Histopathological Investigation of the Giant Prawn Macrobrachium rosenbergii in the Extensive Culture Ponds of Nellore Region, Andhra Pradesh, India

Abstract

The present study was carried out in Muthukur area of Nellore region of Andhra Pradesh located at 14.29 19 latitude and 80.10383 longitude), India since this area is actively engaged with aquaculture activities of fish and prawn farming. A recent data indicated that 280 to 984 kg per hectare per crop achieved in Macrobrachium rosenbergii under extensive system in a culture period of 180 to 210 with stocking density of 3 to 5 juveniles per square meter. Since the scampi Macrobrachium rosenbergii was the candidate as well as prominent species in that region, histopathological study was carried out to the see quality of the prawn for the present study. During the investigation of shrimp disease in the culture pond, the prawn Macrobrachium rosenbergii were found to die due to swollen head disease having enlargement of cephalothoracic region containing gill, heart and hepatopancreas, etc. Another kind of symptom of black spots were noticed on the dorsal portion of anterior exoskeleton in the cephalothorax region. Enlargement of pigmentary with black spots formed in the periphery of dorsal side of exoskeleton might be due to the presence of suspected white spot syndrome virus. This kind of disease was found to attack commonly in Macrobrachium rosenbergii in most of the culture ponds. Apart from the study of shrimp disease in culture ponds, attempts were also made to identify the disease in the post larvae of Macrobrachium rosenbergii in the hatchery in and around Nellore region. Mass mortality was found to occur in the post larval stages due to a kind of white muscle disease. It has led to great loss of economy not only to the entrepreneurs involved in the hatchery at Nellore region but also to the country as well. WSSV was characterised by prominent eosinophilic to pale basophilic intra nuclear inclusion bodies in hypertrophied nuclei of most commonly in the epithelial cells and connective tissue cells of the above target tissues. Result of the study showed that multiple infection is quite common in the prawn to be cultured once the water quality has become deteriorated and It is suggested that although it is a extensive culture system, water management and supplement of feeds are prerequisite to maintain the pond.