Measurement of corticosterone metabolites in chicken droppings

Validation of Fecal Glucocorticoid Metabolites as Non-Invasive Markers for Monitoring Stress in Common Buzzards (Buteo buteo)

For wild animals, being in captivity in wildlife centers can cause considerable stress. Therefore, it is necessary to establish and validate non-invasive tools to measure chronic stress during rehabilitation. Eight Common Buzzards which lived in permanent husbandry were placed individually into prepared aviaries and their feces were collected before, during and after a stress event for biological validation over a period of seven days. The extracted fecal glucocorticoid metabolites (fGCMs) were analyzed with three different enzyme immune assays (EIA) to find the most suitable one. Additionally, we aimed to investigate the stability of fGCM levels after defecation because further metabolization by bacterial enzymes can lead to changed results. The Cortisone-EIA performed best in males and females and showed that the stress event led to an fGCM increase of 629% (557% in females and 702% in males) in relation to basal values. We found no significant differences between the sexes, but observed significant differences between different times of day. FGCM concentration significantly changed after eight hours at room temperature. Our study successfully validated the non-invasive measurement of fGCM as a stress indicator in Common Buzzards and could therefore lay the foundation for future studies providing new insights for animal welfare research in Buzzards.

Does the provision of live black soldier fly and yellow mealworm larvae improve Muscovy duck welfare?

BACKGROUND

The provision of environmental enrichments to Muscovy ducks could reduce the expression of the aggressive behaviors. The aim of the present study was to evaluate the effects of black soldier fly (BSF) and yellow mealworm (YM) live larva provision on Muscovy duck performance, excreta corticosterone metabolites (ECM), behavior, and blood parameters.

METHODS

A total of 126 3-day-old female Muscovy ducklings were allotted to 18 pens (6 replicates/treatment, 7 birds/pen) and assigned to 3 experimental treatments: a control group fed commercial feed, and two experimental treatments fed commercial feed plus the 5% (based on the expected daily feed intake, as fed basis) of BSF and YM live larvae (BSF and YM groups, respectively). A two-phase feeding program was applied: starter (from 3 to 31 days of age) and grower-finisher (from 32 to 55 days of age). The live weight, average daily gain, average daily feed intake, and feed conversion ratio were calculated. Larva consumption times were collected, and video recordings were performed during 3 periods (P) each day: the hour before (P1), during (P2), and after (P3) the larva administration. ECM were evaluated at 3, 31, and 55-day-old. Finally, the total red and white blood cell counts, serum proteins, lipids, and liver and renal function serum enzymes were evaluated on 12 birds/treatment.

RESULTS

The experimental treatment did not affect the growth performance of the birds (P > 0.05). Larva consumption times were always similar between the two insect species, except at 14-18 days of age, were BSF larvae were consumed faster than YM larvae (P < 0.001). The birds showed less walking activity during P2, and preening behavior increased in YM birds during P3. The C birds increased the attack behavior over the weeks (P < 0.05). During weeks 1-3 the YM group reduced the attack frequency (P1 > P3; P < 0.05). Finally, the provision of live BSF and YM larvae significantly reduced the ECM at 55 days of age and the heterophil to lymphocyte ratio (P < 0.05).

CONCLUSIONS

Live BSF and YM larva supplementation in Muscovy duck improves duck welfare, without impairing birds' growth performance.

Lameness in Pregnant Sows Alters Placental Stress Response

Pregnant sows from commercial pig farms may experience painful states, such as lameness, an essential indicator in assessing sow welfare. We investigated the effect of lameness during the last third of pregnancy on reproductive performance and placental glucocorticoid concentrations in sows. Periodic locomotion assessments were carried out on two commercial pig farms using a validated 0-5 scoring system (from 0: normal locomotion; to 5: a downer animal). Sows from both farms (N = 511) were grouped based on their average locomotion scores. On Farm 1, 30 sows were selected and grouped as either Not Lame (NL = 16; X¯ = 0-1) or Lame (L = 14; X¯ > 1). On Farm 2, 39 sows were selected and grouped as either Not Lame (G1 = 12; X¯ = 0-1), Moderately Lame (G2 = 13; X¯ = 1.1-2), or Severely Lame (G3 = 14; X¯ ≥ 2.1). Reproductive data (gestation length, litter weight, average piglet weight, litter size, and the number of piglets born alive/mummified/stillborn) were recorded on both farms. Moreover, on Farm 2, piglet intrauterine growth restriction score and the number of piglets dead during the first week were also recorded, and placenta samples were collected to determine their cortisol/cortisone concentrations. A linear mixed model was used to analyze the data. The proportion of lameness in pregnant sows (N = 511) was >40%, and the gestation length tended to decrease with the presence of lameness (p < 0.1) in both farms. G2 sows had a higher placental cortisol/cortisone ratio than G1 and G3 sows (p < 0.01). In conclusion, lameness was high in the sows assessed, which may decrease sow gestation length and reduce placental efficiency in protecting the offspring from the sows' stress response.

Camel (Camelus spp.) Urine Bioactivity and Metabolome: A Systematic Review of Knowledge Gaps, Advances, and Directions for Future Research

Up to the present day, studies on the therapeutic properties of camel (Camelus spp.) urine and the detailed characterization of its metabolomic profile are scarce and often unrelated. Information on inter individual variability is noticeably limited, and there is a wide divergence across studies regarding the methods for sample storage, pre-processing, and extract derivatization for metabolomic analysis. Additionally, medium osmolarity is not experimentally adjusted prior to bioactivity assays. In this scenario, the methodological standardization and interdisciplinary approach of such processes will strengthen the interpretation, repeatability, and replicability of the empirical results on the compounds with bioactive properties present in camel urine. Furthermore, sample enlargement would also permit the evaluation of camel urine's intra- and interindividual variability in terms of chemical composition, bioactive effects, and efficacy, while it may also permit researchers to discriminate potential animal-intrinsic and extrinsic conditioning factors. Altogether, the results would help to evaluate the role of camel urine as a natural source for the identification and extraction of specific novel bioactive substances that may deserve isolated chemical and pharmacognostic investigations through preclinical tests to determine their biological activity and the suitability of their safety profile for their potential inclusion in therapeutic formulas for improving human and animal health.

Multifactorial Evaluation of Regrouping Effects on Performance and Welfare in Two Italian Dual-Purpose Chicken Breeds: Bianca di Saluzzo and Bionda Piemontese

Simple Summary

Local chicken breeds Bionda Piemontese (BP) and Bianca di Saluzzo (BS) are promising for use in small-scale poultry farms, which adopt free-range and/or organic farming practice. However, in practical conditions, it can happen that animals are subjected to regrouping, creating a new flock by mixing different groups. Such situations may provoke a stressful response in birds, compromising their welfare. To evaluate the resilience of BP and BS breeds to adverse management practices (regrouping), the present study aimed to assess the birds’ welfare status through a multifactorial approach. As a result, the practice of regrouping immediately compromised the welfare status and the productive performances in both BP and BS hens, but, in the following weeks, birds displayed a reliance, which help them adapt to the new stressful conditions.

