Biomethane technology for grid injection

This is a poster that describes the state-of-the art and perspectives for biomethane as technology for grid injectio

Chapter 26. High throughput field phenotyping (HTFP) of wheat and weed cover in field experiments using RGB images: assessment of crop-weed competition with a simple ecophysiological model

International audienceThe early stages of growth for two winter wheat cultivars, Apache and Rubisko, were studied in field experiments based on destructive measurements and visible images. They cover the period from the three-leaf stage to tillering at four sampling dates. Maps of fractional vegetation cover (FVC) were established for both the crops and weeds. FVC was automatically determined from the images with an SVM-RBF classifier, using Bag of Visual Words vectors as inputs. The heterogeneity in populations and crop-weed competition were studied using descriptive and inferential statistics. The impact of weeds on crops was evaluated by comparing the results with simulations under unstressed conditions

Proxi-detection to monitor the growth status of wheat in the presence of weeds using low-cost and simple digital tools to track the emergence of stress

International audienceThis study combines proximal sensing technology based on a mobile visible imaging device and a dynamic ecophysiological model to estimate the growth status of two winter wheat crops (Apache and Rubisko cultivars) in the presence of uncontrolled broadleaf weeds. Working at early growth stages and on four different dates, each plot was photographed and then destructive biomass samples were collected. After calibration, crop aboveground biomass is inferred from an image indicator, the fractional vegetation cover (FVC). A supervised image classification algorithm was used to calculate FVC for crop (FVCc) and for weeds (FVCw). Analysis of FVC measurements focused on stand heterogeneity by comparing their variability and the impact of weeds on crop growth. Over time, the discrepancy between plant biomass derived from the image and data simulated from a simple ecophysiological model increased for most areas of the plot, indicating the presence of crop stress. At the same time, the weed pressure (WP) study concluded that weeds did not have a major influence on crop growth, although locally some areas showed a negative impact on crop growth. Therefore, weeds were not the major stress observed on the later dates of the study. These low-cost technologies aim to determine stress in wheat crop and support farmers in their transition to agroecology for highly accurate plot monitoring

GWAS of digestive efficiency in chicken

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Phenotypic timeline of gastrointestinal tract development in broilers divergently selected for digestive efficiency

International audienceSustainability of poultry farming relies on the development of more efficient and autonomous production systems in terms of feed supply. This implies a better integration of adaptive traits in breeding programs, including digestive efficiency, to favor the use of a wider variety of feedstuffs. The objective of the study was to better characterize the kinetics of development of the digestive tract in broilers, in relationship with digestive efficiency by measuring various digestive parameters as well as serum color. Absolute and relative growth of gastrointestinal tract organs were compared between 2 divergent chicken lines selected on digestive efficiency (AMEn) during 7 wk of development. We show that as early as 7 d of age, these 2 lines differs for several organs developments and that these differences remain visible later on. In addition, the allometry of the gizzard and intestine segments is different between the 2 lines, with efficient birds putting more effort in the upper part of the digestive tract during postnatal development and lessefficient birds putting more effort in the lower part of the gastrointestinal tract. Interestingly, we also showed that differences in serum pigmentation, which is a good biomarker for digestive capacity, could be a convenient diagnostic tool to discriminate between chickens with high or low digestive efficiency at early stages of development. In conclusion, this study showed that selection of chickens for AMEn had large impacts in gastrointestinal development including at early stages and is a valuable resource for further studies on the genetic and physiological control of the response of the animal to feed variations

Towards a Standardized Procedure for the Production of Infective Spores to Study the Pathogenesis of Dermatophytosis

Dermatophytoses are superficial infections of human and animal keratinized tissues caused by filamentous fungi named dermatophytes. Because of a high and increasing incidence, as well as the emergence of antifungal resistance, a better understanding of mechanisms involved in adhesion and invasion by dermatophytes is required for the further development of new therapeutic strategies. In the last years, several in vitro and in vivo models have emerged to study dermatophytosis pathogenesis. However, the procedures used for the growth of fungi are quite different, leading to a highly variable composition of inoculum for these models (microconidia, arthroconidia, hyphae), thus rendering difficult the global interpretation of observations. We hereby optimized growth conditions, including medium, temperature, atmosphere, and duration of culture, to improve the sporulation and viability and to favour the production of arthroconidia of several dermatophyte species, including Trichophyton rubrum and Trichophyton benhamiae. The resulting suspensions were then used as inoculum to infect reconstructed human epidermis in order to validate their ability to adhere to and to invade host tissues. By this way, this paper provides recommendations for dermatophytes culture and paves the way towards a standardized procedure for the production of infective spores usable in in vitro and in vivo experimental models

Relationship between intestinal and blood metabolome and fecal digestive efficiency in chicken

