Production d’alevins de Tilapia (Oreochromis niloticus) avec 3 aliments à base de sous-produits agro-industriels au Nord du Sénégal

L’étude a été réalisée dans un étang de la station piscicole de Richard TOLL au Nord du Sénégal entre 2013 et 2014. Elle a permis de tester la performance de deux aliments à base de sous-produits agro industriels locaux (A1 et A2) à un aliment (A3) importé de la Chine sur la croissance des alevins de tilapia (Oreochromis niloticus) du fleuve Sénégal. Les qualités nutritionnelles des aliments A1, A2 et A3 sur la croissance et le taux de mortalités des alevins sont déterminés pour chaque aliment. La méthodologie est accentuée sur la mesure des paramètres physico-chimiques, le suivi de la croissance des alevins et le test en triplicata de ces trois aliments dans des appas de 2m3. Les résultats obtenus ont montré que l’aliment A2 a donné les meilleures performances que l’aliment A1 avec des croissances moyennes individuelles respectives de 0,21±0,04g/j et 0,12±0,03g/j. Les gains de poids moyens et taux de conversion alimentaire sont respectivement 3,09±0,53g et 1,79±0,26 g pour l’aliment A2 et 1,82±0,45g et 1,64±0,01 g pour l’aliment A1. Statistiquement, les résultats obtenus avec l’aliment A2 ne sont pas différents de ceux obtenus avec l’aliment A3 importé de la Chine.© 2015 International Formulae Group. All rights reserved.Mots clés: Alevins, Oreochromis niloticus, aliment, croissance, performanceEnglish Title:  Production of young Tilapia fish (Oreochromis niloticus) with 3 foods containing under agroindustrial products in the North of SenegalEnglish AbstractThe study was carried out in a pond of the piscicultural station of Richard-TOLL in the North of Senegal between 2013 and 2014. It allowed to test the performance of two food containing local agro industrial by-products (A1 and A2) with a food (A3) imported from China for the growth of young tilapias fish (Oreochromis niloticus) of the Senegal river. Nutritional qualities of the food A1, A2 and A3 on the growth and the death rate of young fish were given for each food. The methodology emphasized on the measure of the physicochemical parameters, the follow-up of the growth of young fish and the test in triplicate of these three food in grabbed of 2 m3.The results obtained showed that A2 food gave the best performances than A1 food with the respective average individual growths of 0, 21±0,04 g/j and 0,12±0,03 g/j. The mean gain of weight and food conversion rate are respectively 3,09±0,53 G and 1,79±0,26 G for A2 food and 1,82±0,45 G and  1,64±0,01 G for A1 food. Statistically analysed, the results obtained with the A2 food are not different from those obtained with the A3 food imported from China.© 2015 International Formulae Group. All rights reserved.Keywords: Fry, Oreochromis niloticus, food, growth, performanc

Evaluation of Water Resources Quality in Sabodala Gold Mining Region and Its Surrounding Area (Senegal)

peer reviewedGeochemical and Geostatistical tools were used to assess: 1) the chemical quality and, geochemical processes in crystalline rock aquifers in Sabodala (Eastern Senegal) and its surroundings and 2) the impact of mining activities on their quality. A total of 26 water samples collected at boreholes, dug wells and stream, were analyzed to determine major and trace elements concentration focused on elements that represent more threats on human health. Boxplots define chemical characteristics of water for each aquifer formation compared to surface waters. Geostatistical analysis show two sources of water mineralization with regard to major elements: a first natural source characterized by Ca-Mg-HCO3 water type from boreholes and unpolluted surface water and a second group characterized by polluted water by nitrates with Na-NO3-Cl type mainly observed in upper weathered aquifers. However, considering trace element, geostatistical analysis showed three water groups: water with very low trace element concentrations encountered in boreholes and unpolluted surface waters, and waters with relatively high trace element concentrations such as Al observed in areas affected by gold mining activities and finally, polluted waters by Ni, Co, Mn and Cr observed at Sabodala. Results show that in eastern Senegal well waters are vulnerable and often affected by pollution

