Acute Toxicity of Aflatoxin B₁to Channel Catfish

Abstract

Both oral and intraperitoneal (IP) administration of 12 mg aflatoxin B1 (AFB1) per kilogram of body weight caused regurgitation of stomach contents by channel catfish Ictalurus punctatus. Detoxification of AFB1 (ammoniation) significantly reduced the incidence of regurgitation. The 10-d median lethal dose (LD50; dose that is lethal to 50% of test organisms) for IPadministered AFB, in channel catfish averaging 19 g was 11.5 mg/kg of body weight, with a 95% confidence interval of 9.5–13.3 mg/kg. Gills, livers, kidneys, spleens, stomachs, and intestines of moribund fish injected with 12 mg AFB1/kg of body weight were extremely pale. Hematocrits, hemoglobin concentrations, and erythrocyte counts of moribund fish were about 10% of those values in control fish. Histological lesions in moribund fish included sloughing of intestinal mucosa and necrosis of hematopoietic tissues, hepatocytes, pancreatic acinar cells, and gastric glands. Spleens showed reduction in volume of the red pulp and reduction in number of leukocytes in the splenic corpuscles. Renal tubular lumens were dilated. Changes in hematocrits, hemoglobin concentrations, and erythrocyte and leukocyte counts of nonmoribund channel catfish following IP injection of 9 mg AFB1/kg of body weight were lowest between 48 and 72 h postinjection.