High levels of corticosterone in feather-plucking parrots (Psittacus erithacus )

Avian Dermatology

Dermatologic conditions are common in avian practice and can be caused by a huge array of potential disorders, ranging from infectious diseases, ectoparasites, metabolic disorders, nutritional deficiencies, and management deficits. The skin is the largest organ in the body and has the potential to lead to significant discomfort and welfare compromise when pathology is present. Some conditions may be relatively pathognomonic based on gross findings, whereas others may require a full diagnostic workup to investigate. Getting to the bottom of skin lesions and disorders often involves identification and correction of the underlying cause, rather than just treating the lesions present in the integument.

Dopamine receptor activation elicits a possible stress-related coping behavior in a wild-caught songbird

Animals experience stress throughout their lives and exhibit both physiological and behavioral responses to cope with it. The stress response can become harmful when prolonged and increasing evidence suggests that dopamine plays a critical role in extinguishing the stress response. In particular, activation of the D2 dopamine receptor reduces glucocorticoids and increases coping behavior, i.e., behavioral responses to adverse stimuli that reduce the harmful effects of stress. However, few studies have examined the effects of dopamine on the stress responses of wild species. We therefore tested the hypothesis that activation of the D2 dopamine receptor influences coping-like behavior in a wild-caught species. We recorded behavior of house sparrows (Passer domesticus) before and after they received injections of D2 dopamine agonists, D2 dopamine antagonists, or saline. House sparrows are common in urban environments and understanding how they cope with stress may help us better understand how animals cope with urban stressors. We found that the birds significantly increased biting of inanimate objects after the agonist but there was no change following the antagonist or saline. The biting of inanimate objects may be a mechanism of behavioral coping. This change in biting behavior was not correlated with general movement. This study supports the hypothesis that D2 dopamine receptor activation is involved in the regulation of the stress response in a wild bird.

Medical Causes of Feather Damaging Behavior

Feather damaging behavior (FDB), also referred to as feather picking, feather plucking, or pterotillomania, is one of the most common and frustrating clinical presentations in captive psittacines. The clinical approach to identify underlying medical conditions associated with FDB is reviewed. Primary feather or skin diseases as well as systemic diseases may lead to this syndrome. This article focuses on the medical causes of FDB documented in the current avian literature. Medical causes are presented using the VITAMIN D algorithm. Key components of the multifaceted therapeutic approach in managing FDB of medical origin are discussed.

ACTH Stimulation Induced Self-Mutilation Behavior in the Golden Conure (Guaruba guarouba)

Simple Summary

Psittacidae are very susceptible to chronic stress and behavioral disorders. We report a successful physiological validation of an enzyme immunoassay for the non-invasive monitoring of adrenocortical activity and, thus, stress in the golden conure. In addition, as an incidental finding, we demonstrate a link between increased glucocorticoid levels and behavioral disorders. Our results are of great relevance for conservation projects and endocrine-behavioral studies of captive golden conures, where the stress evaluation is a fundamental part of animal welfare programs.

Abstract

Psittacidae are very susceptible to chronic stress and behavioral disorders. Information regarding the endocrinology of the golden conure is scarce, especially about adrenocortical activity. Endocrine studies using non-invasive methods are useful, because they allow longitudinal analysis with high numbers of samples without causing additional stress and are viable in the psittacidae management. The objective was to physiologically validate an enzyme immunoassay for measuring glucocorticoid metabolites (GCMs) in this species. Serial droppings were collected from 16 animals. First, one subgroup received adrenocorticotropic hormone (ACTH; Synacthen Depót^®) and the other group served as controls. This procedure was reversed afterwards. All birds presented self-mutilation approximately 6 h after the ACTH injection. This behavior disappeared after two days. Peak concentrations (on average nine times higher than baseline values) of GCMs were found 6 (4–8) h after ACTH administration; in all (but one) animals also a second peak was found 14 (10–20) h post injection. GCM levels returned to the baseline after 24 h. We physiologically validated a cortisone enzyme immunoassays to measure adrenocortical activity in the golden conure. Such non-invasive methods are important for studies, which are related to welfare, reproductive, and conservation programs. In addition, we could demonstrate a link between increased glucocorticoid levels and behavioral disorders.

