Hepatopancreatic alterations in Litopenaeus vannamei (Boone, 1939) (Crustacea: Decapoda: Penaeidae) experimentally infected with a Vibrio alginolyticus strain

As in other countries, the presence of disease has affected and limited the development of shrimp culture in Venezuela. Vibriosis is one of the most prevalent, causing high mortality not only in larval cultures but also in shrimp production. The present work shows the histological changes in hepatopancreas of Litopenaeus vannamei experimentally induced by a strain of Vibrio alginolyticus. The shrimps were infected by the immersion technique, being exposed to a concentration of 5.2 x 10(7) bacteria/ml. As soon as their behavior indicated a moribund condition, the animals were sacrificed, and their hepatopancreata were fixed and processed for histological observation. Light microscopical observations revealed loss of the acinar structure of the digestive gland and sloughing off of cellular lining because of cytolisis. The acinar cellular content was dispersed within the lumina and among the acini, Clusters of hemocytes, in the majority loaded with bacteria, were observed under the connective tissue capsule surrounding the hepatopancreatic lobes and in the hemal spaces of the connective tissue sheath surrounding the tubules. (C) 2000 Academic Press.