Nivas S Naveen, Kaippilly Dinesh, Gopalakrishnan Ayyaru, John Anisha Shafni, Sravani Savva, Dayalane Saranya, Ganesan Keerthika
Kerala University of Fisheries and Ocean Studies, Panangad road, Kochi, Kerala 682506, India.
Kerala University of Fisheries and Ocean Studies, Panangad road, Kochi, Kerala 682506, India.
J Invertebr Pathol. 2025 Sep;212:108379. doi: 10.1016/j.jip.2025.108379. Epub 2025 Jun 6.
Mud crab (Scylla serrata) aquaculture is a critical contributor to coastal economies and export markets in India. However, the sector faces significant challenges from Mud Crab Reovirus (MCRV), a highly pathogenic virus reported to cause mass mortalities and severe economic losses. This study assessed the performance of different rearing systems-open pen, cage-in-pen, and external cage systems-focusing on their efficacy in managing MCRV transmission, mortality, and production outcomes. The open pen system exhibited the highest mortality rate (73 ± 4.57 %) and MCRV infection rate (89.04 ± 3.04 %), primarily due to direct contact and cannibalistic behavior among crabs, which facilitated viral transmission. In contrast, the cage-in-pen and external cage systems significantly reduced mortality (18 ± 2.21 % and 19.1 ± 2.88 %, respectively) and MCRV prevalence (64.13 ± 4.35 % and 65.21 ± 3.78 %, respectively) by physically isolating individuals. These systems achieved higher production yields (11.2 ± 1.5 kg and 10.8 ± 1.8 kg) compared to the open pen system (3.5 ± 0.2 kg). Histopathological and transmission electron microscopy (TEM) analyses confirmed MCRV infection, with cytoplasmic basophilic and eosinophilic inclusions observed in the hepatopancreas, gills, and muscle tissues of infected crabs. TEM revealed icosahedral viral particles (∼70 nm) concentrated in the cytoplasm of connective tissue cells, validating previous findings on MCRV replication. This study highlights the critical role of individual compartmentalized systems, such as cage culture, in mitigating MCRV transmission and improving mud crab survival and productivity. While cage culture offers an immediate solution, long-term strategies like enhanced disease surveillance, selective breeding programs, and biosecurity measures are essential for sustainable mud crab aquaculture. These findings provide actionable insights for farmers and policymakers to strengthen the resilience of mud crab farming against MCRV outbreaks.
锯缘青蟹（Scylla serrata）养殖是印度沿海经济和出口市场的重要贡献者。然而，该行业面临着来自锯缘青蟹呼肠孤病毒（MCRV）的重大挑战，据报道，这种高致病性病毒会导致大规模死亡和严重的经济损失。本研究评估了不同养殖系统——开放式围栏、围栏内网箱和外置网箱系统——的性能，重点关注它们在管理MCRV传播、死亡率和生产结果方面的效果。开放式围栏系统的死亡率最高（73 ± 4.57%），MCRV感染率也最高（89.04 ± 3.04%），主要原因是螃蟹之间的直接接触和同类相食行为，这促进了病毒传播。相比之下，围栏内网箱和外置网箱系统通过物理隔离个体，显著降低了死亡率（分别为18 ± 2.21%和19.1 ± 2.88%）和MCRV流行率（分别为64.13 ± 4.35%和65.21 ± 3.78%）。与开放式围栏系统（3.5 ± 0.2千克）相比，这些系统实现了更高的产量（11.2 ± 1.5千克和10.8 ± 1.8千克）。组织病理学和透射电子显微镜（TEM）分析证实了MCRV感染，在受感染螃蟹的肝胰腺、鳃和肌肉组织中观察到细胞质嗜碱性和嗜酸性包涵体。TEM显示二十面体病毒颗粒（约70纳米）集中在结缔组织细胞的细胞质中，验证了先前关于MCRV复制的研究结果。本研究强调了个体分隔系统，如网箱养殖，在减轻MCRV传播以及提高锯缘青蟹存活率和生产力方面的关键作用。虽然网箱养殖提供了一个即时解决方案，但加强疾病监测、选择性育种计划和生物安全措施等长期策略对于锯缘青蟹可持续养殖至关重要。这些发现为养殖户和政策制定者提供了可操作的见解，以增强锯缘青蟹养殖对MCRV爆发的抵御能力。
