Lactococcosis [Lactococcus garvieae (LG)] is one of the most prevalent bacterial diseases affecting grey mullet (Mugil cephalus) aquaculture. Therefore, the present research evaluated the efficacy of formalin‐killed LG vaccine with an oil‐based adjuvant in grey mullet under laboratory and field trials. The laboratory evaluation for LG vaccine and its cross‐protection upon challenge in grey mullet found that single‐dose immunization of formalin‐killed LG with adjuvant resulted in 91.4% and 100% relative per cent survival (RPS) when challenged with homologous and heterologous strains. The levels of specific antibody titre and lysozyme activity increased significantly in the vaccinated group. Immune gene expression at 24 hr after challenge showed an increase in levels of pro‐inflammatory and anti‐inflammatory cytokines. A parallel field trial experiment was conducted to investigate the long‐term effectiveness of the LG vaccine. Results demonstrated that at one month and three months post‐immunization with heterologous strain, 100% RPS was recorded in the vaccinated group. The findings suggested that the formalin‐inactivated LG vaccine strain (S3) protected grey mullet against LG infection for a period of three months.

中文翻译：

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福尔马林灭活的加维乳杆菌疫苗在养殖的鱼（M头）中的功效。

乳球菌病[乳球菌（LG）]是影响灰mul鱼（Mugil cephalus）的最普遍的细菌性疾病之一）水产养殖。因此，本研究在实验室和现场试验中评估了福尔马林杀死的LG疫苗与油基佐剂在gray鱼中的功效。实验室对LG疫苗及其在灰鱼中攻击后的交叉保护的实验室评估发现，用佐剂单次免疫福尔马林杀死的LG疫苗，在受到同源和异源菌株攻击时可分别获得91.4％和100％的相对存活率（RPS） 。接种组中的特异性抗体滴度和溶菌酶活性显着增加。攻击后24小时的免疫基因表达表明促炎和抗炎细胞因子水平增加。进行了平行现场试验实验，以研究LG疫苗的长期有效性。结果表明，在接种异源菌株后的一个月和三个月，接种组记录了100％的RPS。研究结果表明，福尔马林灭活的LG疫苗株（S3）在三个月的时间内可以保护gray鱼免受LG感染。