D. G. Satterlee

Fear and distress in Japanese quail chicks of two lines genetically selected for low or high adrenocortical response to immobilization stress

Behavioral and adrenocortical reactivity to stressful stimulation was examined in 12- and 13-day-old chicks of two lines of Japanese quail selected over several generations for exaggerated (HS: high stress) or reduced (LS: low stress) plasma corticosterone (B) response to brief immobilization stress. Plasma B concentrations and tonic immobility (TI) fear reactions were measured in unstressed (control) and stressed (overnight cooping) chicks of both lines. The stress treatment was applied over a period of 12-20 hr and it involved capture by the experimenter, inescapable exposure to an unfamiliar environment and to strange conspecifics, reductions in ambient temperature and floor space, and the deprivation of food and water. Chicks of the HS line were more susceptible to the induction of TI and they remained immobile longer than did LS chicks. Therefore HS chicks were considered to be more fearful than their LS counterparts. Stress treatment elicited a marked adrenocortical response that was more pronounced in HS than in LS chicks. Stress treatment also increased susceptibility to TI but did not significantly affect the duration of immobility. These findings suggest that selecting the quail for differential corticosterone response to a particular stressor had exerted an unconscious and concomitant effect on underlying fearfulness as well as on their adrenocortical reactivity to several other stressful situations. The results are further discussed in terms of a putative relationship between adrenocortical activation and fearfulness.

THREAT-INDUCED BEHAVIOURAL INHIBITION IN JAPANESE QUAIL GENETICALLY SELECTED FOR CONTRASTING ADRENOCORTICAL RESPONSE TO MECHANICAL RESTRAINT

1. Behavioural and adrenocortical responses to brief mechanical restraint were examined in 28-d-old female Japanese quail of two lines which had been genetically selected over several generations for either reduced (LS, low stress) or exaggerated (HS, high stress) plasma corticosterone response to brief immobilisation in a metal box. 2. As expected, quail of the LS line showed lower adrenocortical responses to restraint than did their HS line counterparts. The LS quail also struggled much sooner and more often during the 5 min restraint period than did the HS ones. Collectively, these and previously reported line differences in behavioural, catecholamine and adrenocortical responsiveness are consistent with an interpretation based on the adoption of active and passive coping strategies respectively by LS and HS quail upon their exposure to alarming stimuli.

Effects of repeated restraint in Japanese quail genetically selected for contrasting adrenocortical responses.

Behavioral and adrenocortical responses to repeated mechanical restraint were compared in 28-day-old to 31-day-old male Japanese quail from two genetic lines divergently selected for reduced (low stress, LS) or exaggerated (high stress, HS) plasma corticosterone (C) responses to brief immobilization. Restraint in a metal crush cage for 5 min elicited immobility and silence in all the birds. Circulating C levels were considerably higher in quail of both lines following restraint than in the undisturbed controls of either line. As expected, both the behavioral and physiological effects were more pronounced in HS than in LS birds. Struggling increased with repeated restraint in HS and LS quail, thus suggesting behavioral habituation to the stressor in both lines. On the other hand, a line effect on the pattern of adrenocortical responses was revealed upon subtracting the change in plasma C concentrations from Day 1 to Day 4 in the undisturbed controls from the corresponding change in restrained birds. Thus, unlike LS quail, in which there were no detectable effects of repeated restraint, the adrenocortical responses of HS birds showed evidence of experience-dependent sensitization. Our results demonstrate the importance of the background genome in determining the patterns of the behavioral and adrenocortical responses elicited by repeated exposure to stressful stimulation. The present results and those of previous studies could be explained in one or both of two ways: that underlying fearfulness is lower in LS than HS quail or that they adopt active or passive coping strategies, respectively. Our findings may also have important implications for poultry welfare and productivity. @ 2000 Elsevier Science Inc.

Timidity in Japanese quail: effects of vitamin C and divergent selection for adrenocortical response.