Abstract

The aim of the present study was to investigate the ability of two Italian slow-growing poultry breeds (namely, Bionda Piemontese, BP, and Bianca di Saluzzo, BS) to cope with a stressful event, such as collective grouping, using a multifactorial approach. A total of 120 hens of BP and BS breeds were homogenously distributed, according to breed, in 12 pens (10 hens/pen; 6 pens/breed), from 18 to 49 weeks of age. At 50 weeks of age, hens were regrouped (Stressful Farm Practice, SFP), by removing separators, both in indoor and outdoor areas. At 49 weeks of age, 24 hens/breed were randomly selected for the evaluation of welfare (ethological and physiological) parameters, at different time points: T0: 1-week pre-SPF; T1: 1-week post-SFP; T2: 3-week post-SFP; T3: 5-week post-SFP. Egg production was recorded from 38 to 56 weeks of age. Grouping produced a social stress in both BS and BP-laying hens, which was expressed in terms of productive traits (reduction of oviposition), behavioral modification (worsening of plumage condition due to feather peaking and extension of the duration of the tonic immobility test) and physiological modification (increased heterophil/lymphocyte ratio and corticosterone metabolites in droppings). Both breeds reacted in a similar way; in fact, no differences were attributed to the breed. At the end of the observation period, the egg rate fully recovered, while the behavioral and physiological parameters partially recovered but failed to recover to those recorded prior to the stressful event.

Feather pulp: a novel substrate useful for proton nuclear magnetic resonance spectroscopy metabolomics and biomarker discovery

Noninvasive biomarkers of stress that are predictive of poultry health are needed. Feather pulp is highly vascularized and represents a potential source of biomarkers that has not been extensively explored. We investigated the feasibility and use of feather pulp for novel biomarker discovery using ¹H-Nuclear Magnetic Resonance Spectroscopy (NMR)-based metabolomics. To this end, high quality NMR metabolomic spectra were obtained from chicken feather pulp extracted using either ultrafiltration (UF) or Bligh-Dyer methanol-chloroform (BD) methods. In total, 121 and 160 metabolites were identified using the UF and BD extraction methods, respectively, with 71 of these common to both methods. The metabolome of feather pulp differed in broiler breeders that were 1-, 23-, and 45-wk-of-age. Moreover, feather pulp was more difficult to obtain from older birds, indicating that age must be considered when targeting feather pulp as a source of biomarkers. The metabolomic profile of feather pulp obtained from 12-day-old broilers administered corticosterone differed from control birds, indicating that the metabolome of feather pulp was sensitive to induced physiological stress. A comparative examination of feather pulp and serum in broilers revealed that the feather pulp metabolome differed from that of serum but provided more information. The study findings show that metabolite biomarkers in chicken feather pulp may allow producers to effectively monitor stress, and to objectively develop and evaluate on-farm mitigations, including practices that reduce stress and enhance bird health.

Translocation stress is reflected in corticosterone metabolites in pheasant (Phasianus colchicus) droppings

Translocation (including transportation and experiencing a new environment) represents a significant stressor for animals. The aim of this study was to assess changes in corticosterone metabolite (CM) levels related to translocation in common pheasants (Phasianus colchicus). Sixteen birds (8 males and 8 females) aged 17 weeks were crated and transported for 3.5 h (distance travelled 140 km) to the target customer. Serial individual droppings were collected from 2 days prior until 3 days after transport. Concentrations of CMs in droppings were determined with a non-commercial cortisone enzyme immunoassay (EIA). Transport stress resulted in increased CM concentrations in the droppings in our study. The CM concentrations significantly increased within 2.5 h of transport (P < 0.01) compared to pre-transport levels (747 ng/g vs. 187 ng/g). After additional 3 h, the CM concentrations fell back to the baseline levels (207.7 ng/g). In the new environment, the second peak (median: 1383 ng/g) was determined with CM concentrations increasing (P < 0.01) compared to baseline levels. This increase was likely connected to the stress resulting from the new environment. The CM levels returned back to the baseline level 26 h after the start of transportation. No differences in concentrations of CM between sexes were found in our study. The utilized cortisone EIA proved suited to detect biologically meaningful alterations in adrenocortical activity of pheasants exposed to procedures related to their transport.

Research Note: It's not just stress-fecal contamination of plumage may affect feather corticosterone concentration

The feather corticosterone concentration (fCORT) is increasingly used to assess long-term stress in birds as this indicator provides the potential to retrospectively evaluate the adrenocortical activity of a bird during the growth period of a feather over several weeks in one sample. However, there is still a lack of knowledge concerning external factors which can potentially influence fCORT in birds. The aim of the present study was to determine whether fCORT in laying hens is affected by previous fecal contamination of the plumage. Fully grown primaries 5 (P5s) of laying hens (n = 40) were used for the study. To test the effects of fecal contamination on fCORT, freshly defecated droppings from laying hens were collected and mixed manually. In order to simulate practical and at the same time standardized contamination, the upper surface of the previously determined middle third of the right P5 of each hen then was evenly coated with the paste prepared from fresh feces. The treated feathers were stored for 24 h protected from light at room temperature under a film cover to prevent evaporation. Thereafter, the applied layer of excreta was removed manually. Contralateral P5s of the same individuals were stored under identical conditions and served as controls. Both treatment and control feathers were washed in an aqueous soap solution, rinsed several times in pure water and air-dried subsequently. After pulverization and methanolic extraction, fCORT was analyzed by ELISA. The mean fCORT of treatment P5s (reference ‘feather length’: 12.88 ± 3.16 pg/mm; reference ‘feather weight’: 7.81 pg/mg ± 1.86 pg/mg) were significantly higher (P < 0.001) than those of control P5s (reference ‘feather length’: 9.76 ± 2.42 pg/mm; reference ‘feather weight’: 5.93 ± 1.44 pg/mg). Our results show that previous contamination with excreta can increase fCORT, which was detectable even after a washing procedure prior to analysis. In conclusion, fecal contamination of feathers is a significant influencing factor that has to be considered when applying fCORT measurements.

No evidence of increased fecal glucocorticoid metabolite levels in capercaillie (Tetrao urogallus) due to wind turbines

Wind energy facilities (WEFs) are a relatively novel impact on wildlife habitats, and an increasing number of studies show negative effects on wildlife. Increased stress-associated hormone levels are an indicator of disturbance effects, and measuring fecal glucocorticoid metabolite (FCM) levels is an established noninvasive method to study disturbance effects on wildlife. We studied whether FCM levels of capercaillie (Tetrao urogallus), a locally threatened forest bird species with proven behavioral responses to WEF, are affected by WEF. Using a before-after-control-impact (BACI) study design at sites in Austria, Germany and Sweden we investigated whether mean FCM levels changed after the construction of WEF and whether there was spatial variation in FCM levels in relation to WEF impacts. By analyzing 553 fecal samples from five wind farms and five control sites, we did not find evidence of increased FCM levels due to WEF when comparing wind farm sites before and after WEF construction with control sites. We further could not detect any spatial variation in FCM levels at wind farms related to turbine effects. There was, however, temporal variation in FCM, with lower FCM levels toward the end of the winter season. Differences among individual study sites emphasize the importance of larger studies with a BACI study design. Facing some methodological limitations, we currently find no evidence for an increase in FCM levels in capercaillie due to WEF.

An exploratory investigation of glucocorticoids, personality and survival rates in wild and rehabilitated hedgehogs (Erinaceus europaeus) in Denmark

BACKGROUND

The European population of hedgehogs (Erinaceus europaeus) is declining. It is therefore essential to optimise conservation initiatives such as the rehabilitation of sick, injured and orphaned hedgehogs. Wild animals placed in captivity may be prone to chronic stress, potentially causing negative health effects. Therefore, the effects of these rehabilitation efforts should consequently be evaluated. Furthermore, hand-raising orphaned hedgehogs is a laborious and costly task, and it is therefore relevant to document whether they have equal post release survival rates compared to their wild conspecifics. The objectives of this research were therefore to conduct an exploratory study of glucocorticoid levels in hedgehogs from different backgrounds and compare the post release survival of translocated, rehabilitated and wild, juvenile hedgehogs as well as the possible effect on survival of differences in shy or bold behaviour (personality) exhibited by individuals.

