Portail Hal-l'Institut Agro Rennes-Angers
Not a member yet
9270 research outputs found
Sort by
Tea, coffee, and cocoa delay milk gastric coagulation in a biomimetic in vitro system (NERDT™) by hindering both acid- and pepsin-induced milk gelation
No full textInternational audienceThis study investigated the effect of mixing whole milk with hot water extract of cocoa, coffee, or tea on milk intragastric coagulation during dynamic in vitro digestion. Milk diluted with water in the same proportion (70:30 v/v) was used as the control. The effect of adding cocoa, coffee, or tea extracts on acid-and pepsin-induced milk coagulation was first studied using a rheometer. The control exhibited a significantly shorter (P < 0.0001) gelation time in acidinduced coagulation than the milk mixtures containing extracts. The delaying effect of extracts on pepsin-induced coagulation was even more pronounced with coffee, causing a marked delay in gelation time, while tea and cocoa completely prevented gel formation under our experimental conditions. The milk mixtures, preheated to 60 °C, were then studied during simulated gastric digestion using the NEar Real Digestive Tract (NERDT TM ) dynamic in vitro digestion system. Samples collected at the stomach exit at different time points were investigated for pH, dry matter and microstructure. During gastric digestion of the control, protein coagulation occurred between 5 to 18 min (pH 6.3 ± 0.01 and 5.7 ± 0.28, respectively), whereas in the presence of cocoa, coffee, or tea, milk coagulation was observed between 18 to 27 min (pH 5.6 ± 0.07 and 4.84 ± 0.22 respectively). Confocal micrographs revealed larger protein aggregates in samples containing extracts, with entrapped milk fat clearly visible. The observed effects are likely due to the high polyphenol content of the extracts, which are known to interact with milk proteins. Our findings therefore suggest that protein-polyphenol interactions delay casein coagulation in the stomach and may alter gastric emptying and subsequent nutrient absorption along the small intestine
Departing from the Colonial Path: A Critical Approach to Studying Fire Regime Changes in West Africa
No full textInternational audienceResearch indicates that, contrary to common perceptions, wildfire activity is declining globally, primarily due to reduced fire activity in savannas. This finding exposes the normative view of fire as hazard and the neutrality of using satellite data for assessing fire regimes, as these overshadow local contexts, histories, and politics that shape them. The evolution of the fire regime concept reflects historical ambiguities in fire science and policy in colonial contexts. Today, fire research is influenced by carbon market considerations and informed by global fire datasets. This paper critically examines whether modern satellite data usage moves away from colonial legacies in fire management, particularly in West Africa. It highlights the complexities of fire regime changes, arguing that current policies oversimplify fire into a “good/bad” dichotomy. The authors propose a framework to document diverse local fire trajectories influenced by factors such as demographic shifts, land cover changes, and biogeography. Through sequence analysis, nine distinct fire trajectories are identified, revealing that while global fire activity in savannas is decreasing, many regions remain stable in terms of fire intensity and seasonality. These insights encourage a reevaluation of fire management strategies in West Africa, moving beyond simplistic classifications to better reflect the diversity of local realities
Crop diversity in rotation and hedgerows: Two important but potentially insufficient levers to support the multifunctionality of agroecosystems
No full textInternational audienceClimate change and biodiversity loss necessitate agricultural systems that support multiple ecological functions simultaneously, i.e. multifunctional agroecosystems. Many studies have shown that crop diversity in rotation and hedgerows positively affect individual functions, but few have examined their combined effect on agroecosystem multifunctionality by considering above-and below-ground functions. The aim of this study was to characterise the effects of crop diversity in rotation and hedgerows on agroecosystem multifunctionality. In 24 winter cereal fields in Brittany (France), we assessed the average multifunctionality index on the basis of eight potential functions: crop production, nutrient cycling, carbon storage, erosion control, pest regulation, weed infestation, pollination and biodiversity conservation. We used