High incidence of hepatic tumours in rats fed mouldy rice contaminated with containing sterigmatocystin

The hepatocarcinogenicity of rice contaminated with Aspergillus versicolor was investigated by feeding two groups of male Donryu rats on a mouldy-rice culture added to the diet in an amount to provide 5 or 10 ppm sterigmatocystin, equivalent to a daily intake of 75 or 150 μg/rat. Of the 13 rats in each test group that died between day 465 (when the first animal with a tumour died) and day 709 (when survivors were killed), 12 of those fed 10 ppm sterigmatocystin and 11 fed 5 ppm developed hepatic tumours, mostly hepatocellular carcinomas. Three haemangiosarcomas were also observed. In view of the high incidence of hepatomas following ingestion of very low levels of sterigmatocystin, increased surveillance of this toxin in feeds and foodstuffs is recommended.