RESULTS

We measured glucocorticoid levels in 43 wild-caught (n = 18) and rehabilitated (n = 25) hedgehogs and compared the post release survival and spatial behaviour of 18 translocated juvenile hedgehogs (eight hand-raised and ten wild) until hibernation. The possible effect on survival of differences in shy or bold behaviour (personality) exhibited by 17 juvenile individuals (seven hand-raised and ten wild) was also examined. Rehabilitated individuals and females had higher levels of faecal corticosterone metabolites compared to wild individuals and males, respectively. Rehabilitated individuals showed higher levels of saliva corticosterone than wild. The personality tests labelled 13 individuals as shy and 11 as bold. Post release survival was 57% for rehabilitated and 50% for wild individuals. Neither background nor personality affected post release survival. Home range measures were 3.54 and 4.85 ha. Mean dispersal length from the release sites was 217 ± 100 m.

CONCLUSION

The higher levels of corticosterone observed in rehabilitated compared to wild hedgehogs calls for consideration of the duration of admission to wildlife rehabilitation centres to reduce stress levels in the patients. Hand-raised juveniles appear to have the same prospects as wild, and personality does not seem to affect post release survival in hedgehogs, indicating that hand-raising of orphaned juvenile hedgehogs is a relevant contribution to the conservation of this species.

Stress, health and the welfare of laying hens

It is essential to understand responses to stress and the impact of stress on physiological and behavioural functioning of hens, so as to assess their welfare. The current understanding of stress in laying hens is comprehensively reviewed here. Most research on stress in hens has focussed on the activity of the adrenal glands, with the most common approach being to measure corticosterone, which is the predominant glucocorticoid produced by birds in response to stress. While these measures are useful, there is a need to understand how the brain regulates stress responses in hens. A greater understanding of the sympathoadrenal system and its interaction with the hypothalamo–pituitary–adrenal axis is required. There is also a lack of knowledge about the many other peptides and regulatory systems involved in stress responses in hens. The usefulness of understanding stress in hens in terms of assessing welfare depends on appreciating that different stressors elicit different responses and that there are often differences in responses to, and impacts of, acute and chronic stress. It is also important to establish the actions and fate of stress hormones within target tissues. It is the consequences of these actions that are important to welfare. A range of other measures has been used to assess stress in hens, including a ratio of heterophils to lymphocytes and haematocrit:packed cell-volume ratio and measures of corticosterone or its metabolites in eggs, excreta, feathers and the secretions of the uropygial gland. Measures in eggs have proffered varying results while measures in feathers may be useful to assess chronic stress. There are various studies in laying hens to indicate impacts of stress on the immune system, health, metabolism, appetite, and the quality of egg production, but, generally, these are limited, variable and are influenced by the management system, environment, genetic selection, type of stressor and whether or not the birds are subjected to acute or chronic stress. Further research to understand the regulation of stress responses and the impact of stress on normal functioning of hens will provide important advances in the assessment of stress and, in turn, the assessment of welfare of laying hens.

Corticosterone in feathers of laying hens: an assay validation for evidence-based assessment of animal welfare

Studies indicate that the evaluation of animal welfare in birds may be carried out with the measurement of the stress-related hormone corticosterone in feathers. However a standardized procedure for corticosterone measurements in feathers is lacking, a validation needs to be carried out for each new species before implementation. The aim of the present study was to establish a valid method to measure corticosterone concentrations in feathers of laying hens in a precise and repeatable manner using an established and commercially available ELISA. Validation was performed with feather pools of tail and interscapular feathers of commercial Lohmann Brown laying hens. Assessment groups, consisting of 5 replicates, were created. All replicates of an assessment group were processed at the same time. Each replicate was run in 4 repetitions by ELISA. Intra-assay and interassay CV was 7.5 and 6.4%, respectively. The serial dilution showed linearity and parallelism. Examining the hormone extraction efficiency by using different methanol volumes resulted in no statistical differences (P > 0.05). Pulverized feathers showed higher corticosterone values than minced feathers (P > 0.05). Differences were shown between 2 feather types (tail vs. interscapular feathers; P < 0.05), as well as between vane and rachis (P < 0.05). Performance of a freeze-thaw cycle led to a decrease of corticosterone concentrations in the samples. A possible effect of UV-A radiation on the stability of corticosterone in the feathers was not found (P > 0.05). With the present study, a valid protocol, feasible for analyzing feather pools of laying hens, was developed. It may provide fundamentals for further investigations on corticosterone in feathers as a noninvasive indicator to evaluate aspects of animal welfare.

Effect of Feed Restriction on the Behaviour and Welfare of Broiler Chickens

Under intensive rearing conditions, the welfare of broiler chickens may be at risk depending on genotype and sex, due to their different growth rates. The practice of quantitative feed restriction may also impact on welfare. This study aimed to evaluate behaviour and corticosterone content in plasma and faeces at different ages using 896 one-day-old chicks housed in 32 pens, allocated to 8 groups, i.e., 2 genotypes (standard vs. high breast yield) × 2 sex × 2 feeding plans (ad libitum vs. restricted, AL vs. FR). The feeding system affected the percentage of standing (9.84% vs. 11.7% in AL vs. FR; p ≤ 0.001), feeding (7.51% vs. 8.17%; p ≤ 0.01) and sitting/lying (67.0% vs. 64.1%; p ≤ 0.001), and the faeces corticosterone content (12.2 vs. 13.6 ng/g in AL vs. FR; p ≤ 0.10). Sex affected the percentage of pecking other chickens, standing and comfort behaviours. Changes in behaviour were recorded between high and standard breast yield genotypes with faeces corticosterone which tended to be higher in the former (p ≤ 0.10). Significant interactions between the main factors and age were observed. Major changes in behaviour were due to feed restriction, which stimulated activity during restriction.

Validation of a noninvasive technique to quantify stress in northern bobwhite (Colinus virginianus)

Examination of the endocrine system through non-invasive fecal sampling may improve population management more than using demographic indicators alone. By addressing the physiological mechanisms that are influencing fitness, management actions can be proactively developed to alleviate stressors. Proactive determination of vulnerable populations is critical for species of concern, such as the Northern Bobwhite (Colinus virginianus), which have suffered decades of population decline. We validated an assay to noninvasively measure the adrenocortical response of captive reared bobwhite through fecal corticosterone metabolites (FCM). All individuals received three sequential 48-hour treatments in which samples were collected every 4 hours, including a reference period, an adrenocorticotropic hormone (ACTH) challenge and a biological stressor (exposure to a hunting dog). Reference FCM values had a mean concentration of 16.75 pg/mg (95% CrI: 13.68, 19.91) with adrenocortical activity increasing by 73% for the duration of the ACTH challenge (29.00 pg/mg; CrI: 25.01, 33.78). FCM concentrations remained similar to that of the reference levels during the biological stressor (16.56 pg/mg; CrI: 13.33, 19.92). Our study validates the use of feces to detect changes in FCM levels in our subject species but also demonstrates the complexity of FCM and the importance of both physiological and biological validation prior to field implementation.

