Portail Hal-l'Institut Agro Rennes-Angers
Not a member yet
9270 research outputs found
Sort by
Human milk vs. Infant formula digestive fate: In vitro dynamic digestion and in vivo mini-piglet models lead to similar conclusions
No full textInternational audienceInfant formula (IF), the only nutritionally adequate substitute for human milk (HM), still needs to be improved to be more biomimetic with HM, including in terms of digestive fate. The latter can be explored using different digestion models. The present study aimed to compare IF and HM digestion using in vivo (mini-piglet) and in vitro (dynamic system, DIDGI®) models. Fresh mature HM was collected and compared with a standard bovine IF. In vivo, 18 Yucatan mini-piglets (24-day-old) received HM or IF and were euthanized 30 min after the last meal. The entire digestive content was collected from the stomach to the colon. In vitro, the same meals were fed to an in vitro dynamic digestion model simulating the term infant at four weeks of age. Digesta were sampled regularly in the gastric and intestinal compartments. Structure (confocal microscopy and laser light scattering) and proteolysis (SDS-PAGE for residual intact proteins, OPA for hydrolysis degree, LC-MS/MS for peptides) were investigated along digestion. The digesta microstructure differed between HM and IF in a similar way between in vitro and in vivo digestion. In vitro gastric proteolysis of caseins and α-lactalbumin was significantly slower for HM than for IF, such as for the early intestinal proteolysis degree. In vitro bioaccessibility of free AAs explained only 30 % of the true ileal digestibility of AAs. Peptide mapping of caseins differed between HM and IF along their digestion. The relative peptide mapping data over six proteins from HM and IF were highly correlated between in vitro and in vivo digestion, particularly at 80 and 120 min of in vitro gastric digestion vs. in vivo stomach data and at 20 and 40 min of in vitro intestinal digestion vs. in vivo proximal jejunum data (r = 0.7-0.9, p < 0.0001, n = 1604). 40 to 50 % of the bioactive peptides identified in vivo were also found in vitro, with a good correlation of their abundances (r = 0.5, p < 0.0001, n = 61). Overall, in vitro and in vivo digestion were in good agreement, both indicating a different digestive fate for HM and IF
A Bayesian Nonparametric Model for Unsupervised Change Detection of Fully Polarimetric SAR Images
No full textInternational audienceThis paper proposes a new method for automatic change detection in multilook polarimetric synthetic aperture radar (PolSAR) images based on unsupervised classification of these data. Changes are identified by comparing multiple classification images. A Bayesian Nonparametric (BNP) approach such as the Dirichlet process mixture model (DPMM) is a potential method for classification tasks. It provides a framework for estimating both the number of components in a mixture model and the parameters of the individual mixture components simultaneously from PolSAR data. Usually, DPMM is treated using Markov chain Monte Carlo (MCMC) or variational Bayes (VB) methods. Here, we propose an expectation-maximization (EM) algorithm to estimate the parameters of the DPMM for high resolution PolSAR images which are modeled by the product model. The performance of the proposed method is evaluated with PolSAR images and the preliminary results on classification and finally on change detection are satisfactory and meet our expectations
The water resources of Lebanon - A review to support water security
No full textInternational audienceThis work reviewed a large and fragmented body of academic and grey literature on water resources in Lebanon. The objective was to assess and curate the existing knowledge base that reflected the importance of water-related concerns. Studies were classified into four topics: water balance, quality, management and governance, each of which was subdivided into sub-topics. Bibliometric analysis was performed, the content was summarised and discussed, and future directions were proposed. In terms of water balance, precipitation requires more research, as available rainfall maps are outdated. Despite an increase in the number of weather stations, their spatial distribution and data continuity remain problematic. Snow cover area and duration differed among studies; thus, it also requires more research. Estimates of evapotranspiration lack comprehensive coverage and often focus on specific crops. Surface-water studies are rare and have low temporal resolution. River flows have high temporal and spatial variability, emphasizing the importance of groundwater, which is overexploited. No consistent trends in climate change impacts were detected. More research is needed in all of the hydrological cycle components. On the other hand, water quality is degrading rapidly with microbiological pollution in most rivers. Groundwater degradation, saltwater intrusion, nitrate pollution, and pesticide contamination pose significant challenges. In addition, emerging pollutants are also being detected. In terms of water management and governance, Lebanon's water framework is complex, involving many laws, institutions, and international partnerships. Despite reforms, challenges remain. Water management has evolved from being state-centred to having increased involvement by international organisations and the private sector. Access to public water networks has improved but remains intermittent. Wastewater networks are expanding, but treatment capacity remains limited. Finally, this work made it possible to quantify the research work and projects carried out in each Lebanese basin, which made it possible to identify gaps in study topics and areas. We hope that this work contributes to the ongoing debate about water security and serves as a resource to support water security and solutions for researchers, educators and policy makers