Stress in captive Blue-fronted parrots (Amazona aestiva): the animalists' tale

Understanding stress physiology is crucial for species management because high levels of stress can reduce reproduction and the individual's ability to face threats to survive. One of the most popular methods for non-invasive monitoring of animal endocrine status is the glucocorticoid (GC) metabolite measurements, which can provide important information about how animals are affected by their surrounding environment. Here, we carried out the biological validation of corticosterone enzyme immunoassays (EIAs), which together with a cortisol EIA was used to quantified the concentrations of urofaecal GC metabolites (uGCMs) in wild and captive Blue-fronted amazon parrots (Amazona aestiva). Urofaecal GC concentrations were significantly higher (P < 0.05) in free-living parrots (157.9 ± 18.5 ng cortisol/g and 61.14 ± 23.5 ng corticosterone/g dry urofaecal sample) than in those kept in captivity, which showed the comparable levels of GC metabolites independently of the management system applied. The higher uGCM levels obtained in the wild population point to an adaptive response for survival and species propagation in a more challenging environment, in comparison with captive animals. Furthermore, the lower uGCM concentrations in captive parrots may indicate an adaptive capacity of the species A. aestiva to captivity and its potential as a legal pet. The corticosterone EIA applied in this study proved to be an effective technique for the adrenocortical activity monitoring in this species. We discuss our findings considering the management and destiny given to wild-caught birds that are kept in confinement or returned to nature.

Personality types in Budgerigars, Melopsittacus undulatus

The current study further characterized personality types in Budgerigars, an avian model that only recently demonstrated individual consistencies in behavior (Callicrate et al., 2011). Several methodological techniques, commonly used in previous examinations of other animal models, were employed. Specifically, Phase I assessed the relationship between Budgerigar personality types and Hypothalamic-Pituitary-Adrenal (HPA) activity, while Phase II sought to examine the persistence of individual behavioral tendencies across varying testing contexts. In comparison to other species, our findings failed to illustrate a clear relationship between Budgerigar personality types and concentrations of corticosterone. However, results provided significant evidence for the consistency of personalities across multiple contexts. In sum, our investigation further defined the expression of personality in the Budgerigar and substantiated the claim for individual tendencies in this species.

An association between feather damaging behavior and corticosterone metabolite excretion in captive African grey parrots (Psittacus erithacus)

Background

African grey parrots (Psittacus erithacus) are kept as pets and are frequently hand-reared. It has been observed that hand-reared African grey parrots may develop behavioral disorders such as feather damaging behavior (FDB). It is well known that chronic stress is involved in behavioral disorders in captive parrots. The main glucocorticoid in birds is corticosterone; its quantification provides information about adrenocortical activity and is considered to be a reliable indicator of stress levels in birds. We analyzed the differences in the excretion of corticosterone metabolites (CM) in the droppings of African grey parrots characterized by: 1. different rearing histories (parent rearing vs. hand rearing); and 2. the presence or absence of FDB in hand-reared parrots.

Methods

A total of 82 African grey parrots that were kept in captivity were considered. According to breeding methods, three groups of birds were defined: 1. The parent-reared (PR) parrots included birds kept in pairs (n = 30 pairs) with a conspecific partner of the opposite sex. All of these birds were healthy and never showed FDB signs; 2. The healthy hand-reared parrots (H-HR) included pet parrots individually kept, that were hand-reared and did not display any sign of FDB (n = 11, 7 males and 4 females); 3. The FDB hand-reared parrot (FDB-HR) included pet parrots individually kept, that were hand-reared and displayed FDB (n = 11, 7 males and 4 females). Droppings were collected in the morning over three alternating days in autumn 2014 and spring 2015. The CM were determined using a multi-species corticosterone enzyme immunoassay kit. Split-plot repeated-measure ANOVA was used to examine any differences using group, season and group × season as the main factors.