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.

Validating a non-invasive technique for monitoring physiological stress in the samango monkey

The non-invasive monitoring of physiological stress can provide conservation and wildlife managers with an invaluable tool for assessing animal welfare and psychological health of captive and free-ranging populations. A significant decrease in free-ranging primate populations globally and an increase in captive-housed primates have led to a need to monitor the stress and general welfare of these animals. We examined the suitability of three enzyme immunoassays (EIAs) for monitoring stress-related physiological responses in the samango monkey, Cercopithecus albogularis erythrarchus. We conducted an adrenocorticotropic hormone (ACTH) challenge on a male and female at the National Zoological Garden, Pretoria, South Africa. Individual faecal samples were collected 8 days pre- and post-ACTH administration and subsequently analysed for faecal glucocorticoid metabolite (fGCM) concentrations. During the study, biological stressors occurred for both the male and female. Two of the three EIAs tested (11-oxoetiocholanolone I and II) were able to reliably monitor fGCM alterations throughout the study period in both sexes. The 11-oxoetiocholanolone I EIA, however, had the lowest mean deviation from the calculated baseline value and was thus chosen as the preferred assay. Both the physiological activation of the stress response and the biological response to a stressor could be monitored with the chosen assay. The successful establishment of a reliable, non-invasive method for monitoring adrenocortical activity in C. albogularis erythrarchus will now allow conservationists, scientific researchers and wildlife managers to evaluate the level of stress experienced, and general welfare, by animals in captivity as well as free-ranging populations.

Monitoring corticoid metabolites in urine of white-tailed sea eagles: Negative effects of road proximity on breeding pairs

The white-tailed sea eagle (Haliaeetus albicilla) is known to be sensitive to disturbance. To better understand potential stressors, we measured corticosterone metabolite levels in H. albicilla excreta and recorded the nest success of breeding pairs. We tested the ability of four enzyme immunoassays (EIA) to measure urinary glucocorticoid metabolites (uGM) in the excreta of one adult female eagle subjected to a controlled physiological stress treatment. We identified corticosterone-21-HS to be the most sensitive EIA to changes in uGM concentration. To exclude a sex bias, we confirmed the assay's applicability with samples collected from similar stress treatments in two juvenile males. We used the identified EIA to measure uGM in wild breeding pairs and tested effects of disturbance. Breeding pairs nesting closer to roads and paths had higher uGM concentrations (p = 0.02), which is likely an effect of human recreational activity and disturbance. There was no difference in uGM concentrations between failed and successful nests. Our results highlight the potential impact of road and path proximity on white-tailed sea eagles, with potential importance for species management and conservation, particularly with respect to nest protection zone legislation.

Non-invasive monitoring of physiological stress in an afrotropical arid-zone passerine bird, the southern pied babbler

Using faecal matter to monitor stress levels in animals non-invasively is a powerful technique for elucidating the effects of biotic and abiotic stressors on free-living animals. To validate the use of droppings for measuring stress in southern pied babblers (Turdoides bicolor) we performed an ACTH challenge on captive individuals and determined the effect of temporary separation from their social group on their faecal glucocorticoid metabolite (fGCM) concentration. Additionally, we compared fGCM concentrations of captive babblers to those of wild conspecifics and examined the effects of dominance rank on fGCM concentration. We found droppings to be a suitable matrix for measuring physiological stress in babblers and that individual separation from the group caused an increase in fGCM levels. In addition, babblers temporarily held in captivity had substantially higher fGCM concentrations than wild individuals, indicating that babblers kept in captivity experience high levels of stress. In wild, free-living individuals, dominant males showed the highest levels of stress, suggesting that being the dominant male of a highly territorial social group is stressful. Non-invasive sampling allows field-based researchers to reduce disturbance related to monitoring adrenocortical function, thereby avoiding artificially increasing circulating corticosterone concentration as it is not necessary to physically restrain study animals.

Human behaviour at the origin of maternal effects on offspring behaviour in laying hens (Gallus gallus domesticus)

Regular visual presence of humans is known to reduce chickens' human-generated stress responses. Here we questioned whether, more than mere visual presence, human behaviour affects laying hen behaviour and subsequently their offspring's behaviour. We hypothesized that human behaviour triggers maternal effects via variations in yolk hormone levels. For five consecutive weeks, two groups of hens were exposed to the same durations of human presence (30 min twice a day, five days a week) but the behaviour of the human differed between groups. The first group (H+) was exposed to predictable arrival of the experimenter, slow movements combined with static presence, stroking during handling and human voice. Whereas the second group of hens (H-) was exposed to unpredictable arrival of the experimenter which remained silent, in motion, and did not provide stroking during handling. At the end of the treatment, we evaluated egg quality and offspring behaviour. We found that avoidance of the experimenter by H+ hens but not by H- hens decreased significantly. Fertility rates and concentrations of yolk progesterone and estradiol in H+ hens' eggs were higher than in H- hens' eggs. Fear of humans, neophobia or the capacity to solve a detour task did not differ significantly between H+ and H- chicks. Social discrimination tests showed that H+ chicks but not H- chicks typically preferred a familiar conspecific to a stranger. These results show that, with the same duration in the presence of the birds, humans through their behaviour engender variations in fertility rates, yolk hormone levels and transgenerational effects on social skills. Rarely explored, our data suggest that maternal effects influence filial imprinting. These data have broad implications for laboratory, commercial systems and conservatory programs where the inevitable presence of humans could trigger maternal effects on offspring phenotype.

Non-invasive measurement of glucocorticoids: Advances and problems

Glucocorticoids (GCs; i.e. cortisol/corticosterone) are a central component of the stress response and thus their measurement is frequently used to evaluate the impact of stressful situations. Their metabolites from faeces of various animal species are more and more taken as a non-invasive aid to assess GC release and thus adrenocortical activity. The current literature review includes an extensive collection (1327 papers) and evaluation (see also Supplementary Tables) of the literature on faecal cortisol/corticosterone metabolite (FCM) analysis published to date. It aims at giving reference for researchers interested in implementing FCM analysis into their study or seeking to improve such methods by providing background knowledge on GC metabolism and excretion, conveying insights into methodological issues and stating caveats of FCM analysis and by highlighting prerequisites for and some examples of a successful application of such methods. Collecting faecal samples and analysing FCMs may appear simple and straightforward, but researchers have to select and apply methods correctly. They also need to be aware of the many pitfalls and potentially confounding factors and, last but not least, have to carefully interpret results. Applied properly, measurement of FCMs is a powerful non-invasive tool in a variety of research areas, such as (stress) biology, ethology, ecology, animal conservation and welfare, but also biomedicine.

