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Viande in vitro - Intérêts, enjeux et perception des consommateurs
No full textInternational audienceLa viande in vitro, produite à partir de cellules en prolifération dans un milieu de culture contenant des facteurs hormonaux, est présentée comme capable de répondre à la demande grandissante en protéines animales sans les inconvénients de l'élevage. Toutefois, ses qualités sanitaires et nutritionnelles,ainsi que son faible impact environnemental potentiel, font débat. Aussi, la viande in vitro ne fait pas consensus. Après avoir décrit ses avantages et ses inconvénients, cet article détaille les enjeux techniques, sociaux et éthiques associés au développement de ce produit. Enfin, les acteurs impliqués, la législation associée et la perception de cette technologie par les consommateurs sont abordés
Morphological features of tooth development and replacement in the rabbit Oryctolagus cuniculus
No full textInternational audienceDental development mechanisms in mammals are highly studied using the mouse as a biological model. However, the mouse has a single, unreplaced, set of teeth. Features of mammalian tooth replacement are thus poorly known. In this paper, we study mammalian tooth development and replacement using the European rabbit, Oryctolagus cuniculus, as a new model. Using 3D-reconstructions associated with histological sections, we obtained the complete description of the histo-morphological chronology of dental development and replacement in rabbit. We also describe in the dentin the presence of holes opening the pulp cavity in newborns. These holes are quickly repaired with a new and fast apposition of dentin from the pre-existing odontoblasts. The detailed dental morphogenesis chronology presented allows us to propose the rabbit Oryctolagus cuniculus as a suitable model to study mammalian tooth replacement
In Nitrate-Rich Soil, Fallopia x bohemica Modifies Functioning of N Cycle Compared to Native Monocultures
No full textInternational audienceThe effects of invasive species at the ecosystem level remain an important component required to assess their impacts. Here, we conducted an experimental study with labeled nitrogen in two types of soil (low and high nitrate conditions), investigating the effects of (1) the presence of Fallopia x bohemica on the traits of three native species (Humulus lupulus, Sambucus ebulus, and Urtica dioica) and (2) interspecific competition (monoculture of the invasive species, monoculture of the native species, and a mixture of invasive/native species) on nitrification, denitrification, and related microbial communities (i.e., functional gene abundances). We found that the species with the higher nitrate assimilation rate (U. dioica) was affected differently by the invasive species, with no effect or even an increase in aboveground biomass and number of leaves. F. x bohemica also decreased denitrification, but only in the soil with high nitrate concentrations. The impacts of the invasive species on nitrification and soil microorganisms depended on the native species and the soil type, suggesting that competition for nitrogen between plants and between plants and microorganisms is highly dependent on species traits and environmental conditions. This research highlights that studies looking at the impacts of invasive species on ecosystems should consider the plant–soil–microorganism complex as a whole
Caractérisation fonctionnelle et performances d’une céréale vivace (Thinopyrum intermedium) : une alternative agroécologique pour les systèmes de grandes cultures d’Europe occidentale.
No full textGrowing perennial grains, yielding several years from one seeding, is suggested as a valuable option toward more agroecological systems, sustaining production and environmental goals. The Thinopyrum intermedium species is studied since it may offer significant grain yields while providing other important ecosystem services regarding soil conservation and natural resources protection. The multifunctionality of the crop is a key aspect of its relevance and value, partially offsetting the lower grain yields as compared to annual grain counterparts. However, a thorough assessment of its above and belowground growth is still missing, and the influence of growth conditions mostly unknown (e.g. water, nitrogen, temperature). This lack of knowledge is strongly hindering the development of suitable management practices to ensure services provision and to increase the agroecosystem sustainability. This work assesses the crop performances in a context of a temporary insertion (2-3 years) into a grain crop rotation. The study is based on 12 fields experiments, either on-farm or in research station, in France and Belgium. This work allowed to characterize the growth and functioning of the crop and to evaluate its performances during two consecutive years (establishment and following year). Several key parameters have been identified (rooting system development, flowering induction, growth dynamic, grain yields components) to understand the potential of grain-forage dual production, soil protection, resources management, and weed control. Results are notably illustrating the crop changes between the establishment year and the following year (above and belowground biomass increase). These changes are important when analyzing the crop ability to capture and use soil resources. Generally, aboveground traits (e.g. biomass, phenology, grain yield components) and belowground traits (e.g. root depth, biomass, diameter, density) indicate an unfavorable resource allocation impacting grain productivity, while favoring the vegetative biomass (roots, stems, leaves) that supports the perenniality of the species. Meanwhile, results of this work are showing a great potential from this perennial grain to build diversified cropping systems, using and conserving resources efficiently, and supporting soil fertility.La culture de céréales vivaces, fournissant une production de grains sur plusieurs années consécutives sans être ressemées, est proposée comme une innovation agroécologique pour des systèmes de culture productifs et plus respectueux de l’environnement. L’espèce Thinopyrum intermedium est ici étudiée car elle propose un potentiel de production en progression et est susceptible de fournir de nombreux services écosystémiques visant la protection du sol et des ressources naturelles. La multifonctionnalité de cette culture est un élément clé de sa valorisation, compensant pour partie les faibles rendements en grains. Cependant, les caractéristiques du développement aérien et racinaire de la céréale sont encore peu évaluées au champ, et l’influence des conditions de culture peu définie (e.g. eau, azote, température). Ce manque de connaissances limite fortement le raisonnement des méthodes de gestion adaptées à la culture et favorisant l’obtention de services