41 research outputs found
Les caractéristiques sensorielles des aliments : quels rÎles jouent-elles dans les aspects qualitatifs et quantitatifs du comportement alimentaire des ovins
A better understanding of feeding behaviour of ruminants would help optimising the use of forages by these animals and improve their zootechnical performances, including welfare, and environmental interests. We studied the role of sensory characteristics of food in qualitative (diet selection) and quantitative (intake) aspects of feeding behaviour in sheep. Thus far these characteristics are believed to have only a discriminating role. We studied their role at similar post-ingestive consequences, on the one, and their role at different post-ingestive consequences, using food learning paradigms, on the other hand. At similar post-ingestive consequences, sensory food characteristics did not influence voluntary daily intake but they influenced i/ short term intake when the motivation to eat induced by the food overruled the satiety state of the animal, and ii/ feeding activities (time spent eating and intake rate). Interestingly, results differed according to quality contrasts between food items. Further studies are needed to elucidate the exact role of sensory characteristics in the regulation of voluntary intake. Sensory characteristics influenced also food preferences when they possessed a hedonic or an a priori value subjectively indicating positive or negative consequences to the animal. The influence of the hedonic value was however difficult to analyse because of a great inter-individual variability in animal response. The hedonic value was furthermore influenced by the context of food presentation; a non preferred food item could become preferred if it was not recently consumed, which indicates an attraction for food diversity and especially for a change in food. During food learning, the hedonic value of sensory characteristics modulates the animal's ability to associate them with post-ingestive consequences. When sensory food characteristics had acquired an a priori value, animals could use them as indicators of post-ingestive consequences. Consequently, they allowed animals to be more efficient in food learning, notably in complex environments, via a generalisation process. Our work is thus reinforcing the validity of the food learning theory in complex environments. Some primary tastes, such umami and bitter tastes, possess an a priori value (positive and negative, respectively). It is expected that these tastes have a role as indicator. In conclusion, sensory food characteristics, because of their role as discriminator, their hedonic value or their role as indicator, influenced different aspects of feeding behaviour in sheep. Therefore, sensory food characteristics have the possibility to improve the use of forage in animal diets and to a certain extent, ameliorate farm animal welfare.Nous nous sommes intĂ©ressĂ©s au rĂŽle des caractĂ©ristiques sensorielles des aliments dans les aspects qualitatifs (sĂ©lection) et quantitatifs (ingestion) du comportement alimentaire des ovins. IndĂ©pendamment des consĂ©quences post-ingestives d'une part, et en interaction avec les consĂ©quences post-ingestives dans les processus d'apprentissage alimentaire d'autre part. A consĂ©quences similaires, les caractĂ©ristiques sensorielles n'ont pas influencĂ© l'ingestion journaliĂšre mais ont influencĂ© i/ l'ingestion Ă court-terme via une modification de l'Ă©quilibre entre motivation et rassasiement, et ii/ les durĂ©es et vitesses d'ingestion. Certaines caractĂ©ristiques sensorielles possĂšdent une valeur hĂ©donique voire une valeur latente potentiellement indicatrice des consĂ©quences, et influencent la sĂ©lection. Lors des apprentissages, la valeur hĂ©donique de ces caractĂ©ristiques module la propension des animaux Ă les associer aux consĂ©quences. D'autres ont un rĂŽle d'indicateur des consĂ©quences qui permet aux animaux d'amĂ©liorer leurs apprentissages notamment en milieu complexe, via un processus de gĂ©nĂ©ralisation, et conforte la validitĂ© de la thĂ©orie des apprentissages alimentaires dans ces milieux. De part leur rĂŽle d'agent discriminant, leur valeur hĂ©donique voire leur rĂŽle d'indicateur, les caractĂ©ristiques sensorielles influencent Ă diffĂ©rents niveaux le comportement alimentaire des ovins, et devraient ĂȘtre considĂ©rĂ©es pour amĂ©liorer l'utilisation des aliments dans les rations et le bien-ĂȘtre des animaux d'Ă©levag
