Institute Francais Du Cheval Et Of Lequitation
Institute Francais Du Cheval Et Of Lequitation
Olivier A.,University Paris - Sud |
Olivier A.,University of Orléans |
Olivier A.,University of Caen Lower Normandy |
Faugloire E.,University of Caen Lower Normandy |
And 3 more authors.
Frontiers in Human Neuroscience | Year: 2017
Maintaining equilibrium while riding a horse is a challenging task that involves complex sensorimotor processes. We evaluated the relative contribution of visual information (static or dynamic) to horseback riders’ postural stability (measured from the variability of segment position in space) and the coordination modes they adopted to regulate balance according to their level of expertise. Riders’ perceptual typologies and their possible relation to postural stability were also assessed. Our main assumption was that the contribution of visual information to postural control would be reduced among expert riders in favor of vestibular and somesthetic reliance. Twelve Professional riders and 13 Club riders rode an equestrian simulator at a gallop under four visual conditions: (1) with the projection of a simulated scene reproducing what a rider sees in the real context of a ride in an outdoor arena, (2) under stroboscopic illumination, preventing access to dynamic visual cues, (3) in normal lighting but without the projected scene (i.e., without the visual consequences of displacement) and (4) with no visual cues. The variability of the position of the head, upper trunk and lower trunk was measured along the anteroposterior (AP), mediolateral (ML), and vertical (V) axes. We computed discrete relative phase to assess the coordination between pairs of segments in the anteroposterior axis. Visual field dependence-independence was evaluated using the Rod and Frame Test (RFT). The results showed that the Professional riders exhibited greater overall postural stability than the Club riders, revealed mainly in the AP axis. In particular, head variability was lower in the Professional riders than in the Club riders in visually altered conditions, suggesting a greater ability to use vestibular and somesthetic information according to task constraints with expertise. In accordance with this result, RFT perceptual scores revealed that the Professional riders were less dependent on the visual field than were the Club riders. Finally, the Professional riders exhibited specific coordination modes that, unlike the Club riders, departed from pure in-phase and anti-phase patterns and depended on visual conditions. The present findings provide evidence of major differences in the sensorimotor processes contributing to postural control with expertise in horseback riding. © 2017 Olivier, Faugloire, Lejeune, Biau and Isableu.
Reiter E.,CNRS Physiology of Reproduction and Behaviors |
Reiter E.,French National Center for Scientific Research |
Reiter E.,University of Tours |
Reiter E.,Institute Francais Du Cheval Et Of Lequitation |
And 5 more authors.
Annual Review of Pharmacology and Toxicology | Year: 2012
The concept of biased agonism has recently come to the fore with the realization that seven-transmembrane receptors (7TMRs, also known as G proteincoupled receptors, or GPCRs) activate complex signaling networks and can adopt multiple active conformations upon agonist binding. As a consequence, the "efficacy" of receptors, which was classically considered linear, is now recognized as pluridimensional. Biased agonists selectively stabilize only a subset of receptor conformations induced by the natural "unbiased" ligand, thus preferentially activating certain signaling mechanisms. Such agonists thus reveal the intriguing possibility that one can direct cellular signaling with unprecedented precision and specificity and support the notion that biased agonists may identify new classes of therapeutic agents that have fewer side effects. This review focuses on one particular class of biased ligands that has the ability to alter the balance between G proteindependent and β-arrestin-dependent signal transduction. © 2012 by Annual Reviews. All rights reserved.
Nielsen B.L.,French National Institute for Agricultural Research |
Jerome N.,French National Institute for Agricultural Research |
Saint-Albin A.,French National Institute for Agricultural Research |
Thonat C.,Bio Sens |
And 4 more authors.
Behavioural Brain Research | Year: 2011
A common set of odorous molecules may indicate female receptiveness across species, as male rats display sexual arousal when exposed to the odour of oestrous faeces from rats, vixens and mares. More than 900 different compounds were identified by GC-MS analyses performed on faeces samples from di-oestrous and oestrous females and from males of the three species. Five carboxylic acids were found in lower concentrations in faeces from all oestrous females. We subjected 12 sexually trained male rats to a 30. min exposure to different dilutions of a mixture of these five molecules in the same proportions as found in female oestrous faeces. The behavioural responses of the rats were compared to those displayed when exposed to water (negative control) and faeces from oestrous female rats (positive control). Frequency of penile erections were found to be significantly dependent on mixture dilution, with two intermediate dilutions eliciting frequencies of penile erections that did not differ from those obtained during exposure to oestrous female rat faeces. Higher and lower dilutions did not elicit more penile erections than observed with water. These results support our hypothesis that a small set of odorous molecules may indicate sexual receptiveness in mammalian females. © 2011 Elsevier B.V.
Pirault P.,Agro ParisTech |
Danvy S.,Institute Francais Du Cheval Et Of Lequitation |
Verrier E.,Agro ParisTech |
Verrier E.,French National Institute for Agricultural Research |
And 2 more authors.
