Effect of prior sporidesmin intoxication on the pancreopathy associated with zinc oxide toxicity

Authors: Embling PP, Smith BL
Publication: New Zealand Veterinary Journal, Volume 47, Issue 1, pp 25-27, Feb 1999
Publisher: Taylor and Francis

Animal type: Livestock, Production animal, Ruminant, Sheep
Subject Terms: Inflammation, Integument/skin/wool/hair/fur/feather, Disease/defect, Mycotoxicosis, Liver/hepatic disease, Fungal/yeast, Alimentary system/gastroenterology, Abdomen, Photosensitivity, Toxicology, Trace elements, Minerals/elememts
Article class: Scientific Article

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Abstract: AIM: To demonstrate the effect of prior sporidesmin-induced liver injury on the pancreopathy of zinc-induced toxicity.
METHODS: Four groups, each of 15 sheep, were given 2 x 2 treatments of sporidesmin (0.3 mg/kg bodyweight spread over 3 consecutive days prior to zinc) and zinc (200 mg Zn/kg bodyweight as ZnO spread over 24 days) starting 4 days after the end of sporidesmin dosing. Liver and pancreatic changes were assessed by serum enzyme changes (serum amylase and gamma glutamyltransferase) or scoring for injury at post-mortem examination (hepatopathy) or by histopathological examination (pancreopathy).
RESULTS: Minor pancreatic injury was caused by the administration of zinc. The pancreopathy associated with zinc oxide toxicity was significantly greater in those sheep receiving zinc after the sporidesmin-induced injury. Pathological and body weight changes associated with sporidesmin toxicity also occurred in both groups dosed with sporidesmin. These were slightly less in the group of sheep receiving zinc after the sporidesmin challenge than in those receiving sporidesmin alone.
CONCLUSIONS: Zinc-induced pancreatic injury is greater if the zinc is administered after liver injury has been caused by sporidesmin. Only minor protection is given by zinc if it is administered after the challenge with sporidesmin.
CLINICAL SIGNIFICANCE: The safety margin for the use of zinc is reduced if zinc is administered after significant liver injury has been caused by prior exposure to high Pithomyces chartawn spore counts.
KEY WORDS: Facial eczema, Pithomyces charturum, sporidesmin, zinc toxicity, pancreas, zinc oxide, liver.

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