BASIC PENTACYSTEINE1 regulates ABI4 by modification of two histone marks H3K27me3 and H3ac during early seed development of Medicago truncatula
No full textInternational audienceIntroduction The production of highly vigorous seeds with high longevity is an important lever to increase crop production efficiency, but its acquisition during seed maturation is strongly influenced by the growth environment. Methods An association rule learning approach discovered MtABI4, a known longevity regulator, as a gene with transcript levels associated with the environmentally-induced change in longevity. To understand the environmental sensitivity of MtABI4 transcription, Yeast One-Hybrid identified a class I BASIC PENTACYSTEINE (MtBPC1) transcription factor as a putative upstream regulator. Its role in the regulation of MtABI4 was further characterized. Results and discussion Overexpression of MtBPC1 led to a modulation of MtABI4 transcripts and its downstream targets. We show that MtBPC1 represses MtABI4 transcription at the early stage of seed development through binding in the CT-rich motif in its promoter region. To achieve this, MtBPC1 interacts with SWINGER, a sub-unit of the PRC2 complex, and Sin3-associated peptide 18, a sub-unit of the Sin3-like deacetylation complex. Consistent with this, developmental and heat stress-induced changes in MtABI4 transcript levels correlated with H3K27me3 and H3ac enrichment in the MtABI4 promoter. Our finding reveals the importance of the combination of histone methylation and histone de-acetylation to silence MtABI4 at the early stage of seed development and during heat stress
Machine Learning to better understand and optimize cheese production
No full textInternational audienc
Safety assessment of post-milking application of a Lacticaseibacillus paracasei strain on the bovine teat skin regarding downstream dairy processes
No full textInternational audienceBovine mastitis (BM) is a major disease in the dairy industry, which negatively impacts the milk quality. In a previous study, we highlighted that a post-milking application of a Lacticaseibacillus paracasei (Lp1542) strain on the bovine teat skin is safe with regard to mammary gland functionality and integrity while having an impact on its microbiota. The present study aims to further evaluate the safety of such strategy by assessing how the presence of this strain in milk can impact the downstream dairy processes. Firstly, the heat sensitivity of Lp1542 was demonstrated for representative milk heat treatment conditions. Secondly, Lp1542 does not interfere with the acidification capabilities of a commercial starter culture nor its proteolytic activities. In conclusion, the combined results highlighted that a topical treatment with Lp1542 is safe with regard to animal health as well as downstream dairy processes inviting us to further explore its effectiveness for BM prevention
Pathotype characterization of Aphanomyces euteiches isolates collected from pea breeding nurseries
No full textInternational audienceIntroductionAphanomyces euteiches Drechsler is an oomycete pathogen that affects legume crops, causing root rot, a severe disease of peas (Pisum sativum L.) worldwide. While significant research progress has been made in breeding pea-resistant varieties, there is still a need for a deeper understanding of the diversity of pathogen populations present in breeding nurseries located in various legume-growing regions around the world.MethodsWe analysed the diversity of 51 pea-infecting isolates of A. euteiches, which were recovered from four American (Athena, OR; Le Sueur, MN; Mount Vernon, WA; Pullman, WA) and three French (Riec-sur-Belon, Templeux-le-Guérard, Dijon) resistance screening nurseries. Our study focused on evaluating their aggressiveness on two sets of differential hosts, comprising six pea lines and five Medicago truncatula accessions.ResultsThe isolates clustered into three groups based on their aggressiveness on the whole pea set, confirming the presence of pathotypes I and III. Pathotype I was exclusive to French isolates and American isolates from Athena and Pullman, while all isolates from Le Sueur belonged to pathotype III. Isolates from both pathotypes were found in Mount Vernon. The M. truncatula set clustered the isolates into three groups based on their aggressiveness on different genotypes within the set, revealing the presence of five pathotypes. All the isolates from the French nurseries shared the same Fr pathotype, showing higher aggressiveness on one particular genotype. In contrast, nearly all-American isolates were assigned to four other pathotypes (Us1, Us2, Us3, Us4), differing in their higher aggressiveness on two to five genotypes. Most of American isolates exhibited higher aggressiveness than French isolates within the M. truncatula set, but showed lower aggressiveness than French isolates within the P. sativum set.DiscussionThese results provide valuable insights into A. euteiches pathotypes, against which the QTL and sources of resistance identified in these nurseries displayed effectiveness. They also suggest a greater adaptation of American isolates to alfalfa, a more widely cultivated host in the United States
Prédiction des besoins nutritionnels de truies gestantes à partir de données de capteurs et d’algorithmes d’apprentissage automatique
