Cooperation with the global South

published in: 2023 - 2022 - 2021 - 2019 - 2018 - 2017 - 2016


Local deities and traditional beliefs in mangroves

Gnansounou SC, Salako KV, Visée C, Dahdouh-Guebas F, Glèlè Kakaï R, Kestemont P, Henry S. 2024. The role of local deities and traditional beliefs in promoting the sustainable use of mangrove ecosystems. Forest Policy and Economics 160:103145. DOI: 10.1016/j.forpol.2023.103145.

Customary laws and traditional beliefs are progressively used in conservation and management of natural resources. However, their effectiveness has received limited attention. This case study from the Benin Republic (West Africa) examines how local deities and traditional beliefs can reduce manmade threats to mangroves. Data were collected from three categories of mangroves (sanctuary, sacralised, and non-deity mangroves) via direct observations, informal interviews, in-depth interviews, focus group discussions and household surveys. We used twelve indicators including the quantity of resources collected, the use value and the perceived diversity of fish and plant species to characterize each category of mangroves. Eight of these twelve indicators showed significant variation among the categories of mangroves. Highly destructive uses were generally associated with non-deity mangroves, whereas moderately and less destructive uses were mostly associated with sacralised and sanctuary mangroves, respectively. Local deities can thus assist to limit unsustainable use of mangrove forests. Among the mangrove users, salt producers and residents with many children collect and commercialise more mangrove resources than others and should be continually involved in sensitization and community engagement to foster the sustainable use of mangroves.

Catfish farming & salinity

Vo SN, Dao HM, Nguyen QD, Dang HQ, Huynh HV, Duong YT, Do HTT, Nguyen HTK, Farnir F, Kestemont P, Antoine-Moussiaux N, Nguyen PT. 2024. Striped catfish farming in different salinity conditions in the Mekong Delta, Vietnam: a comparison of management and economic efficiencies. Aquaculture International. DOI: 10.1007/s10499-023-01376-1.

This study aimed to identify differences in management and cost–benefit characteristics of striped catfish (Pangasianodon hypophthalmus) nursery and grow-out farms in freshwater and brackish water areas in the Mekong River Delta (MRD) of Vietnam. One hundred ten striped catfish farms in both areas (50 nursery and 60 grow-out farms) were stratified and sampled for an interview to determine their management and cost–benefit characteristics. The results indicated that the survival rate and yield of fish nursed in brackishwater farms were higher than those in freshwater farms..

Black soldier fly larvae meal combined with chitinase

Agbohessou PS, Mandiki R, Mes W, Blanquer A, Gérardy M, Garigliany M-M, Lambert J, Cambier P, Tokpon N, Lalèyè PA, Kestemont P. 2024. Effect of fatty acid-enriched black soldier fly larvae meal combined with chitinase on the metabolic processes of Nile tilapia. British Journal of Nutrition:1–16. DOI: 10.1017/S0007114523003008.

The aim of this study is to determine to what extent the addition of chitinase to black soldier fly (BSF) larval meal enriched or not with long-chain PUFA (LC-PUFA) could improve growth, protein digestion processes and gut microbial composition in Nile tilapia. Two different types of BSF meal were produced, in which larvae were reared on substrates formulated with vegetable culture substrate (VGS) or marine fish offal substrate (FOS). The BSF raised on VGS was enriched in α-linolenic acid (ALA), while that raised on FOS was enriched in ALA + EPA + DHA. Six BSF-based diets, enriched or not with chitinase, were formulated and compared with a control diet based on fishmeal and fish oil (FMFO)...


Spatial Optimization Methods for Malaria Risk Mapping

Morlighem C, Chaiban C, Georganos S, Brousse O, van Lipzig NPM, Wolff E, Dujardin S, Linard C. 2023. Spatial Optimization Methods for Malaria Risk Mapping in Sub-Saharan African Cities Using Demographic and Health Surveys. GeoHealth 7:e2023GH000787. DOI: 10.1029/2023GH000787.