Glucocorticoid measurement in plasma, urates, and feathers from California condors (Gymnogyps californianus) in response to a human-induced stressor

Vertebrates respond to stressful stimuli with the secretion of glucocorticoid (GC) hormones, such as corticosterone (CORT), and measurements of these hormones in wild species can provide insight into physiological responses to environmental and human-induced stressors. California condors (Gymnogyps californianus) are a critically endangered and intensively managed avian species for which information on GC response to stress is lacking. Here we evaluated a commercially available I125 double antibody radioimmunoassay (RIA) and an enzyme-linked immunosorbent assay (ELISA) kit for measurement of CORT and GC metabolites (GCM) in California condor plasma, urate, and feather samples. The precision and accuracy of the RIA assay outperformed the ELISA for CORT and GCM measurements, and CORT and GCM values were not comparable between the two assays for any sample type. RIA measurements of total CORT in condor plasma collected from 41 condors within 15 minutes of a handling stressor were highly variable (median = 70 ng/mL, range = 1-189 ng/mL) and significantly different between wild and captive condors (p = 0.02, two-tailed t-test, n = 10 wild and 11 captive). Urate GCM levels (median = 620 ng/g dry wt., range = 0.74-7200 ng/g dry wt., n = 216) significantly increased within 2 hr of the acute handling stressor (p = 0.032, n = 11 condors, one-tailed paired t-test), while feather section CORT concentrations (median = 18 pg/mm, range = 6.3-68 ng/g, n = 37) also varied widely within and between feathers. Comparison of multiple regression linear models shows condor age as a significant predictors of plasma CORT levels, while age, sex, and plasma CORT levels predicted GCM levels in urates collected within 30 min of the start of handling. Our findings highlight the need for validation when selecting an immunoassay for use with a new species, and suggest that non-invasively collected urates and feathers hold promise for assessing condor responses to acute or chronic environmental and human-induced stressors.

Effect of Two Transport Options on the Welfare of Two Genetic Lines of Organic Free Range Pullets in Switzerland

Simple Summary

Animal welfare has been of increasing interest to consumers and producers of animal products in Europe. Issues during transport affect both the wellbeing and the productivity of livestock. This study was conducted to analyze two practice-oriented transport variants of organically mixed-held white and brown pullets. No significant difference could be found between the transport variants. Instead, we discovered clear differences between the two genetic pullet lines.

Abstract

The welfare of two genetic lines of organic layer hen pullets—H&N Super Nick (HNS) and H&N Brown Nick (HNB)—was compared during two commercial transport variants of 15 flocks of mixed-reared birds. Birds were either transported overnight (with a break in travel), or were transported direct to the layer farm (without a break in travel). Samples of feces were collected non-invasively from 25 birds of each genetic line per flock for each transport variant before transportation to evaluate baseline values of glucocorticoid metabolites, and at 0 h, 3 h, 6 h, 10 h, 24 h, 34 h, 48 h, 58 h, and 72 h after the end of transportation, to measure transportation and translocation stress. We assessed the fear toward humans with the touch test before transportation, and we checked the birds’ body condition by scoring the plumage condition and the occurrence of injuries. Body weight before and weight loss after transportation were determined, and ambient temperature was measured before, during, and after transportation. Stress investigations showed no significant differences between the transport variants (effect: −0.208; 95% confidence interval (CI): (−0.567; 0.163)). Instead, we discovered differences between the pullet lines (effect: −0.286; 95% CI: (−0.334; 0.238)). Weight loss was different between the transport variants (2.1 percentage points; 95% CI: (−2.6; −1.5)) and between the genetic lines, as HNB lost significantly less weight than HNS (0.5 percentage points; 95% CI: (0.3; 0.7)).

An integrated analysis of social stress in laying hens: The interaction between physiology, behaviour, and hierarchy

Livestock is the category of animals that suffers the most severe welfare problems. Among these, physical, physiological, and behavioural distress caused by artificial grouping are some of the challenges faced by these animals. Groups whose members are frequently changed have been reported as socially unstable, which could jeopardise the welfare of animals. Here, we assessed the effect of social instability on aggression, stress, and productivity in groups of laying hens (Gallus gallus domesticus). We studied 36 females, distributed into three stable groups (without group membership change) and three unstable groups (where the dominant member was rotated every week) over the course of 10 weeks. We evaluated the frequency of agonistic interactions, glucocorticoid metabolites (GCM) concentrations, and egg production. In both treatments, dominant hens produced more eggs compared to intermediate and subordinates, and intermediate hens had the highest GCM concentrations. Socially unstable groups had lower productivity and higher frequencies of agonistic interactions than stable groups. Social instability also affected GCM of the animals: in stable groups, subordinate hens had higher concentrations than dominants; in unstable groups, this pattern was reversed. Our results point to a social destabilisation in groups whose members were alternated, and suggest the welfare of individuals in unstable groups was compromised. Our results pointed to a complex relationship between hierarchy, productivity, physiological stress and aggression in laying hens, and have implications for their husbandry and management and, consequently, for their welfare levels.

Incubation temperature affects the expression of young precocial birds' fear-related behaviours and neuroendocrine correlates

The influence of embryonic microclimate on the behavioural development of birds remains unexplored. In this study, we experimentally tested whether chronic exposure to suboptimal temperatures engendered plasticity in the expression of fear-related behaviours and in the expression of the corticotropin-releasing factor in the brains of domestic chicks (Gallus g. domesticus). We compared the neurobehavioural phenotypes of a control group of chicks incubated in an optimal thermal environment (37.8 °C) with those of a group of experimental chicks exposed chronically in ovo to suboptimal temperatures (27.2 °C for 1 hour twice a day). Chronic exposure to a suboptimal temperature delayed hatching and decreased growth rate and experimental chicks had higher neophobic responses than controls in novel food and novel environment tests. In addition, experimental chicks showed higher expression of corticotropin-releasing factor than did controls in nuclei of the amygdala, a structure involved in the regulation of fear-related behaviours. In this study, we report the first evidence of the strong but underappreciated role of incubation microclimate on the development of birds’ behaviour and its neurobiological correlates.

Behavioural and hormonal effects of member replacement in captive groups of blue-fronted amazon parrots (Amazona aestiva)

Social species in captivity may face allostatic overload due to artificial grouping and other social constraints. In rescue centres, groups of psittacines are constantly mixed due to the arrival and/or release of individuals; this procedure is potentially harmful to animal welfare. This study aimed at evaluating the possible impacts of mate replacement on the stress levels of captive blue-fronted amazon parrots (Amazona aestiva). During five weeks, we recorded agonistic interactions and dropping-glucocorticoid metabolites (GCM) concentrations of individuals allocated in a group whose members were kept constant and in a group subjected to frequent member replacement. In both groups, non-linear hierarchies developed, without sex differences regarding aggression or hierarchical positions. The replacement of individuals had no effect on the number of agonistic interactions or on the animals' stress levels. In both groups, higher-ranking individuals had higher stress loads than subordinates. Our study, the first to investigate the social dynamics of A. aestiva, indicated that introducing or removing individuals in captive groups does not seem to affect the welfare of the birds in the short term. This information favours release and reintroduction programs and is relevant for conservation management of this, and possibly other parrot species with similar environmental requirements.

Lipids in maternal diet influence yolk hormone levels and post-hatch neophobia in the domestic chick

We assessed whether the ratio of dietary n-6/n-3 polyunsaturated fatty acids (PUFA) during egg formation engenders transgenerational maternal effects in domestic chicks. We analyzed yolk lipid and hormone concentrations, and HPA-axis activity in hens fed a control diet (high n-6/n-3 ratio) or a diet enriched in n-3 PUFAs (low n-6/n-3 ratio) for 6 consecutive weeks. Their chicks were tested for neophobia during the first week of life. We found higher corticosterone metabolites in droppings of hens fed the diet enriched in n-3 and significantly higher concentrations of yolk progesterone, androstenedione, and estradiol in their eggs compared to controls. Chicks of hens fed the n-3 enriched diet showed a lower body mass at hatch than controls and expressed higher neophobia when exposed to a novel object. These results add support to the hypothesis that the nutritional state of female birds produces variation in yolk hormone levels and engender maternal effects.

