title: One size does not fit all: Monitoring faecal glucocorticoid metabolites in marsupials.
abstract: Marsupial research, conservation, and management can benefit greatly from knowledge about glucocorticoid (GC) secretion patterns because GCs influence numerous aspects of physiology and play a crucial role in regulating an animal's response to stressors. Faecal glucocorticoid metabolites (FGM) offer a non-invasive tool for tracking changes in GCs over time. To date, there are relatively few validated assays for marsupials compared with other taxa, and those that have been published generally test only one assay. However, different assays can yield very different signals of adrenal activity. The goal of this study was to compare the performance of five different enzyme immunoassays (EIAs) for monitoring adrenocortical activity via FGM in 13 marsupial species. We monitored FGM response to two types of events: biological stressors (e.g., transport, novel environment) and pharmacological stimulation (ACTH injection). For each individual animal and assay, FGM peaks were identified using the iterative baseline approach. Performance of the EIAs for each species was evaluated by determining (1) the percent of individuals with a detectable peak 0.125-4.5days post-event, and (2) the biological sensitivity of the assay as measured by strength of the post-event response relative to baseline variability (Z-score). Assays were defined as successful if they detected a peak in at least 50% of the individuals and the mean species response had a Z⩾2. By this criterion, at least one assay was successful in 10 of the 13 species, but the best-performing assay varied among species, even those species that were closely related. Furthermore, the ability to confidently assess assay performance was influenced by the experimental protocols used. We discuss the implications of our findings for biological validation studies.
authors.affiliation: Wildlife Reproductive Centre, Taronga Conservation Society Australia, Dubbo, NSW, Australia; Centre for Integrative Ecology, School of Life and Environmental Sciences, Deakin University, Geelong, VIC, Australia. Electronic address: kerry.fanson@deakin.edu.au.
authors.forename: Kerry V
authors.initials: KV
authors.lastname: Fanson
authors.affiliation: School of Biological Sciences, The University of Queensland, Brisbane, QLD, Australia.
authors.forename: Emily C
authors.initials: EC
authors.lastname: Best
authors.affiliation: School of Biological Sciences, The University of Queensland, Brisbane, QLD, Australia; Department of Environment and Heritage Protection, Brisbane, QLD, Australia.
authors.forename: Ashley
authors.initials: A
authors.lastname: Bunce
authors.affiliation: Centre for Integrative Ecology, School of Life and Environmental Sciences, Deakin University, Geelong, VIC, Australia.
authors.forename: Benjamin G
authors.initials: BG
authors.lastname: Fanson
authors.affiliation: Wildlife Biology Unit, School of Agriculture and Food Sciences, The University of Queensland, Gatton, QLD, Australia; Native Species Breeding Program (NSBP), Perth Zoo, South Perth, WA, Australia.
authors.forename: Lindsay A
authors.initials: LA
authors.lastname: Hogan
authors.affiliation: Wildlife Biology Unit, School of Agriculture and Food Sciences, The University of Queensland, Gatton, QLD, Australia.
authors.forename: Tamara
authors.initials: T
authors.lastname: Keeley
authors.affiliation: Graham Centre for Agricultural Innovation & School of Animal and Veterinary Sciences, Charles Sturt University, Wagga Wagga, NSW, Australia.
authors.forename: Edward J
authors.initials: EJ
authors.lastname: Narayan
authors.affiliation: Department of Biomedical Sciences, University of Veterinary Medicine, Vienna, Austria.
authors.forename: Rupert
authors.initials: R
authors.lastname: Palme
authors.affiliation: Wildlife Conservation and Science, Zoos Victoria, Parkville, VIC, Australia.
authors.forename: Marissa L
authors.initials: ML
authors.lastname: Parrott
authors.affiliation: Fowlers Gap Arid Zone Research Station, Centre of Ecosystem Science, School of Biological Earth and Environmental Sciences, University of New South Wales, Kensington, NSW, Australia.
authors.forename: Trudy M
authors.initials: TM
authors.lastname: Sharp
authors.affiliation: Conservation Medicine Program, School of Veterinary and Life Sciences, Murdoch University, Murdoch, WA, Australia; Perth Zoo Veterinary Department, Perth Zoo, South Perth, WA, Australia.
authors.forename: Kim
authors.initials: K
authors.lastname: Skogvold
authors.affiliation: Moonlit Sanctuary, Pearcedale, VIC, Australia.
authors.forename: Lisa
authors.initials: L
authors.lastname: Tuthill
authors.affiliation: Department of Biological Sciences, Macquarie University, Sydney, NSW, Australia.
authors.forename: Koa N
authors.initials: KN
authors.lastname: Webster
authors.affiliation: Wildlife Reproductive Centre, Taronga Conservation Society Australia, Dubbo, NSW, Australia; Department of Psychology, Franklin and Marshall College, Lancaster, PA, USA.
authors.forename: Meredith
authors.initials: M
authors.lastname: Bashaw
mesh_terms: D000324:Adrenocorticotropic Hormone / Q000008:administration & dosage / Q000494:pharmacology; D000818:Animals; D005243:Feces / Q000737:chemistry*; D005260:Female; D005938:Glucocorticoids / Q000737:chemistry* / Q000378:metabolism; D006728:Hormones / Q000008:administration & dosage / Q000494:pharmacology; D008297:Male; D008394:Marsupialia / Q000502:physiology*; D008991:Monitoring, Physiologic / Q000379:methods / Q000662:veterinary*; D013312:Stress, Physiological / Q000502:physiology
chemical_list: D005938:Glucocorticoids; D006728:Hormones; D000324:Adrenocorticotropic Hormone
keywords: Adrenal; Corticosterone; Cortisol; Enzyme immunoassay; Non-invasive; Validation