Responses to isolation in Japanese quail genetically selected for high or low sociality

Glycerol is not suitable for the cryopreservation of quail semen

1. This study investigated the potential use of glycerol as a cryoprotectant for quail sperm cells. Its role in maintaining sperm fertilising ability in vivo and in vitro quality parameters, such as motility, was assessed.2. The data showed that the presence of glycerol in semen samples was associated with infertility, which suggested that removal prior to insemination is mandatory. Removal through serial dilution centrifugation was associated with fewer than 5% of motile sperm cells and resulted in no fertility.3. In conclusion, glycerol alone is not suitable for quail semen cryopreservation, and other approaches need to be investigated to develop cryobanking programmes for this species.

Welfare of ducks, geese and quail on farm

This Scientific Opinion concerns the welfare of Domestic ducks (Anas platyrhynchos domesticus), Muscovy ducks (Cairina moschata domesticus) and their hybrids (Mule ducks), Domestic geese (Anser anser f. domesticus) and Japanese quail (Coturnix japonica) in relation to the rearing of breeders, birds for meat, Muscovy and Mule ducks and Domestic geese for foie gras and layer Japanese quail for egg production. The most common husbandry systems (HSs) in the European Union are described for each animal species and category. The following welfare consequences are described and assessed for each species: restriction of movement, injuries (bone lesions including fractures and dislocations, soft tissue lesions and integument damage and locomotory disorders including lameness), group stress, inability to perform comfort behaviour, inability to perform exploratory or foraging behaviour and inability to express maternal behaviour (related to prelaying and nesting behaviours). Animal-based measures relevant for the assessment of these welfare consequences were identified and described. The relevant hazards leading to the welfare consequences in the different HSs were identified. Specific factors such as space allowance (including minimum enclosure area and height) per bird, group size, floor quality, characteristics of nesting facilities and enrichment provided (including access to water to fulfil biological needs) were assessed in relation to the welfare consequences and, recommendations on how to prevent the welfare consequences were provided in a quantitative or qualitative way.

Japanese quail classified by their permanence in proximity to a high or low density of conspecifics: a search for underpinning variables

Test of sociality in poultry is mainly based on the bird's individual ability to make quick social discriminations. In recent years, a density-related permanence (DRP) test has been developed that enables us to classify young birds (while in groups) according to their individual permanence in proximity to either a high or low density of conspecifics (HD or LD, respectively). Thus, the result of the classification depends not only on the bird's individual response but also on the outcome of the social interactions within the whole group. The birds' performance in DRP was associated with underlying differences in social responses of their individuals. Quails in homogeneous groups of LD residents responded with less compact groups and higher levels of agonistic interactions to the presence of an intruder and showed higher levels of agonistic interactions among cage-mates than the homogeneous groups of HD birds. An acute stressor also induced a higher corticosterone response in the LD birds than in their HD counterparts. The present study addressed the question of whether contrasting DRP performance by Japanese quail can also reflect underlying differences in fearfulness and social reinstatement responses. Thus, LD and HD categorized juvenile birds underwent one of the following tests: tonic immobility (TI), open-field (OF), or a one-way runway. Results showed that HD birds required more inductions and developed shorter responses (P ≤ 0.05) in the TI test and walked more, faster, and greater distances in the OF (P ≤ 0.05) than their LD counterparts. No differences between groups were found in short social reinstatement responses. The present findings suggest that underlying fearfulness is lower in the HD than in the LD birds. A reduced fearfulness could be regarded as an additional favorable trait of the HD-classified quail to cope with environmental challenging situations.

Psychological and Physiological Stress in Hens With Bone Damage

Abnormalities in bone development in humans and non-humans can lead to impaired physical and psychological health; however, evidence is lacking regarding the role of individual psychosocial factors in the development of poor bone conditions. Addressing this lack of knowledge, we used low-productive laying hens (n = 93) and assessed behavioral responses to an open-field test [at 17, 18, 29, 33 weeks of age (wa)], an aerial predator test (at 39 wa), and a social reinstatement test (at 42 wa). Bone condition was assessed using a palpation technique on five occasions (at 16, 29, 33, 45, 58 wa), with half of the hens experiencing damage (deviations, fractures, or both) at 29 wa and all hens by 58 wa. Corticosterone (CORT) concentration in feathers (at 16, 33, 58 wa) and body weight (at 23, 47, 58 wa) were also investigated. We hypothesized that lighter birds (at 23 wa) with higher CORT (at 16 wa) and open field-induced fear collected before the onset of lay (at 17 and 18 wa) are associated with a worse bone condition when in lay. We also hypothesized that those birds with more damage at the peak of laying (at 29 wa) would be lighter at 47 and 58 wa and more fearful by showing higher open field-induced (at 29 and 33 wa) and predator-induced fear responses, however, acting less socially toward conspecifics. These hens were also expected to have higher CORT (at 33 and 58 wa). Our results show no association between open-field fear level and fear behavior, CORT concentration, or body weight on the one hand (all measured before starting to lay) and bone damage at 29 wa on the other. When in lay, bone damage was associated with more pecking and less crossing zones when faced with an open-field situation at 29 wa and improved sociality at 42 wa. This study provides the first evidence of a relationship of bone health with fear, sociality, and stress response. When in poor bone condition, our hens had enhanced psychological stress measured by fear behavior reactivity but not physiological stress measured as feather CORT concentration.

