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[hal-04735026] Exploring neuronal markers and early social environment influence in divergent quail lines selected for social motivation
Many species, including humans exhibit a wide range of social behaviors that are crucial for the adaptation and survival of most species. Brain organization and function are shaped by genetic and environmental factors, although their precise contributions have been relatively understudied in the context of artificial selection. We used divergent lines of quail selected on their high versus low level of motivation to approach a group of conspecifics (S + and S-, respectively) to investigate the influence of genetic selection and early social environment on sociability. We observed distinct sex-and brainregion-specific expression patterns of three neuronal markers: mesotocin, and vasotocin, the avian homologues of mammalian oxytocin and vasopressin, as well as aromatase, the enzyme that converts androgens into estrogens. These markers displayed pronounced and neuroanatomically specific differences between S + and S-quail. Additionally, in a second experiment, we assessed the influence of early social environment on social skills in juvenile birds. Mixing S + and S-resulted in more S-males approaching the group without affecting the sociability of S + or other behaviors, suggesting that the early social environment may influence the results of genetic selection. In conclusion, the divergent quail lines offer a valuable model for unraveling the neuronal and behavioral mechanisms underlying social behaviors.
ano.nymous@ccsd.cnrs.fr.invalid (Lucas Court) 14 Oct 2024
https://hal.science/hal-04735026v1
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[hal-04699728] L’élevage de poulets biologiques : les verrous à lever et les opportunités offertes par cette production
La France est actuellement au premier rang des productions européennes de poulets biologiques. Cette production ne représente toutefois encore que quelques pourcents de la production nationale. L’élevage avicole biologique est souvent considéré comme respectueux du bien-être animal et de l’environnement. Cependant, au-delà de ces images positives que l’élevage avicole biologique et les produits biologiques véhiculent, certaines contraintes déjà identifiées limitent leur développement. Le contact avec la faune sauvage présentant un risque sanitaire, la gestion du parcours, les tensions sur l’environnement dues à une excrétion des déjections sur le parcours difficilement maîtrisable et la sensibilité au contexte économique et aux comportements de consommation sont autant d’obstacles. L’élevage biologique offre néanmoins des opportunités 1) pour l’animal : le parcours facilite l’expression de nombreux comportements et permet la consommation d’insectes et de plantes possédant diverses propriétés (nutritionnelle, médicinales…) ; 2) pour l’éleveur : une amélioration des conditions de travail ainsi qu’une plus grande satisfaction sont mises en avant ; 3) pour l’environnement : le parcours constitue une source de biodiversité. Après une présentation des conditions d’élevage des poulets biologiques en France et en Europe, nous proposons d’identifier les barrières à l’extension de l’élevage biologique et les leviers/opportunités pour les dépasser.
ano.nymous@ccsd.cnrs.fr.invalid (Karine Germain) 17 Sep 2024
https://hal.inrae.fr/hal-04699728v1
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[hal-04717662] Deleterious effect of social instability on broiler chicken learning abilities and behaviour
Broiler chickens are reared in very large groups and are submitted to repeated encounters with unknown conspecifics. Our aim was to assess the consequences of these encounters on broiler chickens learning abilities, social behaviour and emotional reactivity. Groups of 5 male medium-growing broiler chickens (JA 957) were reared under stable or unstable social conditions (n=16 groups in each condition). Under the unstable conditions, the 5 birds of the groups changed every 3–4 days from 1 to 52 days of age. Broiler chickens were tested in an associative learning task (conditioned place preference) between 14 and 18 days of age. A highly palatable food (mealworms) was delivered in a particular environment with coloured stripes and preference for this environment was then tested. Social behaviours were analysed between 21 and 43 days of age. Emotional reactivity of the birds when faced with novelty (reactivity to unknown food, object and human) was assessed at the end of the rearing period (46–51 days of age). Only birds from the stable condition were able to associate the palatable food to the environment in which it was delivered (p = 0.02). Furthermore, these birds had a higher social proximity than those from the unstable condition (p < 0.01) and showed less aggressive interactions such as aggressive pecking (p = 0.06), threat (p < 0.01) or facing each other with wing flapping in front of another bird (p = 0.03). The social conditions tested had no significant effect on their emotional reactivity. Our results evidenced that chickens exposed to social instability have some learning abilities impaired compared to chickens maintained in stable social conditions. In addition, social instability increases aggressive interactions between conspecifics, while social stability favours bird proximity. In conclusion, being reared in unstable social conditions likely impairs bird adaptation to their rearing environment and increases deleterious consequences of aggressive interactions with conspecifics.
ano.nymous@ccsd.cnrs.fr.invalid (Cécile Arnould) 02 Oct 2024
https://hal.inrae.fr/hal-04717662v1
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[hal-04677329] Horses can learn to identify joy and sadness against other basic emotions from human facial expressions
Recently, horses and other domestic mammals have been shown to perceive and react to human emotional signals, with most studies focusing on joy and anger. In this study, we tested whether horses can learn to identify human joyful and sad expressions against other emotions. We used a touchscreen-based automated device that presented pairs of human portraits and distributed pellets when the horse touched the rewarded face. Six horses were trained to touch the sad face and 5 the joyful face. By the end of training, horses' performances at the group level were significantly higher than chance level, with higher scores for horses trained with the sad face. At the individual level, evidence of task learning varied among horses, which could be explained by individual variations in horses' ability to identify different human facial expressions or attention issues during the tests. In a generalization test, we introduced portraits of different humans than those presented during training. Horses trained with the joyful face performed better than chance, demonstrating generalization. Conversely, horses trained with the sad face did not. Horses also showed differences in learning performance according to the nonrewarded emotion, providing insights into horses' cognitive processing of facial expressions.
ano.nymous@ccsd.cnrs.fr.invalid (Plotine Jardat) 26 Aug 2024
https://hal.inrae.fr/hal-04677329v1
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[hal-04667540] Do sheep (<i>Ovis aries</i>) discriminate human emotional odors?
While sheep can detect and discriminate human emotions through visual and vocal cues, their reaction to human body odors remains unknown. The present study aimed to determine whether sheep ( Ovis aries ) can detect human odors, olfactorily discriminate stressed from non-stressed individuals, and behave accordingly based on the emotional valence of the odors. Axillary secretions from 34 students were collected following an oral examination (stress odor) or a regular class (non-stress odor). Fourteen female and 15 male lambs were then exposed to these odors through a habituation-dishabituation procedure. The habituation stimulus was presented four times for one minute, followed by the dishabituation stimulus presented once for one minute. Behavioral variables included spatiality relative to target odors, approach/withdrawal, ear positioning, sniffing, ingestion, and vocalization. Both female and male lambs more often positioned their ears backwards/forwards, and asymmetrically when exposed to the dishabituation stimulus, but regardless of their stress or non-stress value. They also changed their approach behavior when exposed to the dishabituation stimuli. Lambs displayed some behavioral signs of discrimination between the habituation and dishabituation odors, but regardless of their relation to stress or non-stress of human donors. In sum, this exploratory study suggests that young sheep respond negatively to the odor of unfamiliar humans, without showing any specific emotional contagion related to the stress odor. This exploratory study suggests young ovines can detect human body odor, a further step toward understanding the human-sheep relationship.
ano.nymous@ccsd.cnrs.fr.invalid (Izïa Larrigaldie) 05 Aug 2024
https://hal.inrae.fr/hal-04667540v1
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[hal-04668790] Facial blushing and feather fluffing are indicators of emotions in domestic fowl (Gallus gallus domesticus)
The study of facial expressions in mammals provided great advances in the identification of their emotions and then in the comprehension of their sentience. So far, this area of research has excluded birds. With a naturalist approach, we analysed facial blushing and feather displays in domestic fowl. Hens were filmed in situations contrasting in emotional valence and arousal level: situations known to indicate calm states (positive valence / low arousal), have rewarding effects (positive valence / high arousal) or induce fear-related behaviour (negative valence / high arousal). Head feather position as well as skin redness of comb, wattles, ear lobes and cheeks varied across these situations. Skin of all four areas was less red in situations with low arousal compared to situations with higher arousal. Furthermore, skin redness of the cheeks and ear lobes also varied depending on the valence of the situation: redness was higher in situations with negative valence compared to situations with positive valence. Feather position also varied with the situations. Feather fluffing was mostly observed in positively valenced situations, except when hens were eating. We conclude that hens have facial displays that reveal their emotions and that blushing is not exclusive to humans. This opens a promising way to explore the emotional lives of birds, which is a critical step when trying to improve poultry welfare.
ano.nymous@ccsd.cnrs.fr.invalid (Cécile Arnould) 07 Aug 2024
https://hal.science/hal-04668790v1
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[hal-04637092] Early and late cognitive and behavioral aspects associated with range use in free-range laying hens (Gallus gallus domesticus)
Individual differences in free-range chicken systems are important factors in fluencing how birds use the range (or not), even if individuals are reared in the same environmental conditions. Here, we investigated how various aspects of the birds ' behavioral and cognitive tendencies, including their optimism/pessimism, cognitive flexibility, sociability, and exploration levels, are associated with range use and how they may change over time (before and after range access). To achieve this, 100 White Leghorn laying hen chicks underwent three distinct behavioral/cognitive tests - the cognitive bias test, the detour test, and the multivariate test -prior to gaining access to the range, between 9 and 39 days of age. After range access was allowed (from day 71), birds ' range use was evaluated over 7 nonconsecutive days (from 74 -91 days of age). Subsequently, a subset of birds, classi fied as high rangers (n = 15) and low rangers (n = 15) based on their range use, underwent retesting on the same three previous tests between 94 and 108 days of age. Our results unveiled a negative correlation trend between birds ' evaluation of the ambiguous cue and their subsequent range use (rho =0.19, p = 0.07). Furthermore, low rangers were faster to learn the detour task ( x2 = 7.34, df = 1, p = 0.006), coupled with increased sociability during the multivariate test (rho = -0.23, p = 0.02), contrasting with their highranging counterparts, who displayed more exploratory behaviors (F[1,27] = 3.64, p = 0.06). These behavioral patterns fluctuated over time (before and after range access); however, conclusively attributing these changes to birds ' aging and development or the access to the range remains challenging. Overall, our results corroborate that behavioral and cognitive individual differences may be linked to range use and offer novel perspectives on the early behavioral and cognitive traits that may be linked to range use. These findings may serve as a foundation for adapting environments to meet individual needs and improve animal welfare in the future.