generalized linear mixed models to analyse the effects of crop diversity in rotation and that of hedgerows on the multifunctionality and functions indices. We did not find any effects of crop diversity in rotation and hedgerows on agroecosystem multifunctionality. We found no effect of crop diversity in rotation on functions and positive effects of hedgerows on crop production and pollination. The multifunctionality, pollination and biodiversity conservation indices decreased with distance from edges. However, we did not find any effects of distance from hedgerows on the multifunctionality and functions indices. Our results suggest that crop diversity in rotation and hedgerows may not be sufficient for enhancing agroecosystem multifunctionality. Other levers, such as reducing input use, may influence agroecosystem multifunctionality. These results improve our understanding of factors that shape agroecosystem multifunctionality and may be used to improve sustainable agricultur
Transcriptomic profiling of laying hen livers in relation to age and interaction with early liferearing conditions
No full textInternational audienceThe laying hen industry aims to extend the productive lifespan of hens for both economic and environmental reasons, despite age-related declines in egg yield and quality. The liver, a central organ in metabolism and reproduction, is proposed to play a key role in sustaining laying performance through lipid metabolism. Here, we investigated age-associated changes in hepatic gene expression and their interaction with early-life rearing conditions in 468 laying hens aged 70 weeks (70w n=241) or 90 weeks (90w n=227), half of which had been reared on the floor and the other half in cages until 60 weeks of age.To elucidate the regulatory mechanisms underlying ageing, we combined three complementary approaches. (1) Differential gene expression analysis identified 2,181 differentially expressed genes (DEG) (15.7% of 13,929 expressed genes; |log2FC|≥1.5), including 1,496 upregulated and 685 down-regulated at 90w, as well as 137 genes showing significant age × rearing interactions. Functional en-richment highlighted that genes upregulated at 90w were mainly associated with DNA repair (FANCI, FANCD2, FAAP24, FAAP100, CENPS, NUCKS1), meiotic-like recombination (TERB1, SYCE2, MEI-OB, MND1, MEIKIN, HORMAD1), and metabolic and inflammatory regulation (EDN1, NR4A3, IGFBP5, ID2, PDGFB, IL12B, CDH13, PPARGC1A). These patterns suggest that hepatic ageing in-volves genome maintenance, epigenetic remodeling, and stress-related transcriptional reprogramming. Conversely, genes downregulated at 90w were enriched for fatty acid synthesis genes, as well as for genes involved in cholesterol and steroid biosynthesis, the latter showing a stronger decrease in cage-reared hens. (2) Weighted gene co-expression network analysis (WGCNA) revealed different age-associated gene modules. We can cite the lightcyan (100 genes), royalblue (50 genes) and lightgreen (67 genes) modules significantly over-expressed at 70w of age. The lightcyan module enriched in fat-ty acid synthesis genes (ACLY, FASN, ACACA, SCD, …), showed a strong positive correlation with liv-er weight (R²=0.59). The royalblue module, gathering cholesterol and steroid synthesis genes (HMGCR, SQLE, MVK, DHCR24, …) and their transcription factor SREBF2) was not correlated to any traits. The lightgreen module, enriched in vitellogenin genes, was negatively correlated with yolk weight (R2=-0.14). The two latter modules showed significant age × rearing system interactions, with stronger expression decreases in cage-reared hens. Finally, regulatory analysis (decouplR) revealed several key transcription factors, including those controlling lipid metabolism (SREBF1, SREBF2, MLXIPL, CREBZF, USF2), which were among the most inactivated in older hens. (3) Clustering, PCA and AFM refined our understanding of the differences in gene expression between the two ages by revealing three groups of 90-week-old hens: one of them (very interesting) had an expression profile similar to that of 70-week-old individuals and behaves phenotypically in a similar way, while the other two differ from the first group in both phenotypes and gene expression with the DE genes involved in the aforementioned metabolic processes.Together, these findings uncover how ageing reshapes hepatic regulatory networks in interac-tion with early-life history. Future studies integrating methylome data will be essential to determine whether these transcriptional shifts reflect genetic or epigenetic adaptive plasticity in long-lived hens.This project is funded by the European GEroNIMO N°101000236 and ANR ‘EFFICACE’ programs