No full textInternational audiencePrecision feeding aims to provide a ration close to the nutritional requirements of each gestating sow, which are calculated using a model (e.g. InraPorc) that requires input data (e.g. sow characteristics) and an estimate of the herd’s farrowing performance. This study evaluated machine-learning methods to predict the daily nutritional requirements of gestating sows based on sensor data as a function of different configurations of virtual farms. Data on 73 gestating sows were recorded by automatons or sensors such as electronic feeders, drinking stations, connected weight scales, and accelerometers. Nine machine-learning algorithms were then trained on various dataset scenarios as a function of different virtual farm configurations (using data from one or two sensors) to predict daily standardized ileal digestible lysine and metabolizable energy requirements for each sow. Adding the inputs usually provided to the InraPorc model (i.e. housing conditions and sow characteristics at artificial insemination) to the sensor data improved the mean average percentage error by 5.6 % for lysine and 2.2 % for energy. The highest coefficients of multiple determination for lysine (R2 = 0.99) and for energy (R2 = 0.95) were obtained for scenarios that involved an automatic feeder and included housing and sow characteristics. For these scenarios, the root mean square error was lower with Gradient Tree Boosting (0.91 MJ/d for energy and 0.08 g/d for lysine) than that with linear regression (2.75 MJ/d and 1.07 g/d, respectively). The results of this study show that the daily nutrient requirements of gestating sows can be predicted accurately with data provided by sensors and machine-learning methods, which paves the way to simpler solutions for precision feeding
Identification of transcriptional modules linked to the drought response of Brassica napus during seed development and their mitigation by early biotic stress
No full textInternational audienceIn order to capture the drought impacts on seed quality acquisition in Brassica napus and its potential interaction with early biotic stress, seeds of the 'Express' genotype of oilseed rape were characterized from late embryogenesis to full maturity from plants submitted to reduced watering (WS) with or without pre-occurring inoculation by the telluric pathogen Plasmodiophora brassicae (Pb + WS or Pb, respectively), and compared to control conditions (C). Drought as a single constraint led to significantly lower accumulation of lipids, higher protein content and reduced longevity of the WS-treated seeds. In contrast, when water shortage was preceded by clubroot infection, these phenotypic differences were completely abolished despite the upregulation of the drought sensor RD20. A weighted gene co-expression network of seed development in oilseed rape was generated using 72 transcriptomes from developing seeds from the four treatments and identified 33 modules. Module 29 was highly enriched in heat shock proteins and chaperones that showed a stronger upregulation in Pb + WS compared to the WS condition, pointing to a possible priming effect by the early P. brassicae infection on seed quality acquisition. Module 13 was enriched with genes encoding 12S and 2S seed storage proteins, with the latter being strongly upregulated under WS conditions. Cis-element promotor enrichment identified PEI1/TZF6, FUS3 and bZIP68 as putative regulators significantly upregulated upon WS compared to Pb + WS. Our results provide a temporal co-expression atlas of seed development in oilseed rape and will serve as a resource to characterize the plant response towards combinations of biotic and abiotic stresses
A method to determine antifungal activity in seed exudates by nephelometry
No full textInternational audienceBackground One of the levers towards alternative solutions to pesticides is to improve seed defenses against pathogens, but a better understanding is needed on the type and regulation of existing pathways during germination. Dormant seeds are able to defend themselves against microorganisms during cycles of rehydration and dehydration in the soil. During imbibition, seeds leak copious amounts of exudates. Here, we developed a nephelometry method to assay antimicrobial activity (AA) in tomato seed exudates as a proxy to assess level of defenses. Results A protocol is described to determine the level of AA against the nonhost filamentous fungus Alternaria brassicicola in the exudates of tomato seeds and seedlings. The fungal and exudate concentrations can be adjusted to modulate the assay sensitivity, thereby providing a large window of AA detection. We established that AA in dormant seeds depends on the genotype. It ranged from very strong AA to complete absence of AA, even after prolonged imbibition. AA depends also on the stages of germination and seedling emergence. Exudates from germinated seeds and seedlings showed very strong AA, while those from dormant seeds exhibited less activity for the same imbibition time. The exudate AA did not impact the growth of a pathogenic fungus host of tomato, Alternaria alternata, illustrating the adaptation of this fungus to its host. Conclusions We demonstrate that our nephelometry method is a simple yet powerful bioassay to quantify AA in seed exudates. Different developmental stages from dormant seed to seedlings show different levels of AA in the exudate that vary between genotypes, highlighting a genetic diversity x developmental stage interaction in defense. These findings will be important to identify molecules in the exudates conferring antifungal properties and obtain a better understanding of the regulatory and biosynthetic pathways through the lifecycle of seeds, from dormant seeds until seedling emergence