Acute Hepatopancreatic Necrosis Disease (AHPND) is a new emerging bacterial disease that has been recently reported to cause mass mortalities in Pacific whiteleg shrimp (Penaeus vannamei). Antibiotics have been used to treat bacterial diseases in shrimp but most of them have been ineffective and have resulted in drug residues in the harvested shrimp products. In this study, an alternative approach was tested for its efficacy in controlling AHPND. The extract of Rhodomyrtus tomentosa seed, a traditional Vietnamese medicine, was tested for antibacterial effect against three AHPND-bacterial strains, Vibrio parahaemolyticus (VPAHPND ) KC12.020, VPAHPND KC13.14.2 and V. harveyi KC13.17.5 in vitro and further evaluated for its potential efficacy in prevention of AHPND in shrimp in vivo. The in vitro studies showed that the antibacterial activity of the R. tomentosa extract was dose-dependent with the strongest bacterial susceptibility (≥ 18.0 mm) at a concentration of around 3500 μg/disc. The in vivo studies showed that, after challenge with the VPAHPND KC12.020 strain, the survival rates for shrimp in the groups that received feed pellets supplemented with 3.5% or 7% of the extract (approximately 48.9% and 52.2%, respectively) were significantly higher than zero survival rate in the positive control group without supplementation of the extract (P < 0.05). These results indicate that the use of the R. tomentosa extract as an alternative therapy for control of AHPND in shrimp could help to minimize disease outbreaks. As a result, the extract is further expected to reduce drug/chemical residues in shrimp products. This article is protected by copyright. All rights reserved.

中文翻译：

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桃金娘（Rhodomyrtus tomentosa）提取物对南美白对虾（Penaeus vannamei）急性肝胰腺坏死病（AHPND）的疗效

急性肝胰腺坏死病 (AHPND) 是一种新出现的细菌性疾病，最近据报道会导致南美白对虾 (Penaeus vannamei) 大量死亡。抗生素已被用于治疗虾的细菌性疾病，但大多数都无效，并导致收获的虾产品中出现药物残留。在这项研究中，测试了另一种方法在控制 AHPND 方面的功效。测试了越南传统药材红桃种子提取物对三种 AHPND 细菌菌株，副溶血性弧菌 (VPAHPND) KC12.020、VPAHND KC13.14.2 和 V. harveyi KC13.17.5 的体外抗菌作用，并进一步评估了其在体内预防虾 AHPND 的潜在功效。体外研究表明，毛茸茸提取物的抗菌活性呈剂量依赖性，在 3500 μg/盘左右的浓度下具有最强的细菌敏感性（≥ 18.0 mm）。体内研究表明，在用 VPAHPND KC12.020 菌株攻击后，接受添加了 3.5% 或 7% 提取物（分别约为 48.9% 和 52.2%）的饲料颗粒的虾的存活率分别为未添加提取物的阳性对照组显着高于零存活率（P < 0.05）。这些结果表明，使用毛茸茸提取物作为控制虾中 AHPND 的替代疗法有助于最大程度地减少疾病爆发。因此，该提取物有望进一步减少虾产品中的药物/化学品残留。本文受版权保护。版权所有。