HAL ENVT (Ecole Nationale Vétérinaire de Toulouse)
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Liver gene expression and its rewiring in hepatic steatosis are controlled by PI3Kα-dependent hepatocyte signaling
No full textInternational audienceInsulin and other growth factors are key regulators of liver gene expression, including in metabolic diseases. Most of the phosphoinositide 3-kinase (PI3K) activity induced by insulin is considered to be dependent on PI3Kα. We used mice lacking p110α, the catalytic subunit of PI3Kα, to investigate its role in the regulation of liver gene expression in health and in metabolic dysfunction-associated steatotic liver disease (MASLD). The absence of hepatocyte PI3Kα reduced maximal insulin-induced PI3K activity and signaling, promoted glucose intolerance in lean mice and significantly regulated liver gene expression, including insulin-sensitive genes, in ad libitum feeding. Some of the defective regulation of gene expression in response to hepatocyte-restricted insulin receptor deletion was related to PI3Kα signaling. In addition, though PI3Kα deletion in hepatocytes promoted insulin resistance, it was protective against steatotic liver disease in diet-induced obesity. In the absence of hepatocyte PI3Kα, the effect of diet-induced obesity on liver gene expression was significantly altered, with changes in rhythmic gene expression in liver. Altogether, this study highlights the specific role of p110α in the control of liver gene expression in physiology and in the metabolic rewiring that occurs during MASLD
Body reserves dynamic of suckling ewes across successive production cycles under outdoor and indoor contrasting farming system conditions
No full textInternational audienceBody reserves (BR) mobilization (BRM) and accretion (BRA) are crucial biological processes in ruminants that help them manage negative energy balance and adapt to changing environments. The BR dynamics (BRD) is affected by the interplay of key factors such as the farming system (FS) characteristics, physiological stage (PhySt), and parity (Par) or cohort (Coh) of the ewes, as well as litter size (LSi) at lambing and during suckling. This study aimed to evaluate the effects of contrasting FS (intensive, indoor (IND) vs. extensive, outdoor (OUT)) on the BRD of Romane ewes. Two flocks were monitored from 2017 to 2021: 173 ewes in IND and 234 in OUT, belonging to Coh17 (born 2017) and Coh18 (born 2018). Ewes were monitored for body weight (BW), body condition score (BCS), backfat thickness (BFT), back muscle thickness (BMT), non-esterified fatty acids (NEFA), β-hydroxybutyrate (BHB), triiodothyronine (T3), and insulin (INS) at five key PhySt (Mating, M; mid-pregnancy, P; before-lambing, bL; after-lambing, aL; and weaning, W). in primiparous (PRIM) or multiparous (MULT) ewes during successive production cycles. Data were analyzed using linear mixed models, with significance threshold set at P ≤ 0.05. There was no isolated effect (P > 0.05) of FS on the BR traits evaluated. However, significant interactions were observed between FS and PhySt and Par (P < 0.001), LSi (P < 0.01), or Coh (P < 0.001) for all BR traits, indicating that FS may influence BR through factors such as feed availability, energy demands, or stress levels across different PhySt. MULT ewes showed better BR recovery than PRIM ewes regardless of FS, suggesting improved metabolic efficiency with maturity. With larger LSi, greater BRM, and slower recovery, was observed regardless of FS, emphasizing the need for tailored nutritional strategies., and Coh18 ewes showed greater capacity to mobilize and rebuild BR than Coh17. BR dynamics was similar in both FS as indicated by comparable levels of BHB (but not NEFA), T3, and BCS around lambing. In both FS, BRM was observed from P until W, and BRA was observed from weaning until next P. In conclusion, BRD in sheep is strongly shaped by PhySt, and to a lesser extent by environmental factors, influencing FS resilience and productivity. These insights support the importance of improving animal adaptive capacities through BR management for enhancing sustainability in diverse FS, particularly in the face of climate variability and rising production costs
De quelles données dispose-t-on pour choisir un vaccin contre les affections respiratoires virales des bovins ?
