title: Properties of herbage in relation to equine dysautonomia: biochemical composition and antioxidant and prooxidant actions.
abstract: To investigate the etiology of equine dysautonomia (ED), a degenerative polyneuropathy affecting grazing horses, the biochemical composition and antioxidant/prooxidant activities of aqueous extracts of plants collected from ED pastures were determined. Plants collected immediately after an outbreak of ED had reduced antioxidant and weak prooxidant activities when compared with control plants (plants collected from ED pastures out of ED season and control plants from ED pastures that were grown under favorable conditions). ED plants also had significantly increased concentrations of fructose and low molecular weight phenolic compounds, significantly more of one amino acid zone (probably valine), significantly less tartaric acid, and a nonsignificant decrease in ascorbic acid content when compared with control plants from ED pastures that were grown under favorable conditions. These findings suggest that ED plants may be under oxidative stress, possibly due to chilling, drought, or fungal colonization. However, experimental drought and chilling of plants did not reproduce the biochemical alterations identified in ED plants. It is possible that the altered biochemical content of ingested plants may contribute, directly or indirectly, to the development of ED in grazing horses.
authors.affiliation: Easter Bush Veterinary Centre, University of Edinburgh, Roslin, Midlothian, Scotland, UK.
authors.forename: B C
authors.initials: BC
authors.lastname: McGorum
authors.forename: S C
authors.initials: SC
authors.lastname: Fry
authors.forename: G
authors.initials: G
authors.lastname: Wallace
authors.forename: K
authors.initials: K
authors.lastname: Coenen
authors.forename: J
authors.initials: J
authors.lastname: Robb
authors.forename: G
authors.initials: G
authors.lastname: Williamson
authors.forename: O I
authors.initials: OI
authors.lastname: Aruoma
mesh_terms: D000821:Animal Feed; D000818:Animals; D000975:Antioxidants / Q000032:analysis*; D001342:Autonomic Nervous System Diseases / Q000209:etiology / Q000662:veterinary*; D006734:Horse Diseases / Q000209:etiology*; D006736:Horses; D016877:Oxidants / Q000032:analysis*; D010636:Phenols / Q000032:analysis*; D010944:Plants / Q000737:chemistry*; D012606:Scotland
chemical_list: D000975:Antioxidants; D016877:Oxidants; D010636:Phenols