Etat de la végétation ligneuse dans trois unités d’utilisation des terres d’une zone agropastorale au Sénégal (région de Kaffrine)

L’étude est réalisée dans les parcours communautaires du département de Koungheul. Cette zone constitue la partie centrale d’un axe de transhumance de saison sèche des ruminants. Sa végétation naturelle, ligneuse en particulier, contribue à l’entretien du cheptel durant les mois de saison sèche et du coup, subit d’importantes pressions d’ordres diverses. Ainsi, l’objectif de l’étude est de caractériser la végétation ligneuse dans trois unités d’utilisation occupation des sols en utilisation une méthode d’échantillonnage aléatoire par des relevés de végétation ligneuse, pour une contribution à la prise de décisions, dans le cadre de la gestion des ressources dans la localité. Les résultats montrent au total la présence de 40 espèces ligneuses relevant de 33 genres et 21 familles avec une proportion importante des espèces de la famille des Combretaceae. Les paramètres étudiés montrent une nette différence entre ces entités témoignant de leur hétérogénéité, mais avec un plus grand niveau de stabilité du peuplement dans la forêt. Le peuplement est globalement jeune avec une importante proportion des individus dans les premières classes de diamètre et de hauteur. Les champs présentent la proportion d’individus adultes la plus importante mais la régénération dans cette entité est faible. Développer des moyens participatifs de gestion des ressources par la régénération assistée peut être un atout considérable de conservation des espèces ligneuses et des écosystèmes.Mots clés : Ligneux, champs, jachères, forêt, hétérogénéité, régénération

Pour une agriculture intelligente face au changement climatique au Sénégal: Recueil de bonnes pratiques d'adaptation et d'atténuation

Climate change is at the present time a new threat which leads to increased frequency and intensity of floods, droughts and cyclones with rising sea levels; thus placing additional demands on a situation already critical in rural areas. In Senegal, as in many countries of the Sahel, those natural phenomena result in a significant drop in harvests, water shortages and worsening health crisis which leads to consequences such as growing food insecurity of the population; thus threatening the progress achieved in regards with the fight against poverty during the last century. Indeed, many farmers live in rural areas which are characterized as low rainfall, saline soils, fragile or degraded soils and limited market access areas. The poverty in which they live, especially those of women, is often worsened by social exclusion. Such farmers are vulnerable because they depend directly on rainfall and seasons. They have little savings while supports from the government or their local authorities remain inadequate. It is essential to strengthen the adaptive capacity of vulnerable countries and communities to cope with the impacts of climate change on agriculture and food security. This document is the result of a multi-criteria analysis of experiences of tackling climate variability, drought and desertification, and land degradation on one hand, and Adaptation to Climate Change in Senegal on the other. It is carried out on the initiative of the national platform for science-policy dialogue on adaptation of agriculture and food security to climate change (C-CASA) for capacity building and informed decision making for adaptation to climate change. This work has received technical and financial support from CCAFS Program (www.ccafs.cgiar.org). It is intended for the use of field workers in the area of adaptation to climate change. It also serves as technologies and tools guide to adapt to climate change impacts in the area of agriculture and food security. The manual is based primarily on (1) both the institutional and peasant experiences of the actors; (2) the recommendations of the reports of the Inter-governmental Panel on Climate Change (IPCC); (3) the procedures manual for assessing climate change impacts and adaptation strategies; (4) the results of development projects and applied research. This is a collection that comes as a complement to other initiatives in the country and ongoing operations which provide practical examples of using the technological options for successful implementation of projects and programs and for the definition of agricultural policies in the Sahel

Valeur socio-économique de l’arbre en milieu malinké (Khossanto, Sénégal)

