A general survey of three types of fish feeds for the incidence of toxigenic mold infestation revealed an alarming level of aflatoxigenic Aspergillus flavus contamination during storage. About 89% of A. flavus strains were toxigenic. The toxicity of crude toxin sample was assessed on Channa punctatuus. The experiment was conducted using pure crystalline aflatoxin B. Four different concentrations (10, 20, 30 and 40 mg/D) of pure toxin in 0.5 ml propylene glycol were administered intraperitoneally to four groups of fish along with a control. Observations were made on day 20, 40, 60 and 80. The treated fish showed loss of appetite, followed by listlessness and increased mucus over body surface. Hemorrhagic patches and tumors were prominent on liver. Histopathologically, liver was the most prominently affected organ leading to classical trabeular hepatoma. The excretory -kidney revealed some pre-neoplastic alteration arising from tubular epithelium. The head -kidney was atrophic, but proliferation of inter-renal lobules was prominent. The muscularis of the stomach showed severe proliferation. The intestine, pyloric caeca and gills were atrophic and necrosed. Formation of atypical glandular masses in mucosal region was marked in the intestine. The spleenic pulps were indistinguishable and showed a monotony of lymphocytes. The total and differential counts of leucocytes revealed a significant rise of lymphocytes in peripheral blood.
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