Dynamics of changes in broiler spatial distribution induced by a robot with autonomous navigation along the growing cycle.

Welfare problems in broiler chickens are associated with accelerated growth in high density and barren environments. Encouraging broiler movement yields benefits by increasing locomotion, foraging, and environmental exploration. Robot sensors with autonomous navigation capabilities developed to collect husbandry information could collaterally induce movement of birds while traversing the chicken houses. This study examines the short-time dynamic of changes in broiler spatial distribution within the robot's zone of influence throughout the growing cycle. Two batches of mixed-sex Cobb-500 were raised in a commercial broiler farm until 42 d of age, in 2 houses divided into 4 equally sized sectors. In half of the sectors an AviSense robot sustained 2-h per day of autonomous navigation. The minute prior and the 4 min following the robot entering the zone of influence were video recorded weekly. Control sectors without a robot were analyzed equivalently. Number of individuals within the zone of influence of the robot were obtained at 1-s intervals and relative density (%) was estimated. Physical interactions between broilers and the robot, as well as interactions with the environment were also recorded. The entrance of the robot triggers within seconds a strong depopulation of the zone with birds walking to neighboring areas (P < 0.03, in all ages). The decreases in relative density induced by the robot appears more pronounced, and repopulation of the zone was slower, in younger than in older birds (P < 0.05). Broilers´ showed physical interactions towards the robot and were also touched and/or slightly pushed by the robots (19 and 84% of videos recorded, respectively). They were also found scratching and/or pecking the ground after the robot passed (64% of videos). Findings strongly suggest that robots, beyond their specific capabilities as environmental sensors, were effective in promoting increased movement in broilers along the growing cycle and could also favor additional exploratory behaviors. Thus, these robots could be considered as environmental enrichment elements that contribute to welfare improvements during intensive rearing.

High-resolution ethograms, accelerometer recordings, and behavioral time series of Japanese quail.

Although many small vertebrates are capable of performing high-speed behaviors, most studies continue to focus on low-resolution temporal scales (>>1 s). Herein, we present video-recordings, behavior time series, and the computer software for video-analysis of Japanese quail within social groups. Home-boxes were monitored using both top and side video-cameras. High-resolution ethograms were developed for analyses. Pairs of females were assigned as either controls or using one of two methods for attachment of an accelerometer (patch or backpack). Behavior was recorded during 1 h on the first 2-days, sampled at 1 s intervals (days 1 and 2). On day 8, an unfamiliar male was placed in the home-box and its behavior was recorded during the first 10 min, sampled every 1/15 s. Male accelerometer recordings were also obtained. Video-recordings and resulting detailed high-resolution behavioral time series are valuable for reuse in comparative studies regarding the temporal dynamics of behavior within social environments. In addition, they are necessary for the assessment of novel machine learning algorithms that could be used for deciphering the output of accelerometer recordings.

Short- and long-term dynamics of the physiological and behavioral response to heat stress and thymol supplementation in Japanese quail.

Organisms have evolved endogenous timing systems that enable them to predict temporal changes and to coordinate complex internal processes. However, temporal dynamics of biological responses are most often ignored in fields such as dietary supplementation of farm animals exposed to artificial environmental challenges. Herein, we hypothesized that the potential for thymol (2-isopropyl-5-methylphenol) to alleviate physiological and behavioral consequences of heat stress is time-dependent on both long-term (i.e. weeks) and short-term (i.e. within day) time scales. First, during 3-weeks adult female Japanese quail (Coturnix japonica) were exposed daily to 9h of increased environmental temperature (34.2 ± 0.1 °C). Controls remained at standard temperatures (23.6 ± 0.1 °C). Simultaneously, half received thymol dietary supplementation and the other half a control basal diet. On day 4, both thymol and heat stress decreased body weight and feed intake respect to controls (basal, standard temperature). After three weeks, feed intake recovered for thymol groups. Therefore, we performed a second experiment focused on the critical first week of treatment, sampling variables three times a day. The beneficial effects of thymol supplementation were mainly observed during the morning, including prevention of high respiratory rates and reduction in the weight of droppings induced by heat stress, and increased walking under both temperatures. In summary, thymol's potential for alleviating heat stress consequences is time-dependent, and can be conceived as an emergent property resulting from the complex interplay between the dynamics of the biological response to thymol and heat stress. Findings highlight the importance of considering time-related factors when developing supplementation protocols to mitigate environmental challenges.

