The hepatopancreatic disease in shrimp has caused great economic losses in recent years, and it is necessary to identify the responsible pathogen and establish control methods. The present study aimed to identify the primary pathogenic bacteria in diseased Litopenaeus vannamei hepatopancreas (HP) and to explore the protective effects of functional bacteria on shrimp. Four pathogenic Vibrio spp. were isolated and identified from shrimp with hepatopancreatic disease, of which Vibrio harveyi HAH could be the primary pathogen causing higher rates of mortality (~ 73%) with observed symptoms. In addition, HAH had five virulence-related genes: luxR, flaB, toxR, vhhA, and vhhB. Anti-Vibrio bacterium M146 and quorum quenching (QQ) bacterium W1B were screened and used as a feed supplement. The results showed that M146 and W1B (dosed at 1.0 × 10⁷ CFU/g) decreased the mortality of shrimp after challenge with HAH. Supplementation with M146 significantly increased the activities of alkaline phosphatase (AKP) and lysozyme (LZM), whereas supplementation with W1B had no significant effect. AKP and acid phosphatase (ACP) activities of shrimp supplemented with W1B showed a significant increase after infection with HAH, whereas a decrease in the activities of AKP and superoxide dismutase (SOD) was observed in the negative control (NC). Supplementation with M146 and W1B significantly decreased the relative messenger RNA expression of Relish and TRAF6. However, after infection with HAH, the M146 and W1B groups exhibited a different pattern of gene expression regulation compared with that in the NC group, which might suggest weakening of the virulence of the pathogen. The results suggest that these two bacteria can protect L. vannamei and that M146 not only inhibited the growth of HAH but also had an immunostimulatory effect on shrimp. On contrast, W1B did not improve the immunity of shrimp, so it is speculated that it may protect the host by affecting the quorum sensing (QS) system of pathogenic bacteria.

近年来，虾类肝胰腺疾病造成了巨大的经济损失，因此有必要找出负责任的病原体并建立控制方法。本研究旨在确定患病的南美白对虾肝胰腺（HP）中的主要致病细菌，并探讨功能性细菌对虾的保护作用。四个致病性弧菌。从患有肝胰腺疾病的虾中分离并鉴定出了其中的虾，其中哈维弧菌HAH可能是导致病死率较高（〜73％）的主要病原体，并有明显症状。此外，HAH具有五个与毒力相关的基因：lux R，fla B，tox R，vhhA和vhhB。筛选了抗弧菌细菌M146和群体猝灭（QQ）细菌W1B，并将其用作饲料补充剂。结果显示M146和W1B（剂量为1.0×10 ⁷ CFU / g）降低了用HAH攻击后虾的死亡率。补充M146可显着增加碱性磷酸酶（AKP）和溶菌酶（LZM）的活性，而补充W1B则无明显作用。补充W1B的虾的AKP和酸性磷酸酶（ACP）活性在感染HAH后显着增加，而在阴性对照（NC）中观察到AKP和超氧化物歧化酶（SOD）的活性降低。补充M146和W1B会显着降低Relish和TRAF6的相对信使RNA表达。然而，感染HAH后，与NC组相比，M146和W1B组表现出不同的基因表达调控模式，这可能表明病原体的毒性减弱。南美白对虾和M146不仅抑制HAH的生长，而且对虾具有免疫刺激作用。相比之下，W1B并不能提高虾的免疫力，因此推测它可以通过影响病原菌的群体感应（QS）系统来保护宿主。