Minimizing N2O and CO2 emissions from urban lawns through sustainable management strategies
No full textInternational audienceLawns, which can represent up to 50–70% of urban green spaces, provide key ecosystem services. However, their greenhouse gas (GHG) emissions depend strongly on management practices. Conventional practices—such as mineral fertilization and irrigation—increase soil nitrous oxide (N2O) emissions and contribute to the carbon footprint of lawns. In contrast, alternative approaches—such as organic fertilization, reduced mowing frequency, and recycling of grass clippings and tree litter on soil surface—may improve carbon storage and reduce GHG emissions. However, litter decomposition may also lead to N2O emissions. This study aimed to assess the impact of 11 conventional and alternative lawn management practices, on carbon dioxide (CO2) and N2O emissions, with a particular focus on comparing the effects of mineral and organic fertilization. GHG fluxes were measured in spring, summer, and autumn, and analyzed in relation to soil temperature, moisture and mineral nitrogen concentrations. Organic fertilization induced 8.1 times less cumulative N2O emissions (2–5 mg N m− 2) than mineral fertilization (34–70 mg N m− 2). Recycling of grass clippings and tree litter on soil surface did not increase CO2 and N2O emissions. Lawns mowed once a year emitted 1.5 times less CO2 (752 mg CO2 m− 2 h− 1) than conventional lawns mowed weekly and receiving mineral fertilizer (1147 mg CO2 m− 2 h− 1). The results suggest that mineral fertilization should be replaced by organic alternatives to reduce N2O emissions, and that spring applications should be delayed or avoided to enhance N use efficiency. Furthermore, reducing mowing frequency and recycling litter on lawns appear to be sustainable alternatives, as they have a low potential for GHG emissions while also supporting soil fertility, carbon storage, water cycling, and biodiversity
Fine roots and N uptake efficiency shape genotypic variability in early vigor of rapeseed under low nitrogen conditions
No full textEarly vigor is a determining factor for successful winter oilseed rape cultivation in low-input systems, as efficient establishment enhances weed competitiveness and tolerance to early pest pressure. Yet the physiological and genetic bases of early vigor remain poorly understood, particularly regarding root traits. Here, we combined high-throughput phenotyping and genetic analysis to dissect early vigor determinants under low nitrogen conditions.A population of 100 recombinant inbred lines and four commercial cultivars were grown under low nitrogen supply up to BBCH 16 in RhizoTubes, allowing non-destructive imaging of root and shoot development. Forty traits were measured or derived, including traits related to carbon and nitrogen metabolism and detailed root system architecture descriptors. Random forest models and QTL mapping were used to identify ecophysiological and genetic determinants of early vigor.Early vigor -assessed by total dry weight, shoot dry weight, leaf area, and projected leaf area -showed strong positive correlations with fine-root dry weight and nitrogen uptake efficiency (NUpE), but weak relationships with fine-scale root system architecture traits. Random forest analyses confirmed fine-root dry weight and NUpE as the main contributors to genotypic variation in early vigor. QTL mapping identified 17 QTLs across 10 chromosomes, including a locus on A01 co-localizing for total, root, and fine-root dry weight, highlighting shared genetic control of shoot and fine-root growth.Altogether, under low nitrogen supply, early vigor is primarily governed by traits related to nitrogen capture and fine-root growth, highlighting fine-root development and nitrogen uptake as promising breeding targets for sustainable winter oilseed rape
MRI monitoring of digestion mechanisms at the scale of a food piece: proof of concept with bread
