Dietary Factors and Hepatoma in Rainbow Trout (Salmo gairdneri). I. Aflatoxins in Vegetable Protein Feedstuffs

Aflatoxins (toxic metabolites of the mold Aspergillus flavus) were present in a commercial trout ration causing hepatoma in rainbow trout. Cottonseed meal and solvent extracts of cottonseed meal and of rations containing cottonseed meal and peanut meal were found by chemical assay and confirmed by duckling assay to contain aflatoxins. Diets containing these materials and a purified test diet to which aflatoxins had been added produced microscopic tumors in 6 months and gross lesions of hepatocarcinoma in 9 months. Similar diets without aflatoxin were negative.