Preprint Brief Report Version 1 Preserved in Portico This version is not peer-reviewed

Indexing Baselines: Determining Physiological Stress in Rescued Orphaned Koala Joeys Under Rehabilitation by Comparing Faecal Cortisol Levels Between Healthy and Impaired Individuals

Version 1 : Received: 11 October 2021 / Approved: 12 October 2021 / Online: 12 October 2021 (10:18:35 CEST)

How to cite: Pahuja, H.; Narayan, E. Indexing Baselines: Determining Physiological Stress in Rescued Orphaned Koala Joeys Under Rehabilitation by Comparing Faecal Cortisol Levels Between Healthy and Impaired Individuals. Preprints 2021, 2021100173 (doi: 10.20944/preprints202110.0173.v1). Pahuja, H.; Narayan, E. Indexing Baselines: Determining Physiological Stress in Rescued Orphaned Koala Joeys Under Rehabilitation by Comparing Faecal Cortisol Levels Between Healthy and Impaired Individuals. Preprints 2021, 2021100173 (doi: 10.20944/preprints202110.0173.v1).

Abstract

Koala (Phascolarctos cinereus) is an iconic folivorous marsupial native to the sclerophyll forests and woodlands of Australia. Due to the ever-changing habitat, this species is highly vulnerable to anthropogenic factors such as habitat loss and fragmentation, and this is reflected in the increasing number of injured and/or diseased koalas over the years. The majority of adult koalas admitted at wildlife hospitals are deceased, either due to natural causes, or have to be euthanized. Thus, orphaned koala joeys constitute a substantial number of wildlife rescues, and mortality is also prevalent in koala joeys being hand-reared/rehabilitated, with little knowledge about the causes of such high rates of mortality. Wildlife hospitals/rehabilitation centres are inherently stressful, and although the hypothalamic–pituitary–adrenal (HPA) axis plays a vital role in mediating the stress endocrine function (by producing glucocorticoids such as cortisol), there are no studies quantifying glucocorticoids in koala joeys. To contribute to this dearth of research, we sampled a total of seven individuals residing at Port Macquarie Koala Hospital and noted their clinical information. Faecal samples were collected from all seven koala joeys during routine cage cleaning. In total, 123 faecal samples were collected, processed and analysed for cortisol using enzyme-immunoassay (EIA). We used the iterative baseline approach to determine baseline and peak concentrations of FCM in koala joeys. Baseline concentrations ranged between 14.11 ng/g – 51.10 ng/g (healthy – sick), whereas, peak FCM concentrations ranged between 25.65 ng/g – 56.58 ng/g (healthy – sick). There was a significant difference (p < 0.05) between FCM concentrations of healthy and impaired individuals. Healthy individuals displayed relatively consistent FCM concentrations, whereas, diseased individuals displayed a significant increase in FCM concentrations over time. Our study provides the first record of baseline and peak FCM concentrations in rescued koala joeys with their associated clinical condition. Future studies can use the iterative baseline approach to determine FCM concentration in wild koala joeys that can serve as a baseline to compare glucocorticoid levels of rescued joeys.

Keywords

Cortisol; Faeces; Glucocorticoids; Iterative baseline; Joey; Koala; Stress

Comments (0)

We encourage comments and feedback from a broad range of readers. See criteria for comments and our diversity statement.

Leave a public comment
Send a private comment to the author(s)
Views 0
Downloads 0
Comments 0
Metrics 0


×
Alerts
Notify me about updates to this article or when a peer-reviewed version is published.
We use cookies on our website to ensure you get the best experience.
Read more about our cookies here.