Objectif: Déterminer la valeur socio-économique des ligneux dans la vie des populations de la communauté rurale de Khossanto, dans la partie orientale du Sénégal et apprécier les savoirs et savoir-faire locaux vis-à-vis de l’arbre.Méthodologie et résultats: Des enquêtes ethnobotaniques ont été menés auprès des populations de la communauté rurale de Khossanto. Nous avons recensé les savoirs et savoir-faire des Malinkés vis-à-vis de l’arbre dans six catégories d’usages : alimentation, fourrage, construction, artisanat, énergie domestique et phytothérapie, avec des niveaux de consensus assez élevés (partout supérieur à 80%). Six espèces multi usages (impliquées dans presque toutes les catégories) s’avèrent être les plus utiles : Cordyla pinnata, Borassus aethiopum, Vitellaria paradoxa, Ziziphus mauritiana, Pterocarpus erinaceus et Adansonia digitata. Les fruits (31%), les feuilles (29%) et le bois (22%) sont les parties les plus utilisées.Conclusion et application des résultats: L’importance socio-économique de l’arbre en milieu malinké est clairement établie autour de six catégories d’usage : le fourrage, l’alimentation humaine, l’énergie domestique, la phytothérapie, la construction et l’artisanat. Cette importance des ligneux a pour corollaire un prélèvement assez intense de certaines parties, qui devient une menace pour ces espèces. Il apparaît important d’asseoir un modèle de gestion durable de ces parcours communautaires.Mots clés : Ligneux, usages, importance, Sénégal , Kédougou

In vitro vasorelaxation mechanisms of bioactive compounds extracted from Hibiscus sabdariffa on rat thoracic aorta

<p>Abstract</p> <p>Background</p> <p>In this study, we suggested characterizing the vasodilator effects and the phytochemical characteristics of a plant with food usage also used in traditional treatment of arterial high blood pressure in Senegal.</p> <p>Methods</p> <p>Vascular effects of crude extract of dried and powdered calyces of <it>Hibiscus sabdariffa </it>were evaluated on isolated thoracic aorta of male Wistar rats on organ chambers. The crude extract was also enriched by liquid-liquid extraction. The various cyclohexane, dichloromethane, ethyl acetate, butanol extracts obtained as well as the residual marc were subjected to Sephadex LH-20 column chromatography. The different methanolic eluate fractions were then analyzed by Thin Layer (TLC) and High Performance Liquid Chromatography (HPLC) and their vascular effects also evaluated.</p> <p>Results</p> <p>The H. Sabdariffa crude extract induced mainly endothelium-dependent relaxant effects. The endothelium-dependent relaxations result from NOS activation and those who not dependent to endothelium from activation of smooth muscle potassium channels. The phytochemical analysis revealed the presence of phenolic acids in the ethyl acetate extract and anthocyans in the butanolic extract. The biological efficiency of the various studied extracts, in term of vasorelaxant capacity, showed that: Butanol extract > Crude extract > Residual marc > Ethyl acetate extract. These results suggest that the strong activity of the butanolic extract is essentially due to the presence of anthocyans found in its fractions 43-67.</p> <p>Conclusion</p> <p>These results demonstrate the vasodilator potential of <it>hibiscus sabdariffa </it>and contribute to his valuation as therapeutic alternative.</p

Root Canal Shaping by Single-File Systems and Rotary Instruments: a Laboratory Study

Introduction: The aim of this study was to compare the shaping ability of two single-file systems and conventional rotary instruments in severely curved root canals of extracted human molars. Methods and Materials: Mesiobuccal canals of 120 mandibular molars with angles of curvature ranging between 25° and 35° and radii of curvature from 5 to 9 mm, were divided into three groups (n=40). In each group the canals were instrumented with either WaveOne (W), Reciproc(R) or ProTaper (P). The time required for canal shaping and the frequency of broken instruments were recorded. The standardized pre and post-instrumentation radiographs were taken to determine changes in working length (WL) and straightening of canal curvature. The presence of blockage or perforation was also evaluated. Data were analyzed using the one-way analysis of variance (ANOVA) and post-hoc Tukey’s test. The level of significance was set at 0.05. Results: Both single-instrument systems reduced the canal preparation time by approximately 50% (P&lt;0.05). No incidence of broken instruments from single-file systems was reported; however, two F2 instruments in the P group were broken (P&lt;0.05). Reduction in WL and straightening of canal curvature was observed in all three systems with the highest scores belonging to P system (P&lt;0.05). No case of blockage or perforation was found during shaping in any group. Conclusion: Single-file systems shaped curved canals with substantial saving in time and a significant decrease in incidence of instrument separation, change in WL, and straightening of canal curvature

