INVESTIGATIONS OF TOXIC EFFECTS IN MICE OF CERTAIN SPECIES OF PENICILLIUM

Several species of Penicillium isolated from corn were tested for toxicity in mice. Corn cultures of the several species were incubated either at 24 or 16°. After the fungi were treated with chloroform, the cultures were dried and ground for mixing with either chicken mash or a purified diet at a ratio of 2:1 or 1:1 mold culture to diluent. Generally, corn cultures were more toxic when incubated at 24°. Penicillium oxalicum and P. viridicatum were clinically toxic, reducing weight gains and increasing the number of deaths. Other isolates which were less toxic, especially when fed at 1:1 ratio, included P. citrinum, P. variabile, P. purpurogenum, P. expansum, P. multicolor, P. frequentans, P. puberulum, and P. urticae. Only P. viridicatum consistently produced gross and microscopic lesions. About 40% of test mice were jaundiced and had green urine positive for bile pigments. Hepatic lesions including greenish discoloration and mottling of surface due to focal areas of necrosis were observed in most of the mice. Microscopic lesions included disseminated focal areas of necrosis, bile ductule cell hyperplasia, cholangitis and periductular fibrosis often accompanied by hypertrophy and hyperplasia of ductal epithelium. Six isolates of P. viridicatum were tested, and only the NRRL culture failed to elicit the gross and microscopic lesions as described above. A portion of the toxic activity of the P. viridicatum culture appeared to be thermolabile as weight gains were greater and mortality less in group of mice fed the corn culture subjected to steaming. © 1968.