Ultra-structural and histochemical analysis of channel catfish (Ictalurus punctatus) liver treated with fumonisin B1

The histopathological effects of fumonisin B1 (FB1) injected intraperitoneally (IP), was evaluated in catfish (Ictalurus punctatus). Fishes were divided into four Groups. Groups II, III and IV were treated IP with FB1 injections of 1; 5 and 10 mg/kg bw/day, respectively, during 21 days. At the 7th, 14th and 21st day, fishes were sacrificed. The livers were hystologicaly analysed by the light and transmission electronic microscopy. Livers from the 7th day showed organelles alterations, particularly in the granular endoplasmatic reticle, mitochondria, nucleus and nucleolus mediated by FB1 doses. The occurrence of processes involved in the necrosis and apoptosis was detected. At the highest FB1 dose,the livers presented an intense response with an accentuate tissue disorganization, absence of cell limits and intense cytoplasm vacuolization. The image analysis showed the occurrence of necrosis in some areas, characterized by fully broken or swollen cells. The apoptosis was observed as the cytoplasm contraction and the chromatin formed masses concentrated in the edge of the nucleus. There was strong evidence that the numerous hepatocytes in the liver from the fishes under the toxic dose of FBs were selectively removed by the apoptosis process.