et la durabilité de l’agroécosystème. Ce travail propose d’étudier le potentiel de cette culture dans le cadre d’une implantation de 2-3 ans au sein d’une rotation céréalière. Il s’appuie sur un réseau de 12 expérimentations en stations ou en plein champ, en France et en Belgique. Ce travail a permis de caractériser le fonctionnement de la culture et d’évaluer ses performances pendant deux années de production consécutives (l’année d’implantation et l’année de repousse suivante). Plusieurs paramètres clés ont été identifiés (développement du système racinaire, conditions de l’induction florale, dynamique de croissance, composantes du rendement en grains) pour la compréhension des performances de production grain-fourrage, de protection des sols, de gestion des ressources et de régulation des bio-agresseurs (adventices) de cette culture. Les résultats présentés illustrent une évolution notable de la culture entre les deux années de production (augmentation de la biomasse racinaire et aérienne) à prendre en compte dans la caractérisation des capacités d’acquisition et d’utilisation des ressources du sol. D’une manière générale, les traits aériens (e.g. biomasse, phénologie, composantes du rendement) et racinaires (e.g. profondeur, biomasse, diamètre, densité) indiquent une allocation des ressources défavorable à la production grainière au profit d’une forte production de biomasse aérienne et racinaire, support de la pérennité de l’espèce. Les résultats de la thèse témoignent aussi d’un fort potentiel de cette culture pour concevoir des systèmes de culture plus diversifiés, plus efficients dans l’utilisation et la conservation des ressources et, favorables à la fertilité du sol
Physicochemical, rheological, and micro-structural properties of yogurts produced from mixtures of camel and bovine milks
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Introducing Perennial Grain in Grain Crops Rotation: The Role of Rooting Pattern in Soil Quality Management
No full textInternational audienceThe use of the perennial grain intermediate wheatgrass (Thinopyrum intermedium (Host) Barkworth & D.R. Dewey) may have the potential to sustain soil health and fertility through the development of an extensive root system. However, references are scarce to demonstrate its potential influence in a context of a limited perennial grain growth phase, integrated into annual grain crops succession. This study aims at determining how early a perennial crop rooting system differs from that of an annual crop through root development and root traits and microbial indicators. Our results indicate that the two-year-old intermediate wheatgrass promotes a denser and deeper rooting system with proportionally more root biomass and length deeper in the soil profile. From the first growing season, the perennial grain demonstrated a suite of root traits typical of a more resource-conservative strategy, and more belowground-oriented resource allocation. Soil fungal biomass indicators were enhanced. Arbuscular mycorrhizal fungi (AMF) indicators were notably found to be improved at 1 m depth during the second growing season. This study provides evidence that grain-based agriculture can benefit from the potential of deeper and long-lived root systems of intermediate wheatgrass to manage soils. The periodic use of a short-term perennial phase in the crop rotation has the potential to improve soil functioning in the long term
Complementarity of grasslands and cereal fields ensures carabid regional diversity in French farmlands
No full textInternational audienceCarabids (ground beetles) are important beneficial insects that contribute to biological control of pests and weeds in crop production. They can be found in different agricultural landscape habitats. However, little has been studied about the composition and similarity of carabid assemblages between two major land covers types: cropland and grassland. In a context of declining grassland areas in farmlands, highlighting complementarities of these two land covers is crucial to encourage land use planning that favors biodiversity. The objective of this study was to evaluate the relative and shared contribution of cereal crops and grasslands to carabid diversity in farmlands. Carabids were sampled in 104 pairs of cereal fields and grasslands in 3 agricultural regions of southeastern France. Carabid diversity was further analyzed with multiple regression models, including different local parameters. The correlations between assemblage similarities and geographical distance of sampled cereal fields and grasslands were also studied. Overall, 115 different species were found, 82 in cereal fields and 95 in grasslands. Per site species number and activity-density were higher in the two study regions with higher grassland cover. Evenness of carabid assemblages were higher in grasslands. Cropland and grassland remained strongly distinct, but assemblages showed higher similarity up to 4 km distance from each other. The study illustrates the major interest in preserving grassland within farmland for land use planners and/or policy makers. We found that grasslands and croplands complement each other. Though they host distinct communities, they provide continuous and different resources to the species throughout the year
Agroecological approaches and other innovations
No full textInternational audienceIn June 2019, the HLPE report on “Agroecological approaches and other innovations for sustainable agriculture and food systems that enhance food security and nutrition”1 was released. This report is the first FAO report dealing prominently with agroecology. It suggests a concise set of 13 agro-ecological principles and points out that there has been much less invest-ment in research on agroecological approaches than on other innovative approaches
Comparative review of three approaches to biofuel production from energy crops as feedstock in a developing country
No full textInternational audienceThis study is a comparative evaluation of three approaches to biofuel production from energy crops including biogas, bioethanol and biodiesel to ascertain which one is the most effective and more energy-efficient than the others. Moreover, the potential of biofuel production from the best option was studied. For this purpose, biogas generation from corn silage, bioethanol generation from corn, and biodiesel production from peanuts in Iran (as a case study) were studied. The results revealed that 10,683.36 m3 of biogas, 2.53 m3 of bioethanol and 0.70 m3 of biodiesel could be produced per each hectare of energy crops. The total greenhouse gas emissions for each MJ energy generation of biogas, bioethanol and biodiesel were 0.01, 0.04 and 0.03 kgCO2eq, respectively. Accordingly, the total annual biogas potential from corn silage (as the best option) in Iran is 3953.74 million m3, which is equivalent to 1515.94 million barrels of oil
