Animal Welfare:Could Adult Play be a False Friend?

International audienceThere is no consensus regarding the functions of play. As play behavior is a characteristic of young stages of development, it has been suggested that the higher prevalence of adult play observed in domestic animals could be the result of their “neotenic retardation.” Functional hypotheses have dealt with the long term benefits, such as “rehearsal,” “motor training” for future adult competencies or “training for the unexpected.” However, there is little consistent experimental evidence favoring a particular hypothesis. The present study aimed to test the functional significance of adult play as a potential reliable indicator of good welfare, a by-product of domestication or a tool for social cohesion. Observations of both a domestic species (the horse) and wild/captive animals (cercopithecids) confirm the literature data that show the greater prevalence of adult play in the domestic/captive situations. This convergence between a domestic and a wild species argue against the idea that adult play may be a mere product of domestication. Moreover, animals living in naturalistic situations had the same low level of adult play as observed in wild animals suggesting that captive/domestic animals do not play only because they are stress free or well fed. Play is not a reliable indicator of welfare: Horses and adult macaques that played the most were also those that exhibited the greatest signals of poor welfare as stereotypic behaviors. Furthermore, adult play was more frequent at times of social disturbances and instability. Adult play is a sign showing that the adult organism needs to evacuate stress

Heavy Metal Tolerance in Stenotrophomonas maltophilia

Stenotrophomonas maltophilia is an aerobic, non-fermentative Gram-negative bacterium widespread in the environment. S. maltophilia Sm777 exhibits innate resistance to multiple antimicrobial agents. Furthermore, this bacterium tolerates high levels (0.1 to 50 mM) of various toxic metals, such as Cd, Pb, Co, Zn, Hg, Ag, selenite, tellurite and uranyl. S. maltophilia Sm777 was able to grow in the presence of 50 mM selenite and 25 mM tellurite and to reduce them to elemental selenium (Se0) and tellurium (Te0) respectively. Transmission electron microscopy and energy dispersive X-ray analysis showed cytoplasmic nanometer-sized electron-dense Se0 granules and Te0 crystals. Moreover, this bacterium can withstand up to 2 mM CdCl2 and accumulate this metal up to 4% of its biomass. The analysis of soluble thiols in response to ten different metals showed eightfold increase of the intracellular pool of cysteine only in response to cadmium. Measurements by Cd K-edge EXAFS spectroscopy indicated the formation of Cd-S clusters in strain Sm777. Cysteine is likely to be involved in Cd tolerance and in CdS-clusters formation. Our data suggest that besides high tolerance to antibiotics by efflux mechanisms, S. maltophilia Sm777 has developed at least two different mechanisms to overcome metal toxicity, reduction of oxyanions to non-toxic elemental ions and detoxification of Cd into CdS

Phenotypic Variation of Pseudomonas brassicacearum as a Plant Root-Colonization Strategy

International audiencePseudomonas brassicacearum was isolated as a major root-colonizing population from Arabidopsis thaliana. The strain NFM421 of P. brassicacearum undergoes phenotypic variation during A. thaliana and Brassica napus root colonization in vitro as well as in soil, resulting in different colony appearance on agar surfaces. Bacteria forming translucent colonies (phase II cells) essentially were localized at the surface of young roots and root tips, whereas wild-type cells (phase I cells) were localized at the basal part of roots. The ability of phase II cells to spread and colonize new sites on root surface correlates with over-production of flagellin as evidenced by sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis of surface proteins and microsequencing. Moreover, phase II cells showed a higher ability to swim and to swarm on semisolid agar medium. Phase I and phase II cells of P. brassicacearum NFM421 were tagged genetically with green fluorescent protein and red fluorescent protein. Confocal scanning laser microscopy was used to localize phase II cells on secondary roots and root tips of A. thaliana, whereas phase I cells essentially were localized at the basal part of roots. These experiments were conducted in vitro and in soil. Phenotypic variation on plant roots is likely to be a colonization strategy that may explain the high colonization power of P. brassicacearum

Four distinct behavioral profiles observed in male monkey rhesus in response to stressful housing conditions

International audienceInvestigations of the pathophysiology of mental disorders have dramatically increased in the last decade. Such studies have almost exclusively been performed in rodents submitted to environmental, pharmacological, surgical or genetic manipulations. Those models can be seen as induced as opposed to spontaneously occurring disorders, therefore carrying poor construct validity. Moreover, the diversity of behavioral changes induced is quite limited, conferring poor face validity. Finally, mimicking such complex disorders in species phylogenetically and behaviourally closer to Humans seems more appropriate. Thus, we investigated the existence of spontaneous atypical behaviors displayed by non-human primates (NHP) housed in stressful conditions and their possible similarity with symptoms of human mental disorders. Stressful conditions, imposed by the breeding process, are defined by a peer-rearing from 5-months to 3-years old followed by housing in single cages; as opposed to large wild-like enclosure in social group. Forty males Macaca mulatta housed in single cage were observed using a scan sampling method, commonly used in Ethology. The parameters assessed were behaviors, body posture and orientation, gaze- direction and location in cage. Factor and cluster analysis were used to study inter-individual differences and revealed 4 distinct profiles. The inactive “depressive-like” profile contains males displaying mainly inactivity, a few changes of behaviors between the scans, a body facing the wall and located at the upper back corners of the cage. The self-centered “anxious-like” profile contains males displaying the higher levels of itching, yawning and selfgrooming. The “active-cautious” profile contains males quite active, exploring the cage and handling the feeding tray a lot, facing the wall as much as the front of the cage but standing at the back down corners of their cage. Finally the “active-aggressive” profile contains males very active but displaying a lot of threatening faces and vocalizations toward the observer and standing at the front of the cage. Motor stereotypic behaviors were observed among the 3 last profiles. These results suggest that NHP differ in their ways of coping with stress. As Humans, some individuals seem to be more severely affected by stressful events than others. The use of behavioral observations might allow us to find spontaneous model animals and forecast new perspectives in the study of mental disorders

Four distinct behavioural profiles observed in male cynomolgus monkeys in response to stressful housing conditions: toward spontaneous mental disorder?