ano.nymous@ccsd.cnrs.fr.invalid (Vitor Hugo Bessa Ferreira) 05 Jul 2024
https://hal.inrae.fr/hal-04637092v1
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[hal-04667798] Behaviours exhibited during training predict physical tiredness in harness trotter horses
Physical activity, especially high-intensity training (HIT), leads to physiological and behavioural changes. The objectives of this randomized cross-over study were to investigate i) the effects of physical exercise on weight, behaviours, and head and ear positions on the days after low-intensity training (LIT) or high-intensity training; and ii) to explore if behaviours, and/or physiological parameters (sweat, salivation and blood lactate levels) during training can predict post-training behaviours. A total of nineteen French trotter horses housed in four different training centres were studied the day before (D pre ) and after LIT or HIT (afternoon after training (D training ) and 2 days after training (D1 Post and D2 Post )). The results showed that horses exhibited i) longer durations of resting and head below the withers (HBW) on D training and D1 Post than on D pre and ii) shorter eating durations on D1 Post and D2 Post than on D pre after HIT. This was associated with significant weight loss on D 2 Post . Several behaviours associated with discomfort ( e.g ., head conflict behaviours, nose behind the vertical, and open mouth), as well as amount of sweat, seemed to predict the durations of resting, HBW and eating on D1 Post . Thus, behaviours are impacted by training, and a combination of behaviours and visible physiological parameters exhibited during training have the potential to predict physical tiredness in harness racing horses.
ano.nymous@ccsd.cnrs.fr.invalid (Noémie Hennes) 05 Aug 2024
https://hal.inrae.fr/hal-04667798v1
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[hal-04667773] Differences in behaviour, facial expressions and locomotion between positive anticipation and frustration in horses
Animal welfare is a result of accumulated negative and positive emotions. Therefore, it is important to limit the former and promote the latter. Doing so requires a precise identification of these emotions. The aim of this study was to characterize the behaviours, facial expressions and locomotor parameters of 21 horses in two conditions with opposite valence, presumed to induce positive anticipation and frustration. In the positive anticipation situation, the horse was led to a bucket of food, knowing that they would be allowed to eat it. In the frustration situation, experimenters indicated to the horse that food was available without allowing them to eat it. In the positive anticipation situation, horses exhibited a lower neck position with the ears forward and upper lip advanced and went faster by increasing their stride frequency accompanied by increased global locomotor activity. In the frustration situation, horses exhibited a higher neck position with the ears backward or to the side, accompanied by ear movements and eye blinks, and interacted more with the experimenters. This study describes new possible indicators of positive anticipations and frustration in horses.
ano.nymous@ccsd.cnrs.fr.invalid (Romane Phelipon) 05 Aug 2024
https://hal.inrae.fr/hal-04667773v1
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[hal-04574339] Exploration of skin redness and immunoglobulin A as markers of the affective states of hens
Non-invasive markers of affective states can help understanding animals' perception of situations and improving their welfare. These markers are scarce in avian species. In this study, we investigate the potential relation between alterations in facial skin redness in hens and their corresponding affective states. Six hens were filmed in both naturally unfolding scenarios and controlled tests designed to elicit various affective states. The facial skin redness was measured from images extracted from the videos. Our observations revealed that hens exhibited the highest degree of facial skin redness in negative situations of high arousal, a high redness in positive situations of high arousal, and the lowest in positive situations of low arousal. In a second study, we further examined whether facial skin redness and secretory immunoglobulin A (S-IgA) can serve as markers for the quality of the human-animal relationship. Two groups of hens, one habituated to humans (n=13) and one non-habituated (n=12), were compared for general fearfulness in an open field test and for fear of humans in a reactivity to human test. In the open-field test, there were no statistical differences in general fearfulness, facial skin redness or S-IgA concentrations between both groups. However, habituated hens exhibited significantly lower fearfulness and facial skin redness in the presence of humans compared to non-habituated hens in the reactivity to human test. Additionally, habituated hens showed significant lower S-IgA concentration in lachrymal fluid in the presence of humans, with no significant differences in saliva or cloacal samples. We propose that changes in facial skin redness reflect variations in affective states and can be used as a marker for assessing the quality of the human-hen relationship. The relationship between S-IgA concentrations and affective states requires further investigation.
ano.nymous@ccsd.cnrs.fr.invalid (Delphine Soulet) 14 May 2024
https://hal.inrae.fr/hal-04574339v1
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[hal-04667802] A field approach to observing changes in behavioural welfare indicators over 2 years in stabled horses
In stabled horses, several behaviours are considered to be important indicators of the state of welfare at the individual level: stereotypies, aggressive behaviours towards humans and the "withdrawn", alert, sternal, lateral and observation postures. Until now, these behaviours have been extensively studied in relation to different horse management practices. However, little is known about their changes or consistency over time. This study aimed to investigate differences in the expression of these behaviours assessed on 44 stabled horses during an initial 3-month period and then again on the same individuals 2 years later. Out of the six behaviours studied, two showed significant differences between the 2 years with medium effect sizes: the levels of aggressiveness towards humans increased (Wilcoxon signed-rank test: V = 65, P = 0.005) and those of recumbent rest during the day decreased (V = 416, P < 0.001) over time. The results also suggested limited evidence of major changes over time in the expression of stereotypies, the "withdrawn", alert and observation postures. However, the principal component analyses carried out on all the behaviours showed that alert and observation postures may slightly decrease over time for some individuals. Regarding stereotypies and the "withdrawn" posture, the results mainly suggested a change at the individual level in the expression of these behaviours over time. This study provided new insights into the dynamic nature of several behaviours when the horses' living conditions are not fundamentally altered and raised hypotheses about the state of welfare of stabled individuals over a 2-year period. (c) 2024 The Authors. Published by Elsevier B.V. on behalf of The Animal Consortium.
ano.nymous@ccsd.cnrs.fr.invalid (A. Ruet) 05 Aug 2024
https://hal.inrae.fr/hal-04667802v1
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[hal-04588500] High-throughput phenotyping to characterise range use behaviour in broiler chickens
A key characteristic of free-range chicken farming is to enable chickens to spend time outdoors. However, each chicken may use the available areas for roaming in variable ways. To check if, and how, broilers use their outdoor range at an individual level, we need to reliably characterise range use behaviour. Traditional methods relying on visual scans require significant time investment and only provide discontinuous information. Passive RFID (Radio Frequency Identification) systems enable tracking individually tagged chickens’ when they go through pop-holes; hence, they only provide partial information on the movements of individual chickens. Here, we describe a new method to measure chickens’ range use and test its reliability on three ranges each containing a different breed. We used an active RFID system to localise chickens in their barn, or in one of nine zones of their range, every 30 seconds and assessed range-use behaviour in 600 chickens belonging to three breeds of slow- or medium-growing broilers used for outdoor production (all <40 g daily weight gain). From those real-time locations, we determined five measures to describe daily range use: time spent in the barn, number of outdoor accesses, number of zones visited in a day, gregariousness (an index that increases when birds spend time in zones where other birds are), and numbers of zone changes. Principal Component Analyses (PCAs) were performed on those measures, in each production system, to create two synthetic indicators of chickens’ range use behaviour. The first two PCA axes represented over 90% of the variance of the five measures and were both consistent over time and correlated with independent visual scans. Contributions of the five measures to the PCAs were similar among breeds, except for the correlation between the number of outdoor accesses and the four other measures. PC1 correlated with time spent inside the barn and zone changes frequency, whilst PC2 was explained by exploration of the range. Taken together, PC1 and PC2 indicators showed that range use increased with age, outdoor temperature (in spring), and did not differ between males and females. Importantly, daily scores for both indicators were repeatable among individuals - particularly in PC1 - showing inter-individual variability on range-use. The characterisation of broiler behaviour around their range with these reliable and repeatable indicators provides novel tools to help understand individual variations of range-use in free-range farming.
ano.nymous@ccsd.cnrs.fr.invalid (Julie Collet) 27 May 2024
https://hal.science/hal-04588500v1
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[hal-04699193] Maternal stress effects across generations in a precocial bird
Prenatal maternal stress (PMS) is known to shape the phenotype of the first generation offspring (F1) but according to some studies, it could also shape the phenotype of the offspring of the following generations. We previously showed in the Japanese quail that PMS increased the emotional reactivity of F1 offspring in relation to (i) a variation in the levels of some histone post-translational modification (H3K27me3) in their brains and (ii) a modulation of the hormonal composition of the eggs from which they hatched. Here, we wondered whether PMS could also influence the behaviour of the second (F2) and third (F3) generation offspring due to the persistence of the specific marks we identified. Using a principal component analysis, we found that PMS influenced F2 and F3 quail profiles with subtle differences between generations. It increased F2 neophobia, F3 fearfulness and F3 neophobia but only in females. Interestingly, we did not find any variations in the level of histone post-translational modification in F3 brains and we observed inconsistent modulations of androstenedione levels in F1 and F2 eggs. Although they may vary over generations, our results demonstrate that PMS can have phenotypical effects into the third generation.