Do glucocorticoids or carotenoids mediate plumage coloration in parrots? An experiment in Platycercus elegans

Conspicuous coloration can indicate phenotypic quality, and may reflect exposure or vulnerability to stress, or access to essential nutrients such as pigments. Although the production of pigmented colours is well understood, much less is known about how structural colours are affected by physiological state. In this study, we tested whether glucocorticoids (corticosterone) predicted expression of plumage coloration in an Australian parrot, the crimson rosella (Platycercus elegans). Parrots provide an interesting and unique test, as they possess conspicuous coloration produced by distinctive pigments known as psittacofulvins, in addition to structural coloration. We have previously documented that coloration in P. elegans is condition-dependent and responds to dietary manipulation. Here, n = 21 P. elegans underwent a dietary manipulation (including food restriction or carotenoid supplementation) during which they moulted, and the change in reflectance was measured for three structural and three pigmentary plumage patches. Stress-induced corticosterone (10 min after handling) measured at the start of the experiment predicted change in coloration in two pigmentary patches (crown and front). We also found that change in stress-induced corticosterone during the experiment was associated with the change in coloration of the crown and two structural patches (cheek and epaulette). Baseline corticosterone (<3 min after handling) was not associated with any measure of coloration. We found no effects of dietary manipulation on baseline or stress-induced corticosterone, but carotenoid supplementation was associated with an increase in a measure of chronic stress (heterophil/lymphocyte ratio), and the corticosterone response to handling decreased over the course of the study. Our results suggest that corticosterone may be linked to colour expression more broadly than previously recognised, including psittacofulvin and structural coloration in parrots, and they confirm the independence of plumage pigmentation in parrots from carotenoid accumulation. Moreover, our study provides new insight into the stress responses of Psittaciformes, one of the most highly threatened avian orders.

Adrenocortical responses in Japanese quail classified by their permanence in proximity to either low or high density of conspecifics

The density-related permanence test (DRP) is used to classify young birds (while in groups) according to their individual permanence in proximity to either a high or low density of conspecifics (HD or LD, respectively). The birds' performance in DRP was associated with underlying differences in the social responses of their individuals. Quails in homogeneous groups of LD residents responded with less compact groups and higher levels of agonistic interactions to the presence of an intruder, and showed higher levels of agonistic interactions among cagemates than the homogeneous groups of HD birds. This study deepen the characterization of DRP evaluating whether contrasting behavior during test is associated with birds' stress responses to challenging situations during rearing. Plasma corticosterone responses were individually assessed after submitting DRP categorized birds to a brief (10 min) partial restraint (mechanical stressor; experiment 1), or after introducing them during 5 min as intruders in homogeneous groups of 6 unknown same category (HD or LD) conspecifics (social stressor; experiment 2). Experiment 1 showed that basal corticosterone levels were similar in all groups and the partial mechanical restraint induced an increase in plasma corticosterone concentration also in all groups. However, the increase induced by the stressor was higher in the LD birds than in their HD counterparts. In experiment 2, compared to controls, social stressor showed no plasma corticosterone changes in the intruders that were introduced in an unfamiliar group of HD conspecifics. However, intruders (both HD and LD) that were visiting the LD residents showed an increased corticosterone response compared to their control counterparts. Results suggest that categorization of birds in the DRP test could have relevance for selection programs oriented to obtain birds better suited to intensive rearing conditions that includes high density of animals and exposure to unavoidable stressors.

Absence of Gut Microbiota Reduces Emotional Reactivity in Japanese Quails (Coturnix japonica)

