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Data paper: Effects of hay pelleting, concentrate proportion, and intake level on digestibility, nitrogen balance, and gaseous exchange in lambs
No full textInternational audiencePelleting facilitates the storage and handling of forages but induces significant decreases in foragedigestibility; the latter are partially compensated by reductions in urinary and methane energy losses,leading to an improvement in the efficiency of metabolisable energy utilisation, especially for fattening.Overall, the net energy content of forages is either unaltered or slightly improved, but net energy intakesignificantly increases. The present data address the interactions between pelleted forages and concentrate feeds on the utilisation of metabolisable energy in lambs.Ninety-six crossbred male lambs, in four batches of 24 animals each, were fed eight diets at two feedinglevels. The study was planned according to a 2 × 4 × 2 factorial arrangement of treatments with threefactors: physical form of forage (chopped, CH, or ground and pelleted, P, cocksfoot hay), percentage ofconcentrate feed (0, 20, 55, 85), and feeding level (above maintenance and 90% of ad libitum). Each lambwas given one diet (physical form of forage × percentage of concentrate feed) at both feeding levels.Animals were fed individually throughout the experiment. DM digestibility was measured over 10 days,with the individual animal as the experimental unit (n = 12/dietary treatment). Organic matter andenergy digestibility (over 10 days) and N balance (over 6 days), as well as gas exchanges (over 4 days),were measured by groups of three lambs such that for those measurements, the experimental unit isthe group (n = 4). Data on digestibility, N balance, and gas exchanges are available. DM intake averaged63.86 ± 18.69 (SD) g per kg BW0.75 across all treatments. Energy and N digestibility averaged 66.54 ± 7.94% and 66.17 ± 5.53%, respectively. Metabolisability and net energy values of diets, as well as digestiveinteractions, can be derived from the dat
Molecular mechanisms modulating beneficial plant root–microbe interactions: What’s common?
No full textInternational audienceIn the current context of climate change, there is a need to develop more sustainable agrifood strategies. As an alternative to the intensive use of chemically synthesized fertilizers and pesticides that pollute water and impact biodiversity, there is a growing interest in using beneficial microbes as biostimulants and/or bioprotection agents. However, their implementation in agriculture remains a challenge due to highly variable outcomes and benefits. Furthermore, there are major knowledge gaps about the molecular mechanisms that regulate different plant-microbe interactions. In the present review, we summarize current knowledge on the molecular mechanisms that control different beneficial plant root-microbe interactions; namely, arbuscular mycorrhiza, the rhizobium-legume symbiosis, ectomycorrhiza, and fungal and bacterial endophytic associations. This includes the signaling pathways required for recognition of microbes as beneficial, the metabolic pathways that provide nutritional benefits to the plant, and the regulatory pathways that modulate the extent of symbiosis establishment depending on soil nutrient availability and plant needs. Our aim is to highlight the main common mechanisms, as well as knowledge gaps, in order to promote the use of microbes, either individually or in consortia, within the framework of a sustainable agriculture that is less dependent on chemicals and more protective of biodiversity and water resources
Assessment of the performances of blood tests for the antemortem diagnosis of aspergillosis in wild or captive aquatic birds
No full textInternational audienceAbstract The antemortem diagnosis of aspergillosis in birds remains a complex challenge. A variety of diagnostic methods are currently available, including direct detection of Aspergillus components, antibody-based assays, and nonspecific markers such as serum protein electrophoresis (SPE), but their diagnostic performances remain limited. The objective of this study was to assess and compare the performances of several diagnostic approaches, specifically, galactomannan index measurement, beta-D-glucan assay, 3-hydroxybutyrate quantification, SPE, and mannoprotein detection tests. A secondary objective was to develop a predictive model of aspergillosis incorporating optimal test thresholds identified in the first phase, combined with clinical signs. A total of 101 serum and 31 plasma samples were collected from 118 aquatic bird of various species in France. Birds were classified into three categories: control individuals ( n = 88), suspected aspergillosis cases ( n = 7), and confirmed cases ( n = 23). While individually considered tests displayed limitations in specificity, predictive modeling revealed that elevated levels of 3-hydroxybutyrate above 0.52 mmol/L (Se = 96%, Sp = 51%) combined with beta-globulins above 6.90 g/L (Se = 78%, Sp = 51%), in conjunction with concurrent respiratory clinical signs, were significantly associated with the occurrence of aspergillosis. A multivariable logistic model combining these variables achieved excellent diagnostic performance, with AUCs up to 0.98 and sensitivity above 98%. These findings suggest that these parameters, particularly when considered alongside clinical signs, may serve as more reliable indicators for detecting aspergillosis in birds