ano.nymous@ccsd.cnrs.fr.invalid (Marion Charrier) 17 Sep 2024
https://hal.science/hal-04699193v1
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[hal-04667737] How Useful Are Existing Protocols in the Quick Assessment of the Welfare of Semi-Feral Horses? Pilot Study on Konik Polski Horses Living in the Forest Sanctuary
Scientifically validated and standardised methods for the evaluation of the welfare of free-living horses are urgently needed by both the owners and managers of these populations and those responsible for implementing national welfare legislation. The aim of the study was to test the feasibility and usefulness of two welfare protocols that could be applied to semi-feral populations: a prototype of welfare assessment template (WAT) for Carneddau semi-feral ponies and the IFCE/INRAE Horse Welfare Protocol. Additionally, the body condition scale designed by Henneke (BCS-H) was employed. The study took place in July/August 2022 and April 2023 to evaluate the welfare of a pilot population of nineteen semi-feral Konik polski horses. The horses scored high or satisfactory under indicators across both protocols; only body condition scores were significantly lower in early spring (BCS-WAT: 1.11 ± 0.57; BCS-H: 3.84 ± 1.17) than in the summer (BCS-WAT: 1.58 ± 0.61; BCS-H: 5.63 ± 1.01). Our study confirmed the feasibility of utilising most of the WAT and IFCE/INRAE welfare indicators in semi-feral horses. Some adaptations, such as considering validation of scales, positive welfare indicators and animals’ free-choice of conditions, have been suggested for future in-field application.
ano.nymous@ccsd.cnrs.fr.invalid (Aleksandra Górecka-Bruzda) 05 Aug 2024
https://hal.inrae.fr/hal-04667737v1
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[hal-04548377] Discrimination of familiar and unfamiliar human voices is independent of prolonged human-animal interaction in domestic chicks
Different animal species, both domestic and wild, can discriminate between various human cues, such as voices, and adjust their behavior based on whether they are familiar or unfamiliar with these cues. To investigate whether this ability extends to a domesticated species not specifically bred for human interaction and whether it can manifest at an early age, even under commercial-like conditions with limited human interaction, we conducted human vocal discrimination tests on domestic chicks at two ages (25 and 67 days old). Our findings showed that chicks could discriminate between familiar and unfamiliar voices at both ages, exhibiting increased vigilance when a known sentence was spoken by an unfamiliar voice compared to a familiar voice. We also found that chicks were more vigilant after a familiar voice delivered an unknown sentence, compared to an unfamiliar voice delivered a known sentence. This suggests a violation of expectation when animals are confronted with mixed familiar/unfamiliar heterospecific signals. Our findings support that neither specific selection for interaction with humans, nor an extended history of exposure to humans, is a prerequisite for animals to discriminate heterospecific cues, such as human voices.
ano.nymous@ccsd.cnrs.fr.invalid (Vitor Hugo Bessa Ferreira) 16 Apr 2024
https://hal.inrae.fr/hal-04548377v1
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[hal-04426412] Feeding predictability as a cognitive enrichment protects brain function and physiological status in rainbow trout: a multidisciplinary approach to assess fish welfare
Cognitive enrichment is a promising but understudied type of environmental enrichment that aims to stimulate the cognitive abilities of animals by providing them with more opportunities to interact with (namely, to predict events than can occur) and to control their environment. In a previous study, we highlighted that farmed rainbow trout can predict daily feedings after two weeks of conditioning, the highest conditioned response being elicited by the combination of both temporal and signalled predictability. In the present study, we tested the feeding predictability that elicited the highest conditioned response in rainbow trout (both temporal and signalled by bubbles, BUBBLE+TIME treatment) as a cognitive enrichment strategy to improve their welfare. We thus analysed long-term effects of this feeding predictability condition as compared with an unpredictable feeding condition (RANDOM treatment) on the welfare of rainbow trout, including the markers in the modulation of brain function, through a multidisciplinary approach. To reveal the brain regulatory pathways and networks involved in the long-term effects of feeding predictability, we measured genes markers of cerebral activity and plasticity, neurotransmitters pathways and physiological status of fish (oxidative stress, inflammatory status, cell type and stress status). After almost three months under these predictability conditions of feeding, we found clear evidence of improved welfare in fish from BUBBLE+TIME treatment. Feeding predictability allowed for a food anticipatory activity and resulted in fewer aggressive behaviours, burst of accelerations, and jumps before mealtime. BUBBLE+TIME fish were also less active between meals, which is in line with the observed decreased expression of transcripts related to the dopaminergic system. BUBBLE+TIME fish tented to present fewer eroded dorsal fin and infections to the pathogen Flavobacterium psychrophilum. Decreased expression of most of the studied mRNA involved in oxidative stress and immune responses confirm these tendencies else suggesting a strong role of feeding predictability on fish health status and that RANDOM fish may have undergone chronic stress. Fish emotional reactivity while isolated in a novel-tank as measured by fear behaviour and plasma cortisol levels were similar between the two treatments, as well as fish weight and size. To conclude, signalled combined with temporal predictability of feeding appears to be a promising approach of cognitive enrichment to protect brain function via physiological status of farmed rainbow trout in the long term.
ano.nymous@ccsd.cnrs.fr.invalid (Aude Kleiber) 21 Mar 2024
https://hal.inrae.fr/hal-04426412v1
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[hal-04524652] Personality of equids: Donkeys and draught horses behave differently in fear and tactile sensitivity tests
Horses and donkeys are used for agriculture, leisure, urban services and therapy. Although these two species obviously behave differently, it is important to measure their behavioural specificity when tested in the same situations and to highlight the existence of some personality dimensions. During 104 breeding shows in France, personality tests validated for horses as measuring fearfulness and tactile sensitivity dimensions were applied to 1-year-old equids: 242 donkeys and 924 draught horses. In fear tests, compared to draught horses, donkeys in-hand moved less during height measurement ( P< 0.0001), walked less rapidly around a novel object (P< 0.015) and refused to move forward more often in front of a novel surface (P< 0.0001). During most tests, donkeys presented less tense posture and less evasive behaviours (P< 0.015). However, during suddenness tests, donkeys in-hand fled similarly to horses. Free in an open field with grass, donkeys walked as much as horses and grazed less (P< 0.0001). Finally, donkeys reacted more to filaments measuring tactile sensitivity (P< 0.0001). These results were often modulated by sex in horses with more reactions in males, and to a lesser degree in donkeys but with more reactions in females. Correlation and principal component analyses (PCA) of these individual characteristics within each species revealed stability of behaviours across fearful situations. In addition, PCA factor loadings revealed concordance between species (inter-factors 1: Kendall Tau = 0.33, P=0.021, inter-factors 2: Kendall Tau = 0.36, P=0.012). This suggested that the two species have similarities in their personality structure. In conclusion, young donkeys behave differently to young draught horses toward static novelties and tactile stimulation, but similarly when confronted with a visual surprise or free in an open field. However, there is probably an underlying common personality structure in the two species. For fearfulness to be considered as a personality dimension in donkeys, further studies are required to demonstrate its stability over time. These results have implications for animal welfare, because the fact that donkeys do not move does not mean that they are not afraid. Physiological measures and finer behavioural observations are required to characterise more precisely fear in donkeys. There are also implications for the safety of inexperienced people unaware of the danger of certain situations, particularly when equids considered to be placid are involved.
ano.nymous@ccsd.cnrs.fr.invalid (Marianne Vidament) 28 Mar 2024
https://hal.inrae.fr/hal-04524652v1
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[hal-04069771] Horses cross-modally recognize women and men
Abstract Several studies have shown that horses have the ability to cross-modally recognize humans by associating their voice with their physical appearance. However, it remains unclear whether horses are able to differentiate humans according to different criteria, such as the fact that they are women or men. Horses might recognize some human characteristics, such as sex, and use these characteristics to classify them into different categories. The aim of this study was to explore whether domesticated horses are able to cross-modally recognize women and men according to visual and auditory cues, using a preferential looking paradigm. We simultaneously presented two videos of women and men’s faces, while playing a recording of a human voice belonging to one of these two categories through a loudspeaker. The results showed that the horses looked significantly more towards the congruent video than towards the incongruent video, suggesting that they are able to associate women’s voices with women’s faces and men’s voices with men’s faces. Further investigation is necessary to determine the mechanism underlying this recognition, as it might be interesting to determine which characteristics horses use to categorize humans. These results suggest a novel perspective that could allow us to better understand how horses perceive humans.
ano.nymous@ccsd.cnrs.fr.invalid (Chloé Gouyet) 14 Apr 2023
https://hal.inrae.fr/hal-04069771v1
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[hal-04524493] Are domesticated animals dumber than their wild relatives? A comprehensive review on the domestication effects on animal cognitive performance
Animal domestication leads to diverse behavioral, physiological, and neurocognitive changes in domesticated species compared to their wild relatives. However, the widely held belief that domesticated species are inherently less "intelligent" (i.e., have lower cognitive performance) than their wild counterparts requires further investigation. To investigate potential cognitive disparities, we undertook a thorough review of 88 studies comparing the cognitive performance of domesticated and wild animals. Approximately 30% of these studies showed superior cognitive abilities in wild animals, while another 30% highlighted superior cognitive abilities in domesticated animals. The remaining 40% of studies found similar cognitive performance between the two groups. Therefore, the question regarding the presumed intelligence of wild animals and the diminished cognitive ability of domesticated animals remains unresolved. We discuss important factors/limitations for interpreting past and future research, including environmental influences, diverse objectives of domestication (such as breed development), developmental windows, and methodological issues impacting cognitive comparisons. Rather than perceiving these limitations as constraints, future researchers should embrace them as opportunities to expand our understanding of the complex relationship between domestication and animal cognition.
