Over time Decay of Cortisol Metabolites in Faecal Pellets of Koalas in Central Queensland

Faecal material can be a valuable source of information for a range of animal health aspects and can be used to measure faecal cortisol metabolites (FCMs). FCM values can relate to physiological stress responses. However, freshly defecated pellets are not always available and environmental conditions, such as temperature and humidity, might affect faecal pellet consistency and FCM levels. Therefore, the impact of environmental conditions on FCMs needs to be evaluated. We collected 107 pellets from two female and two male koalas, exposed them to three types of treatments, and analysed FCMs in these samples with three enzyme immunoassays (EIAs). After analysis, the original FCM values were mathematically corrected for water loss. Results show that the FCMs were more stable when measured using tetrahydrocorticosterone (50c) and 5α-pregnane-3β,11β,21-triol-20-one (37e) EIAs, and were less stable when measured with the cortisol EIA. With 50c, the FCM values did not vary significantly over time either before or after the adjustment with water in the environment treatment group. For samples kept under constant low (25 °C) and high (35 °C) temperatures, the 50c FCM values did not vary significantly over time, after adjustments were made for water loss. Thus, this study highlights the importance of considering the suitability of faecal field samples for FCM analysis. Because water loss was the main driver of FCM changes, we strongly recommend collecting koala pellets that are freshly defecated, despite the effort and time it might take to collect such pellets.

Faecal Cortisol Metabolites as an Indicator of Adrenocortical Activity in Farmed Blue Foxes

Welfare studies of blue foxes would benefit from a measurement of faecal cortisol metabolites (FCMs) as a non-invasive, physiological stress parameter reflecting hypothalamus–pituitary–adrenal (HPA) axis activity. Before implementation, a species-specific validation of such a method is required. Therefore, we conducted a physiological validation of an enzyme immunoassay (EIA) to measure FCMs in blue foxes. Twenty individuals (nine males and eleven females) were injected with synthetic adrenocorticotrophic hormone (ACTH) and faecal samples were collected every third h for two days. The FCM baseline levels were assessed based on the first sampling day (control period, 144 samples), followed by the ACTH injection and the second day of sampling (treatment period, 122 samples). FCMs were analysed with a 5α-pregnane-3ß,11ß,21-triol-20-one EIA. We compared the estimated mean FCM concentrations of the treatment samples to the baseline average. All samples for the two periods were collected at the same time of the day, which enabled to test the data also with an hourly pairwise comparison. With the two statistical approaches, we tested whether a possible diurnal fluctuation in the FCM concentrations affected the interpretation of the results. Compared to the baseline levels, both approaches showed 2.4–3.2 times higher concentrations on time points sampled 8–14 h after the ACTH injection (p < 0.05). The estimated FCM concentrations also fluctuated slightly within the control period (p < 0.01). Inter-individual variations in FCM levels were marked, which highlights the importance of having a sufficient number of animals in experiments utilising FCMs. The sampling intervals of 3 h enabled forming of informative FCM curves. Taken together, this study proves that FCM analysis with a 5α-pregnane-3ß,11ß,21-triol-20-one EIA is a valid measurement of adrenocortical activity in the farmed blue foxes. Therefore, it can be utilised as a non-invasive stress indicator in future animal welfare studies of the species.

Give Them a Toy or Increase Time out of Kennel at Lawn Areas: What Is the Influence of These Interventions on Police Dogs’ Welfare?

This work was aimed at identifying the effectiveness of two interventions applied to a group of eight kennelled police dogs. Interventions consisted of access to a lawn area (350 m2) and “toy” (a 30 cm jute rag roll, hanging from the kennel ceiling), both available for 15 min a day, for four days in a row. We collected behavioural data and faecal samples for cortisol metabolites evaluation before, during and after interventions. Faecal cortisol metabolites levels were significantly reduced (Friedman, X2(3) =12.450; p = 0.006) during the second round of intervention, regardless of the type of intervention, indicating that the interventions can have a beneficial cumulative effect. Regarding the frequency of stereotyped behaviour, cluster analysis identified two groups of individuals: (1) high-stereotyping individuals (n = 3) that had a tendency to reduce stereotyping behaviours in the lawn intervention when compared to toy intervention (Friedman, X2(3) = 2.530; p = 0.068), and (2) low-stereotyping animals (n = 5) that did not present significant behavioural changes during the experiment. The variety of behavioural and endocrine parameters evaluated highlights the need to account for the individual in behaviour and welfare research. Overall, our results suggest that even simple environmental enrichment can be an effective method to mitigate behaviour and physiological signs of stress.