Background: Recent studies have demonstrated an effect of the gut microbiota on brain development and behavior leading to the concept of the microbiota-gut-brain axis. However, its effect on behavior in birds is unknown. The aim of the present study was to determine the effect of the absence of gut microbiota on emotional reactivity in birds by comparing germ-free (GF) quails to those colonized (COL) with gut microbiota. Material and Methods: From hatching, the quails of both groups GF (n = 36) and COL (n = 36) were reared in sterile isolators. The COL quails were colonized at day 2 by introducing a pool of droppings from conventional adult females into the drinking water and feed. The quails were weighed individually on day 2, 6, and 14. From day 8, emotional reactivity was assessed in each group in the isolators through several behavioral tests. Results: GF quails showed a considerable decrease in emotional reactivity demonstrated by spending less time in tonic immobility during the tonic immobility test (242 s ± 31 vs. 331 s ± 32, p ≤ 0.05), traveling a shorter distance (3,897 cm ± 242 vs. 4,827 cm ± 278, p ≤ 0.05) at a lower velocity (6.55 cm/s ± 0.4 vs. 8.1 cm/s ± 0.5, p ≤ 0.05) during the social separation test and spending more time near an object at the beginning of the novel object test (33.7 s ± 6.4 vs. 18.5 s ± 4.1, p ≤ 0.05). No difference in growth was found between the 2 groups. Conclusion: For the first time, this study demonstrates that the absence of gut microbiota reduces emotional reactivity in Japanese quails in situations of fear and social perturbation without influence on growth.

Genetics and Genomics of Social Behavior in a Chicken Model

The identification of genes affecting sociality can give insights into the maintenance and development of sociality and personality. In this study, we used the combination of an advanced intercross between wild and domestic chickens with a combined QTL and eQTL genetical genomics approach to identify genes for social reinstatement, a social and anxiety-related behavior. A total of 24 social reinstatement QTL were identified and overlaid with over 600 eQTL obtained from the same birds using hypothalamic tissue. Correlations between overlapping QTL and eQTL indicated five strong candidate genes, with the gene TTRAP being strongly significantly correlated with multiple aspects of social reinstatement behavior, as well as possessing a highly significant eQTL.

Effects of different monochromatic LED light colours on fear reactions and physiological responses in Mulard ducks

Although the effects of monochromatic light on behaviour and performance of birds have been extensively studied, it is not known how rearing Mulard ducks in different monochromatic lights affects their fear reactions, physiological responses to stress and welfare. A total of 108 newly hatched Mulard ducks, representing three replicates, were housed in either blue light (BL), green light (GL), red light (RL) or white light (WL) for 12 weeks. Ducks were exposed to a light/dark schedule of 23 L/1 D, and food and water were provided ad libitum. At the beginning of the 13th week of the rearing period, behavioural measurements of fear were assessed by using a tonic immobility test, open field test and fear of man test. Physiological responses of the birds to stress such as heterophil : lymphocyte ratio, total leukocyte count and plasma concentrations of corticosterone were also assessed. Results demonstrated that birds exposed to both RL and WL displayed higher levels of behavioural indicators of fear including tonic immobility durations (P < 0.01), latency to first immobilisation (P < 0.001) and avoidance of man index (P < 0.001), and higher levels of physiological indicators of stress such as heterophil : lymphocyte ratios (P < 0.001) and plasmas concentrations of corticosterone (P < 0.001), and lower total leukocytic counts (P < 0.01) compared with birds exposed to either BL or GL. Rearing Mulard ducks in BL or GL appeared to reduce their fear reactions and physiological responses to stress and to enhance their ability to cope with the environment and may therefore improve their welfare.

A medium density genetic map and QTL for behavioral and production traits in Japanese quail

BACKGROUND

Behavioral traits such as sociability, emotional reactivity and aggressiveness are major factors in animal adaptation to breeding conditions. In order to investigate the genetic control of these traits as well as their relationships with production traits, a study was undertaken on a large second generation cross (F2) between two lines of Japanese Quail divergently selected on their social reinstatement behavior. All the birds were measured for several social behaviors (social reinstatement, response to social isolation, sexual motivation, aggression), behaviors measuring the emotional reactivity of the birds (reaction to an unknown object, tonic immobility reaction), and production traits (body weight and egg production).

RESULTS

We report the results of the first genome-wide QTL detection based on a medium density SNP panel obtained from whole genome sequencing of a pool of individuals from each divergent line. A genetic map was constructed using 2145 markers among which 1479 could be positioned on 28 different linkage groups. The sex-averaged linkage map spanned a total of 3057 cM with an average marker spacing of 2.1 cM. With the exception of a few regions, the marker order was the same in Japanese Quail and the chicken, which confirmed a well conserved synteny between the two species. The linkage analyses performed using QTLMAP software revealed a total of 45 QTLs related either to behavioral (23) or production (22) traits. The most numerous QTLs (15) concerned social motivation traits. Interestingly, our results pinpointed putative pleiotropic regions which controlled emotional reactivity and body-weight of birds (on CJA5 and CJA8) or their social motivation and the onset of egg laying (on CJA19).

CONCLUSION

This study identified several QTL regions for social and emotional behaviors in the Quail. Further research will be needed to refine the QTL and confirm or refute the role of candidate genes, which were suggested by bioinformatics analysis. It can be hoped that the identification of genes and polymorphisms related to behavioral traits in the quail will have further applications for other poultry species (especially the chicken) and will contribute to solving animal welfare issues in poultry production.