ano.nymous@ccsd.cnrs.fr.invalid (Vitor Hugo Bessa Ferreira) 28 Mar 2024
https://hal.inrae.fr/hal-04524493v1
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[hal-04192779] Transcriptomic signature related to poor welfare of sport horses
Highlights: • The same housing conditions influence behavioural indicators differently according to horses. • Aggressiveness is the behavioural indicator the most correlated to gene expression. • Aggressiveness was associated with molecular pathways related to inflammation. • Stereotypies were correlated to gene expression when combined to faecal microbiota. • Aggressiveness and stereotypies in horses covary with physiological alterations. Abstract: The improvement of horse welfare through housing conditions has become a real issue in recent years and have highlighted the detrimental effect of individual housing of horses on their health and behaviour. In this new study, we analysed the blood transcriptome of 45 sport horses housed individually that were previously examined for their behaviour and gut microbiota. We performed differential and regression analyses of gene expression, followed by downstream bioinformatic analyses, to unveil the molecular pathways related to the behavioural changes associated with welfare impairment in these sport horses. We found that aggressiveness towards humans was the behavioural indicator the most correlated to blood gene expression and that the pathways involved belonged mainly to systemic inflammation. In contrast, the correlations between genes, alert postures and unresponsiveness towards the environment were weak. When blood gene expression profiling was combined with faecal microbiota of a sub-population of horses, stereotypies came out as the most correlated to blood gene expression. This study shows that aggressiveness towards humans and stereotypies are behavioural indicators that covary with physiological alterations. Further studies are needed regarding the biological correlates of unresponsiveness to the environment and alert postures.
ano.nymous@ccsd.cnrs.fr.invalid (A. Foury) 31 Aug 2023
https://hal.science/hal-04192779v1
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[hal-04219741] Comment les volailles perçoivent et interprètent leur environnement : recherche scientifique et exemples d’applications
La science s’intéresse de longue date aux pratiques d’élevage et à la notion de sensibilité animale. En accord avec ces questionnements, il existe une demande sociétale croissante pour l’amélioration des conditions de vie des animaux de rente. Cette amélioration nécessite des connaissances de leurs capacités cognitives, qui permettent à l’animal de traiter, mémoriser, interpréter ce qui se passe dans son environnement. Ces connaissances permettent d’expliquer voire limiter certains comportements observés en élevage. [ Cet article est issu d’une synthèse présentée aux 14èmes Journées de la Recherche Avicole des 9-10 mars 2022 à Tours. (Calandreau et al., 2022) ]
ano.nymous@ccsd.cnrs.fr.invalid (Rachel Degrande) 27 Sep 2023
https://hal.inrae.fr/hal-04219741v1
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[hal-04524456] Chronic dietary exposure to a glyphosate-based herbicide in broiler hens has long-term impacts on the progeny metabolism
Glyphosate-based herbicides (GBH) are the most commonly used herbicides in agriculture. Sev-eral studies reported possible adverse effects on human and animal models after a GBH exposure. However, the effects of a temporary maternal exposure on the progeny have been poorly documented, especially in avian mod-els. We investigated the effects of a hen chronic dietary exposure to a GBH on the progeny, obtained during the period following the withdrawal of GBH from the diet. Hens were exposed to a GBH via their food for 6 wk, after which the GBH was removed from their food. Eggs from these hens were collected 3 wk after the GBH was withdrawn for 1 wk. We monitored the growth perform-ances, metabolic parameters, and behavior from the progeny of the hens (Ex-GBH chicks, n = 186) and com-pared them with those of unexposed control-hen prog-eny (CT chicks, n = 213). Ex-GBH chicks were more likely to explore their new environment than CT chicks during the open-field test. In addition, they had an increased fattening and blood triglycerides level, whereas their food consumption was similar to CT chicks. Quantitative PCR on the chemerin system and FASN in chicks livers indicate a transcriptional activity in favor of fatty acid synthesis, and lipidomic analysis on chicks abdominal adipose tissue reveal a global increase in monounsaturated fatty acid and a global decrease in polyunsaturated fatty acids. Seven genes involved in the synthesis of fatty acids were identified with the open access LIPIDMAP software, and their disturbance in Ex-GBH chicks was confirmed via qPCR. Taken together, these results suggest that the progeny of hens temporarily exposed to a GBH are more likely to fatten, even with a balanced diet. The removal of GBH from their contaminated environment would therefore not be sufficient to completely restore their health, has it could induce transgenerational effects.
ano.nymous@ccsd.cnrs.fr.invalid (Anthony Estienne) 28 Mar 2024
https://hal.inrae.fr/hal-04524456v1
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[hal-04129091] Environmental enrichment improves cognitive flexibility in rainbow trout in a visual discrimination task: first insights
Research on fish cognition provides strong evidence that fish are endowed with high level cognitive skills. However, most studies on cognitive flexibility and generalization abilities, two key adaptive traits for captive animals, focused on model species, and farmed fish received too little attention. Environmental enrichment was shown to improve learning abilities in various fish species, but its influence on cognitive flexibility and generalization abilities is still unknown. We studied farmed rainbow trout ( Oncorhynchus mykiss ) as an aquaculture model to study how environmental enrichment impacts their cognitive abilities. Using an operant conditioning device, allowing the expression of a motivated choice, we measured fish cognitive flexibility with serial reversal learning tests, after a successful acquisition phase based on two colors discrimination (2-alternative forced choice, 2-AFC), and their ability to generalize a rewarded color to any shape. Eight fish were divided into two groups: Condition E (fish reared from fry stages under enriched conditions with plants, rocks and pipes for ~9 months); Condition B (standard barren conditions). Only one fish (condition E) failed in the habituation phase of the device and one fish (condition B) failed in the 2-AFC task. We showed that after a successful acquisition phase in which the fish correctly discriminated two colors, they all succeeded in four reversal learnings, supporting evidence for cognitive flexibility in rainbow trout. They were all successful in the generalization task. Interestingly, fish reared in an enriched environment performed better in the acquisition phase and in the reversal learning (as evidenced by fewer trials needed to reach the learning criterion), but not in the generalization task. We assume that color-based generalization may be a simpler cognitive process than discriminative learning and cognitive flexibility, and does not seem to be influenced by environmental conditions. Given the small number of individuals tested, our results may be considered as first insights into cognitive flexibility in farmed fish using an operant conditioning device, but they pave the way for future studies. We conclude that farming conditions should take into account the cognitive abilities of fish, in particular their cognitive flexibility, by allowing them to live in an enriched environment.
ano.nymous@ccsd.cnrs.fr.invalid (Valentin Brunet) 15 Jun 2023
https://hal.inrae.fr/hal-04129091v1
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[hal-04300666] First report of reindeer (Rangifer tarandus tarandus) response to human-given cues
Many argue that the animal understanding of human referential communication is a by-product of domestication. However, the domestication hypothesis is not unanimously supported as some nondomesticated species such as sea lions, dolphins, or African elephants perform well in the understanding of human pointing gesture. There is a need to study species with different levels of domestication across different taxa to understand the emerging communicative sociocognitive skills in animals that provide them with the ability to comprehend human-given cues. We conducted a pilot study to assess the performance of eight sledging reindeer following a commonly used human-given cue (a pointing gesture associated with gaze at the target and local enhancement) in a two-way choice task. Domestic reindeer are considered semicaptive, because of their husbandry system in free-ranging conditions, with limited control of their reproduction. We observed that the willingness of the reindeer to participate in the test was age-related, with the younger individuals which lack experience with humans being reluctant to approach the experimenters. Within the more experienced working sledging reindeer, two individuals showed excellent skills and followed the human-given cues 9 out of 10 times. Reindeer show great potential in following a human indication to locate hidden food with minimal training when properly tamed. The effect of previous experience with humans requires further investigation. This is the first demonstration in cervids of an ability to make use of experimenter-given cues in an object-choice task.
ano.nymous@ccsd.cnrs.fr.invalid (Océane Liehrmann) 22 Nov 2023
https://hal.inrae.fr/hal-04300666v1
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[hal-04109688] Cognitive enrichment to increase fish welfare in aquaculture: A review
While most animals have received increasing attention for their welfare, consideration for fish welfare has started more recently, particularly since the recognition that fish have emotions and complex cognitive abilities. Housing conditions in fish farms do not always meet fish ethological requirements as these conditions lack sufficient sensory and cognitive stimulations. An approach to address this issue involves enriching the rearing environment by including social, food, physical, or cognitive stimuli. Cognitive enrichment (CE) is a recent but promising concept to improve fish welfare by manipulating the predictability and controllability of their environment. It relies not only on the ability of fish to predict positive and negative events but also on their ability to perform and succeed in operant conditioning. In our present review, we identified four categories of CE: (i) feeding predictability, (ii) predictability of a negative event, (iii) operant conditioning through self-feeders, and (iv) learning experiences. Existing CEs were reviewed for their effects on behaviour, brain, zootechnical performances, and welfare in terms of physiological stress or physical integrity in the aquarium and farmed teleost fish. The review highlights unbalanced categories and the lack of adequate multidisciplinary analyses to assess the effects of these categories on fish welfare. Providing free access to self-feeders seems to be a good strategy, given its positive effects on zootechnical and physiological parameters. Other categories showed contradictory and species-dependent results; hence, further studies are required to confirm the benefits of CE on fish welfare. Finally, further investigations should also validate current CE systems and assess other strategies that may trigger positive emotions in fish.
