Portail HAL ONIRIS VetAgroBio Nantes
Not a member yet
11563 research outputs found
Sort by
Exploring the molecular cargos associated with extracellular vesicles extracted from bone tissue to identify novel players in osteoblast function
No full textInternational audienceExtracellular vesicles (EVs), composed of proteins, lipids, and nucleic acids, are key mediators of intercellular communication across various tissues. However, research on EVs isolated directly from bone tissue remains limited. Here, we identified for the first time and characterized two EV subpopulations extracted from bone tissue and enhanced our understanding of their roles in bone physiology. These two EV subpopulations were reproducibly isolated: a large EV population (lEV; 237.7 ± 8.8 nm) and a small EV population (sEV; 109.2 ± 8.3 nm), both exhibiting the expected shape and presence of EV and bone cell markers. Comparative analysis of their cargos revealed unique or enriched proteins and miRNA profiles for each, suggesting shared functional characteristics with bone cells, including osteocytes, osteoblasts, and osteoclasts. Notably, lEVs contained proteins such as FHL2 and pleiotrophin, along with miRNAs including miR-15b-5p, miR-29a-3p, and miR-128-3p, all of which are involved in early osteogenic signaling pathways such as Hippo, TGF-β, and Wnt. Furthermore, sEVs contained ALP, PAPSS2, and miR-125b, both known regulators of matrix mineralization. Both EV subpopulations were internalized by stromal ST2 and preosteoblastic MC3T3-E1 cells. We present evidence that lEVs significantly enhanced ALP activity in ST2 cells, indicating early osteogenic stimulation, whereas sEVs partially promoted matrix mineralization in primary osteoblasts. Our findings provide novel insights into the role of bone-derived EVs as possible complementary mediators of osteogenesis in vivo and highlight the potential of their cargos in advancing bone regeneration strategies.NEW & NOTEWORTHY This study identifies for the first time two extracellular vesicle (EV) subpopulations isolated from young male mice bone tissue, with distinct mean size and molecular signature. Analysis of the protein and miRNA cargos of these EVs indicates that the large and small EVs are involved in different stages of osteogenesis, from commitment to the formation of mineralized tissue. These findings provide new insights into the role of bone-derived EVs in bone physiology
Algae extract supplementation boosts humoral immunity induced by attenuated PRRSV-1 vaccination
No full textInternational audienceBackground: Porcine reproductive and respiratory syndrome (PRRS) remains a major concern for the swine industry worldwide due to its significant economic impact and its association with respiratory co-infections. Vaccination is a key strategy for PRRS control; however, the most effective commercial anti-PRRSV vaccines to date—live attenuated vaccines, also named modified live virus (MLV) vaccines—provide only partial protection. This study investigates whether oral supplementation with formulated Ulva-derived seaweed extracts can enhance immune responses to PRRSV-1 MLV vaccination. Methods: Two supplementation protocols using commercial seaweed extracts formulated with vitamin A and D (Searup®) were tested: one starting one day post-vaccination for five consecutive days (post-vaccination), and another beginning one day before vaccination and continuing for two days post-vaccination (pre-vaccination). In this exploratory farm-based experimental setting, pigs were divided into six groups: three vaccinated groups (supplemented with seaweed either pre- or post-vaccination or not supplemented), and three non-vaccinated control groups receiving the same supplementation regimes. Serum cytokine levels, PRRSV viral loads, and anti-PRRSV antibody responses were measured to assess immune modulation. Results: Post-vaccination supplementation had no significant effect on vaccine viral load or humoral response, though a modest reduction in viral persistence was noted at 12 days post-vaccination (dpv). In contrast, pre-vaccination supplementation significantly increased vaccine virus levels at 4 dpv (p = 0.048) and enhanced anti-PRRSV IgG levels (p = 0.029). This protocol also induced an early and sustained decrease in pro-inflammatory cytokines, suggesting an immunomodulatory effect of algal extract supplemented with Vitamins A and D. We present here for the first time, in field conditions and in the target species, significant immune modifications upon realistic oral supplementation with Searup®. These findings are consistent with previous studies demonstrating the potential of pre-vaccination seaweed supplementation as a cost-effective, practical strategy to enhance humoral responses to PRRSV vaccination. Further studies are needed to evaluate its impact on neutralizing antibody production, cellular responses and protection against heterologous field PRRSV strains. © The Author(s) 2025