Saanen and Alpine goats experience neophobia when offered novel feeds
International audienceFeed neophobia is a reluctance to eat a novel feed that can last from minutes to days. While it can prevent animals from ingesting toxins, it may also have negative effects on growth and animal welfare. In ruminants, feed neophobia has mainly been studied in sheep and cattle, and only a few studies have focused on goats. This study assessed feed neophobia in goats and aimed to determine whether this is breed-dependent. Six-month-old Saanen (n = 18) and Alpine (n = 13) goats were repeatedly placed in an experimental environment, with a familiar feed, for 5 min per day (days 1â7). The familiar feed was then replaced by two novel feeds on consecutive days (d8-d9), and the second novel feed was offered a second time (d10). Saanen goats habituated better to the situation as, on the last day with the familiar feed, they consumed more, with a greater intake rate, and spent less time near conspecifics than Alpine goats. They also showed a higher approach index than Alpine goats, meaning that they spent more time head in the feed trough while being close to it. Breed however did not influence the behavioural responses of goats when they were exposed to novel feeds. When first exposed to the novel feeds and regardless of their respective palatability, the goats reduced their intake compared to when they received the familiar feed, though they sampled the novel feeds by eating small amounts. They also approached the novel feeds less and spent more time near conspecifics. At the 2nd exposure to the second novel feed, the main behavioural responses were reversed, as intake increased and the time spent near conspecifics decreased, to reach the levels recorded with the familiar feed. Only the approach index remained lower. Thus, our results highlight that goats of both breeds displayed feed neophobia when first exposed to different novel feeds, but the situation was reversed after only one short-term exposure. Further research using more novel feeds, different feed-presentation schemes and longer tests will help to improve the understanding of feed neophobia in goats
Valeurs hĂ©doniques des odorants en exposition prĂ©natale : un levier prĂ©coce pour orienter le comportement alimentaire dâindividus de la naissance au sevrage ?
National audienceLes odeurs de par leur valeur hĂ©donique (innĂ©e ou acquise) influencent le comportement des animaux. Dans un contexte alimentaire, les odeurs orientent les prĂ©fĂ©rences et modulent l'ingestion des individus. Dans un contexte Ă©motionnel, elles apaisent l'animal ou le placent dans un Ă©tat d'alerte. Plusieurs Ă©tudes se sont intĂ©ressĂ©es aux effets dâexpĂ©riences olfactives prĂ©coces sur le comportement alimentaire et Ă©motionnel de l'animal (principalement rongeurs). NĂ©anmoins, peu dâĂ©tudes restreignent la pĂ©riode d'exposition olfactive Ă la pĂ©riode prĂ©natale et les rĂ©sultats de cette exposition sur le comportement de la descendance varient en fonction de la variable mesurĂ©e, de lâodorant testĂ©, etc⊠Les expĂ©riences olfactives prĂ©natales reprĂ©sentent pourtant un levier prometteur pour orienter le comportement des animaux d'Ă©levage via un rappel olfactif dans leur vie future. Cela pourrait moduler l'acceptabilitĂ© d'un aliment nouveau ou diminuer le stress ressenti face Ă certaines pratiques d'Ă©levage. Ainsi, ce projet Ă©value les effets d'une exposition prĂ©natale Ă un odorant sur le comportement alimentaire et le bien-ĂȘtre de rats, de la naissance Ă l'adolescence.En 2017, l'acceptabilitĂ© et la valeur hĂ©donique de