ano.nymous@ccsd.cnrs.fr.invalid (Aude Kleiber) 14 Mar 2024
https://hal.inrae.fr/hal-04109688v1
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[hal-04300609] What drives horse success at following human-given cues? An investigation of handler familiarity and living conditions
Cues such as the human pointing gesture, gaze or proximity to an object are widely used in behavioural studies to evaluate animals’ abilities to follow human-given cues. Many domestic mammals, such as horses, can follow human cues; however, factors influencing their responses are still unclear. We assessed the performance of 57 horses at a two-way choice task testing their ability to follow cues of either a familiar ( N = 28) or an unfamiliar informant ( N = 29). We investigated the effects of the length of the relationship between the horse and a familiar person (main caregiver), their social environment (living alone, in dyads, or in groups) and their physical environment (living in stalls/paddocks, alternating between paddocks and pastures, or living full time in pastures). We also controlled for the effects of horses’ age and sex. Our results showed that horses’ success rate at the task was not affected by the familiarity of the informant and did not improve with the relationship length with the familiar informant but did increase with the age of the horses. Horses living in groups had better success than the ones kept either in dyads or alone. Finally, horses housed in small paddocks had lower success than those living on pasture. These results indicate that with age, horses get better at following human-given indications regardless of who the human informant is and that an appropriate living and social environment could contribute to the development of socio-cognitive skills towards humans. Therefore, such aspects should be considered in studies evaluating animal behaviour.
ano.nymous@ccsd.cnrs.fr.invalid (Océane Liehrmann) 22 Nov 2023
https://hal.inrae.fr/hal-04300609v1
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[hal-04011829] Horses discriminate human body odors between fear and joy contexts in a habituation-discrimination protocol
Animals are widely believed to sense human emotions through smell. Chemoreception is the most primitive and ubiquitous sense, and brain regions responsible for processing smells are among the oldest structures in mammalian evolution. Thus, chemosignals might be involved in interspecies communication. The communication of emotions is essential for social interactions, but very few studies have clearly shown that animals can sense human emotions through smell. We used a habituation-discrimination protocol to test whether horses can discriminate between human odors produced while feeling fear vs. joy. Horses were presented with sweat odors of humans who reported feeling fear or joy while watching a horror movie or a comedy, respectively. A first odor was presented twice in successive trials (habituation), and then, the same odor and a novel odor were presented simultaneously (discrimination). The two odors were from the same human in the fear or joy condition; the experimenter and the observer were blinded to the condition. Horses sniffed the novel odor longer than the repeated odor, indicating they discriminated between human odors produced in fear and joy contexts. Moreover, differences in habituation speed and asymmetric nostril use according to odor suggest differences in the emotional processing of the two odors.
ano.nymous@ccsd.cnrs.fr.invalid (Plotine Jardat) 02 Mar 2023
https://hal.inrae.fr/hal-04011829v1
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[hal-04168459] Captive Blue-and-yellow macaws (Ara ararauna) show facial indicators of positive affect when reunited with their caregiver
In mammals, human-animal bonding is recognized as a source of positive affect for companion or farm animals. Because this remains unexplored in birds, we investigated captive parrots’ perspective of the human-animal relationship. We used a classical separation-reunion paradigm and predicted that variations in parrots’ facial displays and behaviours would indicate their appraisal of the relationship. The test was divided into three phases of two minutes each: the bird was placed in an unfamiliar environment with a familiar caregiver (union), then the bird was left alone (separation) and finally, the caregiver returned (reunion). The test was repeated 10 times for each bird and video recorded in order to analyze their behaviour. The data show significantly higher crown and nape feather heights, higher redness of the skin and higher frequency of contact-seeking behaviours during the union and reunion phases than during the separation phase during which they expressed long distance contact calls. We observed the expression of eye pinning during the union and reunion phases in one out of five macaws. We argue that variation in facial displays provides indicators of parrot’s positive appraisal of the caretaker presence. Our results broaden the scope for further studies on parrots’ expression of their subjective feelings.
ano.nymous@ccsd.cnrs.fr.invalid (Aline Bertin) 17 Nov 2023
https://hal.inrae.fr/hal-04168459v2
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[hal-04052261] Behavioural indicators of range use in four broiler strains
Free-range systems provide an outdoor range for broilers to give them the possibility to express a higher frequency and a wider range of behaviours, such as exploration, compared with those raised indoors. Greater variability in outdoor range use between individuals of the same flock is often reported. Individual variation in range use may result from differences in early-life behaviour or genetic background. Understanding how earlylife behaviour influences range use may provide opportunities to enhance and predict range use. Previous studies have shown that range use could be influenced by the animal’s personality traits such as social motivation, boldness and foraging motivation. Therefore, this study investigated personality traits in several broiler strains, namely Hubbard JA757, Hubbard S757N, White Bresse and a dual-purpose strain; we examined the latter as it represents a potential solution to the ban of 1-day-old chick culling. The present study also investigated early-life behaviours, before range access, of range use to identify and assess the stability of these early-life indicators among the four broiler strains. For that purpose, we recorded the behaviour and range use of 100 male chickens per strain, both in the barn and during individual tests, before and after range access. We examined which behaviours were time consistent, whether early-life behaviours were influenced by genetic variation and whether early-life behavioural indicators predicted range use regardless of genetic variation. There was a significant (p < 0.001) difference between strains in several early-life behaviours, including the time spent resting or standing. Range use was time consistent regardless of the strain as our range use indicator followed a high-quality linear regression model (R2 > 0.7) for 82–99% of the individuals depending on their strain. Besides, time consistency of social motivation and boldness seemed to depend on the strain. Even though foraging showed low (rho = 0.2–0.4) positive correlations with range use in three of the four studied strains, there were no significant and strong correlations in the four studied strains between early-life behavioural indicators and range use. In conclusion, our results show that the link between chick behaviour (before range access) and range use can be modulated by the bird’s strain. It is crucial to consider all these different factors to better understand how range use varies within and between flocks.
ano.nymous@ccsd.cnrs.fr.invalid (Claire Bonnefous) 30 Mar 2023
https://hal.inrae.fr/hal-04052261v1
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[hal-04185480] Short photoperiod modulates behavior, cognition and hippocampal neurogenesis in male Japanese quail
The mechanisms underlying the photoperiodic control of reproduction in mammals and birds have been recently clarified. In contrast, the potential impact of photoperiod on more complex, integrative processes, such as cognitive behaviors, remains poorly characterized. Here, we investigated the impact of contrasted long and short photoperiods (LP, 16 h light/day and SP, 8 h light/day, respectively) on learning, spatial orientation abilities, and emotional reactivity in male Japanese quail. In addition, we quantified cell proliferation and young cell maturation/migration within the hippocampus, a brain region involved in spatial orientation. Our study reveals that, in male quail, SP increases emotional responses and spatial orientation abilities, compared to LP. Behaviorally, SP birds were found to be more fearful than LP birds, exhibiting more freezing in the open field and taking longer to exit the dark compartment in the emergence test. Furthermore, SP birds were significantly less aggressive than LP birds in a mirror test. Cognitively, SP birds were slower to habituate and learn a spatial orientation task compared to LP birds. However, during a recall test, SP birds performed better than LP birds. From a neuroanatomical standpoint, SP birds had a significantly lower density of young neurons, and also tended to have a lower density of mature neurons within the hippocampus, compared to LP birds. In conclusion, our data reveal that, beyond breeding control, photoperiod also exerts a profound influence on behavior, cognition, and brain plasticity, which comprise the seasonal program of this species.
ano.nymous@ccsd.cnrs.fr.invalid (Marion Georgelin) 22 Aug 2023
https://hal.inrae.fr/hal-04185480v1
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[hal-04213124] Horses discriminate between human facial and vocal expressions of sadness and joy
Communication of emotions plays a key role in intraspecific social interactions and likely in interspecific interactions. Several studies have shown that animals perceive human joy and anger, but few studies have examined other human emotions, such as sadness. In this study, we conducted a cross-modal experiment, in which we showed 28 horses two soundless videos simultaneously, one showing a sad, and one a joyful human face. These were accompanied by either a sad or joyful voice. The number of horses whose first look to the video that was incongruent with the voice was longer than their first look to the congruent video was higher than chance, suggesting that horses could form cross-modal representations of human joy and sadness. Moreover, horses were more attentive to the videos of joy and looked at them for longer, more frequently, and more rapidly than the videos of sadness. Their heart rates tended to increase when they heard joy and to decrease when they heard sadness. These results show that horses are able to discriminate facial and vocal expressions of joy and sadness and may form cross-modal representations of these emotions; they also are more attracted to joyful faces than to sad faces and seem to be more aroused by a joyful voice than a sad voice. Further studies are needed to better understand how horses perceive the range of human emotions, and we propose that future experiments include neutral stimuli as well as emotions with different arousal levels but a same valence.
ano.nymous@ccsd.cnrs.fr.invalid (Plotine Jardat) 21 Sep 2023
https://hal.science/hal-04213124v1
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[hal-03744960] Early castration in foals: Consequences on physical and behavioural development
Background The impact of very early castration of foals has not yet been studied despite the many positive effects observed in dogs and cats. Objectives The objective of the study was to compare castration at 3 days and 18 months and assess their subsequent morphological and behavioural development. Study design This was a randomised, blinded clinical study. Methods Twenty-two Welsh ponies underwent either early (3-day old, EC group, n = 11) or traditional (18-month old, TC group, n = 11) castration. Animals were followed up to 3 years of age. All ponies were castrated using a primary closure technique under general anaesthesia. Weight and morphometric measurements were monitored monthly from birth until 8 months of age in both groups. Then, measurements were taken every 3 months until 2 years of age and then every 6 months until 3 years of age. Temperament tests were performed on all animals when they were 1- and 3-years old. Results No differences were observed between the EC and TC groups in terms of physical development from birth until 40 months of age or in terms of temperament and behaviour at either 1 or 3 years of age. Main limitations The study included only one breed (Welsh ponies) and only 22 animals that were castrated before 2 years of age, precluding comparison with castration performed at older ages. Conclusions We demonstrate that early castration at 3 days does not interfere with morphological or behavioural development.
