Abstract
Toxicities of bracken fern were studied for feeding periods of 5-1O days (experiment A), 20-80 days (experiment B) and 11-15 months (experiment C) in 149 albino female and male guinea pigs weighing approximately 200g. Guinea pigs were fed ad lib. the bracken diet containing 30% (Wt./Wt.) dry powdered young fronds, 0.012% thiamine and 0.01% ascorbic acid. In experiment C, animals were fed the bracken diet for 90-100 days and were then returned to the control diet. Control groups received the basal diet containing the same percents of above vitamins. Each experiment was repeated 3 times. Hematuria and intense edema in urinary bladder were prominent at the 5th day in experiment A. Panmyelopathy in the bone marrows and hematuria were manifested in experiment B. In experiment C, 25-38% of survivors had a relapse of hematuria. Tumorous changes were recognized in urinary bladder of all the survivors; transitional cell carcinoma and hyperplastic or precancerous changes were found in 67% and 33% of animals, respectively. In the intestines, tumorous changes including carcinoma (53%) and carcinosarcoma (13%) were recognized in 83.3% of survivors.