No full textInternational audienceTo improve our understanding of gastrointestinal digestion of solid foods, spatially resolved insights into disintegration mechanisms at the particle level are needed. Magnetic resonance imaging (MRI), despite its noninvasive and multiscale capabilities, remains underexploited for such purposes. This study pursued two objectives: (1) to develop an MRI-compatible miniaturized setup for static in vitro oral-gastric-intestinal digestion, and (2) to apply this system to investigate online the digestion of a bread piece measuring a few millimetres using MRI (UTE 3D morphometric imaging and T 2 mapping), supplemented by chemical analyses of starch and protein hydrolysis. The setup comprises a circulation loop of the digestion fluid, linking an MRI-compatible digestion cell to a remote pH-stat system, which enables real-time control of temperature, pH, enzyme addition, and sampling. MRI results correlated well with peptide and polysaccharide release kinetics in the digestion fluid. UTE 3D imaging showed stable bread volume during gastric digestion, followed by volume loss, surface roughening, and fluid ingress into pores during intestinal digestion, consistently with gluten hydrolysis. T 2 analysis distinguished more mobile water in the pores and less mobiles ones in bread. An increase in the amount of more mobile protons suggested erosion-driven exposure and internal enzymatic attack. The release of starch hydrolysis products was shown to be independent on the breakdown of the gluten network and could be monitored with T 2 in the digestion fluid. In conclusion, this MRI-compatible setup enables time-lapse, submillimetric resolution monitoring, offering valuable insights into bread piece digestion, and could be adapted to various solid food matrices
Which factors impact calcium bioaccessibility in dairy and plant-based products during static in vitro digestion?
No full textInternational audienceCalcium deficiency is widespread worldwide. In western countries, the main source of dietary calcium are dairy products, although some plant foods can also contribute. This work aimed to determine the solubility and the bioaccessibility of calcium from various food sources and to investigate how food components impact these two properties. A static in vitro gastrointestinal digestion model (INFOGEST) was used for two types of samples: (1) model solutions consisting in calcium solutions to which a compound present in dairy or plant products presumed to interact with calcium was added and (2) plant and dairy products. Calcium bioaccessibility was determined by measuring the soluble calcium concentration relative to total calcium concentration in the samples. The soluble calcium content was measured at different times during gastric and intestinal digestion using inductively coupled plasma-optical emission spectrometry. In vitro digestion indicated that the low pH during the gastric phase promoted the calcium solubilization. During the intestinal phase, however, calcium solubility decreased due to the pH increase to about 7. Phosphate, palmitic acid, micellar casein and phytate appear to interact with calcium, decreasing its solubility in the intestinal phase, probably through the formation of insoluble complexes. The calcium bioaccessibility of dairy matrices (yogurt, cheese, milk) was particularly high (between 19 and 34 %). However, calcium bioaccessibility was more disparate for plant-based dairy alternatives (between 5 and 20 %) and whole plant foods (between 1 and 27 %). In terms of the quantity of bioaccessible calcium per serving, dairy products (yogurt, cheese, milk) were the best sources
Cartographic tools for evaluating land cover transitions: implications for landscape management and almond diversity conservation
No full textInternational audienceOver the past four decades, rapid urbanization has profoundly affected the sustainability of urban and peri-urban agriculture (UPA) as well as the diversity of native fruit tree ecotypes. Despite the ecological and agricultural importance of Tunisia’s coastal regions, few studies have addressed the impacts of urbanization on local fruit tree diversity and orchard dynamics. To fill this gap, the present study employs remote sensing to map and quantify the evolution of urban expansion and the degradation of almond orchards between 1980 and 2023. In addition, field surveys were conducted to complement the spatial analysis and to assess the economic, social, and ecological importance of UPA, here defined as all agricultural activities carried out within and around urban areas. These surveys also provided insights into the effects of urbanization on almond cultivation. Cartographic analyses reveal a marked transformation of the landscape under the pressure of urbanization. In Kalâa Kebira, tree crops decreased from 3,234.2 ha in 1980, with a loss of 621 ha by 2023, while urban areas expanded from 145 ha to 1,307.2 ha. In Bouficha, almond and olive plantations declined by 29.4% between 1980 and 2012 (from 11,927.32 ha to 8,420.9 ha), before recovering to 10,666.19 ha by 2023, despite urbanization reaching 1,130.69 ha. This regeneration can be attributed to the central economic role of agriculture (accounting for 80% of local income), government-supported