Low tumor incidence in rats with long-term feeding of fusarenon-X, a cytotoxic trichothecene produced by Fusarium nivale.

In order to examine tumorigenic effects of fusarenon-X, a trichothecene compound produced by Fusarium nivale, feeding experiments on 151 male Donryu rats were carried out. Daily dose of 105 micrograms (7 ppm in the diet) or 50 micrograms (3.5 ppm)/animal of fusarenon-X was given for 1 or 2 years. Although the animals of the experimental groups showed lower body weight than controls and were more liable to be afflicted by pulmonary infections, tumor incidences were as low as that of the control group. However, several unusual tumors as follows were observed only in the experimental groups: 1 adenocarcinoma of the stomach, 2 papillary carcinomas of the urinary bladder, 1 adrenocortical adenoma, and 1 leukemia.