No full textNational audienceLe Comité de suivi des médicaments vétérinaires, placé auprès du directeur de l’Anses-ANMV, vient de rédiger un article suite à l’étude des informations publiées dans le cadre de l’utilisation de certains vaccins chez les bovins. Les stratégies vaccinales ont été explorées selon les catégories d’animaux, les types de vaccins (vivants versus inactivés, voie injectable versus intranasale) et les pathogènes viraux (virus respiratoire syncytial et para influenza 3). Une recherche bibliographique avec des mots clés dans des moteurs de recherche a été conduite. La combinaison des résultats trouvés pour chaque type de vaccin indépendamment des titulaires d’AMM a été réalisée.Il en ressort la difficulté de dégager des recommandations relatives à la vaccination contre les affections respiratoires virales des bovins et l’importance des mesures zootechniques, hygiéniques et préventives autres que vaccinales à ne pas négliger dans la prévention du risque infectieux respiratoire transmissible chez les bovins. Des études complémentaires d'efficacité réalisées sur le terrain seraient nécessaires. Les déclarations de pharmacovigilance restent aussi indispensables pour évaluer l'efficacité sur le terrain des différents vaccins
Integrated Co-extraction Protocol for Transcriptomic and 1H NMR Metabolomic Analysis of Multi-species Biofilms
No full textInternational audienceCapturing produced, consumed, or exchanged metabolites (metabolomics) and the result of gene expression (transcriptomics) require the extraction of metabolites and RNA. Multi-omics approaches and, notably, the combination of metabolomics and transcriptomic analyses are required for understanding the functional changes and adaptation of microorganisms to different physico-chemical and environmental conditions. A protocol was developed to extract total RNA and metabolites from less than 6 mg of a kind of phototrophic biofilm: oxygenic photogranules. These granules are aggregates of several hundred micrometers up to several millimeters. They harbor heterotrophic bacteria and phototrophs. After a common step for cell disruption by bead-beating, a part of the volume was recovered for RNA extraction, and the other half was used for the methanol- and dichloromethane-based extraction of metabolites. The solvents enabled the separation of two phases (aqueous and lipid) containing hydrophilic and lipophilic metabolites, respectively. The 1H nuclear magnetic resonance (NMR) analysis of these extracts produced spectra that contained over a hundred signals with a signal-to-noise ratio higher than 10. The quality of the spectra enabled the identification of dozens of metabolites per sample. Total RNA was purified using a commercially available kit, yielding sufficient concentration and quality for metatranscriptomic analysis. This novel method enables the co-extraction of RNA and metabolites from the same sample, as opposed to the parallel extraction from two samples. Using the same sample for both extractions is particularly advantageous when working with inherently heterogeneous complex biofilm. In heterogeneous systems, differences between samples may be substantial. The co-extraction will enable a holistic analysis of the metabolomics and metatranscriptomics data generated, minimizing experimental biases, including technical variations and, notably, biological variability. As a result, it will ensure more robust multi-omics analyses, particularly by improving the correlation between metabolic changes and transcript modifications
Larval motility assay using WMicrotracker™: a high throughput test to discriminate between resistance and susceptibility to anthelmintic drugs in nematodes
No full textAbstract Grazing ruminants suffer from various helminth infections particularly those caused by gastrointestinal nematode (GIN) parasites, which have a considerable impact on their welfare and productivity. Treatment predominantly relies on macrocyclic lactone (ML) anthelmintics, but their widespread application has led to the emergence of drug-resistant parasite populations worldwide. The standard method for detecting resistance, the Faecal Egg Count Reduction Test (FECRT), is susceptible to misinterpretation, leading to flawed management decisions that undermine parasite control efforts. Thus, there is a pressing need for robust resistance detection methods in field