Fearfulness affects quail maternal care and subsequent offspring development

Our study investigated relationships between a precocial bird’s fearfulness and maternal care, and the implication of maternal care as a vector for non-genomic transmission of fearfulness to chicks. We compared care given to chicks between two sets of female Japanese quail selected to present either high (LTI) or low fearfulness (STI). Chicks, from a broiler line, were adopted by these females following a sensitization procedure. Chicks’ fearfulness after separation from their mother was assessed by well-established procedures. LTIs took longer to present maternal responses, pecked chicks more during the first days post-hatch, presented impaired maternal vocal behaviour and were globally less active than STI females. Chicks mothered by LTIs presented more fearful reactions than did chicks mothered by STIs, supporting the hypothesis of a non-genetic maternal transmission of fearfulness. We suggest that the longer latencies required by LTIs to become maternal are a consequence of their greater fear of chicks, and that their lower general and vocal activity could be components of a heightened antipredatory strategy. We discuss the transmission of maternal fearfulness to fostered chicks, taking into account the possible implication of several well-known mechanisms underlying maternal effects.

Social discrimination in Japanese quail Coturnix japonica chicks genetically selected for low or high social reinstatement motivation

Japanese quail chicks of two lines genetically selected for low levels of social reinstatement behaviour (LSR) or high levels of social reinstatement behaviour (HSR) were housed in groups of three. The approach/avoidance tendencies of an individual chick from each group towards a familiar cagemate and a stranger from another group placed at opposite ends of a runway were measured at 7 days of age. Quail chicks of both genetic lines preferentially approached, spent longer near, and showed shorter mean distances from the cagemate than the stranger. Irrespective of stimulus type, the HSR quail generally showed shorter approach latencies, spent longer within 15 cm of the goal boxes, made more entries into these areas, and travelled further during the test than did their LSR counterparts. These findings demonstrated that Japanese quail chicks, of two genetic lines reared in small groups, successfully discriminated between familiar cagemates and strangers. They also suggest that there are no straightforward relationships between underlying social motivation and social preferences.

Species specificity of social reinstatement in Japanese quail Coturnix japonica genetically selected for high or low levels of social reinstatement behaviour

Divergent lines of Japanese quail Coturnix japonica showing high (HSR) or low (LSR) levels of social reinstatement (SR) behaviour (as measured in a treadmill apparatus) have been developed. However, it was not known if selection had influenced social reinstatement tendencies in a general or a species-specific fashion. Therefore, the present study compared the SR behaviour of quail chicks of the HSR and LSR lines and of a Control line when the goal box of the treadmill was empty or when it contained small, same-species groups of either Japanese quail, domestic fowl or Guinea fowl chicks. The results clearly demonstrated that the SR behaviour of Japanese quail chicks is species-specific and that this specificity has not been influenced during genetic selection, over sixteen generations, of the HSR and LSR lines. The HSR chicks showed more locomotor activity in the treadmill than did those of the other lines regardless of the nature of the goal-box stimulus. The results are discussed in terms of general activity, underlying fearfulness and social motivation.

Effect of group disruption on social behaviour in lines of Japanese quail (Coturnixjaponica) selected for high or low levels of social reinstatement behaviour

Japanese quail of lines selected for high (HSR) or low (LSR) levels of social reinstatement (SR) behaviour were reared in groups of three. At 3 and 6 weeks of age, one group member was replaced with an unfamiliar conspecific bird. Behaviour following introduction of the intruder was similar at both ages. Quail of both lines spent more time immobile after introduction of the intruder than before its introduction. In the LSR, but not the HSR line, inter-individual distances between intruders and other chicks, were greater than those between familiar chicks. Birds of both lines pecked more between unfamiliar than between familiar birds. Pecks, not associated with escape or avoidance by the pecked bird, were more frequent in HSR groups. Selection for HSR behaviour appears to have increased non-aggressive exploration of intruder whereas selection for LSR behaviour has decreased interest in or increased shunning of intruders.

Evidence of phenotypic and genetic relationships between sociality, emotional reactivity and production traits in Japanese quail