Citizen preferences for risk communication associated with emerging food risks linked to climate change
No full textInternational audienceClimate change is significantly disrupting weather patterns, resulting in negative impacts on the resilience of agrifood systems. One consequence is an increase in emerging food safety risks driven by climate change to humans, animals, and plants resulting from newly identified hazards, which requires policy action to both mitigate, and adapt to, emerging food risks. Although there is evidence that risk perception associated with novel threats may result in heightened citizen concerns, it is not known whether people's concerns about emerging food safety hazards necessitate specific risk communication strategies. A semi-structured interview protocol was developed to understand citizen priorities for risk communication in relation to emerging food safety risks, and to understand if these differed from their preferences and priorities for communication about established risks. Twenty participants from each of the UK, France, Germany, and Hungary were recruited into the study. The results indicated that, although study participants did not distinguish emerging food safety risks specifically from existing food safety risks, they categorised systemic risks (which were potentially associated with climate change drivers) as distinct from acute risks (which had immediately impacted public health and were not categorised as systemic risks, despite the possibility of being caused by climate change). It is concluded that dedicated emerging food safety risk communication is needed to only engage citizens in developing protective behaviours in relation to emerging food safety risks. In addition, it is also relevant to both adaptive and mitigatory actions to reduce the impacts of emerging food safety risks associated with climate change
Microbial risk and health burden associated with the domestic preparation of lentils in France and Hungary
No full textInternational audienceLentils are promoted as an alternative protein source due to their agricultural and nutritional benefits. However, information on the microbial risks associated with lentil consumption in domestic settings is limited. The countries of France and Hungary were selected to represent the lentil consumption in two different supply chains. Bacillus cereus was identified as a pathogen of concern in both hot and cold dishes, whereas Listeria monocytogenes was only identified in cold dishes. A probabilistic model accounting for uncertainty and variability was constructed, estimating the microbial concentration at subsequent stages of domestic handling: cooking, cooling, and 24-96 h of chilled storage. The number of foodborne illness cases and daily adjusted life years (DALY) were estimated at the point of consumption. The results were analysed at each stage; for example, at 96 h, B. cereus showed mean values of 2.52 [1.75; 4.12] log CFU/g in France and 2.03 [1.24; 3.56] log CFU/g in Hungary. For Listeria monocytogenes, the mean estimates were lower at 0.48 [-0.20; 1.16] log CFU/g in France and 0.69 [0.07; 1.36] log CFU/g in Hungary. The overall number of foodborne illness cases from both pathogens was computed based on the consumption frequency. They were estimated to be 0 [0-44] cases per 100,000 in France and 0 [0-5.8] in Hungary. The uncertainty intervals are relatively large, reflecting uncertainty in the estimates, meaning that the risk is not an absolute zero. Moreover, it is likely that dietary shifts towards less meat consumption, as promoted by various institutions, will occur. Extended batch cooking practices can pose an additional risk of foodborne illnesses in the future
Motivations et perspectives professionnelles et personnelles des étudiants vétérinaires souhaitant devenir praticien