International audienceInvestigations of the pathophysiology of mental disorders have dramatically increased in the last decade. Such studies have however almost exclusively been performed in rodents submitted to environmental, pharmacological, surgical or genetic manipulations. In other words those models can be seen as induced as opposed to spontaneously occurring disorders, therefore carrying poor construct validity. Moreover, the diversity of behavioral changes induced is quite limited, conferring poor face validity. Finally, mimicking such complex disorders in species phylogenetically and behaviourally closer to Humans seems more appropriate. Thus, we investigated the existence of spontaneous atypical behaviors displayed by non-human primates (NHP) housed in stressful conditions and their possible similarity with symptoms of human mental disorders. Stressful conditions, imposed by the breeding process, are defined by a peer-rearing from 5-months old to 3-years old followed by housing in single cages; as opposed to large wild-like enclosure in social group. Forty males Macaca mulatta housed in single cage were observed using a scan sampling method, commonly used in Ethology. The parameters assessed were behaviors, body posture and orientation, direction of gaze and location in cage. Factor and cluster analysis were used to study inter-individual differences and revealed 4 distinct behavioral profiles. The inactive “depressive-like” profile contains males displaying mainly inactivity, a few changes of behaviors between the scans, a body facing the wall and located at the upper back corners of the cage. The self-centered “anxious-like” profile contains males displaying the higher levels of itching, yawning and self grooming. The “active-cautious” profile contains males quite active, exploring the cage and handling the feeding tray a lot, facing the wall as much as the front of the cage but standing at the back down corners of their cage. Finally the “active-aggressive” profile also contains males very active but displaying a lot of threatening faces and vocalizations toward the observer and standing at the front of the cage. Plus, motor stereotypic behaviors were observed among the 3 last profiles. These results suggest that NHP differ in their ways of coping with stress. As Humans, some individuals seem to be more severely affected by stressful events than others. The use of behavioral observations might allow us to find spontaneous model animals and forecast new perspectives in the study of mental disorders

Behavioral thermoregulation and reproductive costs in the bimodal reproductive speciez Zootoca vivipara

National audienc

Data from: Experimental evidence of early costs of reproduction in conspecific viviparous and oviparous lizards

Reproduction entails costs, and disentangling the relative importance of each stage of the reproductive cycle may be important to assess the costs and benefits of different reproductive strategies. We studied the early costs of reproduction in oviparous and viviparous lizard females of the bimodal reproductive species Zootoca vivipara. Egg-retention time in oviparous females is approximately one third of the time in viviparous females. We compared the vitellogenesis and egg-retention stages which are common to both reproductive modes. Precisely, we monitored the thermoregulatory behaviour, the weight gain and the immunocompetence of the females. Moreover, we injected an antigen in half of the females (immune challenge) to study the trade-offs between reproductive mode and immune performance, and between different components of the immune system. Finally, we experimentally induced parturition in viviparous females at the time of egg-laying in oviparous females. Oviparous and viviparous females did not show strong differences in response to the immune challenge. However, viviparous females spent more time thermoregulating while partially hidden and gained more weight than oviparous females. The greater weight gain indicates that the initial period of egg-retention is less costly for viviparous than for oviparous females or that viviparous females are able to save and accumulate energy at this period. This energy may be used by viviparous females to cope with the subsequent costs of the last two thirds of the gestation. Such an ability to compensate the higher costs of a longer egg-retention period may account for the frequent evolution of viviparity in squamate reptiles

Early-life experience differentially affects cynomolgus monkey depressive-like behaviours in farming conditions: the cumulative effect of adversity?

National audienc

Depressive-like behavioral profiles in captive-bred single- and socially-housed rhesus and cynomolgus macaques: a species comparison.

This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY).International audienceBackground: To unravel the causes of major depressive disorder (MDD), the third leading cause of disease burden around the world, ethological animal models have recently been proposed. Our previous studies highlighted a depressive-like profile among single- and socially-housed farm-bred cynomolgus macaques. Although phylogenetically close, cynomolgus and rhesus macaques, the two most commonly used macaque species in biomedical research, differ on several levels such as patterns of aggression, reconciliation, temperament, or dominance styles. The question of whether one captive macaque species was more vulnerable than another in the development of a pathological profile reminiscent of MDD symptoms was explored. Methods: Behavioral data (including body postures, orientations, gaze directions, inter-individual distances, and locations in the cage) were collected in farming conditions. Using an unbiased validated ethological scan-sampling method, followed by multiple correspondence and hierarchical clustering analyses, 40 single- and 35 socially-housed rhesus macaques were assessed. Independently, for each housing condition, inter-species comparisons were made with previously acquired data on farm-bred cynomolgus monkeys. Results: Consistent with our previous studies, we found depressive-like characteristics (e.g., inactivity, low level of investigation and maintenance, long time spent inactive while facing the wall) among single- and socially-housed rhesus macaques. Species-specificities were reported in non-depressive time budgets and in the prevalence of the pathological profiles. Conclusions: Our results suggest that rhesus may be more vulnerable to developing a despair-like state than cynomolgus macaques, both in single- and in social-housing conditions. Therefore, rhesus macaques are more suitable for use as a "spontaneous" model of depressive disorders