The social behavior of animals, which is partially controlled by genetics, is one of the factors involved in their adaptation to large breeding groups. To understand better the relationships between different social behaviors, fear behaviors and production traits, we analyzed the phenotypic and genetic correlations of these traits in Japanese quail by a second generation crossing of two lines divergently selected for their social reinstatement behavior. Analyses of results for 900 individuals showed that the phenotypic correlations between behavioral traits were low with the exception of significant correlations between sexual behavior and aggressive pecks both at phenotypic (0.51) and genetic (0.90) levels. Significant positive genetic correlations were observed between emotional reactivity toward a novel object and sexual (0.89) or aggressive (0.63) behaviors. The other genetic correlations were observed mainly between behavioral and production traits. Thus, the level of emotional reactivity, estimated by the duration of tonic immobility, was positively correlated with weight at 17 and 65 days of age (0.76 and 0.79, respectively) and with delayed egg laying onset (0.74). In contrast, a higher level of social reinstatement behavior was associated with an earlier egg laying onset (-0.71). In addition, a strong sexual motivation was correlated with an earlier laying onset (-0.68) and a higher number of eggs laid (0.82). A low level of emotional reactivity toward a novel object and also a higher aggressive behavior were genetically correlated with a higher number of eggs laid (0.61 and 0.58, respectively). These results bring new insights into the complex determinism of social and emotional reactivity behaviors in birds and their relationships with production traits. Furthermore, they highlight the need to combine animal welfare and production traits in selection programs by taking into account traits of sociability and emotional reactivity.

The relationship between adrenocortical function and Hsp70 expression in socially isolated Japanese quail

Physiological responses to social isolation stress were compared in 56-day-old male Japanese quail. Birds were fed pretreated diets for 3 days as follows: (i) Basal diet (control); (ii) Basal diet+1500 mg/kg metyrapone (BM); (iii) Basal diet+30 mg/kg corticosterone (BCO); (iv) Basal diet+250 mg/kg ascorbic acid (BC); (v) Basal diet+250 mg/kg α-tocopherol (BE); (vi) Basal diet+250 mg/kg ascorbic acid and 250 mg/kg α-tocopherol (BCE). The birds were subsequently socially isolated in individual opaque brown paper box for 2 hours. Plasma corticosterone (CORT) concentration and heart and brain heat shock protein 70 (Hsp 70) expressions were determined before stress and immediately after stress. Two hours of isolation stress elevated CORT concentration significantly in the control and BE birds but not in the BC, BCE and BM birds. There was a significant reduction in CORT concentration after isolation stress in the BCO group. Isolation stress increased Hsp 70 expression in the brain and heart of control and BM birds. However, brain and heart Hsp 70 expressions were not significantly altered in the isolated BC, BCE and BE birds. Although, the CORT concentration of BM birds was not affected by isolation stress, Hsp70 expression in both brain and heart were significantly increased. Moreover, exogenous corticosterone supplementation did not result in elevation of Hsp 70 expression. It can be concluded that, although Hsp 70 induction had not been directly affected by CORT concentration, it may be modulated by the HPA axis function via activation of ACTH.

A place to hide in the home-cage decreases yolk androgen levels and offspring emotional reactivity in Japanese quail

An animal's emotional responses are the result of its cognitive appraisal of a situation. This appraisal is notably influenced by the possibility of an individual to exert control over an aversive event. Although the fact that environment controllability decreases emotional responses in animals is well established, far less is known about its potential trans-generational effects. As the levels of avian yolk hormones can vary according to the mother's environment, we hypothesized that housing environment of mothers would modulate the quality of her eggs and in turn her offspring's behaviour. Two groups of female Japanese quail were constituted: a group that had access to a place to hide in their home-cage (Hd, n = 20) and a group that had nowhere to hide (NoHd, n = 20) when stressed. Both groups were submitted to daily human disturbances for a twenty-day-period. Hd females produced eggs with both less testosterone and androstenedione than did NoHd females. The emotional and social reactivity of Hd females' offspring were lower and their growth was slower than those of NoHd females' offspring. Our results show that a minor difference in housing environment had substantial effects on eggs and offspring. The presence of a shelter probably helped quail to cope with daily human disturbances, producing less reactive offspring. This transgenerational effect caused by an opportunity to hide could lead to applications in care of laboratory animals, conservation biology and animal welfare.

Social instability in laying quail: consequences on yolk steroids and offspring's phenotype

Individual phenotypic characteristics of many species are influenced by non-genetic maternal effects. Female birds can influence the development of their offspring before birth via the yolk steroid content of their eggs. We investigated this prenatal maternal effect by analysing the influence of laying females' social environment on their eggs' hormonal content and on their offspring's development. Social instability was applied to groups of laying Japanese quail females. We evaluated the impact of this procedure on laying females, on yolk steroid levels and on the general development of chicks. Agonistic interactions were more frequent between females kept in an unstable social environment (unstable females) than between females kept in a stable social environment (stable females). Testosterone concentrations were higher in unstable females' eggs than in those of stable females. Unstable females' chicks hatched later and developed more slowly during their first weeks of life than those of stable females. The emotional reactivity of unstable females' chicks was higher than that of stable females' chicks. In conclusion, our study showed that social instability applied to laying females affected, in a non-genetic way, their offspring's development, thus stressing the fact that females' living conditions during laying can have transgenerational effects.