Vector-borne diseases, such as malaria, are affected by the rapid urban growth and climate change in sub-Saharan Africa (SSA). In this context, intra-urban malaria risk maps act as a key decision-making tool for targeting malaria control interventions, especially in resource-limited settings. The Demographic and Health Surveys (DHS) provide a consistent malaria data source for mapping malaria risk at the national scale, but their use is limited at the intra-urban scale because survey cluster coordinates are randomly displaced for ethical reasons. In this research, we focus on predicting intra-urban malaria risk in SSA cities—Dakar, Dar es Salaam, Kampala and Ouagadougou—and investigate the use of spatial optimization methods to overcome the effect of DHS spatial displacement....

Emotional experiences after a disaster

Henriet E, de Longueville F, Henry S. 2023. Contrasted place-based emotional experiences after a disaster. International Journal of Disaster Risk Reduction 98:104118. DOI: 10.1016/j.ijdrr.2023.104118.

Emotion-place-disaster research tends to focus more on people and communities than on places and their specificities. Our study aims to explore disparities in people's place-based emotional experiences in the recovery period in a region of the Philippines affected by Typhoon Haiyan. We used anoriginal data collection game in which respondents were asked to associate pictures of places with emoticons and to explain these associations. A fully integrated mixed data analysis was then used to characterize non-Typhoon and Typhoon-related place-based emotional experiences. The large panel of descriptive results reveals predominantly positive emotional experiences that intertwine tangible and intangible facets of the person-place relationship. A variety of emotions and their meanings, individual and group concerns, and experiences before, during and after the disaster combine to produce contrasting place-based emotional experiences. In particular, the heterogeneity of the material impacts of the Typhoon on places and their implications for disaster recovery are described and discussed. We argue that further developments in the field should take into account the diversity of place-based emotional experiences highlighted in this research, which can improve disaster preparedness and response strategies and play an important role in disaster recovery.

Hazard Impacts, Vulnerability and Perception in Bujumbura (Burundi)

Nsabimana J, Henry S, Ndayisenga A, Kubwimana D, Dewitte O, Kervyn F, Michellier C. 2023. Geo-Hydrological Hazard Impacts, Vulnerability and Perception in Bujumbura (Burundi): A High-Resolution Field-Based Assessment in a Sprawling City. Land 12:1876. DOI: 10.3390/land12101876.

Rapid urbanization, demographic pressure, and sprawl of cities are key factors in the vulnerability and damage related to geo-hydrological hazards. Dysfunctional urban services that favor informal settlements are at the forefront of elements that increase vulnerability. Cases of cities that suffer from geo-hydrological hazards are increasingly reported in many regions, especially in tropical countries in the Global South. Yet, studies on such examples are rare and commonly overlook the human and societal components of hazard risks. Here, we focus on Bujumbura, a city in Africa that has experienced rapid unplanned growth and sprawl into unserviced areas because of the non-application or a lack of a valid urban planning law. After filling in the gap in data collected using high-resolution field surveys and focus group discussions, this study highlights various factors of vulnerability to geo-hydrological hazards in the urban area...

Highland Agricultural Soils of Bukidnon, Philippines

Scientist TPA, Calalang G, Bock L, Colinet G, Hallet V, Walpole P. 2023. Natural and Anthropogenic Factors Affecting the Development of Two Highland Agricultural Soils of Bukidnon, Philippines. The Philippine Agricultural Scientist 106:116–130.

This research was conducted in two highland areas of Bukidnon, Philippines: Miarayon, a sub-catchment of the upper Cagayan de Oro River; and Bendum, a sub-catchment of the upper Pulangui River. Due to their pyroclastic parent rock materials, soils in the upper Cagayan de Oro are classified as Andic Cambisol in open and convex positions, and Andic Umbrisol in concave and depressed positions. Soils in the upper Pulangui are classified as Pisoplinthic Acrisol, Ferralic Nitisol, and Acric Nitisol in areas with ultramafic rock parent materials, and Haplic Cambisol with pyroclastic deposits. Element contents in rocks were congruent to the total soil element content analysis results except for the total calcium which was higher in Miarayon. This is attributed to the parent rocks and soil management. Total magnesium and iron were highlighted in upper Pulangui soils because of their ultramafic rock parent materials. Soil management practices and length of cultivation were identified as anthropogenic factors affecting soil development...

