Portail Hal-l'Institut Agro Rennes-Angers
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Impact of the microstructure of two beef co-products on postprandial plasma amino acid kinetics
No full textInternational audienceThe increasing demand for proteins is driving the search for alternative food sources. From this point of view, the valorization of co-products, such as meat co-products that are little valorized in human nutrition, is a promising way, in line with the principle of the circular economy. The present study focused on two protein ingredients of bovine origin, co-products of the fat rendering process, Greasy Greaves Recovered Proteins (GGRP) and Water Recovered Proteins (WRP), previously shown to display valuable but different functional properties. The aim of the present study was to evaluate the nutritional quality of these proteins and the relationship between the structure of these two meals and the postprandial plasma amino acid (AA) kinetics. The structure adopted by these two meals during the gastric digestion was investigated using an in vitro semi-dynamic model (INFOGEST). Gastric digesta were collected at 0, 40, 80 and 120 min; their microstructure was analyzed by confocal microscopy, particle size distribution by laser diffraction, and their viscosity was measured by oscillation test. The nutritional quality and postprandial AA kinetics were determined in vivo on ten growing pigs, cannulated at the ileal level and catheterized in the jugular vein, and receiving over a 2.5-day period one of the two experimental meals according to a cross-over design. Ileal digesta and blood samples were collected during the 9 postprandial hours and AA contents were analyzed by ion-exchange chromatography. Data were statistically analyzed using linear models. WRP and GGRP presented a similar and moderate true ileal protein digestibility (81-84%, p>0.05), however due to their different amino acid profile, the DIAAS was much lower for WRP than GGRP with a value of 18 vs. 74% with Trp being the first limiting AA for both protein sources. The plasma AA concentration reached its maximal value between 3 h and 5 h postprandial for WRP and GGRP, thus qualifying both protein ingredients as slowly digested sources. GGRP tended to have a slower appearance rate of plasma AA. This could be explained by the higher viscosity of this meal (25 to 35 times higher) than that of WRP meal (p < 0.05). Nevertheless, the viscosity of both meals sharply decreased during digestion by an equivalent factor (around 34), from 1.3 to 0.04 Pa.s at 10 s-1 for WRP, and from 35 to 1 Pa.s for GGRP. In addition, the GGRP digesta contained a higher proportion of very large particles than the WRP ones. The higher viscosity and larger particle size for GGRP digesta than for WRP ones could explain the trend for the slower rates of digestion and absorption of GGRP. Overall, the GGRP bovine co-product appears as an interesting dietary protein source for human, while WRP presents mainly valuable functional properties but low nutritional ones
Nitrogen Nutrition Modulates the Response to Alternaria brassicicola Infection via Metabolic Modifications in Arabidopsis Seedlings
No full textInternational audienceLittle is known about the effect of nitrogen nutrition on seedling susceptibility to seed-borne pathogens. We have previously shown that seedlings grown under high nitrate (5 mM) conditions are less susceptible than those grown under low nitrate (0.1 mM) and ammonium (5 mM) in the Arabidopsis-Alternaria brassicicola pathosystem. However, it is not known how seedling metabolism is modulated by nitrogen nutrition, nor what is its response to pathogen infection. Here, we addressed this question using the same pathosystem and nutritive conditions, examining germination kinetics, seedling development, but also shoot ion contents, metabolome, and selected gene expression. Nitrogen nutrition clearly altered the seedling metabolome. A similar metabolomic profile was observed in inoculated seedlings grown at high nitrate levels and in not inoculated-seedlings. High nitrate levels also led to specific gene expression patterns (e.g., polyamine metabolism), while other genes responded to inoculation regardless of nitrogen supply conditions. Furthermore, the metabolites best correlated with high disease symptoms were coumarate, tyrosine, hemicellulose sugars, and polyamines, and those associated with low symptoms were organic acids (tricarboxylic acid pathway, glycerate, shikimate), sugars derivatives and β-alanine. Overall, our results suggest that the beneficial effect of high nitrate nutrition on seedling susceptibility is likely due to nutritive and signaling mechanisms affecting developmental plant processes detrimental to the pathogen. In particular, it may be due to a constitutively high tryptophan metabolism, as well as down regulation of oxidative stress caused by polyamine catabolism
A frequency-domain model to predict surface soil moisture, root zone soil moisture and aquifer recharge
No full textInternational audienceThis study aims to develop and evaluate a new simple unsaturated zone model in frequency domain interconnecting different types of ground or satellite-based observations (effective rainfall, surface soil moisture, root zone soil moisture, groundwater recharge) of a single dynamic system. The proposed formulation based on 5 coherent transfer functions (Tfs) linking observations 2 by 2, with a limited number of parameters, is rooted in the Nash linear reservoir model. The curve shape of the TFs can be adjusted by key parameters such as flow complexity, response time and the share of surface runoff each of which carries distinct and well-defined physical interpretations. The model's efficacy was assessed using surface soil moisture, root zone soil moisture and and recharge data in a fractured crystalline-rock aquifer situated in Ploemeur, South Brittany, France. Each TF's was initially independently optimized, with parameters assigned through a detailed review of the literature and consideration of the physical characteristics of the site. The outcomes highlighted the methodology's potential, offering a comprehensive depiction of root-zone soil moisture and aquifer recharge dynamics. In the subsequent phase, the model parameterized via a joint optimization of TFs. we find out that the joint approach has the ability to elevate the accuracy and reliability of the model, ensuring its stable and robust behavior. The simplicity of the procedure, with a small number of easily interpretable parameters, makes it suitable for broader applications in different regions