Dynamics of Salmonella Shedding and Welfare of Hens in Free-Range Egg Production Systems

The current study investigated the effect of environmental stressors (i.e., weather changes) on Salmonella shedding in free-range production systems and the correlations with behavioral and physiological measures (i.e., fecal glucocorticoid metabolites). This involved longitudinal and point-in-time surveys of Salmonella shedding and environmental contamination on four commercial free-range layer farms. The shedding of Salmonella was variable across free-range farms and in different seasons. There was no significant effect of season on the Salmonella prevalence during this investigation. In this study, the combined Salmonella most probable number (MPN) counts in environmental (including feces, egg belt, dust, nest box, and ramp) samples were highest in samples collected during the summer season (4th sampling, performed in February). The predominant serovars isolated during this study were Salmonella enterica serovar Mbandaka and Salmonella enterica serovar Typhimurium phage types 135 and 135a. These two phage types were involved in several egg product-related Salmonella outbreaks in humans. Multilocus variable-number tandem-repeat analysis (MLVA) results indicated that MLVA types detected from human food poisoning cases exhibited MLVA patterns similar to the strains isolated during this study. All Salmonella isolates (n = 209) were tested for 15 different genes involved in adhesion, invasion, and survival of Salmonella spp. We also observed variations for sopA, ironA, and misL There were no positive correlations between fecal corticosterone metabolite (FCM) and Salmonella prevalence and/or shedding in feces. Also, there were no positive correlations between Salmonella prevalence and Salmonella count (log MPN) and any of the other welfare parameters.IMPORTANCE In this study, the welfare of laying hens and Salmonella shedding were compared over a prolonged period of time in field conditions. This study investigated the long-term shedding of Salmonella serovars in a free-range egg production system. Given that there is increasing demand for free-range eggs, it is essential to understand the risks associated with such a production system.

Correlating bacterial shedding with fecal corticosterone levels and serological responses from layer hens experimentally infected with Salmonella Typhimurium

Salmonella Enteriditis and Salmonella Typhimurium are commonly isolated during egg-related outbreaks of salmonellosis and represent a significant international public health issue. In Australia, Salmonella Typhimurium is the most common serovar identified in egg product related foodborne outbreaks. While a number of studies have investigated Salmonella shedding and host responses to infection, they have been conducted over a short time period. The present study sought to characterise bacterial shedding and host responses to infection in hens infected with only Salmonella Typhimurium or co-infected with both Salmonella Typhimurium and Salmonella Mbandaka over a 16 week period. Salmonella shedding was quantified using the most probable number and qPCR methods and was highly variable over the course of the experiment. On day 1, fecal corticosterone metabolites in birds infected with Salmonella Typhimurium (674.2 ± 109.3 pg/mg) were significantly higher than control (238.0 ± 12.62 pg/mg) or co-infected (175.4 ± 8.58 pg/mg) birds. The onset of lay occurred between weeks 6–8 post-infection (pi) and Fecal corticosterone metabolite (FCM) concentrations increased in both control and co-infected birds. Antibody responses to infection were monitored in both serum and yolk samples. Salmonella Typhimurium specific antibody was lower in co-infected animals than monoinfected animals. Bacterial loads in internal organs were characterised to determine persistence. Spleen, liver and caecal tonsils were positive for bacteria in both groups, indicating that Salmonella was not cleared from the birds and internal organ colonization could serve as a reservoir for continued bacterial shedding.

Egg production performance, egg yolk antioxidant profile and excreta concentration of corticosterone in golden pheasants (Chrysolophus pictus) fed diets containing different levels of green vegetables

In order to study the effect of feeding graded levels of green vegetables on egg production performance and egg yolk antioxidant status, 27 female golden pheasants (GP) were randomly distributed into three groups of nine each in an experiment based on completely randomized design. The diets of the birds in groups T₁ , T₂ and T₃ contained 1.4%, 2.7% and 5.0% of green vegetables respectively. Feeding of experimental diets started on 12th February (day 1) and was continued till 30 June 2012. Average number of eggs laid and egg mass produced by the hens in group T₃ was higher (p < 0.004) than those of T₁ and T₂ . Hen day egg production was lowest (p < 0.001) in group T₁ . Roche yolk colour score was highest (p < 0.01) in T₃ followed by T₂ and was lowest in T₁ . Other external and internal egg quality parameters were similar among the groups. Total antioxidant capacity (TAC) of egg yolk was higher (p < 0.04) in group T₃ as compared to other two groups. Egg yolk concentration of total carotenoids, β-carotene, total sulfhydryl, protein-bound sulfhydryl and non-protein-bound sulfhydryl was higher (p < 0.05), whereas concentration of malondialdehyde was lower (p < 0.024) in group T₃ as compared to other two groups. Excreta concentration of corticosterone was highest (p < 0.012) in T₁ , followed by T₂ , and was lowest in T₃ . Egg yolk concentration of TAC and TSH was positively and that of malondialdehyde was negatively correlated with carotenoids intake. Excreta concentration of corticosterone was negatively correlated with carotenoids intake. It was concluded that incorporation of green vegetables in the diet at 5% on dry matter basis would improve egg production, egg yolk antioxidant status and the ability of the captive GP to combat stress.

Fecal Glucocorticoid Analysis: Non-invasive Adrenal Monitoring in Equids

Adrenal activity can be assessed in the equine species by analysis of feces for corticosterone metabolites. During a potentially aversive situation, corticotrophin releasing hormone (CRH) is released from the hypothalamus in the brain. This stimulates the release of adrenocorticotrophic hormone (ACTH) from the pituitary gland, which in turn stimulates release of glucocorticoids from the adrenal gland. In horses the glucocorticoid corticosterone is responsible for several adaptations needed to support equine flight behaviour and subsequent removal from the aversive situation. Corticosterone metabolites can be detected in the feces of horses and assessment offers a non-invasive option to evaluate long term patterns of adrenal activity. Fecal assessment offers advantages over other techniques that monitor adrenal activity including blood plasma and saliva analysis. The non-invasive nature of the method avoids sampling stress which can confound results. It also allows the opportunity for repeated sampling over time and is ideal for studies in free ranging horses. This protocol describes the enzyme linked immunoassay (EIA) used to assess feces for corticosterone, in addition to the associated biochemical validation.

Welfare indicators in laying hens in relation to nest exclusion

Consumer concerns about the welfare of laying hens are increasing, leading to increased interest in identifying reliable ways to assess welfare. The present study evaluated invasive and non-invasive welfare indicators in relation to a stressful challenge. The study included 126 Lohmann Selected Leghorn hens housed in furnished cages. Welfare indicators were measured between 61 and 70 wk of age in birds excluded from their nests for 5 consecutive d and control birds that had continuous access to nests. Baseline recordings were carried out in both groups prior to and post exclusion period. The assessed indicators were: corticosterone metabolites in droppings (FCM), corticosterone concentration in yolk, corticosterone concentration in plasma, irregularities of eggshells, heterophil to lymphocyte (H:L) ratio, tonic immobility duration, and feather cover. Behavioral observations showed that the birds had a clear preference for using the secluded nest sites, confirming that they were likely to perceive nest exclusion as an undesirable experience. Further, elevated levels of FCM in droppings, yolk corticosterone concentrations, H:L ratios and irregular eggshells were detected in both nest deprived and control birds during the exclusion. This suggests that these indicators were able to detect an increased stress response arising from nest deprivation, and it is hypothesized that the stress spread to birds in adjacent cages with access to nests. There was a positive and consistent correlation between FCM in droppings and eggshell irregularities, also supporting the use of eggshell irregularities as a potential non-invasive welfare indicator. However, the pattern of the stress response varied between indicators and correlations were generally few and inconsistent, highlighting the complexity of the relationship among welfare indicators.