PLoS ONE | Year: 2013
Since horse breeds constitute populations submitted to variable and multiple outcrossing events, we analyzed the genetic structure and gene flows considering horses raised in France. We used genealogical data, with a reference population of 547,620 horses born in France between 2002 and 2011, grouped according to 55 breed origins. On average, individuals had 6.3 equivalent generations known. Considering different population levels, fixation index decreased from an overall species FIT of 1.37%, to an average F̄IS of -0.07% when considering the 55 origins, showing that most horse breeds constitute populations without genetic structure. We illustrate the complexity of gene flows existing among horse breeds, a few populations being closed to foreign influence, most, however, being submitted to various levels of introgression. In particular, Thoroughbred and Arab breeds are largely used as introgression sources, since those two populations explain together 26% of founder origins within the overall horse population. When compared with molecular data, breeds with a small level of coancestry also showed low genetic distance; the gene pool of the breeds was probably impacted by their reproducer exchanges. © 2013 Pirault et al.
Coulon M.,French National Institute for Agricultural Research |
Nowak R.,CNRS Physiology of Reproduction and Behaviors |
Nowak R.,French National Center for Scientific Research |
Nowak R.,University of Tours |
And 7 more authors.
Psychoneuroendocrinology | Year: 2013
Friendly interactions between humans and animals such as gentling or petting have been shown to have positive behavioural and physiological consequences in many species. In primates, rodents and dogs, oxytocin has been associated with tactile contact and anti-stress effects that may influence bonding and responses to stress situations. However the activation of the oxytocinergic system in other human-animal interactions such as with herbivores, had not yet been studied. Sixteen female lambs were reared by artificial feeding reinforced with 3× 30. s daily stroking sessions. At 6 weeks of age, the test consisted in measuring first plasma oxytocin and cortisol responses in lambs during a first 6-min phase in the home pen where the familiar caregiver gently stroked the lamb, and then physiological and behavioural responses in a test pen during a 20-min - phase of social isolation followed by a 20-min - phase of reunion with its familiar caregiver. The lambs expressed behavioural agitation during the whole period of isolation. A strong affiliative response towards the human and a sustained reduction of the agitation behaviour were observed during reunion. Lambs' behaviours when isolated and when in contact with the human were correlated suggesting a response to social separation from the familiar caregiver more than to social isolation from congeners. No significant changes in cortisol levels were observed during the test. Oxytocin levels did not vary during human contact, but increased when the familiar caregiver left the lamb alone in the test pen. In conclusion, lambs displayed affiliative responses towards their caregiver, and the lack of cortisol response during isolation while oxytocin was released suggest an anti-stress effect of oxytocin. © 2012 Elsevier Ltd.
Pillet E.,CNRS Physiology of Reproduction and Behaviors |
Pillet E.,French National Center for Scientific Research |
Pillet E.,University of Tours |
Duchamp G.,CNRS Physiology of Reproduction and Behaviors |
And 8 more authors.
Theriogenology | Year: 2011
Hen egg yolk is normally used as a cryoprotective agent in semen freezing extenders, but its use has sanitary and practical disadvantages. Moreover the protection afforded by egg yolk has not yet been completely elucidated. The objective of this study was to compare the egg yolk plasma fraction to whole egg yolk in stallion freezing extender. Plasma contains mainly Low Density Lipoproteins (LDL), which are widely presumed to be the cryoprotective agent in egg yolk. Plasma can be produced on an industrial scale, sterilised by gamma-irradiation and incorporated in a ready-to-use extender (our ultimate objective). Plasma samples were subjected to different doses of gamma-irradiation (3, 5, 10 kGy) without dramatic chemical changes that may affect their cryoprotective properties. Stallion semen was frozen with whole egg yolk as a control and with sterilised egg yolk plasma. A fertility trial was conducted on a total of 70 mares' cycles. Fertility per cycle was 60% after insemination of semen frozen in our control extender containing egg yolk (EY), compared to 69% for the extender containing sterilised egg yolk plasma (EYP) (P > 0.05). Post-thaw motility and membrane integrity of spermatozoa were also analysed. Motility parameters were not significantly different between extenders except for the variable VAP (for EY versus EYP, VAP: 63 μm.s-1 versus 59 μm.s-1, a, b: P < 0.001; PROG: 41% versus 39%, RAP30: 56% versus 54%; RAP40: 51% versus 48%, P > 0.05). Membrane integrity was better preserved in EY than in EYP but the difference between extenders was small (P < 0.05). Our results demonstrated that sterilised egg yolk plasma has the potential to replace egg yolk in stallion freezing extender. This experiment led to the development of a ready-to-use extender called INRA-Freeze® (IMV-Technologies, France). © 2011 Elsevier Inc.
Franceschini I.,CNRS Physiology of Reproduction and Behaviors |
Franceschini I.,French National Center for Scientific Research |
Franceschini I.,University of Tours |
Franceschini I.,Institute Francais Du Cheval Et Of Lequitation |
And 5 more authors.