Reconstitution comparée des écosystèmes Weichselien et Saalien Supérieur en Europe de l’ouest et du sud
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Une application Shiny pour l'analyse reproductible et interactive de données de RNA-seq
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A new stochastic SIS-type modelling framework for analysing epidemic dynamics in continuous space
No full textWe propose a new stochastic epidemiological model defined in a continuous space of arbitrary dimension, based on SIS dynamics implemented in a spatial Λ-Fleming-Viot (SLFV) process. The model can be described by as little as three parameters, and is dual to a spatial branching process with competition linked to genealogies of infected individuals. Therefore, it is a possible modelling framework to develop computationally tractable inference tools for epidemics in a continuous space using demographic and genetic data.We provide mathematical constructions of the process based on well-posed martingale problems as well as driving space-time Poisson point processes. With these devices and the duality relation in hand, we unveil some of the drivers of the transition between extinction and survival of the epidemic. In particular, we show that extinction is in large parts independent of the initial condition, and identify a strong candidate for the reproduction number R0 of the epidemic in such a model
OsKAT1 is a short Shaker potassium channel involved in root to shoot potassium translocation and contributes to rice grain yield
No full textInternational audienceSignificance: K+ transport from root to shoot is a critical process for sustaining physiological functions in aerial organs. We report here a short inward channel OsKAT1, localized in the root stele of rice, which contributes to root–shoot K+ translocation. Functional comparison between OsKAT1 and its C-terminal extended chimera OsKAT1-C1 in both Xenopus oocytes and Arabidopsis roots demonstrates that the short channel OsKAT1 mediates more efficient K+ transport than the chimera carrying a canonical C terminus. Under field conditions, OsKAT1 activity shows significant contributions to K+ accumulation in shoots and grain yield of rice, highlighting its agronomic importance.Abstract: Shaker potassium channels play essential roles in K+ uptake and distribution in plants. Studies on Shaker channels in Arabidopsis have provided a paradigmatic framework, but the rice genome encodes an additional member, OsKAT1, whose function remained poorly defined. OsKAT1-type channels are characterized by an innately short cytosolic C terminus, forming a unique clade of monocot-specific short Shakers that is prevalent in Poaceae species. In rice, OsKAT1 is predominantly expressed in the root stele. Disruption of OsKAT1 (KO mutation) leads to a significant reduction in K+ secretion into the xylem sap delivered to the shoot. Patch-clamp experiments on root stele protoplasts of WT and KO plants indicate that OsKAT1 functions as an inward channel. Functional analyses in Xenopus oocytes reveal that despite activating at weakly negative voltages, OsKAT1 is intrinsically incapable of mediating substantial outward currents—a property attributed to its truncated C terminus. Together with outward K+ channel activity, this feature enables stelar cells to remain significantly permeable to K+ around the K+ equilibrium potential. When expressed in Arabidopsis, OsKAT1 contributes to K+ transport in the xylem sap, but only in wild-type plants that express SKOR, a Shaker channel specialized for this role. These results demonstrate that OsKAT1 constitutes apreviously unrecognized component of K+ translocation to shoots and shed light on the energization and regulation underlying this function. Moreover, OsKAT1 is shown to improve rice adaptation to environmental conditions and enhance grain yield under field conditions through its facilitating root-to- shoot ion translocation
Oil palm spreads, but rubber still there-mapping the continuous but slow changes of plantations area in Southern Thailand
No full textSource Agritrop Cirad (https://agritrop.cirad.fr/616499/) * Autres projets (id;sigle;titre): ;DYNAMOST;(THA) Dynamics of Oil Palm Plantation in Southern Thailand//International audienceSoutheast Asia is undergoing rapid land use transitions, largely driven by smallholders responding to fluctuations in crop prices and market opportunities. In Southern Thailand, oil palm cultivation has gained increasing importance—historically the main rubber-producing region. This study analyzed land use changes in the Krabi, Trang, and Nakhon Si Thammarat provinces (2 million hectares in total) between 2012 and 2022 and utilized the Land Change Modeler framework to predict future trends for 2022–2032. The novelty of this study lies in the use of a spatially explicit modeling framework to quantify and forecast smallholder-driven conversions from rubber to oil palm, an underexplored dynamic in Thailand compared to the large-scale plantation systems