Aggressive dominance can decrease behavioral complexity on subordinates through synchronization of locomotor activities.

Social environments are known to influence behavior. Moreover, within small social groups, dominant/subordinate relationships frequently emerge. Dominants can display aggressive behaviors towards subordinates and sustain priority access to resources. Herein, Japanese quail (Coturnix japonica) were used, given that they establish hierarchies through frequent aggressive interactions. We apply a combination of different mathematical tools to provide a precise quantification of the effect of social environments and the consequence of dominance at an individual level on the temporal dynamics of behavior. Main results show that subordinates performed locomotion dynamics with stronger long-range positive correlations in comparison to birds that receive few or no aggressions from conspecifics (more random dynamics). Dominant birds and their subordinates also showed a high level of synchronization in the locomotor pattern, likely emerging from the lack of environmental opportunities to engage in independent behavior. Findings suggest that dominance can potentially modulate behavioral dynamics through synchronization of locomotor activities.

High-resolution behavioral time series of Japanese quail within their social environment.

The behavioral dynamics within a social group not only could depend on individual traits and social-experience of each member, but more importantly, emerges from inter-individual interactions over time. Herein, we first present a dataset, as well as the corresponding original video recordings, of the results of 4 behavioral tests associated with fear and aggressive response performed on 106 Japanese quail. In a second stage, birds were housed with conspecifics that performed similarly in the behavioral tests in groups of 2 females and 1 male. By continuously monitoring each bird in these small social groups, we obtained time series of social and reproductive behavior, and high-resolution locomotor time series. This approach provides the opportunity to perform precise quantification of the temporal dynamics of behavior at an individual level within different social scenarios including when an individual showing continued aggressive behaviors is present. These unique datasets and videos are publicly available in Figshare and can be used in further analysis, or for comparison with existing or future data sets or mathematical models across different taxa.

Expression of aggressiveness modulates mesencephalic c-fos activation during a social interaction test in Japanese quail (Coturnix japonica).

It is well known that during a social conflict, interactions are dependent on the animal's propensity to behave aggressively as well as the behavior of the opponent. However, discriminating between these two confounding factors was difficult. Recently, a Social Interaction (SI) test using photocastrated males as non-aggressive stimuli was proposed as a useful tool to evaluate aggressiveness. The avian Intercollicular- Griseum centralis complex (comparable to mammalian periaqueductal gray) has been reported as a crucial node in the descending pathways that organize behavioral and autonomic aspects of defensive responses and aggressiveness. Herein, using the SI test, we evaluated whether mesencephalic areas are activated (expressed c-fos) when photostimulated adult males are confronted with non-responsive (non-aggressive) opponents. Furthermore, we also examined whether mesencephalic activation is related to male performance during the SI test (i.e., aggressive vs. non-aggressive males) in birds reared in enriched or in standard environments. Five mesencephalic areas at two anatomic levels (intermediate and rostral) and locomotion during SI testing were studied. Aggressive males showed increased c-fos expression in all areas studied, and moved at faster speeds in comparison to their non-aggressive and control counterparts. Non-aggressive males and the test controls showed similar c-fos labeling. In general, rearing condition did not appear to influence c-fos expression nor behavior during the SI test. Findings suggest that mesencephalic activation is involved when males are actively expressing aggressive behaviors. This overall phenomenon is shown regardless of both the environmental stimuli provided during the birds´ rearing and the potentially stressful stimuli during the SI trial.

