Detection of equine atypical myopathy-associated hypoglycin A in plant material: Optimisation and validation of a novel LC-MS based method without derivatisation.
Authors: González Medina Sonia, Hyde Carolyne, Lovera Imogen, Piercy Richard J
Journal: PloS one
Summary
Atypical myopathy, a frequently fatal acquired myopathy caused by hypoglycin A (HGA) toxicity from certain plants, remains a significant threat to grazing horses worldwide, yet reliable detection methods for HGA in plant material have been limited by technical complexity and cost. González Medina and colleagues developed and validated a novel liquid chromatography-mass spectrometry (LC-MS) method that eliminates the need for chemical derivatisation—a step that previously complicated and limited the sensitivity of detection—achieving accuracy of 84–94% with excellent reproducibility (3–6%) and importantly halving the previous limit of quantitation to 0.5 μg/g. Testing across multiple plant species, the team confirmed that *Acer pseudoplatanus* (sycamore maple) is the primary HGA source in European pasture trees, whilst identifying that HGA concentrations vary considerably between plants, suggesting that pasture risk assessment cannot rely on presence alone. This more sensitive, simpler, and more cost-effective detection tool provides practitioners and research teams with the capacity to rapidly screen forage and pasture samples, identify high-risk grazing areas before outbreaks occur, and investigate the environmental and seasonal factors driving variable HGA production. Farriers, vets and yard managers can now better inform clients about atypical myopathy risk on their land, potentially preventing cases through targeted pasture management and early warning systems.
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Practical Takeaways
- •Plant material suspected of containing hypoglycin A can now be reliably tested using a simpler, more sensitive method, enabling better identification of toxic forage sources on affected properties
- •Sycamore (Acer pseudoplatanus) seeds and seedlings are the primary risk in European pastures; removing these trees or preventing horses from accessing fallen seeds may reduce atypical myopathy outbreaks
- •Earlier detection of lower toxin concentrations allows for more proactive pasture management and feed analysis before horses are exposed to dangerous levels
Key Findings
- •A novel LC-MS method for detecting hypoglycin A in plant material was validated with 84-94% accuracy without requiring chemical derivatisation
- •The limit of quantitation for hypoglycin A was reduced to 0.5 µg/g, halving the previous detection threshold of 1 µg/g
- •Acer pseudoplatanus (sycamore maple) is confirmed as the primary source of hypoglycin A in European pasture trees
- •The new method demonstrates high precision (3-16%) and reproducibility (3-6%) with excellent linearity (R² = 0.999)