ano.nymous@ccsd.cnrs.fr.invalid (Juliette Cognie) 03 Aug 2022
https://hal.inrae.fr/hal-03744960v1
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[hal-03751952] Horses form cross-modal representations of adults and children
Recently, research on domestic mammals' sociocognitive skills toward humans has been prolific, allowing us to better understand the human-animal relationship. For example, horses have been shown to distinguish human beings on the basis of photographs and voices and to have cross-modal mental representations of individual humans and human emotions. This leads to questions such as the extent to which horses can differentiate human attributes such as age. Here, we tested whether horses discriminate human adults from children. In a cross-modal paradigm, we presented 31 female horses with two simultaneous muted videos of a child and an adult saying the same neutral sentence, accompanied by the sound of an adult's or child's voice speaking the sentence. The horses looked significantly longer at the videos that were incongruent with the heard voice than at the congruent videos. We conclude that horses can match adults' and children's faces and voices cross-modally. Moreover, their heart rates increased during children's vocalizations but not during adults'. This suggests that in addition to having mental representations of adults and children, horses have a stronger emotional response to children's voices than adults' voices.
ano.nymous@ccsd.cnrs.fr.invalid (Plotine Jardat) 16 Aug 2022
https://hal.inrae.fr/hal-03751952v1
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[hal-04185498] Effects of domestication on responses of chickens and red junglefowl to conspecific calls: A pilot study
Beyond physical and zootechnical characteristics, the process of animal domestication has also altered how domesticated individuals, compared to their wild counterparts, perceive, process, and interact with their environment. Little is known, however, on whether and how domestication altered the perception of conspecific calls on both domesticated and wild breeds. In the present work, we compared the vigilance behavior of domestic and captive-born wild fowl following the playback of chicken alarm calls and contentment calls (control). The playback tests were performed on four different breeds/lines. We first compared the behavioral reaction of domesticated White Leghorn (WL, a breed selected for egg production) and Red Junglefowl (RJF) hens (ancestor of domestic chickens). We also compared the behavior of Red Junglefowl hens selected for high or low fear of humans (RJF HF and RJF LF, respectively), a proxy to investigate early effects of domestication. Contrary to our expectations, no breed/line reacted accordingly to the calls, as the increase in vigilance behavior after the playback calls was similar for both alarm and contentment calls. Although no call discrimination differences were found, breeds did differ on how they reacted/habituated to the calls. Overall, WL were more vigilant than RJF, and birds from the RJF LF line decreased their vigilance over testing days, while this was not the case for the RJF HF line. These results suggest that birds under commercial-like conditions are unable to discriminate between alarm and contentment calls. Interestingly, domestication and selection for low fear of humans may have altered how birds react to vocal stimuli. It is important to consider that farmed animals may interpret and be affected by the vocalizations of their conspecifics in unexpected ways, which warrants further investigation.
ano.nymous@ccsd.cnrs.fr.invalid (Vitor Hugo Bessa Ferreira) 22 Aug 2023
https://hal.inrae.fr/hal-04185498v1
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[hal-03626271] Pet-directed speech improves horses’ attention toward humans
In a recent experiment, we showed that horses are sensitive to pet-directed speech (PDS), a kind of speech used to talk to companion animals that is characterized by high pitch and wide pitch variations. When talked to in PDS rather than adult-directed speech (ADS), horses reacted more favorably during grooming and in a pointing task. However, the mechanism behind their response remains unclear: does PDS draw horses’ attention and arouse them, or does it make their emotional state more positive? In this study, we used an innovative paradigm in which female horses watched videos of humans speaking in PDS or ADS to better understand this phenomenon. Horses reacted differently to the videos of PDS and ADS: they were significantly more attentive and their heart rates increased significantly more during PDS than during ADS. We found no difference in the expressions of negative or positive emotional states during PDS and ADS videos. Thus, we confirm that horses’ perception of humans can be studied by means of video projections, and we conclude that PDS attracts attention and has an arousing effect in horses, with consequences on the use of PDS in daily interactions with them.
ano.nymous@ccsd.cnrs.fr.invalid (Plotine Jardat) 31 Mar 2022
https://hal.inrae.fr/hal-03626271v1
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[hal-03746208] Positive effects of bubbles as a feeding predictor on behaviour of farmed rainbow trout
Occupational enrichment emerges as a promising strategy for improving the welfare of farmed animals. This form of enrichment aims to stimulate cognitive abilities of animals by providing them with more opportunities to interact with and control their environment. Predictability of salient daily events, and in particular predictability of feeding, is currently one of the most studied occupational enrichment strategies and can take several forms. In fish, while temporal predictability of feeding has been widely investigated, signalled predictability (based on a signal, such as light or sound) has received little attention. Depending on the type of predictability used and the ecology of the species, the effects on fish welfare often differ. The present study aimed to determine which feeding predictability would be most appropriate for rainbow trout, the main continental farmed fish in Europe, and what the consequences might be for their welfare. We tested four feeding predictability conditions: temporal (based on time of day), signalled (based on bubble diffusion), temporal + signalled (based on time and bubble diffusion), and unpredictable (random feeding times). Behavioural and zootechnical outcomes recorded were swimming activity, aggressive behaviours, burst of accelerations, and jumps, emotional reactivity, and growth. Our results showed that rainbow trout can predict daily feedings relying on time and/or bubbles as predictors as early as two weeks of conditioning, as evidenced by their increased swimming activity before feeding or during feed omission tests, which allowed to reinforce their conditioned response. Temporal predictability alone resulted in an increase in pre-feeding aggressive behaviours, burst of accelerations, and jumps, suggesting that the use of time as the sole predictor of feedings in husbandry practices may be detrimental to fish welfare. Signalled predictability with bubbles alone resulted in fewer pre-feeding agonistic behaviours, burst of accelerations, and jumps than in the temporal predictability condition. The combination of temporal and signalled predictability elicited the highest conditioned response and the level of pre-feeding aggression behaviours, burst of accelerations and jumps tended to be lower than for temporal predictability alone. Interestingly, fish swimming activity during bubble diffusion also revealed that bubbles were highly attractive regardless of the condition. Rainbow trout growth and emotional reactivity were not affected by the predictability condition. We conclude, therefore, that the use of bubbles as a feeding predictor could represent an interesting approach to improve rainbow trout welfare in farms, by acting as both an occupational and physical enrichment.
ano.nymous@ccsd.cnrs.fr.invalid (Aude Kleiber) 31 Aug 2022
https://hal.inrae.fr/hal-03746208v1
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[hal-03839676] Weaned horses, especially females, still prefer their dam after five months of separation
Under natural conditions, foals stop nursing from their dam at approximately-9 months old, but their bond persists until 1.5-2.5 years of age. In contrast, in horse breeding, foals are generally artificially weaned and totally separated from their dam at 5-7 months. However, it is not known whether the bond between the dam and her foal is maintained after artificial weaning. The aim of this study was (1) to assess whether foals still recognise and prefer their dam over other familiar mares several months after weaning and (2) to evaluate whether the preference for the dam is more pronounced in fillies or colts. Fifteen fillies and 19 colts were weaned at the age of 7 months old (complete separation from the mother). At the age of one year (i.e., 5 months after the separation), they underwent a test evaluating their preference for their dam or a familiar mare from their natal group. Significantly more foals first approached their dam; they also sniffed and tended to look more often at her. This finding indicates that artificially weaned horses remember and still exhibit a preference for their dam, suggesting that the bond persists even after 5 months of separation. Moreover, fillies exhibited a stronger preference for both mares than colts: they looked at them more frequently, sniffed them for a longer duration and spent more time in proximity to both mares than colts. This suggests that fillies generally have an even stronger attachment to their dam as well as to other mares from their natal group. This study calls into question the practice of artificial weaning at 5-7 months of age. (c) 2022 The Authors. Published by Elsevier B.V. on behalf of The Animal Consortium.
ano.nymous@ccsd.cnrs.fr.invalid (Léa Lansade) 14 Apr 2023
https://hal.inrae.fr/hal-03839676v1
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[hal-03757036] Multiple handlers, several owner changes and short relationship lengths affect horses’ responses to novel object tests
Despite numerous studies emerging on the human-horse relationship, significant gaps exist in the identification of the horse and handler factors that influence the quality of their relationship. Here, we explore key factors affecting human-animal relationships: the number of regular handlers an animal has, the length of the relationship with the handler, the number of owner changes, and the familiarity of the handler. A total of 76 horses participated in two novel object tasks (walking on novel surfaces and being touch with a novel object) to determine whether horses react differently to novel situations depending on whether they are handled by a familiar or an unfamiliar person. We observed that having multiple regular handlers negatively affected the horse reluctance towards novel surfaces and novel object. In horses used to be handled by multiple persons, 68% were showed reluctant behaviours towards the novel surfaces while 75% of the horses handled by only one person did not show reluctant behaviours. Similarly, 26% of the horses with multiple regular handlers refused to be touched with a novel object while only 13% of the horses with only one regular handler refused to be touched with the object. The relationship length between the horse and the familiar handler decreased the horse reluctance towards the novel surfaces and the novel object. The longer the relationship the less reluctant were the horses. Horses sold more than once were also more reluctant to the novel object. These horses had higher chances to refuse to be touched with the novel object than the horses still owned by their breeder or their first buyer. Finally, older horses (> 18 yo) had higher success at walking on the surface when led by someone familiar (87%) compared to led by someone unfamiliar (15%). Our findings suggest that the horse-human relationship may take time to develop as it is shaped by multiple factors involving the horse’s previous and current interactions with humans that affect their everyday life.