Social motivation affects the display of individual discrimination in young and adult Japanese quail (Coturnix japonica)

A simultaneous two-choice test was used to investigate discrimination between a familiar (F) and an unfamiliar conspecific (U) in Japanese quail, selected for high (HSR) or low (LSR) social reinstatement behavior (tendency to rejoin and stay close to conspecifics). Animals were 1-week unsexed and 6-week-old male quail. One-week-old LSR quail and 6-week-old male HSR quail displayed discrimination after 24 hr of pair contact (p < 0.05), and a tendency to discriminate (p < 0.10) was found in adult male LSR quail. After 1 week of pair contact, results were similar in LSR quail chicks, but no discrimination was evidenced in adult quail of either line. Therefore, Japanese quail are able to discriminate between a familiar cagemate and an unfamiliar conspecific after only 24 hr of pair contact. Moreover, this study reveals for the first time in this species that social motivation and age both influence the display of individual discrimination.

Behavioural and hormonal effects of social isolation and neophobia in a gregarious bird species, the European starling (Sturnus vulgaris)

Separating gregarious individuals from their group members often results in behavioural and physiological changes, like increased levels of corticosterone. Testosterone and corticosterone, in particular, have been implicated in the response of mammals to novelty. Data in birds are, however, rare. The presence or absence of group members may also influence an individual's response to novel stimuli. We assessed the behaviour and hormonal response of European starlings (Sturnus vulgaris) to a novel object in two different situations and seasons: each starling was tested when separated and when in contact with its group members in May/June (breeding season) and again in September/October (non-breeding season). Starlings are gregarious throughout the year, but as foraging flocks are small during the breeding season and large during the non-breeding season, we assumed that non-breeding starlings would be more affected by social isolation. Overall, starlings had higher levels of corticosterone, lost more body mass, and were more active when they were separated from their group. Isolated individuals, however, did not show a greater neophobic response than individuals in the presence of their group members in either season. Circulating levels of testosterone and corticosterone were higher after a test with novel object than after a test with only the familiar feeding dish in both sexes and seasons. However, control tests for handling effects confirmed only the increase in testosterone. Our study shows that social isolation is stressful for unrelated and unpaired members of a wild flocking bird species and demonstrates that novelty can lead to a rise in testosterone in birds.

Nongenomic inheritance of emotional reactivity in Japanese quail

Avian scientific literature includes few reports on the influence of characteristics of mothers on the behavior of their offspring. By comparing young domestic Japanese quail raised by adoptive mothers with high levels of general emotional reactivity (E+ mothers) to young raised by adoptive mothers with low levels of general emotional reactivity (E- mothers), we evaluated the influence of characteristics of mothers on the behavioral development of their offspring. Our results revealed that general emotional reactivity was higher in young raised by E+ mothers than in young raised by E- mothers. These differences were significant in the presence of mothers as well as after separation from them, suggesting direct as well as long-term maternal influence. Young raised by E+ mothers also presented delayed increases in weight.

Early T-maze behavior and broiler growth

In the laboratory and at a commercial farm in Argentina, chicks that showed a short latency to exit a T-maze (LEX) (HP, high performance) gained more weight than those with a longer LEX (LP, low performance). The present study re-examined this relationship and evaluated additional T-maze measures using broilers reared in quasi-intensive, environmentally controlled conditions. In the T-maze, a mirror strategically placed at the end of a corridor stimulates the test chick to leave the isolation chamber (start box) and to move toward its reflection. Having done so, it can then see other birds and thereby be further stimulated to completely exit the maze. However, when a test bird hesitates or stops at the mirror, its performance categorization may be confounded. Herein, the T-maze performance of 3-d-old broiler chicks was assessed using three different measurements: 1) the latency to exit the start box (LEB), 2) the latency to reach the mirror section of the maze (LRM), and 3) LEX. The fastest (top 25%) and slowest (bottom 25%) of the birds within a sex and within each of the three T-maze criteria were classified as HP and LP chicks, respectively. The relationships between these measures and body weight were examined in 4-, 42-, and 56-d-old males and females. Irrespective of the T-maze classification criteria used, HP and LP chicks had similar body weights at 4 d of age. However, chicks classified as HP according to LEB or LRM measures were heavier at 42 and 56 d of age than LP ones (P < 0.02 for all comparisons). These differences were apparent in both sexes. On the other hand, there were no detectable differences in body weight at the latter ages between chicks categorized as HP or LP according to their LEX scores. The present results indicate that 1) broiler chicks that exit the T-maze start box and reach the mirror quickly subsequently grow faster than their slower LP counterparts and 2) LEB and LRM are better predictors of growth than the LEX value used in previous studies.