diffĂ©rents odorants ajoutĂ©s Ă un aliment standard ont Ă©tĂ© dĂ©terminĂ©es chez des rates (6 odorants, Ă 2 doses diffĂ©rentes). Puis, en 2018, nous avons mis en place une mĂ©thode d'odorisation maternelle spĂ©cifique, avec 3 odorants sĂ©lectionnĂ©s d'aprĂšs les rĂ©sultats de 2017, et nous avons vĂ©rifiĂ© le passage de l'odorant dans le liquide amniotique mais pas dans le lait par GC-MS-MS (exposition olfactive prĂ©natale uniquement). Ainsi, l'acĂ©tophĂ©none, Ă la dose de 0.01%, a Ă©tĂ© choisie pour passer Ă l'Ă©tude d'une exposition olfactive prĂ©natale et ses effets sur la descendance. Dans une 1Ăšre Ă©tude (2019), l'acĂ©tophĂ©none a simplement Ă©tĂ© ajoutĂ©e Ă l'aliment maternel. Les effets d'un rappel de cette odeur familiĂšre ont Ă©tĂ© testĂ©s sur les comportements de la descendance, Ă la naissance par un test de motivation olfactif (crawling) puis Ă l'adolescence via l'Ă©tude du comportement alimentaire (acceptabilitĂ© d'un aliment nouveau odorisĂ©) et de la rĂ©activitĂ© Ă©motionnelle (tests de Light/Dark et Open Field en prĂ©sence de l'odeur). Des rĂ©sultats prĂ©liminaires semblent montrer une augmentation de la motivation olfactive Ă la naissance en prĂ©sence de l'odeur familiĂšre, mais les effets semblent ne pas perdurer jusqu'Ă l'adolescence. Par consĂ©quent, en 2020, nous avons cherchĂ© Ă augmenter la valence positive de l'odorant perçu in utero. Pour cela, l'aliment odorisĂ© a Ă©tĂ© prĂ©sentĂ© comme un aliment friandise (prĂ©sent uniquement au dĂ©but de l'offre alimentaire et sous une forme plus appĂ©tante). Les mĂȘmes indicateurs comportementaux ont Ă©tĂ© mesurĂ©s sur la descendance de la naissance Ă l'adolescence. Certains tests ont Ă©tĂ© filmĂ©s et ont nĂ©cessitĂ© le dĂ©veloppement d'un logiciel de tracking home-made pour l'analyse des vidĂ©os. La compilation de toutes les donnĂ©es est en cours pour mener les analyses statistiques en 2022
Influence des facteurs sociaux sur les rythmes circadiens comportementaux des vertébrés non humains
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Utilisation de techniques dâintelligence artificielle pour Ă©tudier et mesurer le comportement animal
International audienceLâĂ©tude du comportement animal est trĂšs demandeuse en temps dâobservation. Lâanalyse automatique de vidĂ©os est une voie prometteuse de simplification. Des mĂ©thodes dâintelligence artificielle (par rĂ©seaux de neurones de type Inception) ont ainsi Ă©tĂ© dĂ©veloppĂ©es en utilisant lâoutil Tensorflow. Deux applications ont Ă©tĂ© mises en Ćuvre pour i) identifier lâactivitĂ© de truies allaitantes bloquĂ©es, dans le but Ă terme dâutiliser le comportement de la truie en sĂ©lection gĂ©nĂ©tique afin dâĂ©viter la mort des porcelets par Ă©crasement, et ii) Ă©tudier le comportement dâagneaux isolĂ©s en parc de test, en sâintĂ©ressant Ă leur positionnement, orientation et mobilitĂ© dans le parc, de façon Ă caractĂ©riser leur rĂ©activitĂ© Ă©motionnelle. Pour lâapplication porcine, des vidĂ©os de diffĂ©rentes truies suitĂ©es, enregistrĂ©es pendant 6 mois sur des journĂ©es complĂštes, ont permis dâobtenir un million dâimages qui ont Ă©tĂ© expertisĂ©es pour obtenir une base dâimages sur lesquelles la posture/activitĂ© de la truie est identifiĂ©e : position assise, debout avec ou sans alimentation, couchĂ©e sur le ventre, activitĂ©s dâallaitement sur le cĂŽtĂ© gauche ou droit, avec trois niveaux dâintensitĂ© dâallaitement. A partir de ces images annotĂ©es, un logiciel intĂ©grant un rĂ©seau de neurones a Ă©tĂ© dĂ©veloppĂ© pour prĂ©dire en temps rĂ©el la posture des truies avec un taux de prĂ©cision de 92 %. Pour lâapplication relative aux agneaux, des vidĂ©os rĂ©alisĂ©es sur un ensemble de 39 animaux ont permis dâĂ©tablir une base de 600 images expertisĂ©es, pour identifier les parties antĂ©rieures et postĂ©rieures de lâagneau. En croisant cette information avec les zones dâintĂ©rĂȘt, il sera possible de savoir pour chaque image dans quelle zone est lâagneau (c.-Ă -d. si sa partie antĂ©rieure y est). Lâalgorithme dĂ©veloppĂ© repose sur 2 rĂ©seaux de neurones permettant de dĂ©tecter lâanimal et de dĂ©terminer sa position dans le parc de 16 m2, puis dâidentifier automatiquement les deux parties du corps de lâagneau avec une prĂ©cision de 80 %. Ces deux applications montrent le potentiel de lâintelligence artificielle pour analyser automatiquement certains comportements, permettant de faciliter lâanalyse comportementale et dâĂ©tendre les plages de mesures (ex. 24h/24)