Granulation behaviour of high lactose dairy superconcentrates
No full textInternational audienceGranulation of whey permeate (WP) and demineralised whey (DW) superconcentrates was evaluated by addition of powder using a high-shear mixer during which consumption of electrical current was monitored. Granulation of DW required 50% more energy than that of WP and the resulting DW granules were larger (~2×) indicating greater resistance to fragmentation. Furthermore, addition of whey protein isolate (WPI) into the back-mix powder resulted in more efficient granulation (reduced energy, finer granules etc.) of superconcentrated WP.This was linked to the higher water-holding capacity of WPI and a simple model based on protein content was proposed to predict occurrence of granulation. This study sheds light on granulation behaviour under these conditions. Interestingly, while high cohesiveness of superconcentrates, which is related to protein content, has been previously shown to negatively impact granulation, increasing the protein content of the granulating powder was shown here to have positive effects, which offers great potential for design of formulated products
CIPANHUB : un web service multi-agent interopérable dédié au suivi expérimental des couverts d'interculture
No full textNational audienceCover crops are an effective tool for reducing nitrogen leaching in agrosystems, and their bio-degradation after destruction provides nitrogen for the following crop, though in highly variable amounts depending on their biomass and the nitrogen they have absorbed. Remote sensing data from Sentinel-2 satellites show great potential for addressing this variability through the development of predictive models based on vegetation indices and parameterised using field measurements of variables of agronomic interest. Doing so requires implementing a short-term but large-scale experimental project on many fields, using a team of data collectors. The experimental protocol for this project is simple in theory, but requires collecting many measurements and metadata. Thus, a web portal was created to make it easier for the data collectors to learn the protocol, simplify the collection of data and metadata, and manage the progress of the project. We developed the portal, called CIPANHUB, using interoperable cartographic distribution protocols (WMS, WFS) and the Flask framework developed in Python, because it is light and easy to use. The data are stored in a PostgreSQL database with the PostGis extension for geography. The portal was developed to follow the path of the data, from the creation of the field to the entry of the results, without preventing users from completing a given step if they do not have all the necessary information. A specific application was created to ensure the reliability of location data using a smartphone. The performance and use of the CIPANHUB portal during the 2 campaigns has been very successful: the service continuity has been close to 100%, and the feedback from users has also been very positive. In conclusion, this open-source web application dedicated to collecting information on networks of fields could easily be adapted to other experimental contexts, particularly in the context of participative science.Les couverts d’interculture pièges à nitrates (CIPAN) constituent un levier très efficace pour la maîtrise des pertes par lixiviation de l’azote dans les agrosystèmes. Leur biodégradation après destruction contribue en outre à fournir de l’azote à la culture suivante, en quantités très variables selon la biomasse et l’azote absorbé par le couvert. Les données de télédétection des satellites Sentinel-2 présentent de fortes potentialités pour cette problématique. Elles permettent d’élaborer des modèles prédictifs fondés sur l’utilisation d’indices de végétation, et paramétrés à partir de mesures au sol des variables d’intérêt agronomiques. Cela implique la mise en oeuvre d’un volet expérimental déployé à grande échelle dans un laps de temps court sur un grand nombre de parcelles, mobilisant de fait une équipe d’une quinzaine de personnes chargées d’appliquer le protocole expérimental. Ce protocole est simple sur le principe, mais demande de réunir un nombre assez important de mesures et de métadonnées ; c’est pourquoi, il a donc été décidé de créer un portail web, pour i) faciliter l’appropriation du protocole par les préleveurs, ii) simplifier l’acquisition des données et des métadonnées, et iii) gérer l’avancement de la campagne. Le portail, baptisé CIPANHUB, a été développé en interne en utilisant des protocoles de diffusion cartographique interopérable (WMS, WFS), et le framework Flask développé en Python, car il est léger et simple d’utilisation. Les données sont stockées dans une base PostgreSQL avec l’extension PostGis pour la géographie. Le portail a été développé pour suivre le chemin de la donnée, de la création de la parcelle à la saisie du résultat d’analyse. Il n’est pas bloquant pour les utilisateurs s’ils ne possèdent pas toutes les informations nécessaires à une étape donnée. Une application dédiée a été créée pour fiabiliser les données de localisation par smartphone. Le bilan du fonctionnement et de l’utilisation du portail CIPANHUB lors des 2 campagnes est très satisfaisant : la continuité de service a été proche de 100 %, et le retour des utilisateurs a été très positif.En conclusion, cette application web open source dédiée à la saisie d’informations collectées sur des réseaux de parcelles pourrait être facilement adaptée à d’autres contextes expérimentaux, et en particulier dans le cadre des sciences participatives