ano.nymous@ccsd.cnrs.fr.invalid (Océane Liehrmann) 22 Aug 2022
https://hal.science/hal-03757036v1
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[hal-03756945] Female horses are more socially dependent than geldings kept in riding clubs
The effect of the sex of horses in personality studies seems an underestimated aspect, specifically for the social dependence personality trait. A simple two-choice test could be a promising tool to address the strength of social dependence in riding horses. The present study aimed, at exploring the effect of sex on social dependence, hypothesising that females will react with more anxiety than castrated males when exposed to social separation. We examined whether a two-choice test will predict social dependence in horses. Twenty-four experienced leisure horses (7 mares and 17 geldings) were tested with a simple two-choice (food vs equine companion) preference and subsequent social dependence test in three sessions within the test (Session1: separation with a preferred companion; Session2: isolation, and Session3: social stimulus, i.e. conspecific passing nearby). During the test, six horses chose the companion (companion-motivated, CM), and 18 horses chose the treats (food -motivated, FM). The choice was skewed for mares, as significantly more mares than geldings preferred the companion over the food (CM: Nmares=4, Ngeldings=2 and FM: Nmares=3, Ngeldings=15). In isolation, CM horses displayed significantly reduced feeding duration and standing still towards increased arousal, i.e. locomotor activity: trotting, cantering, pawing and vocalisations, as compared to FM horses that were calmer and more comfortable without companions than CM horses. Our results indicate that mares, compared to geldings, showed weaker interest in feeding, and longer bouts of movement (walk and trot), which indicated the prevailing willingness to reunite with the companions and were more socially dependent compared to castrated male horses. The authors propose that this simple two-choice test can be used as another test to assess social dependence in horses.
ano.nymous@ccsd.cnrs.fr.invalid (Aleksandra Górecka-Bruzda) 24 Aug 2022
https://hal.science/hal-03756945v1
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[hal-03760602] Welfare issues and potential solutions for laying hens in free range and organic production systems: A review based on literature and interviews
In free-range and organic production systems, hens can make choices according to their needs and desires, which is in accordance with welfare definitions. Nonetheless, health and behavioral problems are also encountered in these systems. The aim of this article was to identify welfare challenges observed in these production systems in the EU and the most promising solutions to overcome these challenges. It is based on a review of published literature and research projects complemented by interviews with experts. We selected EU specific information for welfare problems, however, the selected literature regarding solutions is global. Free range use may increase the risk of infection by some bacteria, viruses and parasites. Preventive methods include avoiding contamination thanks to biosecurity measures and strengthening animals' natural defenses against these diseases which can be based on nutritional means with new diet components such as insect-derived products, probiotics and prebiotics. Phytotherapy and aromatherapy can be used as preventive and curative medicine and vaccines as alternatives to antibiotics and pesticides. Bone quality in pullets and hens prevents keel deviations and is favored by exercise in the outdoor range. Free range use also lead to higher exposure to variable weather conditions and predators, therefore shadow, fences and guard animals can be used to prevent heat stress and predation respectively. Granting a free range provides opportunities for the expression of many behaviors and yet many hens usually stay close to the house. Providing the birds with trees, shelters or attractive plants can increase range use. Small flock sizes, early experiences of enrichment and personality traits have also been found to enhance range use. Severe feather pecking can occur in free range production systems, although flocks using the outdoor area have better plumage than indoors. While many prevention strategies are facilitated in free range systems, the influence of genetics, prenatal and nutritional factors in free range hens still need to be investigated. This review provides information about practices that have been tested or still need to be explored and this information can be used by stakeholders and researchers to help them evaluate the applicability of these solutions for welfare improvement.
ano.nymous@ccsd.cnrs.fr.invalid (Claire Bonnefous) 09 Sep 2022
https://hal.inrae.fr/hal-03760602v1
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[hal-03753546] Domestic hens succeed at serial reversal learning and perceptual concept generalisation using a new automated touchscreen device
Improving the welfare of farm animals depends on our knowledge on how they perceive and interpret their environment; the latter depends on their cognitive abilities. Hence, limited knowledge of the range of cognitive abilities of farm animals is a major concern. An effective approach to explore the cognitive range of a species is to apply automated testing devices, which are still underdeveloped in farm animals. In screen-like studies, the uses of automated devices are few in domestic hens. We developed an original fully automated touchscreen device using digital computer-drawn colour pictures and independent sensible cells adapted for cognitive testing in domestic hens, enabling a wide range of test types from low to high complexity. This study aimed to test the efficiency of our device using two cognitive tests. We focused on tasks related to adaptive capacities to environmental variability, such as flexibility and generalisation capacities as this is a good start to approach more complex cognitive capacities. We implemented a serial reversal learning task, categorised as a simple cognitive test, and a delayed matching-to-sample (dMTS) task on an identity concept, followed by a generalisation test, categorised as more complex. In the serial reversal learning task, the hens performed equally for the two changing reward contingencies in only three reversal stages. In the dMTS task, the hens increased their performance rapidly throughout the training sessions. Moreover, to the best of our knowledge, we present the first positive result of identity concept generalisation in a dMTS task in domestic hens. Our results provide additional information on the behavioural flexibility and concept understanding of domestic hens. They also support the idea that fully automated devices would improve knowledge of farm animals’ cognition.
ano.nymous@ccsd.cnrs.fr.invalid (Rachel Degrande) 18 Aug 2022
https://hal.inrae.fr/hal-03753546v1
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[hal-03755536] Physical Enrichment Triggers Brain Plasticity and Influences Blood Plasma Circulating miRNA in Rainbow Trout (Oncorhynchus mykiss)
Physical enrichment is known to improve living conditions of fish held in farming systems and has been shown to promote behavioral plasticity in captive fish. However, the brain’s regulatory-mechanism systems underlying its behavioral effects remain poorly studied. The present study investigated the impact of a three-month exposure to an enriched environment (EE vs. barren environment, BE) on the modulation of brain function in rainbow trout (Oncorhynchus mykiss) juveniles. Using high-throughput RT-qPCR, we assessed mRNA genes related to brain function in several areas of the trout brain. These included markers of cerebral activity and plasticity, neurogenesis, synaptogenesis, or selected neurotransmitters pathways (dopamine, glutamate, GABA, and serotonin). Overall, the fish from EE displayed a series of differentially expressed genes (neurotrophic, neurogenesis, and synaptogenesis markers) essentially localized in the telencephalon, which could underpin the beneficial effects of complexifying the environment on fish brain plasticity. In addition, EE significantly affected blood plasma c-miRNA signatures, as revealed by the upregulation of four c-miRNAs (miR-200b/c-3p, miR-203a-3p, miR-205-1a-5p, miR-218a-5p) in fish blood plasma after 185 days of EE exposure. Overall, we concluded that complexifying the environment through the addition of physical structures that stimulate and encourage fish to explore promotes the trout’s brain function in farming conditions.
ano.nymous@ccsd.cnrs.fr.invalid (Emilie Cardona) 22 Aug 2022
https://hal.inrae.fr/hal-03755536v1
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[hal-03768888] Horse welfare: A joint assessment of four categories of behavioural indicators using the AWIN protocol, scan sampling and surveys
Domesticated horses (Equus caballus) can be exposed to a compromised welfare state and detecting a deterioration in welfare is essential to modify the animals' living conditions appropriately. This study focused on four categories of behavioural indicators, as markers of poor welfare: stereotypies, aggressiveness towards humans, unresponsiveness to the environment and hypervigilance. In the scientific literature, at least three assessment methods can be used to evaluate them: the Animal Welfare Indicators (AWIN) protocol, behavioural observations using scans and surveys. The question remains as to whether all these three methods allow an effective assessment of the four categories of behavioural indicators. To address this issue, the repeatability at a three-month interval and convergent validity of each measure (correlations between methods) were investigated on 202 horses housed in loose boxes. Overall, the repeatability and convergent validity were limited, highlighting the difficulty in assessing these indicators in horses. However, stereotypies and aggressiveness measures showed higher repeatability and convergent validity than those of unresponsiveness to the environment and hypervigilance. Behavioural observations using scans enabled the four categories of behavioural indicators to be detected more effectively. Suggestions of improvements are proposed for one-off measures such as those performed with the AWIN protocol. Regardless of the assessment method, very limited correlations were observed between the four categories of behavioural indicators, suggesting that they should all be included in a set of indicators used to assess the welfare state of horses, in conjunction with physiological and health measures.
ano.nymous@ccsd.cnrs.fr.invalid (Alice Ruet) 20 Feb 2023
https://hal.science/hal-03768888v1
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[hal-03595640] Impact of natural and artificial prenatal stimulations on the behavioural profile of Japanese quail
As the sensory systems of vertebrates develop prenatally, embryos perceive many environmental stimuli that can influence the ontogeny of their behaviour. Whether the nature and intensity of prenatal stimuli affect this ontogeny differently remains to be investigated. In this context, this study aimed to analyse the effects of prenatal auditory stimulation (natural stimulation, NS; predator vocalisations or artificial stimulation, AS; metallic sounds) on the subsequent behaviour of young Japanese quail (Coturnix coturnix japonica). For this, behavioural variables recorded during ethological tests evaluating emotional and social reactivity were analysed using a principal component analysis. This analysis revealed significant differences between the behavioural profile of stimulated chicks and that of non-exposed chicks. Indeed, chicks exposed to NS expressed more intense emotional responses in fearful situations, but less neophobia when exposed to a novel environment or object, whereas chicks exposed to AS appeared more sensitive to social isolation. Our results show that the acoustic environment of embryos can influence the way young birds subsequently interact with their social and physical environment after hatching, and face challenges in changing living conditions.