Social influences on circadian behavioural rhythms in vertebrates
International audienceAlthough photoperiodic cycles are known to be the most powerful entraining agent of circadian rhythms in homeotherms, social factors can also play a role in synchronizing activity rhythms. Here we review social influences on circadian behavioural rhythms in vertebrates, focusing on the types of possible effects and the types of stimuli eliciting these effects. Social factors can strongly influence rhythms by inducing full entrainment, mutual synchronization or desynchronization. Such effects have been observed in social species living in a constrained environment, between mothers and offspring in altricial mammals, between sexual partners or competitors, and between social partners linked by hierarchical relationships. However, the presence of social partners sometimes induces weaker influences, such as partial entrainment or relative coordination with masking effects. A weak effect of social cues on rhythms between social and sexual partners has also been reported. The stimuli involved in these social influences were olfactory stimuli or social stress in rodents and auditory stimuli in birds and mammals. Social cues sometimes have no significant effects on rhythms, not only in solitary species, but also in social species. We discuss the technical problems with such research, in particular the difficulty of recording simultaneously the activities of several individuals. Finally, we point out that knowledge of a species' behaviour and life history may significantly improve chronobiological research. Social characteristics and different levels of organization (group, relationship or individual levels), in particular, should be considered when studying social influences on behavioural rhythms
Effect of environmental exposure to a maternally-learned odorant on anxiety-like behaviors at weaning in mice
International audienceEarly sensory experience, such as exposure to maternal or other environmental factors, is considered to influence neurocognitive development and behaviors. In many species, exposure to odorants during pregnancy or lactation impacts the morpho-functional development of the olfactory circuitry with changes in olfactory sensitivity, feeding behavior and food preferences at birth or later. However, few studies have investigated the impact of a perinatal exposure to odorants on the anxiety-like behavior of animals to stressfull stimuli. Here, we exposed mice to heptaldehyde (HEP) during pregnancy and lactation and measured the anxiety-like behavior of their offspring to stress-inducing novel stimuli at weaning in presence or absence of odorants. We applied a combined social and maternal separation as a stressor and measured the anxiety-like behavior in an open field (OF) in presence of two odorants, HEP or alpha-pinene (AP) as a control odorant. Although the presence of the odorant during the social separation did not influence anxiety-like behavior, we found that, if mice born to non-odorized mothers exhibited a decreased exploratory behavior in the presence of both odorants, the effect was restricted to AP for the mice perinatally exposed to HEP. These results show that anxiety-like behaviors during a stress-inducing event could be reduced by the presence of a familiar odorant. We propose that the recall of an early olfactory experience could contribute to the improvement of animal welfare in various situations associated with husbandry practices
Chronic perinatal odour exposure with heptaldehyde affects odour sensitivity and olfactory system homeostasis in preweaning mice
