Portail des publications scientifiques de VetAgro Sup
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Bénéfices / risques du lactulose lors d'encéphalopathie hépatique canine
No full textNational audienceBien que le lactulose soit indiqué comme un laxatif osmotique, sa capacité à neutraliser l'ammoniac et sa faible toxicité en font un principe actif intéressant dans la prise en charge globale de l'encéphalopathie hépatique chez le chien
Welfare impacts during and after reproductive procedures for in vivo embryo production and transfer in Holstein dairy heifers
No full textInternational audienceEmbryo technologies are routinely used in cattle, but the links between embryo technologies and cattle welfare have been poorly investigated. The aim of this study was to describe the behavioural, physiological and clinical responses of Holstein dairy heifers during and after five reproductive procedures: dominant follicle removal (DFR) by transvaginal follicular puncture, superovulation, double artificial insemination (AI1 and AI2), embryo flushing (EF), and embryo transfer (ET). This longitudinal cross-over design used twelve nulliparous pubescent and cycled Holstein heifers, each acting as their own control. Behavioural recordings (video and continuous monitoring sensors), physiological and clinical examinations, and blood sampling were performed at regular intervals on each reproductive procedure from the start of contention up to 24 h after the end of the procedure. The heifers changed their behavioural and physiological responses during and after each of the five reproductive procedures. During the procedures, they displayed more abnormal postures of the body (e.g. arched back during all procedures; P < 0.05), hindlimbs (e.g. base-wide stance during all procedures except EF; P < 0.05), and head (e.g. lowered head during AI2, EF and ET; P < 0.05). They also displayed more signs of agitation, moving their body more (e.g. stepping aside during DFR, AI1 and ET; P < 0.05), their feet more (e.g. hoof lifting during DFR, EF and ET; P < 0.05) and their head more (e.g. neck stretching forward during AI2, EF, and ET; P < 0.05). They also showed increases in both plasma cortisol concentration (during AI2 and EF; P < 0.05) and heart rate (during DFR and AI2; P < 0.05). However, we did not observe any inflammatory response in plasma pro-inflammatory cytokines and haptoglobin or in macroscopic appearance of the vulvae 2 h after the procedures. During the 24 h after the procedures, the heifers spent less time ingesting and standing up after DFR (P < 0.05), less time ruminating after EF (P < 0.05), more time with activity after superovulation and more time without activity after EF (P < 0.05). Each reproductive procedure has specific responses in the heifers. Taken together, our findings suggest that heifer welfare was impacted both during and after the procedures involved in embryo production and in vivo transfer protocol. Acknowledging that some discomfort/pain may be present, it may be welfare-friendly to develop and apply refinement strategies during and after embryo technology procedures
Combining diversified prairies with wheat to promote beneficial plant-soil ecological interactions and the coupling of carbon and nitrogen biogeochemical cycles in agroecosystems
No full textInternational audienceMobilizing plant functional diversity appears as a promising avenue to promote agroecosystems multifunctionality and stability in order to face agriculture challenges in terms of production, limitation of inputs, conservation of soils, and mitigation of greenhouse gases emissions. In natural or semi-natural ecosystems, a high level of plant functional diversity might trigger beneficial plant-soil ecological interactions, leading to several mechanisms of coordination over time between plant nutrient demand and soil offer (i.e., “synchrony”). As perennial prairies can reach a considerable degree of functional diversity within a small area, their implementation with crops can be a precious lever to promote such mechanisms. Among those, a seasonal scale coordination between plants nutrient demand and the relative balance between microbial construction and microbial decomposition of Soil Organic Matter (SOM) was associated with prairies encompassing fast-growing species. This leads to improved plant primary productivity combined with reduced nutrient losses, and increased microbial originated carbon (C) storage in the soil. Moreover, the modulation of nitrogen (N) symbiotic fixation depending on photosynthesis activity by legumes within the prairies allows N enrichment of the agroecosystem. We conceived an experimental design with new agroecosystems called “agroprairies” which gather perennial diversified prairies and winter wheat (Triticum aestivum) cultivated in alternating bands. Four functionally different prairies were designed to vary across nutrient acquisition strategies and proportion of legumes. The experiment also included plots with each cover grown alone, as well as a perennial crop (Thinopyrum intermedium). We explored the effects of plant functional diversity on soil biogeochemical C and N cycles and soil microbial communities and activities. We conducted measurements of plant production, soil microbial C dynamics (microbial C use efficiency, soil microbial respiration, microbial biomass, microbial growth), five hydrolytic or oxidative exoenzyme activities related to C, N and phosphorus (P) cycles and abundances of the soil microbial communities (bacteria, archaea and fungi). These measurements were performed in January 2024 during winter at a time where plant nutrient demand is low, and in May 2024 at the maximum plant biomass production. We found that soil biogeochemical C and N cycles and abundances and activities of microbial communities strongly varied between January and May, and that some of these variables, as well as the production of wheat differed depending on the functional characteristics of the prairies
Seroprevalence of West Nile, Usutu and tick-borne encephalitis viruses in equids from south-western France in 2023
