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Effets d'une restriction alimentaire et d'une réalimentation sur les performances et le métabolisme de porcs européens (Large White) et caribéens (Créole) en croissance en climat tropical
No full textReduction of feed intake is a common physiological response of growing pigs facing stressful environmental conditions. The aim of the present experiment was 1) to study the effects of a short-term drastic feed restriction and subsequent refeeding on pig metabolism, and 2) to study the differential response between 2 breeds, the Large White (LW) breed that has been selected for high growth performance and the Creole (CR) breed, which is characterized by its good adaptation to harsh tropical environmental conditions. An assay with a total of 36 castrated male pigs (18 LW and 18 CR) was carried out. For each breed, half of the animals were restrictively-fed at 50% of the standard allowance for 7 days and were then fed normally for the next 15 days. Growth performance, thermoregulatory responses and plasma metabolites were measured before, during and after feed restriction in the 2 groups. Results show that for all the measured traits, the difference in the response between the 2 breeds is small and rarely significant. Irrespective of breed, during feed restriction, ADG and feed efficiency were reduced (-75%, P< 0.001; -58%, P< 0.05, respectively), but that was counterbalanced by an increase in those same parameters during refeeding (+25%, P< 0.001 ; +49%, P< 0.001, respectively). Feed restriction also reduces skin temperature (-0.6°C, P< 0.01), rectal temperature (-0.4°C, P< 0.01) and respiratory rate (-12 breaths per minute, P< 0.01). Moreover, the results suggest that certain metabolites, such as alkaline phosphatase and blood urea, could be potential biomarker candidates for feed restriction
Adaptation des systèmes de polycultures-élevages aux variations de prix et de taille de l’exploitation : simulation à partir du modèle bioéconomique Orfee.
No full textLes systèmes en polyculture-élevage (PCE) dominaient en France jusque dans les années 1950 mais
laissent de plus en plus la place à des fermes spécialisées, plus grandes et moins nombreuses.
L’objectif est d’analyser quels sont les facteurs qui influent le plus sur l’évolution de la part d’élevage et
de cultures dans une exploitation agricole. L’étude porte plus particulièrement sur l’effet des prix et de la
surface agricole des exploitations. Des simulations ont été réalisées avec le modèle bioéconomique
Orfee sur trois fermes types en PCE localisées en Lorraine, en Normandie et en Midi-Pyrénées. Le
contexte normand sort comme le système le plus stable, du fait de la forte rentabilité du lait. Par contre
l’arrêt total du lait est observé en cas de baisse durable du prix des produits animaux de plus de 20%.
La part élevage-culture est la plus sensible aux variations de prix dans le système de Midi-Pyrénées où
les rentabilités par travailleur des cultures et du système bovin naisseur sont proches. Les exploitations
en bovin viande maintiennent l’élevage sur les prairies permanentes quel que soit la conjoncture.Until the 1950s, crop-livestock systems (combination of crop and livestock farming) ruled France. Since
then, specialized systems less numerous and bigger have been prevailing. The objective of this study is
to analyse the impacts of price variations and land expansion on crop-livestock farming systems.
Simulations were run using the bioeconomical model Orfee applied to three farm types in Lorraine,
Normandie and Midi-Pyrénées. The Norman context seems to be the most stable, as a result of milk
profitability. But, milk production is stopped for price drop higher than -20%. The livestock-crop share is
the most sensitive to price variations in the Midi-Pyrénées system where the returns per worker of the
crops and the beef system are close. Beef suckler farms keep livestock on permanent pasture
regardless of the price variation
Estimation de la diversité génétique entre et intra lignées françaises de truite arc-en-ciel
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La réintroduction de l'élevage dans un territoire spécialisé en grande culture est-elle durable ? Evaluation multicritère de scénarios de recouplage.Innovations
No full textCoupler productions animales et végétales à l’échelle d’une exploitation ou d’un territoire contribuerait à
améliorer leur durabilité (bouclage des cycles des nutriments, circularité des ressources, résilience face
aux aléas climatiques ou de marché, moindre dépendance aux intrants, création d’emploi,…), mais au
sein de territoires spécialisés en grande culture, le recouplage culture-élevage n’est pas vraiment
constaté. Une étude de faisabilité a été menée avec comme objectifs (i) d’imaginer des voies de
réintroduction possibles de l’élevage, i.e. acceptables par les acteurs concernés, dans un territoire
spécialisé en grande culture, (ii) d’évaluer en multicritère à l’échelle des exploitations et si possible à
l’échelle du territoire la durabilité des scénarios imaginés. Ceux-ci s’appuient sur la création d’ateliers
d’élevage collectifs bovin ou ovin, en interaction avec des exploitations céréalières du territoire. Si
l’impact semble être quasiment neutre sur les aspects technico-économiques de l’exploitation
céréalière, le scénario basé sur l’introduction d’un atelier ovin présente un niveau d’interaction plus
élevé entre ateliers grâce à l’insertion de la luzerne dans l’assolement du système céréalier et le
pâturage des moutons pendant les intercultures, et un profil de durabilité intéressant en améliorant le
bilan humique des sols.