parasites. We investigated the potential of the WMicrotracker TM (WMi) motility assay, previously unexplored in ML resistance assessment. The assay first compared ivermectin (IVM) susceptibility among wild-type Bristol N2 (N2B), IVM-selected (IVR10), and nhr-8 loss-of-function (AE501; nhr8(ok186) ) Caenorhabditis elegans strains. Dose-response curves indicated differences in IVM susceptibility among strains, with IVR10 exhibiting a 2.12-fold decrease in sensitivity compared to N2B. Cross-resistance between IVM, moxidectin (MOX), and eprinomectin (EPR) was explored, demonstrating reduced susceptibility in IVR10 across all drugs compared to N2B. Further investigation was conducted using Haemonchus contortus ( H. contortus ) to assess the assay’s applicability in discriminating susceptible from resistant isolates. Results revealed significant differences in drug potency between susceptible and resistant isolates, with MOX demonstrating the highest efficacy. Resistance factors (RF) highlighted the substantial resistance of the resistant isolate to EPR. The motility assay effectively discriminated susceptible from resistant isolates in both C. elegans and H. contortus . Our findings demonstrate, for the first time, the relevance of the motility assay by WMi as a functional indicator of resistance in nematodes, offering a promising avenue for detecting resistance to MLs. This research sheds light on a novel approach for monitoring drug resistance, vital for effective parasite management strategies
Étude du déterminisme biologique et génétique des biomarqueurs associés à la dynamique des réserves énergétiques corporelles chez les ovins
No full textThe management of body reserves (BR), through the cyclical processes of mobilization (BRM) and accretion (BRA), is a crucial biological mechanism for resilience in ruminants, enabling adaptation to energy deficits and variable environments. Research of proxies for this BR dynamics (BRD) is of great interest for improvement of BR resilience through genetic selection. In the present PhD, the objectives were i) to better understand the phenotypic variability of key plasma biomarkers linked to BR, ii) investigate genetic determinism of biomarkers, and iii) to assess the predictive value of biomarkers to evaluate BR resilience. To address these objectives, primiparous and multiparous meat sheep, reared in two contrasted farming systems (FS: indoor vs outdoor) were monitored longitudinally throughout the productive cycles. Plasma biomarkers concentrations: non-esterified fatty acids (NEFA), β-hydroxybutyrate (BHB), triiodothyronine (T3), and insulin (INS), and body condition traits including body condition score (BCS), were measured at five physiological stages (PhySt): mating (M), mid-pregnancy (P), before lambing (bL), after lambing (aL), and weaning (W).Characterization of BRD showed BRM predominated from P until W, while BRA occurred from W until the next P in both FS, regardless of parity (Par), litter size and cohort, suggesting BRD in sheep is strongly shaped by PhySt and to a lesser extent by environmental factors. However, plasma biomarkers concentrations varied between FS depending on PhySt and Par. A functional principal component analysis and unsupervised clustering highlighted individual variability in plasma biomarker trajectories. Two to three distinct trajectories were identified for each biomarker depending on FS and/or Par. Most trajectories showed transient increases in biomarker concentrations during BRM followed by declines, but differed mainly in concentrations reached and/or PhySt when peaks were observed. Repeatability across cycles was observed for major clusters. Greater individual variability in biomarkers concentrations was particularly observed around lambing. Genetic analyses of biomarkers showed that concentrations, at specific or across PhySt, were heritable (NEFA: 0.08 to 0.16; BHB: 0.07 to 0.12; T3: 0.09 to 0.33; INS: 0.04 to 0.16), as well as changes over time (0.01 to 0.23). Genetic correlations for each biomarker between PhySt varied according PhySt (0.19 to 0.95). Most genetic correlations between biomarkers were low to moderate, but changes in T3 appeared highly correlated to changes in NEFA, BHB and INS during BRA. A genome-wide association study using single-step GBLUP identified significant SNPs on chromosomes 6, 11, and 25 for NEFA, BHB, T3, and