Identification of Koala (Phascolarctos cinereus) Faecal Cortisol Metabolites Using Liquid Chromatography-Mass Spectrometry and Enzyme Immunoassays

The koala (Phascolarctos cinereus) is an arboreal folivorous marsupial endemic to Australia. Anthropogenic activities and climate change are threats to this species’ survival and are potential stressors. A suitable non-invasive method is needed to objectively detect stress in koalas. Under conditions of stress, the concentration of the hormone cortisol in plasma or in saliva is elevated, and this would provide a convenient measure; however, collecting blood or saliva from wild animals is both practically difficult and stressful, and so likely to confound any measurement. In contrast, measurement of cortisol metabolites in faeces provides a practical and non-invasive method to objectively measure stress in koalas. Unfortunately, the identity of the main faecal cortisol metabolites of koalas is unknown. In this study, we have used both untargeted liquid chromatography–mass spectrometry (LC-MS) and enzyme immunoassays (EIAs) to identify several faecal cortisol metabolites in two koalas, one female (18 months old, 4.1 kg) and one male (4 years old, 6.95 kg) upon administration of hydrocortisone (cortisol) sodium succinate. The LC-MS analysis identified tetrahydrocortisol along with several other isomers as cortisol metabolites. After a survey of five enzyme immunoassays, we found that two metabolites, tetrahydrocortisol and 3β-allotetrahydrocortisol, could be detected by EIAs that used antibodies that were raised against their structurally similar corticosterone counterparts, tetrahydrocorticosterone and 3β-allotetrahydrocorticosterone, respectively. While the 3β-allotetrahydrocortisol metabolite was detected in the faeces of only one of the two animals studied, tetrahydrocortisol was detected in both. These results ultimately indicate that tetrahydrocortisol is likely the main faecal cortisol metabolite in koalas, and we demonstrate that it can be measured by an EIA (50c) that was originally developed to measure tetrahydrocorticosterone.

‘Kindergarten’ keeping-system in farrowing house: effect the socialization of piglets on weight performances, fecal cortisol metabolite level and post-weaning behavior

This study aimed to examine whether litters’ let-together system before weaning (‘kindergarten-system’) has any stress effect and effect on post-weaning behavior, respectively. One week before weaning piglets were socialized by removing four adjacent farrowing crate walls. After weaning, piglets from the same experimental groups were housed in the same rearing crates. The piglet’s body weight was measured at birth than weekly till the 7th life-week. Fecal cortisol metabolites were measured for evaluation of the adrenocortical activity. Personal observation and evaluation were carried out for behavioral analyses after weaning. There were no significant differences in weight development and cortisol metabolite levels between the control and experimental groups. Behavioral analysis showed that pigs grow up in a socialized system, rapidly evolve ranking in the rearing crates, and the self-maintenance and social behavior were more pronounced. In control groups, the activity involving movement (exploring, walking, and running) was much more decisive. Recent work suggested the beneficial effect of the ‘kindergarten’ system in the farrowing house in animal welfare aspects.

Seasonal Variations of Faecal Cortisol Metabolites in Koalas in South East Queensland

The Koala (Phascolarctos cinereus) is an endemic marsupial inhabiting four states of Australia. Urbanisation, declining habitat, drought and fires are threatening the survival of this flagship species. These threats may cause acute and chronic stress in koalas, which might also be associated with occurrence of infectious diseases in koala populations. Stress may induce an increase in cortisol reflected in increased faecal cortisol metabolite (FCM) values. To be able to use faecal cortisol metabolites to measure stress levels in this species, our aim was to determine baseline values for males and females during breeding and non-breeding season. A total of 351 defecations were collected fortnightly, twice a day, for 12 months from koalas at a wildlife facility in South East Queensland. Samples were analysed with three different enzyme immunoassays (EIAs): a cortisol, 5α-pregnane-3β,11β,21-triol-20-one (37e) and tetrahydrocorticosterone (50c) EIA. The latter, which also reacts with tetrahydrocortisol, the main metabolite in koala faeces, was found to have the highest biological sensitivity and, therefore, is the most suitable EIA to measure stress levels in koalas. Utilising this EIA, we found significant differences (p < 0.05) in FCM values between males and females, breeding and non-breeding season, and between morning and evening samples. Values of faecal cortisol metabolites established in stress-free koalas in this study can serve as a reference for future studies in koalas.