No full textInternational audienceThe circulation of West Nile virus (WNV), Usutu virus (USUV), and tick-borne encephalitis virus (TBEV) was investigated in south-western France during the first six months of 2023, following the emergence of WNV in equids in Gironde, a département in south-western France, in 2022. Blood samples were collected from 494 horses located in the Gironde département and divided into three zones: the Confluence zone, the Intermediate zone and the Arcachon Basin. Samples were tested for WNV-, USUV- and TBEV-specific antibodies. An overall seroprevalence of 14% (95% CI [11–18%]) for orthoflavivirus antibodies was detected in Gironde. The highest seroprevalence rates for WNV and USUV were observed in the Confluence Zone (9%, 95% CI [6–13%] and 5%, 95% CI [3–8%], respectively), where the type of housing (animals kept in pasture only) and proximity to a special bird protection area were identified as risk factors for WNV seropositivity. This study presents the first seroprevalence investigation of WNV, USUV and TBEV infections in equids located on the Atlantic coast of France and demonstrates intense circulation of WNV in this region, as well as evidence of equine USUV-specific infection
La sortie des ruminants au pâturage ou en transhumance favorise-t-elle la diffusion et/ou la transmission de la fièvre Q ?
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Impacts of Plant Protection Products on Biodiversity: Limits of Risk Assessment and Avenues to Ground Liability
No full textInternational audiencePlant protection products (PPPs) are intended to protect plants against pests. However, they are also known to contribute unequivocally to the decline of biodiversity due to their negative impact on biological groups such as terrestrial invertebrates, birds, and amphibians. At the intersection of ecotoxicology, social sciences, and law, numerous studies address the discrepancy between the regulatory framework's objectives to protect biodiversity and the actually observed impacts of legally used PPPs. The main reasons put forward are the normalization constraints of ecotoxicity tests andthe inability to anticipate effects in the current substance‐by‐substance risk assessment process given the complexity of multifactorial interactions in the ecosystems and the real conditions of PPP use. Therefore, the greater the consideration given to the systemic complexity of indirect effects, the less possible it is to quantify the contribution of a given cause, in our case, a PPP. This is a core issue in legal disputes regarding the liability of those who develop PPPs, those who use them, as well as decision‐makers who approve them. This article explores legal possibilities to better address the missing link between substance‐by‐substance assessment and authorization processes, and biodiversity protection instruments. The aim is to question the division of roles between scientific expertise, legal disputes, and public policy
Advancing standardization of diagnostics and antimicrobial susceptibility testing for pathogenic mycoplasmas of livestock origin: insights from the MyMIC network
No full textInternational audienceAbstract Background Mycoplasma infections pose a significant economic burden and represent a serious health and welfare concern for the livestock sector. Their control often requires repeated antimicrobial treatments. Antimicrobial susceptibility testing (AST) procedures for veterinary mycoplasmas lack standardization. Furthermore, clinical breakpoints (CBPs) are not available to interpret AST data (i.e., Minimum Inhibitory Concentration, MIC values) and categorize isolates as susceptible, resistant, or intermediate to the different antimicrobials used in livestock, nor epidemiological cut-offs (ECOFFs), which are a prerequisite to define CBPs. In 2023, the MyMIC network - a consortium of 22 laboratories specializing in veterinary mycoplasmas- was established to support efforts in standardizing diagnostics and AST, including clinical interpretation. Its initial goals were to (i) review routine diagnostic practices in frontline laboratories and examine veterinarians’ prescribing habits and (ii) assess practices for culture, identification and AST used in expert laboratories and how these practices may affect MIC results as collected for five major livestock pathogens (M. bovis , M. gallisepticum , M. synoviae , M. hyopneumoniae and M. hyorhinis ). Results A first survey targeting veterinarians from the avian, porcine, and ruminant livestock sectors provided 468 complete responses from 39 countries worldwide, giving an account of current trends in the treatment and first-line diagnosis of veterinary mycoplasmoses. Macrolides, tetracyclines, pleuromutilins, florfenicol and fluoroquinolones were the most frequently administered antimicrobials, with usage varying by livestock sector. Veterinarians reported requesting diagnostic in 40–75% of clinical cases, but only one-third requested AST regularly. A separate survey within the consortium highlighted significant variability in the media and methods used by specialized laboratories, particularly for MIC determination, which relied mostly on in-house broth dilution techniques. This methodological diversity limited our ability to aggregate collected MIC data for establishing ECOFFs. Conclusions Several concerns regarding best practices for antimicrobial treatments of mycoplasma infections may be linked to the lack of AST in frontline laboratories. Based on information collected in expert laboratories, we identified multiple sources contributing to inconsistent MIC results. The next step will be to establish consensus gold-standard AST methods tailored to specific mycoplasma-antimicrobial combinations to generate reliable MIC data for defining ECOFFs. Subsequently, the development of ready-to-use commercial MIC plates for use in frontline laboratory will support veterinarians in selecting appropriate treatments
Les particularités diagnostiques de l’anémie hémolytique à médiation immune du chat.