INS. Finally, an integrative approach was developed to construct an individual composite criterion for BR resilience, considering deviation from optimum physiological thresholds and multivariate atypicality, and using BCS, NEFA, and T3. The BR resilience score allowed to classify ewes as three categories: Least Resilient (17%), Intermediate (68%), or Very Resilient (15%). Low-resilient ewes showed higher NEFA increases and BCS loss during BRM, whereas high-resilient ewes exhibited lower levels and/or variations throughout trajectories.In conclusion, present findings support that key biomarkers of BR are useful proxies that could be used, in combination with body condition traits, to better evaluate BR resilience and considered in genetic selection with adapted procedure of phenotyping for improvement of such trait.La dynamique des réserves énergétiques corporelles (DRC) stockées sous forme de tissus adipeux, alternance de périodes de mobilisation (MRC) et d'accrétion (ARC) des RC, est un mécanisme biologique crucial pour la résilience métabolique des ruminants, leur permettant de s'adapter aux déficits énergétiques. La recherche de proxies pour la DRC présente un grand intérêt pour l'amélioration génétique de cette aptitude. Dans le cadre de cette thèse, les objectifs étaient i) de mieux comprendre la variabilité phénotypique des biomarqueurs plasmatiques clés associés aux RC, ii) d'étudier le déterminisme génétique des biomarqueurs, et iii) d'évaluer le potentiel de ces biomarqueurs pour évaluer la résilience métabolique. Pour atteindre ces objectifs, des brebis allaitantes primipares et multipares, élevées dans deux systèmes d'élevage (SE) contrastés (bergerie vs extensif) ont été suivies de manière longitudinale sur plusieurs cycles de production. Les concentrations des biomarqueurs plasmatiques : acides gras non estérifiés (AGNE), β-hydroxybutyrate (BHB), triiodothyronine (T3) et insuline (INS), ainsi que des caractéristiques de l'état corporel, dont la note d'état corporel (NEC), ont été mesurées à cinq stades physiologiques (StPhy) : lutte, mi-gestation (G), avant et après la mise-bas et sevrage (S).La caractérisation de la DRC a montré que la MRC intervient de la G au S, tandis que l’ARC se produit du S à la G quel que soit le SE, la parité (Par), la taille de portée et la cohorte, ce qui suggère que la DRC chez les ovins est fortement influencée par les StPhy, et dans une moindre mesure par des facteurs environnementaux. Cependant, les concentrations des biomarqueurs plasmatiques varient entre les SE en fonction du StPhy et de la Par. Une analyse de clustering a mis en évidence une variabilité individuelle dans les trajectoires des biomarqueurs plasmatiques. Deux à trois trajectoires ont été identifiées pour chaque biomarqueur en fonction du SE et/ou de la Par. La plupart des trajectoires montrent des augmentations transitoires des concentrations de biomarqueurs pendant la MRC, suivies de baisses. Ces trajectoires diffèrent principalement par les concentrations atteintes et/ou le StPhy auquel les pics sont observés. Une répétabilité entre les cycles a été observée pour les clusters majoritaires. Une plus grande variabilité individuelle dans les concentrations de biomarqueurs est observée autour de la mise-bas. Les analyses génétiques ont montré que les concentrations des biomarqueurs sont héritables (AGNE : 0,08 à 0,16 ; BHB : 0,07 à 0,12 ; T3 : 0,09 à 0,33 ; INS : 0,04 à 0,16). Les corrélations génétiques pour chaque biomarqueur variaient entre PhySt (0,19 à 0,95). La plupart des corrélations génétiques entre les biomarqueurs sont faibles à modérées, mais les variations de T3 semblent fortement corrélées aux variations d’AGNE, BHB et INS pendant l’ARC. Une étude d'association génomique a permis d’identifier des SNP significatifs sur les chromosomes 6, 11 et 25 pour les AGNE, le BHB, la T3 et l'INS. Enfin, une approche intégrative a permis d'élaborer un critère composite individuel pour la résilience métabolique, en tenant compte de l'écart par rapport aux seuils physiologiques optimaux et de l'atypicité multivariée, en combinant la NEC, les AGNE et la T3. Le score de résilience ainsi obtenu permet de classer les brebis en trois catégories : les moins résilientes (17 %), les intermédiaires (68 %) et les plus résilientes (15 %). Les brebis peu résilientes présentent une forte augmentation des AGNE et une perte de NEC pendant la MRC, tandis que les brebis très résilientes maintiennent des trajectoires stables.En conclusion, les résultats confirment l’intérêt des biomarqueurs clés des RC pour mieux évaluer la résilience métabolique chez les ovins, en combinaison avec l’état corporel, et qu’ils pourraient être utilisés en sélection génétique avec une procédure adaptée de phénotypage afin d'améliorer cette résilience