Environmental complexity: A buffer against stress in the domestic chick.

Birds kept in commercial production systems can be exposed to multiple stressors from early life and this alters the development of different morphological, immunological and behavioural indicators. We explore the hypothesis that provision of a complex environment during early life, better prepares birds to cope with stressful events as well as buffers them against future unpredictable stressful episodes. In this study, 96 one day old pullets were randomly distributed in eight pens (12 birds/pen). Half of the chicks (N = 48) were assigned to a Complex Environment (CENV: with perches, a dark brooder etc.) the others to a Simple Environment (SENV: without enrichment features). Half of the birds from each of these treatments were assigned to a No Stress (NSTR, 33°C) or to an acute Cold Stress (CSTR, 18-20°C) treatment during six hours on their second day of life. At four weeks of age, chicks with these four different backgrounds were exposed to an Intermittent Stressful Challenges Protocol (ISCP). In an immunological test indicative of pro-inflammatory status Phytohemagglutinin-P (PHA-P), the response of CSTR birds was ameliorated by rearing chicks in a CENV as they had a similar response to NSTR chicks and a significantly better pro-inflammatory response than those CSTR birds reared in a SENV (five days after the CSTR treatment was applied). A similar better response when coping with new challenges (the ISCP) was observed in birds reared in a CENV compared to those from a SENV. Birds reared in the CENV had a lower heterophil/lymphocyte ratio after the ISCP than birds reared in SENV, independently of whether or not they had been exposed to CSTR early in life. No effects of stress on general behaviour were detected, however, the provision of a CENV increased resting behaviour, which may have favoured stress recover. Additionally, we found that exposure to cold stress at an early age might have rendered birds more vulnerable to future stressful events. CSTR birds had lower humoral immune responses (sheep red blood cells induced antibodies) after the ISCP and started using elevated structures in the CENV later compared to their NSTR conspecifics. Our study reflects the importance of the early provision of a CENV in commercial conditions to reduce negative stress-related effects. Within the context of the theory of adaptive plasticity, our results suggest that the early experience of the birds had long lasting effects on the modulation of their phenotypes.

Insights into thermal stress in Japanese quail (Coturnix coturnix): dynamics of immunoendocrine and biochemical responses during and after chronic exposure.

Avian require comfortable temperatures for optimal development and heat stress is a high concern in warm weather countries. We aimed to assess the dynamics of immunoendocrine and biochemical variables responses of birds exposed to a heat stressor applied during daylight hours, during the chronic stress and the recovery periods. We hypothesize that variables involved in the birds response will be differentially and gradually modified during those periods. Female quail (n = 210) were housed in six rearing boxes. At 29 days of age, the temperature in three boxes was increased from 24 to 34 °C during the light period throughout the nine days (Stress Treatment). The other three boxes remained at 24 °C and were used as controls. The subsequent 12 days were considered as recovery period. Different sets of 12 birds/treatment were blood-sampled at 29 (basal), 32, 35, 38 (stress), 41, 44, 47, and 50 (recovery) days of age, respectively. Immunoendocrine (corticosterone, lymphoproliferation, heterophil/lymphocyte ratio (H/L), and antibody response) and biochemical (glucose, total proteins, globulins, and albumin) variables were assessed. During stress, progressive corticosterone and H/L increments, and antibody titers and lymphoproliferation decreases were detected. No clear pattern of changes was found in biochemical variables. During recovery, while corticosterone and lymphoproliferation had recovered three days after the stressor ended, H/L and antibody responses required respectively nine and 12 days to recover to their basal levels, respectively. Findings suggest that immunity is already threatened when heat stress is sustained for three or more days. However, the system appears resilient, needing six to 12 days to recover to their basal responses.

Distribution and concentration of maternal progesterone in the yolk of Greater Rhea eggs (Rhea americana).