Urinary Steroid Metabolome Signature Is Associated With Pre-Frailty and Frailty Phenotype in Older Adults

Background: Frailty is characterized by an increased vulnerability and a decline in physiological reserve. Frailty has been previously linked to cortisol concentrations and blunted diurnal cortisol secretion. Our objective was to determine the association of urine steroid metabolome and its diurnal variation with frailty and prefrailty in older adults. Methods: Cross-sectional study of community-dwelling adults ≥ 50 years. Participants with adrenal disorders, end-stage renal or liver disease, on exogenous steroids or drugs affecting steroid metabolism were excluded. All participants completed day and night separate urine collection. Frailty was assessed using a phenotype model (weight loss, exhaustion, grip strength, low physical activity, and slow walking pace). Participants were characterized as frail if they met at least three criteria, pre-frail if they fulfilled one or two criteria, and robust if no criteria were met. Urine samples were analyzed with the liquid-chromatography, high-resolution, accurate-mass mass spectrometry for 25 urine steroid metabolites. Results: Of 119 participants, 60 (50.4%) were women, without sex differences in age or education status. On frailty assessment, 5 (4.2%) participants were frail and 33 (27.7%) were prefrail, with equal sex distribution. Urine steroid metabolome analysis demonstrated 21/25 steroids were higher in men vs women. In an age adjusted model, presence of prefrailty or frailty was associated with a higher ratio of total cortisol metabolites/total androgen metabolites (TCM/TAM) in men (estimate 0.64, P-value= 0.0004), but not in women. In men, after adjusting for age, among cortisol metabolites, lower day to night ratio of 5α-Tetrahydrocortisol (estimate -0.36, P-value= 0.0419) and β-Cortol (estimate -0.35, P-value= 0.0238) were associated with frail or prefrail phenotype. After adjusting for age, higher ratio of TCM/TAM was associated lower gait speed in men (estimate -1.2, P-value= 0.046) and women (estimate -3.9, P-value= 0.012); and lower hand grip strength in men (estimate -0.04, P-value= 0.046) but not in women. Conclusion: We showed that a higher glucocorticoid to androgen ratio and a flattened circadian steroid variation were associated with presence of frail or prefrail phenotype in men. Further studies should examine the role of steroid metabolism and HPA axis impairment, and the associated sex differences, in the functional decline in aging population.

Intestinal Parasites and Fecal Cortisol Metabolites in Multi-Unowned-Cat Environments: The Impact of Housing Conditions

Housing conditions were assessed in different unowned multi-cat management models in order to evaluate their impact on the occurrence of intestinal parasites and fecal cortisol metabolite (FCM) levels. Fresh stool fecal samples were collected from rescue shelters, catteries and feline colonies for coprological analyses in order to detect intestinal parasite patency and fecal cortisol metabolites. A questionnaire provided information about the facilities, management and housing conditions of cats, including information about dog exposure, enclosure size, environment enrichment and changes to group composition. Overall, intestinal parasite infection was detected in 58.2% of fecal samples collected. The occurrence of intestinal parasites detected in free-roaming cats was 82.2%, mainly due to helminth infection. The parasite infection rate was 57.3% in rescue shelters and 34.6% in catteries. In confined cats, protozoa infection was more likely detected in rescue shelters than in catteries (RR = 2.02 (1.30–3.14), p = 0.0012). Although the FCM values were very variable between cats, the enclosure size and parasite infection were correlated with the average FCM. A small enclosure size was correlated with high fecal cortisol metabolites (p = 0.016). Protozoa-positive samples showed higher FCM levels than negative samples (p = 0.0150). High dog exposure was statistically associated with protozoa infection (p = 0.0006). The results indicated that improving housing, especially in terms of floor space and avoiding dog exposure, reduces stress and can thus be applied to make control strategies in multi-unowned-cat environments more efficient, especially when cats are confined.

Non-Invasive Physiological Indicators of Heat Stress in Cattle

Cattle are susceptible to heat stress, especially those kept on high levels of nutrition for the purpose of maximising growth rates, which leads to a significant heat increment in their bodies. Consequences include compromised health and productivity and mortalities during extreme events, as well as serious economic loss. Some measures of heat stress, such as plasma cortisol and temperature in the rectum, vagina, or rumen, are invasive and therefore unlikely to be used on farms. These may cause additional stress to the animal due to handling, and that stress in itself can confound the measure. Consequently, it is desirable to find non-invasive alternatives. Panting score (PS), cortisol metabolites in faeces, milk, or hair, and the infrared temperature of external body surfaces are all potentially useful. Respiratory indicators are difficult and time consuming to record accurately, and cortisol metabolites are expensive and technically difficult to analyse. Infrared temperature appears to offer the best solution but requires further research to determine the thresholds that define when corrective actions are required to ensure optimal health and productivity. Research in this area has the potential to ultimately improve the welfare and profitability of cattle farming.