[Occurrence of PR-toxin-producing Penicillium roqueforti in corn silage].

Feeding the maize silage infected with the mold Penicillium roqueforti resulted in 112 dairy cows in the loss of appetite, stoppage of rumen activity and gut inflammation. The abortion of first-calvers in the seventh and eighth month was observed. The mold P. roqueforti produced on the sterile maize silage, at the temperature of 20 degrees C, up to 160 mg of PR-toxin per kg after 22 days of cultivation. The maximum production in the liquid medium was 900 mg of PR-toxin per litre, at the temperature of 13 degrees C after 50 days of cultivation. The isolated PR-toxin was identified spectrophotometrically and by the thin-layer chromatography after detection by 3-methyl-2-benzothiazoline-hydrochloride. The dose of 0.01 microgram PR-toxin was extremely toxic for 40-hr old chicken embryos.U