irrigation projects, and the engagement of a new generation of farmers. Field surveys highlight the high genetic diversity and good conservation status of native almond ecotypes in the Kalâa Kebira region, reflecting traditional management practices that safeguard local genetic resources. This diversity represents an asset for adapting to climatic constraints, particularly drought. Conversely, in Bouficha, the expansion of orchards through the introduction of selected or imported almond varieties has led to a reduction in local genetic variability. This process has intensified genetic erosion, already exacerbated by rapid urbanization and recurrent droughts, threatening the resilience of these agroecosystems. These findings underscore the urgent need for concrete sustainable management policies for fruit trees particularly almonds to preserve this valuable native diversity. Recommended measures include ex situ conservation in gene banks, participatory selection, and in situ agroecological zoning. Furthermore, comprehensive analysis and the development of an in-situ conservation strategy are required. In the absence of such actions, this diversity risks being progressively replaced by uniform cultivars in the medium term and could disappear in the long term under drought stress, resulting in a significant loss of biodiversity at the national scale
Subsoils, but not toeslopes, store millennia-old PyC in a gently sloping catchment under temperate climate after centuries of cultivation
No full textInternational audiencePyrogenic carbon (PyC) is the carbonaceous solid residue of incomplete combustion of biomass. It is a continuum of mostly condensed and aromatic molecules. PyC persists for longer in soils relative to non-PyC organic carbon. However, estimates of PyC residence time vary greatly. The time and spatial scales investigated are not always adapted to the long-residence time and vertical and lateral mobility of PyC in the soil profile and the landscape. In addition, agricultural land-use and shallow slopes are under-represented in the PyC literature.We measured the concentrations and stocks of PyC down to 60 cm along three toposequences in a small agricultural catchment with shallow slopes and homogeneous soil parent material in the west of France. We used two methods (chemo-thermal oxidation – CTO and hydropyrolysis – HyPy) of PyC quantification that cover the intermediate to highly condensed part of the PyC continuum, and also measured the radiocarbon values in both total soil organic carbon (SOC) and the PyC fraction. There was likely little persistent PyC inputs to the catchment in the last 150 years which gave us access to the resultant, long term PyC distribution in the landscape. In particular, we aimed to investigate whether the vertical and horizontal distribution of PyC were similar or differed from SOC and whether they were affected by the soil types along the slope.Topographic position was not the main driver of PyC stocks in this landscape. The stock of PyCCTO to 60 cm depth averaged 2.5 ± 0.22 t ha−1 across topographic positions. PyC stocks were the highest in a Solimovic Cambisol at the toeslope (3.3 ± 0.26 t ha−1), likely formed following changes in erosion dynamics with land-use. Contrary to previous reports, erosion redistributed already aged PyC without enrichment or depletion. PyCHyPy concentrations in the topsoil decreased from upslope (median = 1.6, IQR = 0.22 g C kg−1 soil) to downslope positions (median = 1.10, IQR = 0.40 g C kg−1 soil), which we tentatively attribute to PyCHyPy leaching following the destabilisation of mineral associations with iron oxides in the water-table affected portion of the transects. The subsoil (30–60 cm) represented between 37 % and 51 % of the PyCCTO stock. PyCHyPy proportion in SOC increased with depth and reached an average of 11 ± 3.3 % at 50–60 cm depth. PyCHyPy had an uncalibrated radiocarbon age of 2520 to 9600 years BP at this depth, significantly older than bulk SOC at the same depth and than PyCHyPy at 0–10 cm (1530 to 2630 years BP). These results confirm the long persistence of PyC in soils and point to a slow advection of PyC towards the soil depth under the pedoclimatic conditions of our study area.Future studies should assess whether erosion modalities and age and quality of PyC affect its fate during erosion events. Identifying the proportion of PyC produced which is quickly transported away from the watershed and that which remains and is stabilised in soils for millennia after a fire is an important knowledge gap that still needs to be investigated to close the terrestrial PyC budget