Hepatic lesions associated with induced aflatoxicosis in the estuarine teleost Etroplus suratensis (Bloch, 1790)

Abstract

Aflatoxicosis is the disease caused due to ingestion or inhalation of aflatoxins, one of the most potent and dangerous groups of mycotoxins, which is produced by fungi of the genera Aspergillus. This fungus grows on feed as well as on feed ingredients used in aquaculture and the tropical humid climate is conducive for its growth and toxin production. The present study was undertaken to assess the susceptibility of a tropical estuarine teleost, Etroplus suratensis (Bloch, 1790) to this toxin by exposing the fishes to aflatoxin B1 (AFB1) incorporated feed at a rate of 0.4 mg AFB1 kg-1 feed, over a period of 8 weeks. On termination of experimental feeding, gross changes such as pale liver with numerous black spots were observed in aflatoxin treated fishes. Progressive damages to the liver which ultimately led to the induction of hepatoma was demonstrated through histopathological and electron microscopic studies. The major histopathological changes such as shrunken pyknotic nuclei, formation of basophilic foci, polyhedral hepatocytes in different sizes, multiple nuclei and mitotic nuclei were observed. The ultrastructural changes such as appearance of electron dense inclusions in the nucleus, loss of structure of microvilli, fragmentation of endoplasmic reticulum, separation of desmosomes, loss of continuity of plasma-lemma and nuclear membranes were also evident. In the present study, susceptibility of the species to aflatoxicosis was demonstrated clearly and the resultant induction of hepatoma indicated the possibility of using this species as an animal model in studies on induction of hepatocarcinomas.