ABSTRACT: The experimental Litopenaeus vannamei were sourced from Hainan Bufeng Aquaculture Co., Ltd., Dongfang, China, with a body length of about 12 cm and a body mass of about 20 g. VpAHPND strain E1 was generously supplied by Prof. Lei Wang, Institute of Oceanology, Chinese Academy of Sciences. Prior to the experiment, the shrimps were cultured in filtered seawater with continuous aeration, maintained at a temperature of 25 ± 1 ℃, pH 8.0 ± 0.2, and salinity of 30 ‰. The culture water was partially replaced daily, with one-third of the volume being renewed each time. After acclimating for 7 days, and the shrimps were tested negative for pathogens, such as WSSV and EHP. Post-nursery shrimps were randomly assigned to control and infected groups, with three replicate tanks each group. Each control tank housed 5 shrimps, while each infection tank housed 30 shrimps. The subsequent infection experiment was conducted using the immersion infection method, and the final concentration of 1 × 107 CFU/mL for challenge. For the control group, three shrimps were randomly collected from each replicate, totaling 9 shrimps. For the challenged group, sampling began when the mortality rate of shrimp reached 50 %, with 6 surviving and 6 moribund shrimps collected from each replicate. A total of 18 surviving and 18 moribund shrimps were collected from the challenged group. After sterile ice-bath anaesthesia, hepatopancreases were dissected from L. vannamei. The tissues were rinsed with 1× PBS, snap-frozen in liquid nitrogen for 15 min, and subsequently stored at −80 ℃. Based on qPCR quantification, the samples were assigned to control, low-copy, or high-copy groups (n = 9 hepatopancreases per group). Proteomic profiling was subsequently employed to identify differentially expressed proteins among the three groups.
Mengqiang Wang 