Vers une meilleure gestion de la douleur des mammifères et poissons destinés à la consommation humaine – Partie 1 : Concepts, mécanismes, causes, détection
No full textInternational audienceCet article propose de dresser un état des lieux des connaissances scientifiques sur la douleur chez les animaux de production destinés à la consommation humaine. La douleur est « une expérience sensitive et émotionnelle désagréable associée ou ressemblant à celle associée à une atteinte tissulaire réelle ou potentielle ». Elle comporte trois composantes : sensitive, émotionnelle et cognitive. Les mécanismes de la douleur sont similaires chez la plupart des espèces : transduction, transmission, intégration. Tout au long de leur vie, les animaux de production sont confrontés à divers contextes pouvant générer de la douleur, avec un impact important sur leurs performances zootechniques, économiques, sur leur santé et sur leur bien-être. La douleur provoquée par certaines interventions en élevage est prévisible et sa prise en charge peut être anticipée, à l’inverse des accidents ou des maladies dont la survenue n’est pas ou peu prévisible. Les animaux manifestent la douleur en modifiant leurs comportements et leurs réponses physiologiques. Pour la détecter, on peut mobiliser l’observation centrée sur les animaux (posture, expression faciale, réaction à la palpation…) mais aussi sur la manière dont ils interagissent avec leur environnement physique (activités, locomotion, utilisation de l’espace…) et social (proximité, interactions, synchronisation)
Utilisation de la détection des anticorps dans le lait de tank pour le dépistage des troupeaux bovins et ovins laitiers ayant connu une circulation du virus de la Maladie Hémorragique Epizootique (EHDV)
No full textThe objective of this study was to evaluate diagnostic performance of a competitive ELISA test for EHDV-8 antibodies applied to both individual and bulk tank milk for detecting dairy cattle and sheep herds and flocks that had experienced EHDV-8 circulation. The analysis performed on individual milk samples from 673 cattle, compared with serum testing, identified inhibition percentage thresholds of 60% or 64% as those maximizing diagnostic performance (sensitivity 96.8% to 97.7%; specificity 98.6% to 98.4% depending on the scenario). Subsequently, a large-scale study including 118 herds from two EHDV-8 infected regions and 289 negative control herds from disease-free areas assessed the relationship between the competitive ELISA response on bulk tank milk and within-herd seroprevalence, as well as the diagnostic performance of a single bulk tank milk test for herd detection at dicerent levels of seroprevalence. A decision threshold of 65% was associated with good detection sensitivity (80.8% to 94.2% for herds with seroprevalence > 5%; 91.5% to 100% for seroprevalence > 15%, depending on the scenario) while maintaining very high specificity (99.7%). A smaller-scale study in 40 dairy sheep flocks from the Pyrénées-Atlantiques region showed similar detection performance, although specificity could not be formally assessed. This study demonstrates that the use of antibody detection in individual and bulk tank milk is a highly ecective tool for screening dairy cattle and sheep herds exposed to Epizootic Hemorrhagic Disease Virus and can be applied in the context of epidemiological studies or surveillance programs.Cette étude avait pour objectif d’évaluer les performances diagnostiques d'un test ELISA compétition Anticorps EHDV-8 appliqué sur le lait individuel et de tank pour la détection des troupeaux bovins et ovins laitiers ayant connu une circulation du virus EHDV-8. L’analyse réalisée sur le lait individuel de 673 bovins, en comparaison de celle mise en oeuvre sur le sérum, a permis de définir les valeurs de pourcentage d’inhibition de 60 % ou 64% comme étant ceux maximisant les performances diagnostiques (sensibilité 96.8% à 97.7 % ; spécificité 98.6 % à 98.4 % selon les scénarii). Par la