Comparative toxicity of Chaetomium contaminated corn and various chemical forms of oosporein in broiler chicks

The toxicity to broiler chicks of Chaetomium contaminated corn and various chemical forms of oosporein were compared by feeding diets containing 60% Chaetomium contaminated corn (300 micrograms oosporein/g diet), and 300 or 150 micrograms/g of purified oosporein in either the K salt, Na salt, or organic acid form from hatching to 3 weeks of age. The Chaetomium contaminated corn diet caused 100% mortality during the first week of feeding. Necropsies revealed extensive visceral and articular gout, enlarged pale kidneys, dehydration, proventricular enlargement with mucosal necrosis, and a dark green discoloration of the gizzard lining. When the mortality percentages of the two experiments conducted were considered collectively, the K and Na salts of oosporein caused significantly higher mortality than the organic acid form of oosporein. The K salt caused the most severe lesions and the organic acid caused the least severe lesions. No mortality occurred at the 150 micrograms/g K salt or 150 micrograms/g organic acid levels. Relative kidney weights were increased by all forms of oosporein at 300 micrograms/g, but at 150 micrograms/g only the K salt caused an increase in kidney weight. The LD50 values, based on mortality from 1 to 10 days, were 5.77, 5.00, and 4.56 mg/kg for oosporein acid, oosporein Na salt, and oosporein K salt, respectively. These results suggest that the salts of oosporein (particularly the K salt) are more toxic than the organic acid, and the natural occurrence of oosporein in a salt form could contribute to the increased toxicity of the Chaetomium contaminated corn.