Effects of an acute stressor on fear and on the social reinstatement responses of domestic chicks to cagemates and strangers

Genetic selection for appropriate levels of sociality (motivation to be with conspecifics) could benefit poultry welfare and performance. Runway tests that require chicks to traverse a corridor in order to reach other chicks in a goal box are commonly used to measure this behavioural trait. However, we need to determine if the chicks' responses in such tests are sensitive to certain experiential variables before we can recommend possible selection criteria for future breeding programmes. The present study focused on fear and on the identity of the stimulus birds. Broiler chicks either remained undisturbed or were exposed to an acute stressor (mechanical restraint) before their tonic immobility fear responses were measured 1h later in Experiment 1. Exposure to the stressor significantly prolonged tonic immobility and, hence, presumably, underlying fear levels. In Experiment 2, the responses of stressed chicks and undisturbed controls were assessed when they were tested individually in a runway with a goal box containing either familiar or unfamiliar chicks of the same age. Our finding that stressed chicks emerged from the start box sooner and spent longer near the stimulus birds suggests that exposure to a frightening event increased social reinstatement motivation. Furthermore, social affiliation was more pronounced when the goal box contained familiar cagemates rather than strange chicks, regardless of prior treatment. This finding demonstrates that broiler chicks that were housed in groups of twelve can discriminate between familiar and unfamiliar conspecifics encountered in novel surroundings. Thus, sociality was positively associated with fearfulness and broilers clearly showed social discrimination in runway tests. These findings highlight the dangers of disregarding variables, such as fear and the capacity for social recognition in tests of social motivation. We strongly recommend that exposure to frightening events prior to test should be avoided and that the identity of the birds in the runway goal box should be standardized, i.e. either familiar or unfamiliar, and noted.

Neonatal handling of Amazon parrots alters the stress response and immune function

The influence of neonatal handling on behavior and immune function was assessed in Orange-winged Amazon parrots (Amazona amazonica). Chicks (n=11) were gently handled daily from 25 days of age until 38 days post-fledging, while control chicks (n=9) were not handled. At 10 days post-fledging ( approximately 66 days of age), chicks were given tests to evaluate tameness (e.g., willingness to perch on an offered finger). They were then restrained for 10 min, either by being held while perching (handled group) or, because they would not perch, by being restrained in a towel (nonhandled group). Serum corticosterone levels were measured and immune status was assessed by: the delayed-type hypersensitivity (DTH) response to phytohemagglutinin-P (PH-P) injection; the humoral response to a killed Newcastle disease virus (NDV) challenge; and heterophil:lymphocyte ratio (H:L). Handled chicks were tamer by all measures of tameness. DTH was greater in nonhandled chicks (P</=0.002), as were serum corticosterone levels (Wilcoxon, P</=0.05), while NDV antibody titers were possibly reduced (P</=0.09). H:L ratios did not differ. We conclude that handling conditioned the birds to be held in a manner that appeared not to be stressful. The greater DTH response of nonhandled chicks suggests that either their DTH response was enhanced by the acute stress of being restrained in a towel, and/or the DTH response of handled chicks was suppressed as a result of the repeated physiologic stress from handling during the neonatal period. In either event, handling produced marked differences in response to types of restraint that would be typically encountered in the husbandry of Amazons in captivity.

Genetic Selection for Poultry Behaviour: Big Bad Wolf or Friend in Need?

Although genetic selection for certain characteristics has compromised the well-being of domestic animals, selective breeding could and probably should be used to improve welfare. Three of the major behavioural problems facing the poultry industry are fear, feather pecking and social stress. However, these and many other behavioural traits respond readily to genetic selection. The present paper reports the results of selective breeding studies in which underlying fearfulness, sociality, feather pecking, adrenocortical responsiveness, and growth rate were manipulated in Japanese quail, Coturnix japonica, or in chickens, Gallus gallus domesticus. The apparent benefits of selection for appropriate levels of these characteristics are discussed, as are the ethical issues involved. The ultimate aims of the selection programmes and the studies described here are to improve the birds ‘ welfare and productivity by increasing their ability to interact successfully with their physical environment, with one another, and with human beings.

Early T-maze behaviour and subsequent growth in commercial broiler flocks

Two batches of 2000 mixed-sex broiler chicks were obtained, one in summer and one in winter. Each flock was housed on the floor at a commercial farm. At 2 or 3 d of age, the latencies to escape from a T-maze were measured in 1044 and 1180 chicks in the summer and winter flocks, respectively. Chicks were assigned to high (HP), moderate (MP) or low (LP) performance categories if their escape latencies were below 40 s, between 40 to 90 s, or above 90 s, respectively. Ninety male and 90 female chicks from each of the 3 categories were weighed when they were 3 d old. The birds then remained undisturbed, apart from routine maintenance, until similar numbers were weighed at 49 d of age. Some birds may have been weighed at both ages. Body weights were higher in males than females and higher in the winter than summer flock at 3 d of age. Significant main effects of chick category as well as gender and season were found at 49 d of age. There were no significant interactions. As expected, 49-d body weights were higher in males than females and in the flock reared in winter than in summer. 5. HP chicks (those that showed rapid escape from the T-maze at 3 d) were also significantly heavier at 49 d than their LP counterparts, with MP chicks occupying an intermediate position. This suggests that early performance in a T-maze test is positively associated with subsequent growth. Furthermore, this relationship was apparent in each of the 2 flocks. Given this positive association, we suggest that this simple, rapid and non-invasive behavioural test could be a useful selection criterion for future breeding programmes.

