The Effect of Rubratoxin in Broiler Chickens

Crystalline rubratoxin produced by Penicillium rubrum was tested for its effects in broiler chickens. The acute oral LD50 in day-old chicks was 83.2 ± 0.67 mg./kg. of body weight. The most characteristic symptom in birds receiving a lethal dose was red mottled livers. When graded doses of dietary rubratoxin were fed for three weeks, a dose of 500 μg./g. of diet was required to cause a significant (P < 0.05) decrease in body weight. A dose of 1000 μg./g. was required for a significant hypertrophy of the liver and atrophy of the bursa of Fabricius. The relative weights of the pancreas, spleen, and heart were not affected. This dose also caused a significant anemia and proteinemia with an increase in serum cholesterol and capillary fragility. Spontaneous hemorrhaging was not observed. These data suggest that rubratoxin has low toxicity to broiler chickens and that rubratoxin, by itself, does not cause hemorrhagic anemia syndrome which P. rubrum has been reported to cause.