No Department of Clinical Sciences Faculty of Veterinary Medicine, Shiraz University, Shiraz, Iran M. Ghorbanpour ghorbanpoor2000@yahoo.com 100319475328460056919 100319475328460056919 No Department of Pathobiology, School of Veterinary Medicine, Shahrekord University, Shahrekord, Iran A. Yektaseresht yektaseresht@shirazu.ac.ir 100319475328460056920 100319475328460056920 No Department of Pathobiology, Faculty of Veterinary Medicine, Shiraz University, Shiraz, Iran