title: Pyrrolizidine alkaloids in Crotalaria taxa from northern Australia: risk to grazing livestock.
abstract: Crotalaria species containing hepatotoxic pyrrolizidine alkaloids grow widely in pastures in northern Australia and have sporadically poisoned grazing livestock. The diverse Crotalaria taxa present in these pastures include varieties, subspecies, and chemotypes not previously chemically examined. This paper reports the pyrrolizidine alkaloid composition and content of 24 Crotalaria taxa from this region and assesses the risk of poisoning in livestock consuming them. Alkaloids present in C. goreensis , C. aridicola subsp. densifolia, and C. medicaginea var. neglecta lack the esterified 1,2-unsaturated functionality required for pyrrole adduct formation, and these taxa are not hepatotoxic. Taxa with high levels of hepatotoxic alkaloids, abundance, and biomass pose the greatest risk to livestock health, particularly C. novae-hollandiae subsp. novae-hollandiae, C. ramosissima , C. retusa var. retusa, and C. crispata . Other species containing moderate alkaloid levels, C. spectabilis and C. mitchellii , also pose significant risk when locally abundant.
authors.affiliation: Department of Primary Industries and Fisheries Queensland, Animal Research Institute, Moorooka, Queensland, Australia. mary.fletcher@dpi.qld.gov.au
authors.forename: Mary T
authors.initials: MT
authors.lastname: Fletcher
authors.forename: Ross A
authors.initials: RA
authors.lastname: McKenzie
authors.forename: Barry J
authors.initials: BJ
authors.lastname: Blaney
authors.forename: Keith G
authors.initials: KG
authors.lastname: Reichmann
mesh_terms: D000818:Animals; D001315:Australia; D002417:Cattle; D002418:Cattle Diseases / Q000139:chemically induced; D056486:Chemical and Drug Induced Liver Injury; D029864:Crotalaria / Q000737:chemistry*; D004032:Diet; D008401:Gas Chromatography-Mass Spectrometry; D008107:Liver Diseases / Q000662:veterinary*; D011763:Pyrrolizidine Alkaloids / Q000032:analysis* / Q000633:toxicity*; D012307:Risk Factors; D013045:Species Specificity
chemical_list: D011763:Pyrrolizidine Alkaloids