Department of Clinical Sciences, Faculty of Veterinary Medicine, Shahid Chamran University of Ahvaz, Ahvaz, Iran.
Department of Clinical Sciences, Faculty of Veterinary Medicine, Shahid Chamran University of Ahvaz, Ahvaz, Iran.
Fish Shellfish Immunol. 2020 Apr;99:505-513. doi: 10.1016/j.fsi.2020.02.033. Epub 2020 Feb 22.
The present study was aimed to examine the efficacy of chitosan-alginate coated vaccines against pathogenicity of Lactococcus garvieae and Streptococcus iniae in rainbow trout. Fish were divided into four groups including: Group A: fish immunized by chitosan-alginate coated vaccine, Group B: fish immunized by non-coated vaccine, Group C: fish feed by chitosan-alginate coated pellets without vaccine and Group D: fish feed by basic diet (non-coated and without vaccine). In groups A and B, the vaccination was carried out for 14 days and after that supplemented with fundamental diet (control diet). Comparable to groups A and B, fish of group C were also fed 14 days with test diets and after that fed control food. On day 0, 20, 40 and 60 of the experiment, serum samples were given. Fish have been challenged with live L. garvieae and S. iniae after 60 days. The levels of bactericidal activity and complement activity among innate immunity components extended on day 20 of the research and after that decreased in group A and B (P < 0.05) all through the examination. The relative expression of IL-6 and IgM in groups A and B extended on examination day 20. The expression of these genes illustrated no advancements in different groups in during the examination (P > 0.05). In group A, the serum antibody titer against L. garvieae and S. iniae broadly raised on day 40 and 60 of examination, whereas in group B, the immune response titer against S. iniae and L. garvieae illustrated a significant elevation on day 60 of the trial (P < 0.05). After challenge with live bacteria, survival rate of 83 ± 9.1%(challenged with S. iniae) and 72.18 ± 9.8% (challenged with L. garvieae) were gotten independently in group A, which were higher than survival of other exploratory groups (P < 0.05). In conclusion, the results of the present examination appear that the orally vaccination of rainbow trout with chitosan-alginate covered vaccine stimulates immunity system and also efficiently protects rainbow trout against Lactococcus garvieae and Streptococcus iniae.
本研究旨在研究壳聚糖-海藻酸钠涂层疫苗对鲤鱼利斯顿氏菌和链球菌的致病性的功效。将鱼分为四组：A 组：用壳聚糖-海藻酸钠涂层疫苗免疫的鱼；B 组：用非涂层疫苗免疫的鱼；C 组：用壳聚糖-海藻酸钠涂层颗粒喂养但无疫苗的鱼；D 组：用基础饮食（无涂层且无疫苗）喂养的鱼。在 A 组和 B 组中，进行了 14 天的疫苗接种，然后补充基础饮食（对照饮食）。与 A 组和 B 组相似，C 组的鱼也用试验饲料喂养了 14 天，然后喂给对照食物。在实验的第 0、20、40 和 60 天，采集血清样本。在 60 天后，鱼受到活利斯顿氏菌和链球菌的攻击。在研究的第 20 天，先天免疫成分的杀菌活性和补体活性得到扩展，此后在 A 组和 B 组中均下降（P < 0.05）。A 组和 B 组的 IL-6 和 IgM 的相对表达在研究第 20 天延长。在整个检查过程中，不同组之间这些基因的表达没有进展（P > 0.05）。在 A 组中，血清抗体滴度针对利斯顿氏菌和链球菌在检查的第 40 和 60 天广泛增加，而在 B 组中，针对链球菌和利斯顿氏菌的免疫反应滴度在试验的第 60 天显著升高（P < 0.05）。在受到活细菌攻击后，A 组的存活率分别为 83 ± 9.1%（受链球菌攻击）和 72.18 ± 9.8%（受利斯顿氏菌攻击），高于其他实验组的存活率（P < 0.05）。总之，本研究的结果表明，壳聚糖-海藻酸钠包被疫苗对虹鳟进行口服免疫可刺激免疫系统，并有效保护虹鳟免受利斯顿氏菌和链球菌的侵害。