Multistage karst-hosted mineralization

Dekoninck A, Barbarand J, Ruffet G, Missenard Y, Mattielli N, Leprêtre R, Mouttaqi A, Verhaert M, Saddiqi O, Yans J. 2023. Intraplate orogenesis as a driver of multistage karst-hosted mineralization: the Imini manganese case (Atlas, Morocco). Mineralium Deposita. DOI: 10.1007/s00126-023-01212-9.

The Imini mining district (southern foreland of the intraplate Atlasic belt of Morocco) hosts the largest Mn resources of North Africa, consisting of two laterally extensive bodies of high-grade pyrolusite-rich manganese ore and a third discontinuous medium-grade coronadite-rich Mn ore in a ~ 10–15-m-thick Cenomanian–Turonian dolostone unit. Until now, the origin and timing of the Mn ore have been poorly constrained. New Pb isotopic ratios show that Triassic series (basalts and ferruginous sandstone) are likely the source of the metals. 40Ar/39Ar dating of K-Mn oxides shows that the Mn-rich orebodies formed during at least three periods: late Cretaceous to late Paleocene (> 58 Ma), late Eocene (ca. 36.3 Ma), and early Burdigalian to early Serravalian probably in two pulses at ca. 19–20 Ma and ca. 13 Ma. These periods coincide with three known building phases of the Atlasic relief during late Cretaceous, late Eocene, and the Early(?)-Middle Miocene. We therefore propose the Atlasic tectonics as the first-order control of the Mn mineralization....

Cholera dynamics in the Congo

Kayembe HC, Bompangue D, Linard C, Mandja B-A, Batumbo D, Matunga M, Muwonga J, Moutschen M, Situakibanza H, Ozer P. 2023. Drivers of the dynamics of the spread of cholera in the Democratic Republic of the Congo, 2000–2018: An eco-epidemiological study. PLOS Neglected Tropical Diseases 17:e0011597. DOI: 10.1371/journal.pntd.0011597

Though the dynamics of the spread of cholera epidemics in the Democratic Republic of the Congo (DRC) have been extensively studied, the drivers of these spread processes remain unclear. In this eco-epidemiological study, we focused on the spread processes of cholera epidemics originating from the shores of Lake Kivu to the areas out of endemic eastern DRC. The increase in the number of suspected cholera cases, the exacerbation of conflict events, and the number of IDPs (internally displaced persons) in eastern endemic areas were associated with an increased risk of cholera spreading outside the endemic eastern provinces... 

Guava & immune response of catfish

Nhu TQ, Hang BTB, Huong DTT, Scippo M-L, Phuong NT, Quetin-Leclercq J, Kestemont P. 2023. Psidium guajava L.- dichloromethane and ethyl acetate fractions ameliorate striped catfish (Pangasianodon hypophthalmus) status via immune response, inflammatory, and apoptosis pathways. Fish & Shellfish Immunology 138:108851. DOI: 10.1016/j.fsi.2023.108851.

Psidium guajava is known to possess immune-modulatory properties in humans and other mammals. Although the positive effects of P. guajava-based diets on the immunological status have been shown for some fish species, the underlying molecular mechanisms of its protective effects remain to be investigated. The aims of this study were to evaluate the immune-modulatory effects of two guava fractions from dichloromethane (CC) and ethyl acetate (EA) on striped catfish with in vitro and in vivo experiments...

 The Twihinate carbonatite (Moroccan Sahara)

Boukirou W, Bouabdellah M, Hoernle K, Hauff F, Slezak P, Chaib M, El Gadarri M, Yans J, Errami A, Levresse G. 2023. The Twihinate carbonatite (Moroccan Sahara): Evidence for compositional mantle heterogeneity and northwestern African plate geodynamics. Chemical Geology 637:121648. DOI: 10.1016/j.chemgeo.2023.121648.

Carbonatites are rocks rich in rare earths, niobium and tantalum, metals now widely used in high-tech and renewable energy. The Cretaceous Twihinate carbonatite in the Moroccan Sahara is a ∼ 5 km diameter ring-shaped intrusion made of an inner core preserving sparse occurrences of medium- to coarse-grained calcite carbonatite encircled by a ring of vuggy siliceous breccia. The Twihinate carbonatite is enriched in large ion lithophile elements (Cs, Rb, Ba, U and Th) and light rare earth elements (LREE), but shows negative anomalies in high field strength elements (particularly Ta, Zr, Hf and Ti)... 