Male Japanese quail chicks of two genetic lines selected for low (LS) or high (HS) adrenocortical responses to mechanical restraint were housed in mixed-line groups of 24 in four compartments of a multitier brooder battery at 20 days of age. Quail in two of the four compartments were given vitamin C (ascorbyl-2-polyphosphate, APP, 1 g L-ascorbic acid/L) solution for 48 h, whereas the other birds received untreated tap water as usual before they were tested at 23 days of age. At test, each quail was placed individually in a dark, sheltered compartment of an emergence box and allowed 1 min to acclimatise before a door was raised allowing access to an illuminated and exposed area. Vocalisation and the latencies to head and full emergence were then recorded to measure its fear levels. More LS quail vocalised than did HS ones. They also emerged more rapidly from the sheltered compartment into the illuminated one than HS birds. These findings further support our hypothesis that decreased fearfulness has accompanied genetic selection for reduced adrenocortical responsiveness. Treatment with APP reduced the latency to emerge fully into the exposed compartment, and there were no line x treatment interactions. These results suggest that vitamin C supplementation alleviated fearfulness, regardless of existing line differences in this behavioural trait.

How acute is the acute stress response? Baseline corticosterone and corticosteroid-binding globulin levels change 24 h after an acute stressor in Japanese quail.

Changes in plasma corticosteroid-binding globulin (CBG) capacity can alter free plasma concentration and tissue availability of glucocorticoids (GC) and hence alter the organismal response to stress. However, CBG change in response to stress has not been extensively studied. While it is clear that chronic stress can causes CBG decline and in some species acute stressors can reduce CBG during the 30-60 min of the stressor, more long-term changes in CBG following an acute stressor has received less attention. Here we investigated corticosterone (CORT: the primary GC in birds) and CBG levels 24h after an acute stressor in a unique study system: Japanese quail divergently selected for CORT reactivity to acute stress. Using this model, we examined the interaction of selected CORT reactivity with CBG response to determine if CBG shows a delayed decline in response to an acute stressor and if that decline varies by selected genetic background. We found lowered CBG capacity, elevated total CORT and free CORT 24h after acute stress in all three quail groups. These results demonstrate for the first time in an avian species that exposure to an acute stressor can affect CBG and CORT 24h later.

Fear-related behaviour in Japanese quail divergently selected for body weight '

Abstract The damaging effects of fear on a number of performance indicators in poultry and other farm animals are becoming increasingly recognised. More specifically, there is growing evidence for a negative association between growth and fearfulness (an underlying behavioural characteristic). The present study examined this putative relationship in Japanese quail from two genetic lines that had been selected over several generations for low (LBW) or high (HBW) body weight at 4 weeks of age and in those of a non-selected control (CON) line. HBW quail were substantially heavier than LBW ones at 31 days of age (197 and 34 g, respectively), with CON birds occupying an intermediate (104 g) position. Birds were observed individually and once only between 26 and 32 days of age in one of three putative tests of fear. Quail of the LBW line showed greater avoidance of a conspicuous novel object placed near the home cage and longer tonic immobility fear reactions, and they vocalized and struggled later and less often during brief mechanical restraint than did the HBW quail. Quail of the control line generally showed intermediate responses. Plasma corticosterone concentrations following mechanical restraint were greater in LBW quail than in CON or HBW ones. Consideration of the intra-individual correlations between behavioural and adrenocortical responses to restraint suggested that the nature of the relationship was labile and that it was sensitive to the background genome. Collectively, the present findings demonstrated that underlying fearfulness was greater in quail that had been genetically selected for low rather than high body weight. The present results thereby support the hypothesis that fearfulness and growth are negatively associated.

Steroidogenic properties of isolated adrenocortical cells from Japanese quail selected for high serum corticosterone response to immobilization

The effect of selection for high stress response on adrenocortical function was examined by measuring the corticosterone response of adrenocortical cells isolated from random-bred Japanese quail and quail selected for high serum corticosterone response to immobilization (high-stress). Highly enriched adrenocortical cells were incubated with various concentrations of ACTH1-24 (ACTH), 8-bromo-cyclic AMP (8Br-cAMP) and pregnenolone for 2 hr. Corticosterone production was measured by radioimmunoassay. Basal corticosterone production values by cells from random-bred and high-stress birds were not different. In contrast, the average maximal ACTH- and 8Br-cAMP-induced corticosterone production by cells from high-stress quail was 89% greater than that of cells from random-bred quail. However, the average pregnenolone-supported corticosterone production by cells from high-stress birds was 34% less than that of cells from random-bred birds. Thus, the data suggest that although random-bred quail cells had a greater potential capacity for corticosterone production, high-stress quail cells had a greater ability to couple ACTH, ACTH-transmembrane-signaling factors and subsequent second messengers with the available steroidogenic enzyme pool. The magnitude of the differences in function between cells from high-stress and random-bred birds was greater for female cells compared to male cells. In addition to differences in cellular function, there were also differences in adrenal and relative adrenal weights between random-bred and high-stress quail. The average, adrenal and relative (mg/100 g body weight) adrenal weights of high-stress quail were 14-16% greater than those of random-bred quail. It is concluded that the enhanced serum corticosterone response of the high-stress quail line is, in part, due to an increase in relative adrenal weight and an increase in adrenocortical cell responsiveness to ACTH.