International audienceExposure to specific odorants in the womb during pregnancy or in the milk during early nursing is known to impact morpho-functional development of the olfactory circuitry of pups. This can be associated with a modification in olfactory sensitivity and behavioural olfactory-based preferences to the perinatally encountered odorants measured at birth, weaning or adult stage. Effects depend on a multitude of factors, such as odorant type, concentration, administration mode and frequency, as well as timing and mice strain. Here, we examined the effect of perinatal exposure to heptaldehyde on the neuro-anatomical development of the olfactory receptor Olfr2 circuitry, olfactory sensitivity and odour preferences of preweaning pups using mI7-IRES-tau-green fluorescent protein mice. We found that perinatal odour exposure through the feed of the dam reduces the response to heptaldehyde and modulates transcript levels of neuronal transduction proteins in the olfactory epithelium of the pups. Furthermore, the number of I7 glomeruli related to Olfr2-expressing OSN is altered in a way similar to that seen with restricted post-natal exposure, in an age-dependent way. These variations are associated with a modification of olfactory behaviours associated with early post-natal odour preferences at weaning
Pas de bien-ĂȘtre possible pour les animaux Ă©levĂ©s dans des conditions intensives
International audienceLâĂ©tat de bien-ĂȘtre de lâanimal suppose « un Ă©tat mental et physique positif liĂ© Ă la satisfaction de ses besoins physiologiques et comportementaux ainsi que de ses attentes » selon la dĂ©finition de lâANSES (2018). Les animaux dâĂ©levage ont de grandes capacitĂ©s Ă©motionnelles et socio-cognitives. Ils peuvent ressentir de nombreuses Ă©motions telles que la peur, la colĂšre, la dĂ©ception, lâennui, le dĂ©goĂ»t ou encore le plaisir. Leurs capacitĂ©s dâĂ©valuation de leur environnement reposent sur de nombreuses compĂ©tences cognitives (catĂ©gorisation, manipulation de quantitĂ©s, raisonnement par infĂ©rence, etc.) et sociales (reconnaissance des congĂ©nĂšres, liens sociaux, etc.).Prendre en compte la sensibilitĂ© Ă©motionnelle et les capacitĂ©s socio-cognitives des animaux dâĂ©levage est indispensable pour mettre en place des conditions de vie favorisant leur bien-ĂȘtre. Cela implique notamment que leur environnement physique et social rĂ©ponde rĂ©ellement Ă leurs besoins et leurs attentes, et que les animaux puissent exercer un contrĂŽle sur cet environnement. Cependant, dans le cas des systĂšmes dâĂ©levage intensifs, systĂšmes qui visent une productivitĂ© maximale par unitĂ© de surface, les conditions de vie des animaux ne leur permettent pas dâexprimer leur rĂ©pertoire comportemental et sont Ă lâorigine de dĂ©sordres physiques et psychologiques (https://revue-sesame-inrae.fr/ameliorer-le-bien-etre-des-animaux-delevage-est-ce-toujours-possible/). Il existe donc un grand Ă©cart entre les conditions de vie proposĂ©es aux animaux et celles qui pourraient ĂȘtre attendues en consĂ©quence de leurs capacitĂ©s socio-cognitives et Ă©motionnelles.Certains de nos travaux ont permis de proposer des solutions pour amĂ©liorer ces conditions de vie, mais celles-ci sont peu ou pas appliquĂ©es en raison de leur coĂ»t et dâune potentielle baisse de rentabilitĂ©. Nos travaux de recherche ont permis de faire avancer les connaissances sur les animaux, de montrer que la sensibilitĂ© psychique des animaux dâĂ©levage doit ĂȘtre respectĂ©e, mais ils ont aussi parfois servi de caution scientifique Ă des productions intensives. Il nous appartient donc de nous questionner sur les types dâĂ©levage qui permettent rĂ©ellement une amĂ©lioration de la qualitĂ© de vie des animaux, mais aussi des Ă©leveurs et des Ă©leveuses, et ce, dans le respect de lâenvironnement. Puisque le bien-ĂȘtre des animaux nâest pas possible dans certains systĂšmes, il sâagit de rĂ©flĂ©chir au moyen faire Ă©voluer les pratiques, les systĂšmes et les filiĂšres pour Ă©lever les animaux dans des conditions respectueuses de leur bien-ĂȘtre