Progesterone is the most concentrated maternal yolk steroid characterized to date in birds; however, no information about it is available in ratite eggs. We collected freshly laid eggs from zoo-housed Greater Rhea females (Rhea americana) bred under similar rearing conditions during two breeding seasons to characterize concentration and distribution of maternal yolk progesterone. After high-performance liquid chromatography analysis, yolk hormone was measured using a commercial electrochemiluminescence immunoassay. Progesterone concentrations were found to vary significantly among the yolk layers, supporting a follicular origin for this steroid in Greater Rhea eggs. Additionally, highly similar mean absolute yolk progesterone concentrations were detected between 2013 and 2015 breeding seasons (1,332.98 ± 82.59 and 1,313.59 ± 85.19 ng/g, respectively). These values are also comparable to those found in some domestic carinate species. Findings suggest that at population level, when rearing conditions are similar, mean absolute yolk maternal progesterone concentrations also appear bounded. Future research on the factors and mechanisms that regulate progesterone deposition in Greater Rhea eggs is needed to better understand whether its levels depend on different rearing conditions.

Chronic stress in Lizards: Studies on the Behavior and Benzodiazepine Receptors in Liolaemus koslowskyi and Cnemidophorus tergolaevigatus.

Behavioral and physiological adaptive responses of animals facing chronic exposure to a single stressor may allow them to overcome its negative effects for future exposures to similar stressful situations. At chemical level, the GABAA /benzodiazepine complex is considered one of the main receptor systems involved in the modulation of stress-induced responses. Here, we describe the behavioral responses of two different lizard species, Liolaemus koslowskyi and Cnemidophorus tergolaevigatus exposed to three potential chronic stressful treatments: (a) high temperature, (b) forced swimming, and (c) simulated predator. Additionally, we aimed to determine in those lizards whether the central-type benzodiazepine receptor (CBR; an allosteric modulator site of the GABAA receptor) is related to adaptive responses to those stressful stimulations. Our results revealed that the simulated predator was the stress condition that showed the largest difference in behavioral responses between the two species, resembling previously described strategies in nature. The basal affinity of CBRs (obtained from undisturbed animals) showed differences between both species, and the simulated predator was the only stressor that altered the affinity of CBRs. L. koslowskyi CBRs showed a decreased receptor affinity, whereas C. tergolaevigatus showed an increased receptor affinity in comparison to their respective control groups. We show for the first time the effects of different types of stressors upon behavioral responses and CBR biochemical parameters in two lizard species. Our findings suggest a potential GABA/benzodiazepine role in the ability of lizards to cope with a repeated exposure to a stressful (e.g., predator) condition.

Validation of a radioimmunoassay for measuring testosterone concentrations in plasma samples of the subterranean rodent Ctenomys talarum: outstandingly elevated levels in the wild and the effect of captivity.

We validated the Coat-a-Count radioimmunoassay (RIA) kit for measuring testosterone in plasma samples of the subterranean rodent Ctenomys talarum and evaluated testosterone levels in free-living and captive individuals. The performance of the assay was evaluated by the assessment of parallelism, accuracy and precision. Moreover, the high specificity of the assay antibody was confirmed by high-pressure liquid chromatography with ultraviolet detector, followed by electrospray ionization tandem mass spectrometry. Results indicated that plasma samples have to be treated with heat and diluted before the RIA for the optimization of the assay. Plasma testosterone concentrations in free-living animals were outstandingly elevated (up to 329 ng/mL), which are among the highest ever reported for mammals. On the other hand, captivity produced a 14-fold decrease in plasma testosterone concentrations, emphasizing that very significant changes in the endocrine milieu may occur in wild animals kept under laboratory conditions. Our results place tuco-tucos as an interesting model for the study of androgen regulation in mammals, suggesting that target tissues may have low sensitivity to the testosterone signal and agree with a scenario of elevated levels of sex hormone-binding globulin in plasma.