Vitamin C supplementation and fear‐reduction in Japanese quail: Short‐term cumulative effects

1. Fear-related behaviour was measured in individually-housed Japanese quail which had received either untreated drinking water (UDW) or a vitamin C solution (ascorbyl-2-polyphosphate, APP, 1 g L-ascorbic acid/1 for 1 or 4 d. Behavioural tests were carried out at 24 or 27 d of age. Water consumption was measured daily and plasma ascorbic acid (AA) content was assayed after differential treatment for 1 or 4 d. 2. The quail in the APP treatment groups drank significantly more than did those receiving untreated drinking water. 3. Supplementation with APP raised plasma AA concentrations substantially above those found in UDW quail. The lower AA concentrations found after APP treatment for 4 d rather than one may have reflected either inter-assay variation or limited intestinal absorption following excess ingestion. 4. Quail treated with APP showed less home-cage avoidance of a novel object and shorter tonic immobility fear reactions than did the UDW birds. The UDW quail showed remarkably similar avoidance and TI scores on test days 1 and 4. Conversely, continued treatment with APP further reduced avoidance scores but, although TI durations fell slightly with continued treatment there were no significant day effects. 5. It was concluded that APP supplementation can reduce underlying fearfulness but that it may not be necessary to continue treatment for longer than 24 h immediately prior to a known frightening event.

Open-Field Temporal Pattern of Ambulation in Japanese Quail Genetically Selected for Contrasting Adrenocortical Responsiveness to Brief Manual Restraint

Japanese quail selected for a low-stress (LS), rather than a high-stress (HS), plasma corticosterone response to brief restraint have been shown to possess lower fearfulness and a nonspecific reduction in stress responsiveness. Detrended fluctuation analysis provides information on the organization and complexity of temporal patterns of behavior. The present study evaluated the temporal pattern of ambulation of LS and HS quail in an open field that represented a novel environment. Time series of 4,200 data points were collected for each bird by registering the distance ambulated every 0.5 s during a 35-min test period. Consistent with their known reduced fearfulness, the LS quail initiated ambulation significantly sooner (P < 0.02) and tended to ambulate more (P < 0.09) than did their HS counterparts. Detrended fluctuation analyses showed a monofractal series (i.e., a series with similar complexity at different temporal scales) in 72% of the birds. These birds initiated their ambulatory activity in less than 600 s. Among these birds, a lower (P < 0.03) autosimilarity coefficient (alpha) was found in the LS quail than in their HS counterparts (alpha = 0.76 +/- 0.03 and 0.87 +/- 0.03, respectively), suggesting a more complex (less regular) ambulatory pattern in the LS quail. However, when the patterns of ambulation were reexamined by considering only the active period of the time series (i.e., after the birds had initiated their ambulatory activity), monofractal patterns were observed in 97% of the birds, and no differences were found between the lines. Collectively, the results suggest that during the active period of open-field testing, during which fear responses are likely less strong and other motivations are the driving forces of ambulation, the LS and HS lines have similar ambulatory organization.

Effects of Vitamin C supplementation on the adrenocortical and tonic immobility fear reactions of Japanese quail genetically selected for high corticosterone response to stress

Abstract Japanese quail chicks (18 days of age), from a line genetically selected for high plasma corticosterone response to brief immobilization stress, were treated for 24 h with either untreated drinking water or with a Vitamin C (1200 ppm of ascorbic acid: AA) solution. The chicks were subsequently either exposed to a stressful cooping procedure (which lasted for 12–21 h and incorporated animal capture inescapable exposure to novelty, a reduction in floor space and in ambient temperature, and food and water deprivation), or they remained undisturbed. Cooping caused considerable elevation of circulating corticosterone concentrations, thus illustrating its stressful nature. Treatment with AA failed to affect the adrenocortical response to cooping, but it significantly attenuated the tonic immobility fear reactions of stressed and unstressed quail. The mechanisms underpinning the behavioural consequences of AA supplementation have yet to be determined. The results are discussed in terms of, first, the relationship between adrenocortical activation and fearfulness, and second, their implications for poultry welfare and performance.