suite, une étude à grande échelle comprenant 118 troupeaux dans 2 régions infectées par l’EHDV-8 et 289 troupeaux témoins négatifs sélectionnés dans des régions indemnes a permis d’évaluer la relation entre la réponse aux test ELISA compétition sur le lait de tank et la séroprévalence intra-troupeau ainsi que les performances diagnostiques d’un test unique appliqué au lait de tank pour la détection des troupeaux selon dicérents niveaux de séroprévalence. Le seuil de décision de 65% était associé à une bonne sensibilité de détection (80.8 à 94.2 % pour des élevages avec une séroprévalence > 5%, 91.5 % à 100% pour des séroprévalences > 15 %, selon les scénarii investigués) tout en étant très spécifique (99.7 %). Une étude à plus petite échelle dans 40 élevages ovins allaitants des Pyrénées Atlantiques était associée aux mêmes performances de détection, même si la spécificité n’a pu être formellement évaluée. Cette étude montre que l’utilisation de la détection des anticorps dans le lait individuel et de tank est un outil très performant pour le dépistage des troupeaux bovins et ovins laitiers ayant connu une circulation du virus de la Maladie Hémorragique Epizootique et peut servir dans le cadre d’études épidémiologiques ou de surveillance
Nutritional Iron Deficiency Enhances Erythrophagocytosis via High FPN and SYK-Mediated Calcium Signaling
No full textMucin Dynamics in the Respiratory Tract of Poly-Infected Dairy Calves: Histological Insights
No full textInternational audienceBovine Respiratory Diseases (BRD) are the leading cause of respiratory illness in young dairy calves, posing serious health, welfare, economic, and antimicrobial resistance challenges. Preventive strategies, such as probiotics, are urgently needed. Respiratory mucus, rich in mucins, forms a key barrier at the host–pathogen interface. While mucin profiles are well documented in humans, their distribution, infection, and antibiotic-induced changes in cattle remain poorly understood. Therefore, we histologically characterized the type and spatial distribution of mucins within the respiratory system of 28 dairy calves coinfected with respiratory pathogens (Bovine Coronavirus, Influenza D virus, and Mycoplasma bovis) with or without tilmicosin treatment. Pathogen coinfection was induced 60 hours after treatment administration. Calves were sampled at eight different time points, up to 19 days post-infection. During necropsy, various respiratory regions were collected, including the cranial, middle, and caudal lobes of the lung. Tissues were stained with haematoxylin and eosin (H&E) and Alcian Blue–Periodic Acid-Schiff (AB-PAS), manually examined and analysed with a supervised QuPath pixel classifier to compare the percentage of PAS- and AB-positive surface area among tissues, representing respectively neutral and acidic mucins. MUC2 immunohistochemistry was additionally measured in a selection of tissues and lesions. In all tissues sampled from the right cranial lobe, BA-positive acidic mucins were predominantly observed in bronchi, while PAS-positive neutral mucins were mostly detected in bronchioles and to a lesser extent in bronchi and alveoli. Coinfection led to the development of bronchiolo-interstitial pneumonia and/or suppurative bronchopneumonia. These pathological lesions coincided with an increase in bronchiolar PAS-positive neutral mucins and bronchial acidic BA-mucins. In contrast, antibiotic treatment alone was associated with a reduction in PAS-positive neutral mucins within the bronchiolar epithelium. To further characterize mucin expression, immunohistochemistry validation targeting MUC2 antigen confirmed its specific localization within lesions of bronchiolitis obliterans. Moreover, in the alveolar regions, the non-infected groups exhibited stronger PAS staining compared with the infected groups, potentially reflecting an adaptation in neutral mucin production associated with the poly-infection. Together, these findings underscore a region-specific distribution of mucin types in the bovine respiratory tract and reveal that both antimicrobial treatment and pathogen challenge significantly reshape mucin profiles concurrently with the development of pneumonia. This highlights respiratory mucus as a dynamic and responsive barrier at the host-pathogen interface. This work was co-funded by the European Union’s Horizon Europe Project 101136346 EUPAH