Exposure to Increased Environmental Complexity during Rearing Reduces Fearfulness and Increases Use of Three-Dimensional Space in Laying Hens (Gallus gallus domesticus)

The complexity of the rearing environment is important for behavioral development and fearfulness. The aim of this study was to test the hypothesis that laying hens reared in a complex aviary system with exposure to mild intermittent stressors would be less fearful, less sensitive to stress, and would use elevated areas of the pen more often as adults than hens reared in a barren cage environment. Laying hens (N = 160) were housed in the same rearing house; half of the birds (n = 80) in an aviary and the other half (n = 80) in cages. At 16 weeks of age, the birds were transported to the experimental facilities. Their behavior was recorded at 19 and 23 weeks of age and analyzed by analysis of variance on individual scores for a fearfulness-related principal component generated using principal component analysis. The results indicate that aviary-reared birds have lower levels of fearfulness compared with cage-reared birds both at 19 weeks and at 23 weeks of age. When comparing the response induced by initial exposure to a novel object at 19 and 23 weeks of age, more aviary-reared birds tended to fly up at 19 weeks compared to the cage-reared birds, indicating a tendency toward a more active behavioral response in the aviary-reared birds than in cage-reared birds. There was no difference between treatments in the flight response at 23 weeks. The groups did not differ in defecation frequency or the concentration of fecal corticosterone metabolites at either age. At 19 weeks, observation of the spatial distribution in the home pens indicated that more aviary-reared birds spent time on the low perch, the elevated platform, and the upper perch, compared to the cage-reared birds. However, at 23 weeks of age, these differences were no longer detected. The results of this study support the hypothesis that increased environmental complexity during rearing reduces fearfulness of adult laying hens.

Loner or socializer? Ravens' adrenocortical response to individual separation depends on social integration

Non-breeding common ravens (Corvus corax) live in complex social groups with a high degree of fission-fusion dynamics. They form valuable relationships and alliances with some conspecifics, while taking coordinated action against others. In ravens, affiliates reconcile their conflicts, console each other after conflicts with a third party, and provide each other with social support - all behaviors that presumably reduce corticosterone levels and alleviate stress. However, how well an individual is socially integrated in a (sub)group might vary substantially. This raises the question whether the social integration of a raven affects its stress responses to fission-fusion dynamics. The present study aims to investigate this effect experimentally by separating single ravens (n=16) individually from their group for four days and subsequently reintroducing them. To determine stress response patterns in the separated individuals we measured the amounts of immunoreactive corticosterone metabolites (CM) in droppings. We compared two enzyme immunoassays, which we validated by conducting an ACTH challenge, and finally decided to apply an 11-oxoetiocholanolone enzyme immunoassay. Additionally, we determined levels of social integration using focal observations. Our findings suggest that a strong social integration is related to low CM levels when the individuals are within the group and high levels during separations, implying that separation leads to stress in these birds. In contrast, poorly socially integrated ravens seem to exhibit the opposite pattern, indicating that to them group living is more stressful than being temporarily separated. We, therefore, conclude that the birds' adrenocortical activity is modulated by their social integration.

Baseline levels of faecal glucocorticoid metabolites and indications of chronic stress in the vulnerable grey-headed flying-fox, Pteropus poliocephalus

The physiological stress hormone levels and physical condition of captured urban flying-foxes experiencing a food shortage were compared with those of free-living rural flying-foxes with access to supplementary food. Glucocorticoid hormone levels were determined by measuring glucocorticoid metabolites (GCMs) from the faeces of individual animals. The rural flying-foxes were in good condition with high Body Condition Indexes (BCIs) and low levels of GCMs, the range of which may be considered the baseline for this species. In comparison, urban flying-foxes had lower BCIs and elevated levels of GCMs: 75% had levels that were higher than the rural range and 30% were higher by an order of magnitude. Such elevated levels of glucocorticoid (‘stress’) hormones are characteristic of chronic stress. While urbanisation can cause chronic stress, given the low BCIs observed, it is more likely that food shortage was the major stressor in this study. While the rural male and female flying-foxes showed no significant differences in either their levels of faecal glucocorticoid metabolites or their BCIs, significantly different results were found between male and female urban flying-foxes: males were in relatively better condition than females but had higher levels of faecal glucocorticoid metabolites. The autumn and winter reproductive constraints on food-restricted flying-foxes probably explain the differences observed. Additional droppings collected under the urban colony gave similar results to those collected from captured flying-foxes at the same location, and could be a useful non-invasive method for determining the levels of physiological stress in flying-fox colonies.

Non-Invasive Measurement of Adrenocortical Activity in Blue-Fronted Parrots (Amazona aestiva, Linnaeus, 1758)

Parrots kept in zoos and private households often develop psychological and behavioural disorders. Despite knowing that such disorders have a multifactorial aetiology and that chronic stress is involved, little is known about their development mainly due to a poor understanding of the parrots' physiology and the lack of validated methods to measure stress in these species. In birds, blood corticosterone concentrations provide information about adrenocortical activity. However, blood sampling techniques are difficult, highly invasive and inappropriate to investigate stressful situations and welfare conditions. Thus, a non-invasive method to measure steroid hormones is critically needed. Aiming to perform a physiological validation of a cortisone enzyme immunoassay (EIA) to measure glucocorticoid metabolites (GCM) in droppings of 24 Blue-fronted parrots (Amazona aestiva), two experiments were designed. During the experiments all droppings were collected at 3-h intervals. Initially, birds were sampled for 24 h (experiment 1) and one week later assigned to four different treatments (experiment 2): Control (undisturbed), Saline (0.2 mL of 0.9% NaCl IM), Dexamethasone (1 mg/kg IM) and Adrenocorticotropic hormone (ACTH; 25 IU IM). Treatments (always one week apart) were applied to all animals in a cross-over study design. A daily rhythm pattern in GCM excretion was detected but there were no sex differences (first experiment). Saline and dexamethasone treatments had no effect on GCM (not different from control concentrations). Following ACTH injection, GCM concentration increased about 13.1-fold (median) at the peak (after 3-9 h), and then dropped to pre-treatment concentrations. By a successful physiological validation, we demonstrated the suitability of the cortisone EIA to non-invasively monitor increased adrenocortical activity, and thus, stress in the Blue-fronted parrot. This method opens up new perspectives for investigating the connection between behavioural disorders and stress in this bird species, and could also help in their captive management.