Results

Different quantities of CM in droppings were found for the three groups. The mean CM value was 587 ng/g in the PR parrots, 494 ng/g in the H-HR parrots and 1,744 ng/g in the FDB-HR parrots, irrespective of the season. The excretion of CM in FDB-HR was significantly higher than in PR or H-HR parrots. CM in droppings were not influenced by the season (autumn vs. spring); furthermore, the interaction between group and sampling season was not significant. Limited to the H-HR and FDB-HR groups, a trend in the significance of the difference in the mean CM excreted by male and female birds was observed, with the levels excreted by males being higher than those excreted by females. When the effect of age was considered (in the two separate groups), there was a statistically significant positive correlation only for H-HR.

Conclusions

The highest amount of CM excretion was found in FDB-HR parrots, and a positive correlation between age and CM excretion was found in H-HR. Given that the CM excretion of both PR and H-HR parrots was similar in our study, future research is recommended to investigate the specific aspects of hand-rearing to improve parrot welfare.

Associations between social behaviour and adrenal activity in female Barbary macaques: consequences of study design

Faecal glucocorticoid metabolite (fGCM) concentrations have been used to evaluate adrenal activity in a variety of species; including as an indicator of the physiological response to social stress. However, across studies, the relationships between dominance rank, social behaviours and adrenal responses can be inconsistent. Differences in the relationship between rank and glucocorticoids may be due to the relative costs of social status, and the relative frequencies of social stressors and potential coping mechanisms. However, the differences in observed relationships between specific social behaviours and glucocorticoids may be partly explained by sampling frequency, as studies often use average fGCM concentrations collected over a period of weeks or months, rather than fGCM concentrations that are temporally-matched with behavioural data. In this study, we directly compared long-term average and temporally-matched data to determine whether particular social behaviours were related to adrenal activity in female Barbary macaques (Macaca sylvanus) at Trentham Monkey Forest, UK; and whether observed relationships were consistent using these two approaches. Average rates of autogrooming were positively correlated with average fGCM; however, this relationship was not robust in temporally-matched samples. Instead, specific social behaviours associated with agonism were associated with fGCM in temporally-matched samples within individuals. These results indicate that analyses of relationships using long-term average fGCM and temporally-matched samples do not necessarily provide comparable results, highlighting that study design is critical in determining associations between an individual's social behaviour and the relative physiological costs involved.

Removing individual rats affects indicators of welfare in the remaining group members

The removal of individuals from social groups, e.g. in order to maintain appropriate stocking densities in groups of rapidly growing young laboratory rats, is often necessary. However, such removals may be stressful and few studies have investigated their effects on the behaviour, physiology and welfare of the remaining group members. In this study we investigated this issue for rats housed at different stocking densities by observing behaviour and recording faecal corticosterone metabolite levels both before and after removal. We found that, irrespective of stocking density, the rats remaining in the home cage significantly increased agonistic behaviour, audible vocalization, aggressive grooming, bar-chewing and climbing behaviour following removal of their cage-mates, and that these behavioural changes were associated with a highly significant post-removal increase in their faecal corticosterone metabolite levels. Taking the behavioural and physiological results together, it appears that the removal of individuals from groups of young laboratory rats resulted in social stress, and thus an apparent impairment of welfare.

Can non-invasive glucocorticoid measures be used as reliable indicators of stress in animals?

Refinement techniques are being increasingly employed in all fields of animal research to try to ensure that the highest standards of welfare are upheld. This review concerns one of the main emerging techniques for the assessment of welfare itself, namely the non-invasive measurement of glucocorticoids (GCs) as indicators of stress. The paper is divided into three sections. The first discusses the relationship between GCs and stress. The second section considers whether factors other than stress are linked to rises in GCs, eg exercise, oestrus cycle and diet. The final part examines the reliability of the non-invasive techniques that measure GCs from samples of saliva and faeces. Although it is important to take into account some caveats associated with the methodologies employed, it is concluded, nevertheless, that these techniques can give accurate and reliable information regarding the welfare status of an individual or group of animals without the procedures themselves causing any kind of distress to the subjects.