Frontiers in Endocrinology | Year: 2013
The prominent role of the G protein coupled receptor GPR54 and its peptide ligand kisspeptin in the progression of puberty has been extensively documented in many mammalian species including humans. Kisspeptins are very potent gonadotropin-releasing hormone secretagogues produced by two main populations of neurons located in two ventral forebrain regions, the preoptic area and the arcuate nucleus. Within the last 2 years a substantial amount of data has accumulated concerning the development of these neuronal populations and their timely regulation by central and peripheral factors during fetal, neonatal, and peripubertal stages of development. This review focuses on the development of the kisspeptin-GPR54 system in the brain of female mice, rats, sheep, monkeys, and humans. We will also discuss the notion that this system represents a major target through which signals from the environment early in life can reprogram reproductive function. ©2013 Franceschini and Desroziers.
Dardente H.,CNRS Physiology of Reproduction and Behaviors |
Dardente H.,French National Center for Scientific Research |
Dardente H.,University of Tours |
Dardente H.,Institute Francais Du Cheval Et Of Lequitation |
And 2 more authors.
Frontiers in Endocrinology | Year: 2014
Living organisms show seasonality in a wide array of functions such as reproduction, fattening, hibernation, and migration. At temperate latitudes, changes in photoperiod maintain the alignment of annual rhythms with predictable changes in the environment. The appropriate physiological response to changing photoperiod in mammals requires retinal detection of light and pineal secretion of melatonin, but extraretinal detection of light occurs in birds. A common mechanism across all vertebrates is that these photoperiod-regulated systems alter hypothalamic thyroid hormone (TH) conversion. Here, we review the evidence that a circadian clock within the pars tuberalis of the adenohypophysis links photoperiod decoding to local changes of TH signaling within the medio-basal hypothalamus (MBH) through a conserved thyrotropin/deiodinase axis. We also focus on recent findings which indicate that, beyond the photoperiodic control of its conversion, TH might also be involved in longer-term timing processes of seasonal programs. Finally, we examine the potential implication of kisspeptin and RFRP3, two RF-amide peptides expressed within the MBH, in seasonal rhythmicity. © 2014 Dardente, Hazlerigg and Ebling.
von Lewinski M.,Graf Lehndorff Institute for Equine Sciences |
Biau S.,Institute Francais Du Cheval Et Of Lequitation |
Erber R.,University of Vienna |
Ille N.,University of Vienna |
And 4 more authors.
Veterinary Journal | Year: 2013
Although some information exists on the stress response of horses in equestrian sports, the horse-rider team is much less well understood. In this study, salivary cortisol concentrations, heart rate (HR) and heart rate variability (HRV), SDRR (standard deviation of beat-to-beat interval) and RMSSD (root mean square of successive beat-to-beat intervals) were analysed in horses and their riders (n= 6 each) at a public performance and an identical rehearsal that was not open to the public. Cortisol concentrations increased in both horses and riders (P< 0.001) but did not differ between performance and rehearsal. HR in horses and riders increased during the rehearsal and the public performance (P< 0.001) but the increase in HR was more pronounced (P< 0.01) in riders than in their horses during the public performance (from 91 ± 10 to 150 ± 15. beats/min) compared to the rehearsal (from 94 ± 10 to 118 ± 12. beats/min). The SDRR decreased significantly during the equestrian tasks in riders (P< 0.001), but not in their horses. The RMSSD decreased in horses and riders (P< 0.001) during rehearsal and performance, indicating a decrease in parasympathetic tone. The decrease in RMSSD in the riders was more pronounced (P< 0.05) during the performance (from 32.6 ± 6.6 to 3.8 ± 0.3. ms) than during the rehearsal (from 27.5 ± 4.2 to 6.6 ± 0.6. ms). The study has shown that the presence of spectators caused more pronounced changes in cardiac activity in the riders than it did in their horses. © 2013 Elsevier Ltd.
PubMed | Institute Francais Du Cheval Et Of Lequitation and Limoges University Hospital Center
Type: | Journal: Parasite (Paris, France) | Year: 2015
In France, some cases of severe toxoplasmosis have been linked to the consumption of horse meat that had been imported from the American continent where atypical strains of Toxoplasma gondii are more common than in Europe. Many seroprevalence studies are presented in the literature but risk assessment of T. gondii infection after horse meat consumption is not possible in the absence of validated serological tests and the unknown correlation between detection of antibodies against T. gondii and presence of tissue cysts. We performed magnetic-capture polymerase chain reaction (MC-PCR) to detect T. gondii DNA in 231 horse meat samples purchased in supermarkets in France and evaluated the performance and level of agreement of the modified agglutination test (MAT) and enzyme-linked immunosorbent assay (ELISA) in the meat juices. The serological tests lacked sensitivity, specificity, and agreement between them, and there was no correlation with the presence of T. gondii DNA in horse meat, raising concerns about the reliability of T. gondii seroprevalence data in horses from the literature. T. gondii DNA was detected in 43% of horse meat samples but the absence of strain isolation in mice following inoculation of more than 100 horse meat samples suggests a low distribution of cysts in skeletal muscles and a low risk of T. gondii infection associated with horse meat consumption. However, to avoid any risk of toxoplasmosis, thorough cooking of horse meat is recommended.