La démarche réalisée pour le diagnostic du territoire et l’évaluation de la durabilité par le calcul
d’indicateurs de performances nourrit les réflexions du RMT ERYTAGE et trace quelques perspectives
pour consolider la boîte à outils de l’évaluateur.Breeding offers lots of qualities complementary with crop production. But is the addition of both of these
productions really sustainable? This article presents results of a feasibility study of coupling the
breeding and the crop productions in a territory specialized in crop productions. After diagnosis of the
agricultural rules of this territory, we identify relevance ways to reintroduce breeding. It leads to identify
scenarios based on collective breeding of cattle or sheep units, separated from crops systems, but
interacting with them. The breeding and the crops interact together by flows of food from the crop
productions to the breeding, and flow of fertilizers from breeding to the crops.Thanks to multi-criteria assessments tools, the farms are estimated about social, environmental and economic sustainability indicators. The results allow to define the farm’s situation before and after reintroduction of breeding in the territory.
Results reveal almost neutral effects on the technical and environmental aspects of the grain farm,
except in “sheep” scenario. Indeed, the ovine breeding modifies the crop rotation system and includes
the sheep’s pasture, which allows a stronger interaction and an improvement of organic soil balance.
The methodology process is discussed on methods, indicators, multi-criteria assessment tools used
Understanding alternatives in data analysis activities
No full textData workers are non-professional data scientists who engage in data analysis activities as part of their daily work. In this position paper, we share past and on-going work to understand data workers’ sense-making practices. We use multidisciplinary approaches to explore their human-tool partnerships. We introduce our current research on the role of alternatives in data analysis activities. Finally, we conclude with open questions and research directions
Muscle resting and TGF-β inhibitor treatment prevent fatty infiltration following skeletal muscle injury
No full textBackground/Aims: Skeletal muscle injuries are the most common type of injury occurring in sports, and investigating skeletal muscle regeneration as well as understanding the related processes is an important aspect of the sports medicine field. The process of regeneration appears to be complex and precisely orchestrated, involving fibro-adipogenic progenitors (FAPs) which are a muscle-resident stem cell population that appears to play a major role in abnormal development of fibrotic tissue or intermuscular adipose tissue (IMAT). Our present study aims to investigate whether muscle resting or endurance exercise following muscle injury may change the behavior of FAPs and subsequently impact the development of fatty infiltrations and fibrosis, two hallmarks of regeneration failure. Methods:We used the validated glycerol muscle injury model to mimic abnormal muscle regenerative conditions in mice. We challenged this specific regeneration model with hindlimb unloading or endurance exercise and, in a second set of experiments, we treated mice with decorin, a TGF-β inhibitor. Results:In this study, we demonstrated that: i) muscle resting just after injury leads to inhibition of IMAT development, ii) TNF-α mediated FAP apoptosis might be perturbed in this specific glycerol model of muscle injury, leading to IMAT development, and iii) treatment with the TGF-β inhibitor decorin decreases IMAT development and might restores FAP apoptosis.Conclusion:In addition to the potential clinical relevance of decorin treatment in situations involving muscle plasticity and regeneration, this study also demonstrates that a period of muscle resting is necessary following muscle injury to achieve efficient muscle regeneration which is associated with a reduction in fatty infiltration. Unreasonably early resumption of exercise brings no gain to regeneration, further highlighting that this resting period is necessary
Foamability of bentonite treated wines : Impact of new Acacia gum fractions obtained by Ionic Exchange Chromatography (IEC)
No full textA protein complex required for polar growth of rhizobial infection threads
No full textDuring root nodule symbiosis, intracellular accommodation of rhizobia by legumes is a prerequisite for nitrogen fixation. For many legumes, rhizobial colonization initiates in root hairs through transcellular infection threads. In Medicago truncatula, VAPYRIN (VPY) and a putative E3 ligase LUMPY INFECTIONS (LIN) are required for infection thread development but their cellular and molecular roles are obscure. Here we show that LIN and its homolog LIN-LIKE interact with VPY and VPY-LIKE in a subcellular complex localized to puncta both at the tip of the growing infection thread and at the nuclear periphery in root hairs and that the punctate accumulation of VPY is positively regulated by LIN. We also show that an otherwise nuclear and cytoplasmic exocyst subunit, EXO70H4, systematically co-localizes with VPY and LIN during rhizobial infection. Genetic analysis shows that defective rhizobial infection in exo70h4 is similar to that in vpy and lin. Our results indicate that VPY, LIN and EXO70H4 are part of the symbiosis-specific machinery required for polar growth of infection threads
Classification ascendante hiérarchique, contrainte d'ordre : conditions d'applicabilité, interprétabilité des dendrogrammes
No full textLa classification ascendante hiérarchique (CAH) avec lien de Ward est une approche fréquemment utilisée pour partitionner des objets d'un espace multi-dimensionnel. Nous discutons ici de la validité théorique des extensions de cette approches à différents types d'entrées (distances, dissimilarités, noyaux, similarités) ainsi que de la pertinence de l'utilisation de sa version contrainte (parfois appelée "CONISS") dans ces divers cas. En particulier, nous étudions les conditions garantissant la cohérence entre les résultats de la CAH et leur représentation graphique classique sous forme de dendrogramme. Nous présentons également une étude de simulations montrant que la version contrainte de la méthode permet, outre des gains computationnels, d'obtenir de meilleurs résultats de classification lorsque la contrainte est cohérente avec la structure des données. Beaucoup de ces résultats sont présents dans une littérature hétéroclite : l'objet de cette communication est de proposer donc un cadre de présentation uniforme et de compléter les résultats existants