T-maze behaviour in domestic chicks: a search for underlying variables

We investigated whether contrasting T-maze behaviour shown by domestic chicks, Gallus gallus domesticus, of a broiler strain reflected underlying differences in their general activity levels, fearfulness or sociality. The time taken by 2-day-old chicks to traverse a T maze and thereby regain visual contact with their companions was measured. Chicks were categorized according to whether they completed this task quickly (HP, high performance, <25 s) or slowly (LP, low performance, >75 s) and then housed in same-category groups, each of eight chicks. In experiment 1, we compared the numbers of HP and LP chicks showing certain home cage behaviours (ambulation, standing, resting, maintenance, pecking, preening). No significant differences were found. In experiment 2, we compared the behaviour of HP and LP chicks in two tests of sociality (home cage proximity, runway) and in two tests of fear (emergence, tonic immobility). The HP chicks stayed closer together in the home cage than did their LP counterparts and they spent significantly longer near a goal box containing conspecifics in the runway than did LP ones. Conversely, there were no significant differences between HP and LP chicks in their latency to emerge from a sheltered area into an exposed and, hence, potentially frightening one or in their tonic immobility fear reactions. These findings suggest that contrasting T-maze performance was unlikely to have reflected differences in underlying activity levels or in fearfulness. Conversely, individual variation in underlying sociality was probably an influential variable. Copyright 1999 The Association for the Study of Animal Behaviour.

Consequences of Surprising Reward Omissions

A surprising reward omission (SRO) occurs when an appetitive reinforcer is not presented (or it is reduced in magnitude or quality) even though there are signals for its impending presentation. Evidence supporting the hypothesis that SROs produce an aversive emotional reaction with physiological and behavioral consequences is reviewed. SROs are followed by pituitary–adrenal activation; changes in immune function; odor emissions in rodents; distress vocalizations in rodents and primates; and increases in locomotion, aggressive behavior, drinking, and eating. SROs can support the acquisition of new escape responses and invigorate previously acquired responses. The review identifies common aspects of these phenomena and areas in which more research is needed.

The behavior of the Japanese or domestic quail Coturnix japonica

This paper reviews the literature pertaining to the behavior of the Japanese or domestic quail Coturnix japonica. Details are given of the classification, characteristics, domestication and the economic and research potential of the species. Further sections deal with sensation and perception (including taste and smell, vision and hearing), maintenance behavior (including feeding and drinking, dust bathing and thermoregulation), development and aging (including vocalization, filial imprinting, sexual imprinting, fear and avoidance responses, sexual maturation and aging), adult learning (including habituation, instrumental conditioning, Pavlovian conditioning and observational learning), photoperiodism, reproductive behavior (including courtship and mating, hormonal control and ontogeny of sexual differentiation, and male and female sexual behavior), parental behavior (including nest-site selection and nest building, incubation behavior and its hormonal control, and hen-chick relationships), and aggressive behavior and dominance (including agonistic behavior and the hormonal control of aggressive behavior).

Effects of CRF on isolated Japanese quails selected for fearfulness and for sociality

The effects of CRF on the behavior and plasma corticosterone levels of isolated Japanese quail chicks were determined. Doses of 15, 30, and 45 micrograms/kg of CRF reduced the number of distress vocalizations emitted during isolation in chicks of a control line. The behavioral responses to a 15 micrograms/kg dose of CRF in lines selected either for high (HSR) or low (LSR) level of sociality or for low (STI) or high (LTI) fearfulness were compared. CRF suppressed vocalizations and increased the number of pecks at food. In LTI and STI chicks, CRF decreased the number of distress calls. In HSR chicks, CRF increased the number of pecks at food and suppressed vocalizations. No effect of CRF was found in LSR chicks. Chicks of the HSR, LSR, LTI, STI, and control lines were injected with 15 micrograms/kg of CRF or saline solution and the level of corticosterone measured following a 15-min isolation period. CRF or isolation alone slightly activated the HPA axis, whereas CRF plus isolation greatly increased corticosterone levels except in the LSR line. These differential responses of LSR chicks and chicks of the other lines, indicate a possible role of CRF in the regulation of social reinstatement behavior.