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Putative Aspergillus niger-induced oxalate nephrosis in sheep
C J Botha1, M Truter, T Bredell
1Department of Paraclinical Sciences, Faculty of Veterinary Science, University of Pretoria, Private Bag X04, Onderstepoort, 0110 South Africa. christo.botha@up.ac.za
Journal of the South African Veterinary Association
|August 6, 2009
Summary
Mouldy maize brewer's grain contaminated with Aspergillus niger caused oxalate nephropathy in sheep. This led to kidney failure and death in several ewes due to oxalic acid poisoning.
Area of Science:
- Veterinary toxicology
- Animal nutrition
- Mycology
Background:
- Sheep were fed a maize-based brewer's grain (mieliemaroek) and Eragrostis curvula hay under zero-grazing conditions.
- The mieliemaroek feed was visibly mouldy, raising concerns about potential contamination.
Observation:
- Clinical signs in ewes included weakness, hind limb ataxia, tremors, and recumbency after 14 days.
- Six ewes died within a week, with post-mortem findings of cachexia, effusions, lung congestion, and pale kidneys.
- Microscopic examination revealed nephrosis and oxalate crystals in renal tubules.
Findings:
- Aspergillus niger was isolated from the mouldy mieliemaroek.
- High-performance liquid chromatography (HPLC) confirmed the presence of oxalic acid in the feed and fungal isolates.
- The findings support a diagnosis of soluble oxalate-induced nephropathy.
Implications:
- Mouldy feed, particularly mieliemaroek contaminated with Aspergillus niger, poses a significant risk of oxalate nephropathy in sheep.
- This highlights the importance of feed quality control and fungal monitoring in animal husbandry to prevent toxicosis.
- Understanding fungal metabolism of feedstuffs is crucial for preventing livestock poisoning incidents.