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Does nocturnal light pollution impair immune function in a wild‐living amphibian?
No full textInternational audienceLight pollution is among the most rapidly growing anthropogenic stressors on Earth. As it spreads far beyond its original source, it affects natural protected areas playing a key role in protecting biodiversity. While physiological impacts of light are extensively studied in laboratory animals and livestock, it is yet unknown what are the physiological effects of low levels of light at night on animals—such as those experienced by wildlife in natural areas exposed to light pollution.Experimental studies suggest that light pollution have deleterious effects on metabolism and immunity (among others) mainly caused by melatonin suppression. Within the One Health framework, alterations of wild animals' immunity and their capacity to combat infections due to light pollution could have far-reaching implications for species conservation, pathogen dynamics and potential for epidemic outbreaks.The aim of this study was to assess, for the first time, whether the effects of light pollution on immunity previously reported in experimental studies, are also observable in a wild species. To do so, we measured a large set of body condition and immune traits, to obtain a comprehensive picture of individuals' health, in 15 natural populations of common toads (Bufo bufo) distributed along a gradient of exposure to light pollution.Although our results reveal a strong negative association between light pollution values of our sites and toads' body mass, associations with immune traits did not fully match our predictions. Toads from the most illuminated sites presented lower levels of inflammatory marker haptoglobin, a decreased albumin to globulin ratio and tended to have more eosinophils than those from the darkest sites. However, these latter associations with immune traits were not specific to light pollution only, but also related to the global urbanisation of the sites.Our study emphasises the need for more studies on the effect of light pollution on physiology in natural conditions of exposure, and its interactions with other anthropogenic perturbations, to be able to truly understand its effects on wildlife. This is critical to identify health risks for wildlife and for prioritizing conservation efforts of menaced taxa
Spatial and temporal risk assessment of Epizootic Hemorrhagic Disease Virus introduction in Europe: A comparative analysis of trade and wind dispersal pathways
No full textInternational audienceEpizootic Hemorrhagic Disease Virus (EHDV), transmitted by Culicoides biting midges, is a threat for the livestock sector in Europe. A quantitative risk assessment model framework was developed to assess the risk of EHDV introduction in Europe, through wind dispersal of Culicoides and trade in live animals. The model integrates meteorological data, wind trajectories, vector biology, livestock trade information and considers disease dynamic in infected sources as well as disease susceptibility in potential destinations. The full risk zone combining both pathways encompassed 42 different countries with 30 in Europe and 12 outside, each with highly-variable levels of risk. The highest risk countries included three sources: France, Spain, Italy, and one disease-free, Germany. The period of highest risk corresponded to the favourable period of Culicoides activity, between May and October. Risk estimates were markedly higher for the wind pathway, spanning 20 countries mainly in Western Europe, compared to the trade pathway that covered 40 countries, including distant Eastern ones, like Romania. The Pathway Risk Ratio (PRR) showed a higher wind pathway contribution in most countries where both pathways were present. France was the primary source country, regardless of the pathway. Alternative scenarios suggested that limiting the source area to 2024 infected areas or considering long trade history could reduce the list of at-risk countries. However, underreporting or reducing PCR testing at borders could increase risk estimates. This research aims to guide disease risk management measures by providing insights into the risk of Culicoides-borne disease extensio