Abstract:
Diplodiosis is an important neuromycotoxicosis of ruminants in South Africa when grazing on
harvested maize fields in winter. It is believed to be caused by mycotoxin(s) synthesised by
Stenocarpella (Diplodia) maydis. Although several metabolites have been isolated from S. maydis
culture material, none of these have been administered to ruminants to reproduce the disease.
The objectives of this study were to isolate diplodiatoxin and to administer it to juvenile goats.
Diplodiatoxin, considered as a major metabolite, was purified from S. maydis-infected maize
cultures (Coligny 2007 isolate). Following intravenous administration of 2 mg and 4 mg
diplodiatoxin/kg body weight for five consecutive days to two juvenile goats, no clinical signs
reminiscent of diplodiosis were observed. Based on previous experimental results and if
diplodiatoxin was the causative compound, the dosage regimen employed was seemingly
appropriate to induce diplodiosis. In addition, intraruminal administration of 2 mg/kg
diplodiatoxin to one goat for three consecutive days also did not induce clinical signs.
It appears as if diplodiatoxin alone is not the causative compound. Other metabolites and/or
mixtures of diplodiatoxin and other mycotoxins, when available in sufficient quantities,
should also be evaluated.