Prospection Hydrogéologique et Géophysique du Système Aquifère du Plateau de Mbé, District de Ngabé, Congo

La prospection hydrogéologique et géophysique entreprise sur les sites des villages d’Imvouba et d’Ingah dans le plateau de Mbé a permis de déterminer la qualité des eaux souterraines et de surface ainsi que les niveaux aquifères favorables à l’implantation des forages productifs. La prospection géophysique utilisant les méthodes des résistivités électriques avec le dispositif Schlumberger est menée dans le but de déterminer les emplacements favorables à l’implantation des forages positifs avec des débits d’exploitation importants pour un approvisionnement en eau potable des populations. Cette prospection géophysique a révélé que la foration devrait se faire à des profondeurs prévisionnelles de 200 à 250 m voir plus afin d’atteindre les débits prévus par le projet. La prospection hydrogéologique des eaux souterraines et de surface a montré la dominance du faciès chimique bicarbonaté et calcique et que la bonne qualité physico-chimique des eaux de la région est remise en cause par la présence de certains éléments comme le fer total, le manganèse, les phosphates et l’aluminium à des teneurs élevées dépassant parfois les concentrations maximales admissibles pour l’eau de boisson (OMS, 2017). Les formations géologiques présentes dans le plateau de Mbé renferment un système aquifère multicouche bien alimentés par l’infiltration directe des eaux de pluie (1600 à 2500 mm/an). The hydrogeological and geophysical prospection carried out on the sites of the Imvouba and Ingah villages in theMbé plateau has made it possible to determine the quality of the groundwater and surface water as well as the aquifer levels, which is favorable to the implantation of the productive boreholes. Geophysical prospecting, based on electrical resistivity methods using the Schlumberger device, was conducted in order to determine the favorable locations for the implantation of positive boreholes with high exploitation rates for a drinking water supply of the populations. This geophysical survey revealed that the drilling should be done at predicted depths of 200 to 250 m or more in order to reach the projected flows of the project. Hydrogeological prospecting of groundwater and surface water has shown the dominance of the bicarbonated and calcic chemical facies. The good physicochemical quality of the waters of the region shows the presence of some elements such as total iron, manganese, phosphates and aluminum at high levels which sometimes exceeds the maximum permissible concentrations for drinking water (WHO, 2017). The geological formations present in the Mbé plateau contain a multilayer aquifer system well fed by the direct infiltration of rainwater (1600 to 2500 mm / year)

Use of environmental isotopes to infer flow in the highly exploited aquifer system of the Diass region (Senegal)

audience: researcher, professionalThe Diass horst multilayered aquifer constitutes a complex hydrogeological system. But stable isotopes are illustrated to be powerful tools for clarifying the origin of recharge water, and the groundwater dynamics due to high exploitation of the system. Used with 3H and 14C, data confirms that most of the investigated groundwater are palaeowaters. Pumping has an impact on groundwater flow evidenced by the different water isotope compositions that illustrates the transient conditions of the system. Mixing of old waters and recently recharged (tritiated) waters occurs in some exploited boreholes, indicates lateral flow to the pumping field through the main groundwater flow directions

Mecanismes De Contamination Des Eaux Souterraines Dans Le Secteur Du Lac Mbeubeuss, Dakar, Senegal

The physicochemistry of groundwater in the immediate environment of the dump, and its surroundings, shows that the true value of the electrical conductivity of groundwater is close to 2000 μS / cm. The value of electrical conductivity that is greater than 2000 μS / cm demonstrates groundwater contamination through the Mbeubeuss Lake landfill, with chemical groundwater facies dominated by Sodium Chloride, Potassium Chloride, and Calcium Chloride. The study of the unsaturated zone of the aquifer and the relationship between the major chemical elements of groundwater, rainwater, and seawater made it possible to specify, on one hand, the sources of mineralization of the groundwater at the Mbeubeuss Lake site and its surroundings. Indeed, the situation close to the sea would suggest a considerable intake of salts by aerosols and sea spray. Based on contribution to this study, the influence of the old sediments of the dry Lake Mbeubeuss and the percolation of leachates resulting from the decomposition of garbage landfilled under the action of rainwater would be added. On the other hand, this study also made it possible to determine the main processes of controlling the mineralization of groundwater. This includes the marine inputs, the dissolution-precipitation of clay minerals present in the geological formations constituting the aquifer, the dilution- concentration, evaporation, and anthropogenic pollution