Développement des unités de croissance de jeunes plants d’essences sahéliennes : Acacia tortilis (Forsk.) Hayne subsp.raddiana (Savi) Brenan, de Balanites aegyptiaca (L.) Del et de Zizyphus mauritiana Lam., (Dakar, Sénégal)

Malgré les usages multiples des plantes ligneuses du Sahel, peu d’études se sont intéressées au suivi de la mise en place des différents segments de tige de jeunes plants de Acacia tortilis (Forsk.) Haynesubsp.raddiana (Savi) Brenan, de Balanites aegyptiaca (L.) Del et de Zizyphus mauritiana Lam. Notre objectif était alors de représenter les différents ordres, leur nombre en fonction de leur période d’apparition et le rapport entre le développement successif des Unités de Croissance (UC) des jeunes plants de A. tortilis, de B. aegyptiaca et de Z. mauritiana a été suivi en milieu semi-contrôlé par une approche visuelle globale à l’échelle du houppier entre octobre 2002 et octobre 2004. Les processus de ramification à l’échelle du houppier révèlent 5 ordres différents d’UC chez A. tortilisà 16 mois, 7 chez B. aegyptiaca à 24 mois et 5 chez Z. mauritiana à 9 mois. Les UC3 et UC4 sont les plus nombreuses chez les jeunes plants de B.aegyptiaca et Z.mauritiana alors que chez ceux de A.tortilis, le nombre des UC2 est nettement supérieur. L’UC1 est la plus longue chez les trois espèces. Le diamètre de l’UC1 à 24 mois est de 79 mm chez B. aegyptiaca, de 39 mm chez Z. mauritiana et de 20 mm chez A. tortilis avec un nombre de noeuds nettement plus important chez A. tortilis. La longueur et le nombre de noeuds feuillés varient d’une espèce à l’autre.Mots-clés : Acaciatortilis, Balanites aegyptiaca, Zizyphusmauritiana, jeune plant, unité de croissance (UC),noeuds

Effect of Deep-Fat Frying on Chemical Properties of Edible Vegetable Oils Used By Senegalese Households

Deep-fat frying performed at high temperatures under atmospheric pressure is a common method of preparing dishes in Senegalese culinary practices. This operation can lead to deterioration of physical, chemical, nutritional and sensory properties of oil, which affects its frying performance. It also results in the production of volatile products such as aldehydes and non volatile fraction which remains in the frying medium. Some of these remaining products have been implicated in producing adverse health effects. Highly oxidized oils may also produce polyaromatic hydrocarbons, which have carcinogenic effect. This work was intended to evaluate the effect of frying on chemical properties of edible vegetable oils. Frying process was applied to meat, fish and potatoes in Senegalese culinary conditions. Ten (10) oil samples, each of three different brands, were purchased from wholesalers and retailers in different neighborhoods of Dakar. The samples were subjected to frying at 220°C for 40 min and then oils were withdrawn in amber bottles samples of which were taken for analysis. Acid value, peroxide value and total polar components were used to evaluate the quality of these oils after initial determination of the iodine value and the moisture and volatile matter content. Acid value increased after 40 min of frying and values ranged from 0.62 to 1.08 mg/kg after frying fish, while those for meat and potatoes ranged from 0.39 to 0.73 and 0.37 to 0.51 mg/kg, respectively. Peroxide value increased slightly for peanut oil (A) and sharply for peanut oil (B) and sunflower oil (C). Frying fish led to high values of total polar components whereas those obtained after frying meat and potatoes during 40 min did not exceed 15.27% except for peanut oil (A). Therefore, frying affects chemical parameter values of edible vegetable oils, which increase at a level depending on the product to be fried. A sharp Total Polar components increase was obtained after frying fish using the three types of oil with values exceeding, sometimes, the maximum level set by the Codex Alimentarius Commission. This latter chemical parameter is considered a good indicator of overall quality of frying oil. Thus in Senegalese culinary practices where frying oil is often reused in families with low-income, such a situation may lead to significant sanitary risks. In view of these results, investigations need to be extended to other types of oil marketed in Senegal.Keywords: edible-oils, quality, frying, fish, mea

