title: Animal grazing selectivity and plant chemistry issues impact on the potential of Rhagodia preissii as an anthelmintic shrub.
abstract: Rhagodia preissii had shown significant in vitro anthelmintic activity in a previous study, we examined the effect of including this shrub in the diet of sheep infected with Trichostrongylus colubriformis. Worm-infected merino wethers were grazed for 7 weeks on either R. preissii or annual pasture, and faecal egg counts (FECs) were conducted weekly. Plant material was collected weekly from eaten and uneaten plants, and analysed for levels of plant secondary metabolites (tannins, oxalates, saponins) and in vitro anthelmintic activity. While mean FECs were consistently lower in sheep grazing R. preissii compared to pasture (reductions of 20-74%), the differences were not significant. There was no relationship between grazing preference (eaten or uneaten) and in vitro anthelmintic activity of plant extracts. The levels of saponins and oxalates did not correlate with grazing preference or in vitro anthelmintic activity, while tannins were not responsible for the anthelmintic activity. While the identity of the grazing deterrent and in vitro anthelmintic compounds remain unknown, the presence of plants which were both highly preferred by the sheep and showed in vitro anthelmintic activity indicates a potential to develop the species as an anthelmintic shrub through selection of shrub populations dominated by such plants.
authors.affiliation: CSIRO Livestock Industries, St Lucia, QLD, Australia. Andrew.kotze@csiro.au
authors.forename: A C
authors.initials: AC
authors.lastname: Kotze
authors.forename: E N
authors.initials: EN
authors.lastname: Zadow
authors.forename: P E
authors.initials: PE
authors.lastname: Vercoe
authors.forename: N
authors.initials: N
authors.lastname: Phillips
authors.forename: A
authors.initials: A
authors.lastname: Toovey
authors.forename: A
authors.initials: A
authors.lastname: Williams
authors.forename: A P
authors.initials: AP
authors.lastname: Ruffell
authors.forename: A
authors.initials: A
authors.lastname: Dinsdale
authors.forename: D K
authors.initials: DK
authors.lastname: Revell
mesh_terms: D027703:Amaranthaceae / Q000737:chemistry*; D000821:Animal Feed; D000818:Animals; D000871:Anthelmintics / Q000032:analysis / Q000494:pharmacology / Q000627:therapeutic use*; D004032:Diet / Q000662:veterinary; D005243:Feces / Q000469:parasitology; D005247:Feeding Behavior; D008297:Male; D010070:Oxalates / Q000032:analysis / Q000494:pharmacology; D010270:Parasite Egg Count / Q000379:methods / Q000662:veterinary; D008517:Phytotherapy / Q000662:veterinary*; D010936:Plant Extracts / Q000032:analysis / Q000494:pharmacology / Q000627:therapeutic use*; D012503:Saponins / Q000032:analysis / Q000494:pharmacology; D012756:Sheep; D012757:Sheep Diseases / Q000188:drug therapy / Q000469:parasitology / Q000517:prevention & control*; D013634:Tannins / Q000032:analysis / Q000494:pharmacology; D014253:Trichostrongylosis / Q000188:drug therapy / Q000469:parasitology / Q000517:prevention & control / Q000662:veterinary*; D014254:Trichostrongylus / Q000187:drug effects / Q000254:growth & development / Q000472:pathogenicity
chemical_list: D000871:Anthelmintics; D010070:Oxalates; D010936:Plant Extracts; D012503:Saponins; D013634:Tannins