Multiple infections in shrimp Litopenaeus vannamei broodstock in commercial hatcheries in Khouzestan Province

Abstract

The present study was carried out to investigate the status of health and disease, and their impact on shrimp broodstock (Litopenaeus vannamei) in Khouzestan Province (Choeibde Area) in the south of Iran. From March 2012 until April 2013, about 140 broodstock and 5000 postlarvae (PLs) were collected from hatcheries and grow out farms. Clinical signs of samples were documented in take history forms and then the samples were transported to Iranian South Aquaculture Institute (Ahvaz). Bacterial and fungal studies were carried out on hemolymph, hepatopancreas and gill tissue and then the shrimps were preserved in Davidson Fixative for histopathology. A part of uropods was also preserved in ethyl alcohol for PCR study and detecting three viruses, WSSV, TSV and IMNV. A part of PLs was also preserved in ethyl alcohol for PCR and the remaining was preserved in Davidson Fixative for histopathology. The results showed that 5 bacteria consisting of Vibrio alginolyticus, V. proteolyticus, V. mimicus, A. hydrophila and Plesiomonas shigelloides and one fungi Aspergillus fumigatus were identified. The results of PCR exhibited that the broodstock was free of the three viruses and the PL was infected with WSSV. In histopathology some tissues showed the effects of Vibrio infection in different organs such as gill and midgut, and the infection of PL tissues showed the Cowdry type A inclusion bodies in WSSV. Two specific signs of abnormality were also exhibited in histopathology that we call them Pseudo inclusion and Reolike particles and we need to conduct a new study to clarify detailed information about these finding. This finding can be used for assessing the health of shrimp culture and prevention of disease in broodstock in Iran.