Emergence of an environmental citizenship in Senegalese rural areas: local development initiatives by the Fannabara association in Missirah (Fatick, Senegal)

In Missirah, a village in Senegal, a group of young ecologists who are part of an association called Fannabara, developed initiatives with the objective of restoring deteriorating ecosystems and promoting local culture. Along with the many numerous to their credit, in cooperation with partners such as the IUCN and the Global Environment Facility (GEF), Fannabara is trying to establish itself as a framework within which the interests of the Missirah communities can be defended. The projects undertaken are in line with a perspective that promotes public-awareness, education and actions for a sustainable development. The project is dependent on obtaining the necessary resources to meet the ecological, economic, social and cultural challenges faced in Missirah. This research shows that the decentralization and accountability context for community-level players – associated with the changes taking place in rural areas, namely as they relate to the participation of populations in the governance of biodiversity – has greatly contributed to the promotion of new local development dynamics.À Missirah, village du Sénégal, des initiatives ont été développées par un groupe de jeunes écologistes regroupés au sein de l’association Fannabara. Leurs objectifs visent la restauration des écosystèmes en dégradation et la promotion de la culture locale. Tout en comptant à son actif de nombreuses réalisations, avec des partenaires comme l’UICN et le Fonds pour l’Environnement Mondial (FEM), Fannabara cherche à se positionner comme le cadre de défense des intérêts des populations de Missirah. Les projets initiés s’inscrivent dans une perspective de sensibilisation, d’éducation et d’actions pour un environnement durable. Le tout étant conditionné par l’obtention de moyens permettant de les réaliser pour répondre aux défis écologiques, économiques, sociaux et culturels à Missirah. Cette recherche montre que le contexte de décentralisation et de responsabilisation des acteurs à la base, associé aux mutations dans les zones rurales, notamment dans leurs dimensions liées à la participation des populations dans la gouvernance de la biodiversité, ont grandement favorisé les nouvelles dynamiques de développement local.En Missirah, una aldea de Senegal, un grupo de jóvenes ecologistas que forman parte de una asociación llamada Fannabara, desarrolló iniciativas con el objetivo de restaurar los deteriorados ecosistemas y promover la cultura local. Contando en su haber con numerosas realizaciones, en cooperación con socios como el IUCN y el Fondo Mundial para el Medio Ambiente (FMMA), Fannabara está tratando de establecerse como un marco dentro del cual los intereses de las comunidades de Missirah puedan ser defendidas. Los proyectos emprendidos están en consonancia con una perspectiva que promueve la concienciación pública, la educación y las acciones para un desarrollo sostenible. El proyecto depende de obtener los recursos necesarios para enfrentarse a los desafíos ecológicos, económicos, sociales y culturales en Missirah. Esta investigación muestra que el contexto de descentralización y responsabilidad de los actores a nivel de la comunidad, asociado a los cambios que tienen lugar en áreas rurales, particularmente en lo referente a su relación con la participación de las poblaciones en el gobierno de la biodiversidad, ha contribuido mucho a la promoción de nuevas dinámicas de desarrollo local

Icacina senegalensis (Icacinaceae), traditionally used for the treatment of malaria, inhibits in vitro Plasmodium falciparum growth without host cell toxicity

<p>Abstract</p> <p>Background</p> <p>With the aim of discovering new natural active extracts against malaria parasites, <it>Icacina senegalensis </it>was selected after an ethnopharmacological survey conducted on plants used in traditional malaria treatment in Senegal.</p> <p>Methods</p> <p>Different concentrations of the plant extract and fractions were tested on synchronized <it>Plasmodium falciparum </it>cultures at the ring stage using the parasite lactate dehydrogenase assay. Their haemolytic activity and <it>in vitro </it>cytoxicity were evaluated. The chromatographic profiles of active fractions were also established.</p> <p>Results</p> <p>The plant extract and fractions revealed anti-plasmodial activity (IC₅₀< 5 μg/mL) with no toxicity (Selectivity indexes >10). The dichloromethane fraction showed stronger anti-plasmodial activity than the total extract.</p> <p>Conclusion</p> <p>Anti-plasmodial activity and toxicity of <it>I. senegalensis </it>are reported for the first time and showed promising results in malaria field research.</p