Lupinosis: response of sheep to different doses of phomopsin

Phomopsin, the mycotoxin produced by Phomopsis leptostromiformis, was found to have a very high toxicity for sheep. When administered as a single, subcutaneous injection over the dose range 1 X 25 to 98 microgram/kg body weight, all sheep given 37 X 5 microgram/kg or more died. Some, though not all, died following lower doses, the minimum lethal dose being 10 microgram/kg. The time course of hepatic response over 21 days after phomopsin administration was followed by plasma biochemical analyses including those for some enzymes (glutamate dehydrogenase, gamma-glutamyl transpeptidase, aspartate aminotransferase and alkaline phosphatase), total bilirubin and the determination of bromosulphophthalein clearance rates. Hepatobiliary impairment was apparent after all dosages of 2.5 microgram/kg and above while 1.25 microgram/kg approximated the 'no effect' level.