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The toxicity of phomopsin for sheep
Author(s) -
PETERSON J. E.,
JAGO M. V.,
PAYNE A. L.,
STEWART P. L.
Publication year - 1987
Publication title -
australian veterinary journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.382
H-Index - 59
eISSN - 1751-0813
pISSN - 0005-0423
DOI - 10.1111/j.1751-0813.1987.tb07329.x
Subject(s) - toxicity , ingestion , flock , lethal dose , zoology , median lethal dose , medicine , biology , toxicology , physiology , veterinary medicine
SUMMARY: Pure phomopsin was administered to young Merino x Border Leicester wethers by single subcutaneous (SC) and by single and multiple intraruminal (IR) injection. The toxicity after IR injection was influenced by the size of individual doses and the time over which the total dose was given. At high levels of ingestion the toxicity of phomopsin may be limited by absorption rates; with low daily doses the capacity to repair liver damage may be sufficient to prevent cumulative effects. By SC injection a single dose of 10μg/kg approximated the LD 50 . By IR injection the overall clinical, biochemical and histological responses closest to these of this SC dose resulted from a single dose of 1,000 μg/kg. The same total dose administered at daily rates of 50 or 200 μg/kg was more toxic and killed all sheep. A single dose of 500 μg/kg caused significant liver damage, but no deaths. Single doses of 125 and 250 μg/kg and repeated daily doses of 12.5 μg/kg over 16 weeks caused no detectable tissue damage. Inappetence was the most sensitive indicator of phomopsin toxicity. About 10% of the sheep differed substantially from the rest of the flock in their susceptibility to phomopsin poisoning.