of neighboring countries. Based on the results, there was a net expansion of oil palm by approximately 137,000 hectares, largely replacing 53,000 hectares of rubber, while paddy fields declined by 80,000 hectares, decreasing from 5% to less than 1% of the total area. Despite this shift, rubber remained the dominant crop, occupying 36.7% of the landscape in 2022. Model validation against the observed 2022 data demonstrated high predictive accuracy, with the projections for 2032 indicating continued but slower oil palm expansion. These findings revealed the continued presence of diversified agricultural landscapes despite strong economic drivers promoting oil palm cultivation. They stress the importance of evidence-based land-use policies that safeguard crop diversity and local food production as a risk mitigation strategy suited to an uncertain climatic and socio-economic future
Multi-trophic arthropod communities modulated by local farming system and landscape heterogeneity
No full textInternational audienceContext Organic farming is increasingly used worldwide in recent decades, but the role of this farming system in shaping the trophic structure of arthropod communities remains poorly understood, especially at different spatial scales. Therefore, the contribution of landscape heterogeneity in shaping arthropod’s trophic guilds remain understudied. Objectives In this study, we assessed how the evenness, the abundance and the taxonomic richness of arthropod trophic groups were shaped by the local farming system, landscape heterogeneity (including the percentage of semi-natural habitats and organic fields), and their interaction. Methods Arthropod’s trophic guilds (ground and vegetation-dwelling) were sampled in 20 spatial independent pairs of conventional (CF) and organic (OF) fields located in Brittany (Western France) by using pitfall traps and sweep nets replicated in time and space. Results A total of 95,822 arthropods belonging to 197 taxonomic groups were sampled. Farming system has a strong overall positive effect on the community structure of both ground- and vegetation-dwelling arthropods. Landscape heterogeneity, alone and in interaction with farming systems, affected positively the diversity and abundance of most trophic groups for both ground- and vegetation-dwelling arthropods. Organic farming therefore affected the trophic composition of arthropod communities not only locally, but also at the landscape scale. Conclusions Our study highlights the strong positive effect of farming system and the landscape heterogeneity on arthropod communities and more importantly the interconnection between different spatial scales in this process. Taking these aspects into account is therefore crucial in understanding arthropod community dynamics in agroecosystems
Sweat sodium composition and sweat loss estimation through wearable sensors and predictive equations in dry and humid hot conditions
No full textInternational audienceIntroduction: Individualized sweat testing is essential for tailoring hydration and nutrition strategies, as water and sodium losses during exercise vary greatly across athletes. The validity of a wearable sweat sensor (S1, Flowbio) and a handheld analyzer (LAQUAtwin, Horiba Advanced Techno) for measuring sweat sodium concentration ([Na + ]) was tested against flame photometry (FP). Additionally, whole body sweat loss (WBSL) estimated by the S1 and by a sweat rate calculator (SRC) was compared to the scale-based method. Methods: Twenty-three recreationally active participants (11 males, 12 females) completed two sessions in hot and dry (40 °C, 36% rh) and hot and humid (30 °C, 81% rh) controlled environmental conditions on a cycling ergometer (74 ± 12 min, 1.9 ± 0.4 W/kg). Participants were instrumented with two S1 sensors and absorbent patches placed on each upper arm. Sweat was extracted from patches to measure [Na + ] with LAQUAtwin and FP. Nude body mass was measured to the nearest 0.005 kg before and after exercise, with fluid intake monitored to determine WBSL. The influence of the method and the condition on the measure of sweat [Na + ] and WBSL was investigated with linear mixed-effects models. Results: The estimated marginal means of sweat [Na + ] in dry conditions for S1 and LAQUAtwin were equivalent (both 53 mmol/L, p = 0.952) and significantly lower than FP (63 mmol, both -10 mmol, p < 0.001). No significant interaction effects were observed between methods and conditions. For WBSL, the S1 estimation (1.479 kg) was not different than the scale measure (1.432 kg, 0.047, p = 0.624) while the SRC estimation (1.202 kg) was significantly lower than the scale and S1 (both p < 0.001), without interactions effects. Conclusion: S1 offers equivalent and more practical collection of sweat [Na + ] compared to the LAQUAtwin during indoor cycling ergometer exercise. However, measurements from both devices should currently be interpreted Frontiers in Physiology 01 frontiersin.org Bandiera et al. 10.3389/fphys.2025.1717275with caution and not considered equivalent to laboratory-grade analyses. Furthermore, S1 is an adequate tool during indoor cycling ergometer exercise to estimate WBSL when scale measurements are impractical, while SRC was found to underestimate fluid loss.</p