DAO 81:163-171 (2008)  -  DOI: https://doi.org/10.3354/dao01955

Loose shell syndrome of farmed Penaeus monodon in India is caused by a filterable agent

S. V. Alavandi1,*, T. D. Babu1, K. S. Abhilash1, K. K. Vijayan1,2, N. Kalaimani1, T. C. Santiago1

1Central Institute of Brackishwater Aquaculture (Indian Council of Agricultural Research), 75 Santhome High Road, Raja Annamalai Puram, Chennai 600 028, India
2Present address: Marine Biotechnology Division, Central Marine Fisheries Research Institute, PO Box 1603, Ernakulam North PO, Kochi 682 018, India

ABSTRACT: Loose shell syndrome (LSS) of farmed black tiger shrimp Penaeus monodon has been reported from Indian shrimp farms since 1998 and is recognized as a major disease problem causing significant economic loss to the shrimp aquaculture sector. Unlike the rapid mortalities associated with viral pathogens such as white spot syndrome virus and yellow head virus, progression of LSS is gradual, leading to low-level progressive mortalities. The signs of LSS include a flaccid spongy abdomen due to muscular dystrophy, space between the exoskeleton and muscle, and a shrunken hepatopancreas. The feed conversion efficiency is reduced, and shrimp have poor meat quality, caused by impairment of the hepatopancreatic functions such as digestion and absorption as evidenced by the atrophy of the hepatopancreas. Histopathological investigations on LSS-affected shrimp showed shrinkage of extensor and flexor muscles with occasional hemocytic infiltration. The hepatopancreas showed inflammation of hepatopancreatic tubules with enlargement of intertubular spaces, hemocytic infiltration, and low levels of lipid reserves in the R cells. In advanced stages of LSS, many tubules were in highly necrotic condition with a sloughed epithelium, reflecting the dysfunction of the digestive gland. LSS could be induced in healthy tiger shrimp by challenge studies using membrane-filtered LSS-affected shrimp tissues, suggesting involvement of a filterable infectious agent.


KEY WORDS: Histopathology · Loose shell syndrome · LSS · Tiger shrimp · Penaeus monodon ·Filterable agent


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Cite this article as: Alavandi SV, Babu TD, Abhilash KS, Vijayan KK, Kalaimani N, Santiago TC (2008) Loose shell syndrome of farmed Penaeus monodon in India is caused by a filterable agent. Dis Aquat Org 81:163-171. https://doi.org/10.3354/dao01955

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