How to meet strong sustainability in dairy farming: an exploratory approach using ecological accounting
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Cartographie de la teneur en CO du sol par combinaison des séries temporelles Sentinel-2 et Sentinel-1 et des spectres de laboratoire Vis-NIR - Application à un site d'étude en Bretagne (France)
No full textInternational audienceMapping Soil organic carbon (SOC) is essential for continuous monitoring of its spatial and temporal dynamics. In this study, we developed a method using time series of Sentinel-2 (S2) data combined with Sentinel-1 (S1) and vis-NIR laboratory spectra to map SOC content of agricultural soils. The study site, located in Brittany (northwest France), is an agricultural area of 1.5 km². Soil samples were collected from agricultural fields within this site, their SOC content measured and their spectra recorded under laboratory conditions. The SOC content ranged from 15.2 to 49.4 g.kg-1. Deep neural network algorithms were implemented after dividing the data set built up from the time series of S2 and S1 images into calibration (70%) and validation (30%) sets. Three random draws of the validation sets were performed to assess model robustness. Four approaches were tested: (1) models developed using S2 bands as a single input, (2) applying multiple factor analysis (MFA) to select 12 of 40 indices calculated from S2 data and adding them to the S2 bands, (3) adding soil moisture derived from the time series of S1 (SM1), and (4) gradually adding five indices calculated from laboratory spectra, in descending order of their correlation with SOC. Model performance was compared based on validation results, and semi-variograms for observed and predicted SOC were then used to analyze the maps generated. Results showed that only models using approach 4 were validated (RPIQ = 1.78±0.19 - 3.07±0.6). The addition of SM1 improved model robustness since predictive performance remained stable over the 3 random draws of the validation sets. In approach 4, laboratory indices showed significant correlations with SOC content. Thus, we were able to validate our models once we added the two indices with the highest correlation. Semivariograms of the predicted values showed lower sill-to-nugget ratios but similar shapes to the observed values. Finally, the developed method allowed us to map 70% of the area of the study site
Définitions : acteurs (avec L Lelli), culture (avec N Guillaumont), gouvernance (avec P Dérioz)
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Principles and evolution of constructed soils in urban horticulture
No full textInternational audienceCities are attempting to develop greening and renaturation strategies whose success depends on the quality and functions of the soils supporting the vegetation. However, urban soils are characterized by significant heterogeneity, both vertically and horizontally, due to diverse and contrasting material inputs that lead to particular characteristics: pollution, lower nutrient content, higher pH, higher compaction reducing root and aerial biomass growth, and low organic matter return. To improve the physico-chemical properties of urban soils and ensure sustainable vegetation growth, one solution is to apply the principles of pedological engineering by reconstituting fertile soils using the surface horizon of agricultural plots. However, this practice is currently controversial because of the current decrease in cultivable surfaces and the ensuing threat on food security. An alternative aimed at protecting natural soil resources is to: (1) rehabilitate existing urban soils where possible, or (2) build fertile soils that support several soil functions from materials resulting from urban activity and deconstruction. The “Système d'informations territoriales énergétiques” (SITERRE) program has developed a soil engineering approach to address this issue. It is more particularly based on the formulation of mixtures of technogenic materials to build fertile Technosols that promote plant growth. Research has led to the selection of relevant agronomic fertility indicators based on two types of vegetation model use – Square/Parks and Street Trees. The results demonstrated that it was feasible to build fertile soils from by-products, ready to be planted as soon as they are produced, and guaranteeing safety for human health and the environment
On the Use of Spatial and Spectral Redundancy to Speed-Up Brillouin Micro-Imaging
No full textInternational audienceWe propose a smart scanning protocol to speed up the acquisition of Brillouin microscopy. It is based on a two-pass algorithm. In a first pass at low signal-to-noise-ratio (SNR),essential pixels located on the convex hull of the Fourier phasor space of the sample are identified, selected and rescanned at highSNR. These essential spectra serve as a decomposition basis for the remaining spectra located inside the convex hull. A second acceleration is gained through the use of superpixels computed on a denoised version of the low SNR image. It allows to reduce the number of pixels on which Brillouin spectra are to be estimated.This protocol recently introduced for Raman microscopy is tested here for the first time on Brillouin hyperspectral images (HSI). A compression by a factor between 3 and 253 with very limited distortion is demonstrated on simulated samples fitted on real samples of cell bones. Further opportunities of improvement are identified and discussed