Submitted to: Mycopathologia
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: April 3, 1998
Publication Date: N/A
Interpretive Summary: Fumonisins are toxins made by Fusarium moniliforme and related molds which grow on corn. Fumonisins occur naturally in corn and corn-based products, and are suspected of causing cancer in humans. Fumonisin B1 (FB1) is the most thoroughly studied fumonisin. To learn about the potential toxicity of other fumonisins, we fed rats test diets containing low (4.6-6.9 ppm), mid (32-53 ppm) or high (219-303 ppm) levels of either fumonisins B2; fumonisin B3; or a fumonisin mixture containing predominately FB1. Other rats were fed a control diet without fumonisins. Half the animals were examined after three weeks. Body weight, liver, and kidney effects caused by the FB2, FB3 and FB1-containing test diets were similar and mimicked those known to be caused by pure FB1. Feeding control diet to all remaining rats for three more weeks reversed most effects. Except for some mild liver lesions found in rats fed the high or mid level FB1 containing diets, tissue abnormalities were absent at the end of the study. Thus, FB2 and FB3 contribute to F. moniliforme toxicity. These fumonisins, and perhaps others, must be considered in addition to FB1 during evaluation of health risks associated with F. moniliforme and fumonisins as well as during development of management and control strategies for these toxins in corn and corn products.
Technical Abstract: Fumonisins are produced by Fusarium moniliforme, are found on corn-based feeds and foods, and are suspected human carcinogens. Fumonisin B1 (FB1) causes kidney and liver toxicity, liver cancer, and disrupts sphingolipid metabolism in rats. Rats (n=10/group) were fed culture materials of fungal isolates to provide low (4.6-6.9 ppm), mid (32-53 ppm) or high (219-303 ppm) levels of fumonisins B2 (FB2CM diet); fumonisin B3 (FB3CM diet); a mixture of FB1, FB2 and FB3 (FB1:FB2:FB3=1.0:0.38:0.15); (FB1CM diet) or control diet lacking detectable fumonisins. Half (n=5/group) the rats were killed after three weeks, at which time the effects of all culture materials were similar, mimicked the effects of purified FB1 and included decreased weight gain, hepatopathy, nephropathy, and increased kidney and liver sphinganine to sphingosine ratios (Sa/So). Feeding control diet to all remaining rats for three additional weeks reversed tissue Sa/So and most toxicological effects. Except for mild bile duct lesions in the high level FB1CM group and apoptotic hepatocytes in one mid- and two high-level FB1CM rats, liver and kidney lesions were absent at the end of the study. Thus, FB2 and FB3 contribute to F. moniliforme toxicity and must be considered in evaluation of health risks related to and development of control strategies for this fungus.