Digestive efficiency (DE) is an essential component of feed efficiency, especially in the context of increasing variety of feedstuffs with variable quality used in poultry diets. However, measuring fecal DE during balance trials is time-consuming nd constraining as birds are placed in individual cages. Moreover, all the mechanisms controlling DE are still not known. The aim of our study was thus to identify biomarkers of DE using intestinal and blood metabolomics. Our study used 60 chickens of an advanced intercross line (8th generation) between two broiler lines divergentl yselected for their fecal DE, based on metabolisable energy corrected to zero nitrogen retention (AMEn). At 3 weeks, fecal AMEn and coefficients of digestive use of lipids, nitrogen and starch were measured during a balance trial, ileal and caecal contents were sampled and blood collected. Metabolome was determined by proton high resolution NMR. Correlation models (canonical partial least squares) were fitted to assess the links between efficiency and metabolites of the 3 compartments. Metabolites differences between animals with high or low levels of DE were mainly involved in amino-acids metabolism (lysine, isoleucine, methionine) and energetic metabolism (glutamate, glucose) in the 3 compartments. High positive correlations were especially found between glucose in caecal content and AMEn and coefficient of DE of nitrogen (Figure 1), which is consistent with the large divergence found in the divergent lines on these criteria. This result suggests an effect of microbial fermentation on DE. These metabolic profiles give us information on mechanisms implied in feed digestion in chickens. Further analyses will estimate if blood metabolome could be used as an indirect criterion of selection of feed and DE. This study has been supported by the EU H2020 Feeda--Gene project and by the INRA program GISA-GALMIDE

Impact de la perception du risque sur les conduites de dépistage de femmes jeunes asymptomatiques non porteuses d’une mutation familiale liée aux gènes BRCA1/2.

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Phenotypic correlations between feed efficiency, growth, and meat quality of slow-growing chickens

International audienceKorat (KR) chicken is a new meat-type chicken breed established with the purpose of developing Small and Micro Community Enterprise Production. This slow-growing chicken has been recognised for its good texture and flavour, but its low feed efficiency is associated with high cost of production which can hamper the development of local production. This has highlighted the importance of studying the trade-off between feed efficiency and meat quality in KR chicken. This study investigated the phenotypic correlations between feed efficiency, growth performance, and meat quality in KR chicken. Individual body weight and feed intake were recorded weekly for 75 male KR chickens for the calculation of feed conversion ratio (FCR) and residual feed intake (RFI). The growth curve was modelled by Gompertz function and meat quality evaluated at 10 weeks of age, through the measurement of pH (pHu), water-holding capacity (WHC) and drip loss (DL) in breast and thigh muscle.Faster growth rate at young age appeared favourable, regarding feed efficiency, since a moderate negative correlation was found between FCR and initial growth rate. Chickens with a higher initial growth and maturation rates were characterised by lower water-holding capacity in meat. This was not associated with acidic meat, since a higher speed of growth (especially in the first weeks) was positively associated with final pH in breast meat. Relationships between RFI and meat quality traits appeared to be weak. While better FCR could be achieved by increased initial growth rate, this seemed to negatively impact water-holding capacity of the meat.RFI appeared as an interesting alternative as a compromise between FCR and meat quality

Broilers divergently selected for digestibility differ for their digestive microbial ecosystems

Improving the digestive efficiency of broiler chickens (Gallus gallus) could reduce organic waste, increase the use of alternative feed not used for human consumption and reduce the impact of feed in production costs. By selecting chicken lines divergently for their digestive efficiency, we showed previously that digestive efficiency is under genetic control and that the two resulting divergent lines, D+ (high digestive efficiency or "digestibility +") and D- (low digestive efficiency or "digestibility -"), also differ for the abundance of specific bacteria in their caeca. Here we perform a more extensive census of the bacteria present in the digestive microbiota of 60 chickens selected for their low apparent metabolizable energy corrected for nitrogen balance (AMEn-) or high (AMEn+) digestive efficiency in a [D+ x D-] F8 progeny of 200 individuals. We sequenced the 16S rRNA genes of the ileal, jejunal and caecal microbiotas, and compared the compositions and predicted functions of microbiotas from the different intestinal segments for 20 AMEn+ and 19 AMEn- birds. The intestinal segment of origin was the main factor structuring the samples. The caecal microbiota was the most impacted by the differences in digestive efficiency, with 41 bacterial species with abundances differing between highly and poorly efficient birds. Furthermore, we predicted that the caecal microbiota of efficient birds might be enriched in genes contributing to the degradation of short chain fatty acids (SCFA) from non-starch polysaccharides. These results confirm the impact of the genetic selection led on digestibility on the caecal microbiota taxonomic composition. They open the way toward the identification of specific, causal genes of the host controlling variations in the abundances of bacterial taxons