ano.nymous@ccsd.cnrs.fr.invalid (Nawel Mezrai) 13 May 2022
https://hal.science/hal-03595640v1
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[hal-03744140] Human-controlled reproductive experience may contribute to incestuous behavior observed in reintroduced semi-feral stallions (Equus caballus)
Equine reproductive behavior is affected by many factors, some remaining poorly understood. This study tested the hypothesis that a period of captivity during the juvenile period and human-controlled reproduction may potentially be involved in the disruption of the development of incestuous mating avoidance behavior in sanctuary-reintroduced male Konik polski horses. Between 1986 and 2000, cases of incestuous behavior in harem stallions born and reared until weaning in the sanctuary were studied. Eight males lived in the sanctuary's feral herd for the rest of their lives (the non-captive group; nC). They gained their own harem of mares without human intervention (no human-controlled reproductive activity, nHC). Another five stallions were removed as weanlings, reared in captivity and then reintroduced as adults (captive, C). Three of these C stallions were used as in-hand breeding stallions, one as a "teaser" (human-controlled reproductive activity, HC) and one was not used for reproduction in captivity (nHC). Reproductive records for 46 mares, daughters of all 13 harem stallions, were scrutinized and cases of incestuous breeding were recorded by interrogation of foal parentage records. C stallions failed to expel more daughters than nC stallions (33% vs. 18%, P = 0.045), and mated with significantly more of them (28% vs. 11%, P = 0.025). Interestingly, HC stallions expelled fewer (60%) and successfully mated with more (33%) daughters that nHC stallions (84% expelled, P = 0.013, and 10% successful mating with daughters, P = 0.010). All HC stallions bred incestuously at least once. We propose that human intervention during a critical period of development of social and reproductive behavior in young stallions, by enforced separation from their natal herd and in-hand breeding, may contribute to their later aberrant behavior and disruption of inbreeding avoidance mechanisms in these stallions. The previous occurrence of human-controlled breeding may be one of the factors promoting incestuous behavior of stallions in natural conditions. The uninterrupted presence of stallions in their harems and herd member recognition may also play important roles in inbreeding avoidance in horses.
ano.nymous@ccsd.cnrs.fr.invalid (Aleksandra Górecka-Bruzda) 17 Apr 2023
https://hal.inrae.fr/hal-03744140v1
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[hal-03627159] Foraging Behavior Shows Individual-Consistency Over Time, and Predicts Range Use in Slow-Growing Free-Range Male Broiler Chickens
Recent research on free-range chickens shows that individual behavioral differences may link to range use. However, most of these studies explored individual behavioral differences only at one time point or during a short time window, assessed differences when animals were out of their social group and home environment (barn and range), and in specific tests or situations. Therefore, it is yet unclear how different behaviors relate to range use and how consistent these behaviors are at the individual level. To fill this gap, we here aimed to describe the behavioral budget of slow-growing male broiler chickens (S757N) when in their social group and home environment during the whole rearing period (from the second week of life to the twelfth week, before slaughter), and to relate observed behavioral differences to range use. For this, we followed a sample of individuals in two flocks ( n = 60 focal chickens out of 200 chickens per flock), over two seasons, during three periods: before range access (from 14 to 25 days old), during early range access (first weeks of range access, from 37 to 53 days old), and during late range access (last weeks of range access, from 63 to 87 days old). By the end of each period, individual tests of exploration and social motivation were also performed, measuring exploration/activity and sociability propensities. Our results show that foraging (i.e., pecking and scratching at the ground) was the only behavior that correlated to range use for all three rearing periods, independent of the season. Foraging was also the only behavior that showed within-individual consistency from an early age and across the three rearing periods. Foraging may, therefore, serve as a useful behavioral predictor of range use in free-range broiler chickens. Our study increases the knowledge of how behaviors develop and relate to each other in a domesticated and intensely selected species, and improves our understanding of the biology of free-range broiler chickens. These findings can, ultimately, serve as a foundation to increase range use and improve chicken welfare.
ano.nymous@ccsd.cnrs.fr.invalid (Vitor Hugo Bessa Ferreira) 03 May 2024
https://hal.inrae.fr/hal-03627159v1
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[hal-03555171] Prenatal maternal stress is associated with behavioural and epigenetic changes in Japanese quail
Prenatal maternal stress (PMS) influences many facets of offspring’s phenotype including morphology, behaviour and cognitive abilities. Recent research suggested that PMS also induced epigenetic modifications. In the present study, we analysed, in the Japanese quail, the effects of PMS on the emotional reactivity and cognitive abilities of the F1 offspring. We also investigated in the hippocampus, the paraventricular hypothalamic nucleus and subnuclei of the arcopallium/amygdala the level of two histone post-translational modifications, H3K4me2 and H3K27me3, known to be impacted by stress. We found that PMS does not affect F1 quail’s learning abilities but increases their emotional reactivity. Moreover, we demonstrated that PMS induced an increased density of H3K27me3 positive cells, in the hippocampus, paraventricular hypothalamic nucleus and dorsal nucleus of the amygdala, but not variations of H3K4me2. As these brain regions are involved in the control of vertebrates’ emotional responses, the effect of PMS on the epigenetic mark H3K27me3 could possibly be a mechanism involved in the behavioural effects we observed in F1 quail.
ano.nymous@ccsd.cnrs.fr.invalid (Marion Charrier) 30 Mar 2022
https://hal.science/hal-03555171v1
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[hal-03627385] A novel male Japanese quail structural connectivity atlas using ultra-high field diffusion MRI at 11.7 T
The structural connectivity of animal brains can be revealed using post-mortem diffusion-weighted magnetic resonance imaging (MRI). Despite the existence of several structural atlases of avian brains, few of them address the bird’s structural connectivity. In this study, a novel atlas of the structural connectivity is proposed for the male Japanese quail ( Coturnix japonica ), aiming at investigating two lines divergent on their emotionality trait: the short tonic immobility (STI) and the long tonic immobility (LTI) lines. The STI line presents a low emotionality trait, while the LTI line expresses a high emotionality trait. 21 male Japanese quail brains from both lines were scanned post-mortem for this study, using a preclinical Bruker 11.7 T MRI scanner. Diffusion-weighted MRI was performed using a 3D segmented echo planar imaging (EPI) pulsed gradient spin-echo (PGSE) sequence with a 200 μm isotropic resolution, 75 diffusion-encoding directions and a b-value fixed at 4500 s/mm 2 . Anatomical MRI was likewise performed using a 2D anatomical T 2 -weighted spin-echo (SE) sequence with a 150 μm isotropic resolution. This very first anatomical connectivity atlas of the male Japanese quail reveals 34 labeled fiber tracts and the existence of structural differences between the connectivity patterns characterizing the two lines. Thus, the link between the male Japanese quail’s connectivity and its underlying anatomical structures has reached a better understanding.
ano.nymous@ccsd.cnrs.fr.invalid (Raïssa Yebga Hot) 08 Dec 2023
https://hal.inrae.fr/hal-03627385v1
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[hal-03663805] Comparing the effects of horse grazing alone or with cattle on horse parasitism and vegetation use in a mesophile pasture
Mixing different herbivore species is assumed to increase vegetation use because of the complementarity of their feeding choices and to reduce animal parasite burden through the dilution effect. Here, we compare the effects of mixed horse-cattle grazing and monospecific horse grazing (1.4 LU/ha) on animal foraging behaviour, sward characteristics and horse parasitism in a mesophile grassland of central France. In both treatments, animals were stocked alternately on two subplots with rotation lengths between 15 and 21 days according to season. The horses quickly acclimated to the cattle, and very few agonistic interactions were observed between them. All the horses selected short (<= 4 cm) and intermediate (5-8 cm) high-quality regrowths and avoided reproductive and dead herbage areas contaminated by their faeces as a consequence of their latrine behaviour. Cattle, which are more constrained by plant height, selected intermediate and tall vegetative swards. However, the alternate stocking of animals also provided them with high-quality regrowth on the shortest patches. Consequently, the cattle used these short patches proportionally to their availability while avoiding reproductive and dead herbage areas. We assume this limited their consumption of infective cyathostome larvae, which are concentrated close to horse dung. Moreover, co-grazing horses and cattle did not reduce sward structural heterogeneity and thus did not enhance overall herbage quality. We conclude that rather than considering mixed grazing as a turn-key solution, its management needs to be adapted to support the complementarity of horse and cattle dietary choices and thus provide the expected benefits of multi-species grazing.
ano.nymous@ccsd.cnrs.fr.invalid (Géraldine Fleurance) 05 Jul 2022
https://hal.inrae.fr/hal-03663805v1
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[hal-03744235] Automatic brushes induce positive emotions and foster positive social interactions in group-housed horses
In mammals, positive tactile contact is recognized as an effective tool for triggering positive affective states. In this study, we investigated the benefits of providing automatic rotative brushes for group-housed horses. Our three aims were: i. to determine whether horses used automatic brushes and if so how they used them; ii. to investigate whether the presence of these brushes induced positive social behaviors (allogrooming), or aggressiveness, as can be observed when there is competition for a desired resource; iii to provide a preliminary explanation of the role of the positive facial expression displayed by some horses while being groomed. Two brushes were installed in a large stable with free access to a paddock in which 40 horses were housed 7h30/day. For four days, video-cameras placed above the brushes continuously filmed the horses. First, analysis of the video footage demonstrated that brushes were used by almost 90% of the horses, mainly on areas that are not easily accessible to another horse during allogrooming, such as the head. Secondly, it revealed that among the horses that used the brush, 25.7% expressed positive social behavior (allogrooming) at the same time, while none expressed aggressive behaviors. The brush thus seems to act as a catalyst for affiliative behaviors rather than competition for a desired resource. Thirdly, we observed their facial expression, especially a positive one, described when the horse are groomed (neck moderately raised, eyes open or half-closed, upper lip extended, ears turned backwards almost in line with the nose). More than half of the horses displayed this while using the brushes. Interestingly, when a horse expressed this face, it had a six times greater chance to subsequently start allogrooming with a conspecific. Several possible explanations are discussed, including a social function. Further research is needed to validate other criteria to help qualify whether or not this positive facial expression is a signal of intentional communication. From a practical point of view, the results show that the brushes provide both a direct benefit to the horses enabling them to conduct self-grooming, and also in all likelihood, an indirect benefit by facilitating positive social interactions. This study encourages the installation of automatic brushes in places where horses are kept to improve their welfare and provide comfort.
ano.nymous@ccsd.cnrs.fr.invalid (Léa Lansade) 08 Jan 2024
https://hal.inrae.fr/hal-03744235v1