No full textAvec l'arrivée sur le marché du travail de jeunes vétérinaires issus de la génération Z (nés entre le milieu des années 1990 et le début des années 2010), les considérations professionnelles évoluent et entraînent des modifications dans la façon de percevoir le travail. Cette thèse a permis dde sonder 1217 étudiants de cette génération Z, actuellement en études ou récemment diplômés, afin de comprendre leurs motivations et perspectives professionnelles mais aussi personnelles. A travers un questionnaire, des sujets liés à la motivation, à la rémunération mais aussi au statut professionnel ont été abordés, puis ont été ensuite approfondis en fonction de certains critères comme le pays de formation, le sexe ou encore le millieu d'origine. De plus, cette thèse permet de comparer certaines attentes avec celles de la génération Y, et de comprendre l'évolution des visions du métier par les futurs praticiens
Le traitement sélectif au tarissement de la vache laitière appliqué au niveau du quartier : enquête sur sa pratique et sa perception
No full textLe TSTQ consiste à ne traiter que certains quartiers au tarissement. Il s'agit d'une alternative au traitement systématique au tarissement permettant de réduire la consommaton d'un élevage. Son étude est encore peu poussée dans la luttérature, nous avons donc conduit des enquêtes qualitatives dans 12 élevages afin de caractériser la façon dont il est conduit sur le terrain ainsi que les perspectives qui l'entourent. Le TSTQ est aisément mis en place dans les exploitations avec robot, et peut également fonctionner an salle de traite avec des adaptations. Il permet de limiter l'utilisation des antibiotiques tout en conservant un bon nieau cellulaire dans ces exploitations. La principale limite à sa diffusion est sa méconnaissance sur le terrain ainsi que le manque de donnes scientifiques caractérisant son efficacité
Inactivation of mesophilic and thermophilic bacterial spores in UHT-treated ambient stable plant-based milk alternatives
No full textInternational audienc
Investigation of marennine quality throughout the main culture phases of Haslea ostrearia in a membrane photobioreactor
No full textInternational audienceMarennine is a blue pigment excreted by the diatom Haslea ostrearia. This pigment is renowned for its antioxidant and antibacterial properties, which have raised research interest. The standard method for obtaining marennine is by harvesting the supernatant from cultures of H. ostrearia and applying a double ultrafiltration approach. Marennine concentration is then assessed by another standard method (UV-visible spectrophotometry). The resulting “blue water” may however contain marennine along with a variety of other molecules, not detectable by spectrophotometry. As changes in supernatant composition are likely to occur depending on culture conditions and modes of operation, it is wondered whether this affects the marennine extract’s quality. This work aims to assess such fluctuations across the exponential, stationary, and senescent phases of a H. ostrearia culture in a membrane photobioreactor (MPBR). Antioxidant and antibacterial bioassays, in conjunction with spectral analyses of marennine extracts, were used to characterize them. Results showed that marennine production peaked during exponential growth phase of the culture and that the resulting extract exhibited the highest antibacterial activity. Antioxidant activity was however unaffected throughout the different growth phases, being solely a function of the marennine concentration as assessed by the standard measurement approach
Comparative impact of acidified glycerol pretreatment on the thermal degradation kinetics of crude wheat straw for potential sustainable valorization
No full textInternational audienceThe relative impact of acidified glycerol pretreatment on thermal disintegration kinetics and thermodynamic parameters of crude wheat straw (WS) was studied using thermogravimetric analysis coupled with Horowitz-Metzger kinetic method under numerous reaction models. The WS fiber was dissolved in acidified glycerol solution under gentle pretreatment conditions of 90 °C for 30 min and was also pretreated by conventional methods including dilute alkaline, acid and hot water to foster a better insight and compare the capability of acidified glycerol for pretreatment of WS fiber. The apparent activation energy values of 27.8–31.8 kJ/mol and 32.3–38.2 kJ/mol were obtained for untreated and glycerol treated WS fibers, whereas the highest values, ranging from 36.2 to 42 kJ/mol, were obtained for alkali treated fiber. The change in enthalpy (ΔH°) for untreated WS fiber was within the range of 50.9 to 59.3 kJ/mol. This was enhanced to 59.8–71.6 kJ/mol, 63.6–74.0 kJ/mol and 63.1–74.9 kJ/mol for acidified glycerol, acid and alkali treated WS fibers. Pretreatment with acidified glycerol and alkali reagents increased the ΔG° values of WS fiber to 181.2 kJ/mol and 178.6 kJ/mol, in contrast to the value of 167.7 kJ/mol for untreated sample