Needle biopsy of the hepatopancreas of the black tiger shrimp Penaeus monodon with Penaeus monodon densovirus detection

Abstract

© 2018 Elsevier B.V. The hepatopancreas of the shrimp is the target organ of several pathogens. Diagnosis of diseases of the hepatopancreas usually required an isolation of the organ and the process cannot avoid sacrificing the shrimp. To save life of the animal, this study was aimed at taking hepatopancreatic tissue from the shrimp by biopsy process. Thirty-two sexually mature adults of the black tiger shrimp Penaeus monodon were used as the shrimp model and small pieces of their hepatopancreatic tissue were taken by needle biopsy. Specific position of the needle penetration was suggested to avoid damage to the heart and the gills. From the lateral view of the carapace of the shrimp, this position was at one-third from the rostral end of a line drawn from the last dorsal spine of the rostrum to the posterior margin of the carapace. From the top view, this point was located at a medial quarter of a line drawn from the midline of the carapace toward the lateral extremity. The needle was inserted vertically at a depth of 1 cm into the hepatopancreas, and small pieces of the tissue were quickly withdrawn into the syringe. After the operation, the shrimp were released into rearing tanks and observed for any mortality or morbidity for two months, during which all the shrimp survived and remained apparently healthy. The hepatopancreatic tissues taken from the biopsy were processed for polymerase chain (PCR) reaction method, fresh smear and histology. The PCR revealed the presence of Penaeus monodon densovirus (PmoDNV) in 40% of the samples. The fresh smear and histology revealed good quality of cell morphology and histological features, as well as PmoDNV inclusions in the PCR-positive samples. This study suggests that needle biopsy of hepatopancreas to detect pathogens, or to evaluate health status, of this organ in shrimp is possible, at least in P. monodon.