Improving fetal dystocia management using simulation in Senegal: midterm results

Background: Maternal mortality, which constitutes the extreme point of the existing inequality between women in poor and rich countries, remains very high in Africa south of the Sahara. The objective of this study was to introduce a new training approach in Emergency Obstetric and Neonatal Care (EmONC) entered in Senegal to strengthen the skills of healthcare providers.Methods: The approach was based on the skills training using the so-called "humanist" method and "lifesaving skills". Simulated practice took place in the classroom through thirteen clinical stations summarizing the clinical skills on EmONC. The evaluation was done in all phases and the results were recorded in a database to document the progress of each learner.Results: With this approach, 432 providers were trained in 10 months. The increase in technical achievements of each participant was documented through the database. The combination of training based on the model “learning by doing” has ensured learning and mastering all EmONC skills and reduced missed learning opportunities as observed in former EmONC trainings.Conclusions: The impact of training on EmONC indicators and the introduction of this learning modality in basic training are the two major challenges in terms of prospects

The evolving SARS-CoV-2 epidemic in Africa: Insights from rapidly expanding genomic surveillance

INTRODUCTION Investment in Africa over the past year with regard to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) sequencing has led to a massive increase in the number of sequences, which, to date, exceeds 100,000 sequences generated to track the pandemic on the continent. These sequences have profoundly affected how public health officials in Africa have navigated the COVID-19 pandemic. RATIONALE We demonstrate how the first 100,000 SARS-CoV-2 sequences from Africa have helped monitor the epidemic on the continent, how genomic surveillance expanded over the course of the pandemic, and how we adapted our sequencing methods to deal with an evolving virus. Finally, we also examine how viral lineages have spread across the continent in a phylogeographic framework to gain insights into the underlying temporal and spatial transmission dynamics for several variants of concern (VOCs). RESULTS Our results indicate that the number of countries in Africa that can sequence the virus within their own borders is growing and that this is coupled with a shorter turnaround time from the time of sampling to sequence submission. Ongoing evolution necessitated the continual updating of primer sets, and, as a result, eight primer sets were designed in tandem with viral evolution and used to ensure effective sequencing of the virus. The pandemic unfolded through multiple waves of infection that were each driven by distinct genetic lineages, with B.1-like ancestral strains associated with the first pandemic wave of infections in 2020. Successive waves on the continent were fueled by different VOCs, with Alpha and Beta cocirculating in distinct spatial patterns during the second wave and Delta and Omicron affecting the whole continent during the third and fourth waves, respectively. Phylogeographic reconstruction points toward distinct differences in viral importation and exportation patterns associated with the Alpha, Beta, Delta, and Omicron variants and subvariants, when considering both Africa versus the rest of the world and viral dissemination within the continent. Our epidemiological and phylogenetic inferences therefore underscore the heterogeneous nature of the pandemic on the continent and highlight key insights and challenges, for instance, recognizing the limitations of low testing proportions. We also highlight the early warning capacity that genomic surveillance in Africa has had for the rest of the world with the detection of new lineages and variants, the most recent being the characterization of various Omicron subvariants. CONCLUSION Sustained investment for diagnostics and genomic surveillance in Africa is needed as the virus continues to evolve. This is important not only to help combat SARS-CoV-2 on the continent but also because it can be used as a platform to help address the many emerging and reemerging infectious disease threats in Africa. In particular, capacity building for local sequencing within countries or within the continent should be prioritized because this is generally associated with shorter turnaround times, providing the most benefit to local public health authorities tasked with pandemic response and mitigation and allowing for the fastest reaction to localized outbreaks. These investments are crucial for pandemic preparedness and response and will serve the health of the continent well into the 21st century