Disturbance of wildlife by outdoor winter recreation: allostatic stress response and altered activity-energy budgets

Anthropogenic disturbance of wildlife is of growing conservation concern, but we lack comprehensive approaches of its multiple negative effects. We investigated several effects of disturbance by winter outdoor sports on free-ranging alpine Black Grouse by simultaneously measuring their physiological and behavioral responses. We experimentally flushed radio-tagged Black Grouse from their snow burrows, once a day, during several successive days, and quantified their stress hormone levels (corticosterone metabolites in feces [FCM] collected. from individual snow burrows). We also measured feeding time allocation (activity budgets reconstructed from radio-emitted signals) in response to anthropogenic disturbance. Finally, we estimated the related extra energy expenditure that may be incurred: based on activity budgets, energy expenditure was modeled from measures of metabolism obtained from captive birds subjected to different ambient temperatures. The pattern of FCM excretion indicated the existence of a funneling effect as predicted by the allostatic theory of stress: initial stress hormone concentrations showed a wide inter-individual variation, which decreased during experimental flushing. Individuals with low initial pre-flushing FCM values augmented their concentration, while individuals with high initial FCM values lowered it. Experimental disturbance resulted in an extension of feeding duration during the following evening foraging bout, confirming the prediction that Black Grouse must compensate for the extra energy expenditure elicited by human disturbance. Birds with low initial baseline FCM concentrations were those that spent more time foraging. These FCM excretion and foraging patterns suggest that birds with high initial FCM concentrations might have been experiencing a situation of allostatic overload. The energetic model provides quantitative estimates of extra energy expenditure. A longer exposure to ambient temperatures outside the shelter of snow burrows, following disturbance, could increase the daily energy expenditure by > 10%, depending principally on ambient temperature and duration of exposure. This study confirms the predictions of allostatic theory and, to the best of our knowledge, constitutes the first demonstration of a funneling effect. It further establishes that winter recreation activities incur costly allostatic behavioral and energetic adjustments, which call for the creation of winter refuge areas together with the implementation of visitor-steering measures for sensitive wildlife.

Effects of diet, time since defecation, and drying process of the droppings on corticosterone metabolite measurements in Japanese quail

The use of noninvasive methods for measuring fecal glucocorticoid metabolites is a useful tool for endocrine assessment particularly in studies where animals cannot be captured, when they should be sampled without disturbing their activities, and/or when welfare needs to be maximized. However, still no complete standardization exists for the methodology, and some confounding variables may play an important role affecting measurements and interpretation of results. The present study focused on whether two different diets (laying feed or seed mixture), the time since defecation (0, 4, 24, or 48 h) and the drying method of those samples (oven-dried or naturally nonoven-dried) may affect concentrations of corticosterone metabolites (CM) measured in male Japanese quail. Half of the birds were provided with plain water (control) and the other half received a corticosterone solution. Birds fed with a seed mixture exhibited higher values of CM (nanogram/gram) in droppings than quail that received a laying feed diet suggesting that diet should be carefully considered as a potential source of variation. As expected both groups exhibited higher CM concentration after corticosterone treatment. While CM concentrations increased significantly in nonoven-dried samples over time (0 < 4 < 24 = 48 h), oven-dried samples exhibited similar high CM values. At 24 and 48 h postdefecation, nonoven-dried samples had similar CM concentrations as all oven-dried samples. Drying of samples may be considered a reliable method to reduce variations due to water loss over time, facilitating comparisons up to 48 h postdefecation. This finding would allow to enhance the range of application of this noninvasive and welfare friendly method to situations where samples cannot be collected or frozen shortly after defecation.

Immunoreactive cortisone in droppings reflect stress levels, diet and growth rate of gull-billed tern chicks

Blood levels of corticosterone have been traditionally analyzed to assess stress levels in birds; however, measuring steroid hormone metabolites in feces and droppings has gained much interest as a noninvasive technique successfully used for such purposed in vertebrates. Diet may affect these fecal metabolite levels (e.g., due to nutritional stress), however, this variable has not been taken into account in studies with chicks despite the great dietary flexibility of many avian species. In this study, we addressed for the first time this key issue and validated the technique in wild gull-billed tern chicks (Gelochelidon nilotica). Several enzyme immunoassays were used to determine the most appropriate test to measure the stress response. Subsequently, we performed an experiment in captivity to assess adrenocortical activity in gull-billed tern chicks fed with two diets: piscivorous vs. insectivorous. Finally, the relation between the chicks' growth rate and excreted immunoreactive glucocorticoid metabolites (EGMs) was also evaluated. We found the immunoreactive cortisone metabolites to be a good index of stress (as being an index of adrenocortical reactivity) in chicks of this species. Fish-fed chicks had higher levels of cortisone metabolites when comparing both concentration and total daily excreted metabolites. Within each treatment diet, cortisone metabolite levels and growth rates were negatively correlated. These findings suggest that the diet should be considered when using this technique for comparative purposes and highlight the trade-off between stress levels and chicks growth rates.

Welfare and performance in layers following temporary exclusion from the litter area on introduction to the layer facility

When introduced to the laying facility, pullets are sometimes temporarily excluded from the litter area in order to help them locate food and water, and to prevent floor-laid eggs. This procedure is not permitted in Sweden, because it involves denying access to both litter and space, which may have a negative effect on bird welfare. The present study investigated how the welfare and performance of layers were affected by this temporary exclusion on introduction of hens to the laying facility. The study included 600 floor-reared Dekalb White layers obtained at 16 wk age and housed in 6 groups of 100 in a conventional single-tier floor-laying system. Birds were either given full access to the litter area during the whole study or were excluded from the litter area during the first 2 wk after transfer to the laying facility. From 18 to 72 wk age, birds in both treatments had full access to the litter area. Excluding birds from the litter area for 2 wk resulted in better feather cover and reduced fearfulness, according to novel object and tonic immobility tests. Furthermore, birds initially excluded from the litter area produced eggs with a lower proportion of shell irregularities than birds with full access to the litter area throughout. No difference was found in corticosterone metabolites in droppings rate of lay, mortality, or proportion of floor-laid eggs. In conclusion, none of the parameters studied indicated that the welfare of laying hens was compromised by temporary exclusion from the litter area on introduction to the laying facility. In fact, some of the data suggested that bird welfare had improved.

Temporal dynamic of adrenocortical and gonadal photo-responsiveness in male Japanese quail exposed to short days

The study evaluated whether different short-term endocrine testicular and adrenocortical responses to short photoperiod exposure can persist over time and particularly when birds exhibit spontaneous cloacal gland recovery. At 11 wk of age, 33 male Japanese quail exposed to long photoperiod were switched to short photoperiod (8L:16D). Another group of males was kept under long photoperiod (n = 11; LD quail). After 5 wk of short photoperiod exposure, quail were classified as nonresponsive or responsive to short photoperiod, depending on whether the cloacal gland volume was above or below 1,000 mm(3) and with or without foam production, respectively. Since 11 wk of age and during a 20-wk period, droppings of all quail were collected to determine corticosterone and androgen metabolites (AM) by enzyme immunoassays. Cloacal gland volume was also determined weekly. Both short photoperiod nonresponsive (SD-NR) and responsive quail showed overall significantly lower (P < 0.01) AM values (518.8 ± 11.9 and 248.6 ± 17.1 ng/g, respectively) than quail that remained under long photoperiod (814.3 ± 24.1 ng/g). However, nonresponsive quail showed a significantly smaller reduction in their AM levels than their responsive counterparts. During the first 6 wk of short photoperiod exposure, SD-NR quail showed similar corticosterone metabolites values than LD quail. Corticosterone metabolite profiles changed from 7 wk of short photoperiod exposure onward, with photoperiodic differences (P < 0.01) persisting up to the end of study (LD: 228.9 ± 22.4 > SD-NR: 133.1 ± 15.5 > short photoperiod responsive: 61.6 ± 17.9 ng/g, respectively). Testicular and adrenocortical glands showed different degrees of activity associated with cloacal gland photoresponsiveness to short photoperiod manipulation. Our findings suggest long-term effects of short photoperiod, both in the hypothalamic-pituitary-gonadal and hypothalamic-pituitary-adrenocortical axis activity of quail, including males that exhibited spontaneous cloacal gland recovery.