title: Hypoglycin A Concentrations in Maple Tree Species in the Netherlands and the Occurrence of Atypical Myopathy in Horses.
abstract: BACKGROUND
  Atypical myopathy (AM) in horses is caused by the plant toxin hypoglycin A, which in Europe typically is found in the sycamore maple tree (Acer pseudoplatanus). Owners are concerned about whether their horses are in danger if they graze near maple trees.
  
  
  OBJECTIVE
  To measure hypoglycin A in the most common maple tree species in the Netherlands, and to determine whether concentration of toxin is a predictor of AM in horses.
  
  
  METHODS
  A total of 278 samples of maple tree leaves, sprouts, and seeds were classified by species. Mean concentrations of hypoglycin A were compared for the type of sample, the season and the occurrence of AM in the pasture (non-AM versus AM). Statistical analysis was performed using generalized a linear model (SPPS22).
  
  
  RESULTS
  Almost all Acer pseudoplatanus samples contained hypoglycin A, with concentrations differing significantly among sources (P < .001). Concentrations were significantly higher in seeds from the AM group than in seeds from the non-AM group (856 ± 677 and 456 ± 358 mg/kg, respectively; P = .039). In sprouts and leaves this was not the case. Acer platanoides and Acer campestre samples did not contain detectable concentrations of hypoglycin A.
  
  
  CONCLUSIONS
  Acer platanoides and campestre seem to be safe around paddocks and pastures, whereas almost all Acer pseudoplatanus samples contained hypoglycin A. In all AM cases, Acer pseudoplatanus was found. Despite significantly higher concentration of hypoglycin A in seeds of pastures where AM has occurred, individual prediction of AM cannot be made by measuring these concentrations because of the high standard deviation.
authors.affiliation: Department of Equine Sciences, Faculty of Veterinary Medicine, Utrecht University, Utrecht, the Netherlands.
authors.forename: C M
authors.initials: CM
authors.lastname: Westermann
authors.affiliation: RIKILT-Wageningen UR, Wageningen, the Netherlands.
authors.forename: R
authors.initials: R
authors.lastname: van Leeuwen
authors.affiliation: RIKILT-Wageningen UR, Wageningen, the Netherlands.
authors.forename: L W D
authors.initials: LW
authors.lastname: van Raamsdonk
authors.affiliation: RIKILT-Wageningen UR, Wageningen, the Netherlands.
authors.forename: H G J
authors.initials: HG
authors.lastname: Mol
mesh_terms: D031002:Acer / Q000737:chemistry*; D000818:Animals; D006734:Horse Diseases / Q000139:chemically induced* / Q000453:epidemiology; D006736:Horses; D007005:Hypoglycins / Q000032:analysis* / Q000633:toxicity; D009135:Muscular Diseases / Q000139:chemically induced / Q000453:epidemiology / Q000662:veterinary*; D009426:Netherlands / Q000453:epidemiology; D018515:Plant Leaves / Q000737:chemistry; D010939:Plant Poisoning / Q000662:veterinary*; D012639:Seeds / Q000737:chemistry*
chemical_list: D007005:Hypoglycins; C041757:hypoglycin
keywords: Acer; Atypical myopathy; Horse; Pasture-associated myopathy