Immunomodulatory effects of docosahexaenoic acid (DHA) in common carp

Nguyen TM, Tran Thi NT, Nguyen TH, Do TNA, Kestemont P. 2023. Immunomodulatory effects of graded levels of docosahexaenoic acid (DHA) in common carp (Cyprinus carpio) – In vitro and in vivo approaches. Fish & Shellfish Immunology 134:108585. DOI: 10.1016/j.fsi.2023.108585.

Resolvins work as anti-inflammatory mediators and are also called the immunomodulators in immune system that have potent multilevel mechanisms of action in disease models and promote resolution in animal models. D-series resolvins (such as DHA) play potent anti-inflammatory roles such as activating factors that reduce inflammation and blocking pro-inflammatory responses. The results of thi study suggest that docosahexaenoic acid is able to modulate an acute inflammation in immune cells by modifying the expression of key genes, with the DHA treatment at a dose of 75 μM/mL inducing the highest anti-inflammatory response. The dietary supplementation of DHA did not influence fish growth and feed utilization in the in vivo model; however, positive effects in immune responses and pathogenic resistance were observed in fish fed a diet supplemented with DHA at 20 g/kg of feed.

Acute toxicity of insecticides in fish

Agbohessi P, Olowo L, Degila B, Houedjissi G, Imorou Toko I, Mandiki SNM, Kestemont P. 2023. Comparative assessment of acute toxicity and histological changes in liver of African catfish Clarias gariepinus exposed to cotton insecticides. Journal of Environmental Science and Health, Part B 0:1–14. DOI: 10.1080/03601234.2023.2168445.

This study investigated the acute toxicity of African catfish (Clarias gariepinus) to insecticides currently used in Benin cotton fields, including Thalis, Vizir, Abamectin, Pyrinex Quick, Chlorpyrifos and Pyro with emphasis on liver histopathological effects. Juveniles of C. gariepinus were exposed for 96 h to increasing concentrations of each pesticide. Lethality was high at very low doses for Vizir, Pyrinex, and Pyro, indicating a high toxicity to C. gariepinus juveniles. During the experiments, the morphological and behavioral responses (discoloration, hyperactivity, lethargy, etc.) were observed in exposed fish, hypothesizing the neurotoxicity of these pesticides. Histopathological alterations observed in liver of contaminated fish were regressive changes, such as necrosis, vacuolation, bleeding, nuclear degeneration, hepatocytes degeneration, sinusoids dilatation, etc. Vizir induced the highest histological alteration indices while the lowest were induced by Thalis, confirming the highest toxicity of Vizir. These results indicate that acute concentrations of these insecticidal molecules have destructive effects on the liver of C. gariepinus.


Mangrove ecosystem services and human wellbeing

Gnansounou SC, Salako KV, Sagoe AA, Mattah PAD, Aheto DW, Glèlè Kakaï R. 2022. Mangrove Ecosystem Services, Associated Threats and Implications for Wellbeing in the Mono Transboundary Biosphere Reserve (Togo-Benin), West-Africa. Sustainability 14:2438. DOI: 10.3390/su14042438.

Mangroves are important coastal ecosystems delivering crucial services to humans. This study explored the diversity of mangrove ecosystem services, their associated threats as well as their contribution to livelihoods and wellbeing of coastal communities in the Mono Transboundary Biosphere Reserve (MTBR) located between Benin and Togo. Most important were provisioning services followed by supporting services, regulating services and cultural services. Major threats to mangrove ecosystem services were changes in water salinity, mangrove overharvesting and illegal, unreported and unregulated fishing. Most of the interviewed persons indicated that the current flow of provisioning, regulating and cultural services does not sustain their wellbeing and livelihoods. However, the perception varied significantly across respondents’ gender, ethnical groups, educational background and country. The two countries showed some similarities but also highlighted important differences which can assist the sustainable management of mangroves in the MTBR.

How COVID-19 impacts on internally displaced persons

Ozer P, Dembele A, Yameogo SS, Hut E, de Longueville F. 2022. The impact of COVID-19 on the living and survival conditions of internally displaced persons in Burkina Faso. World Development Perspectives 25:100393. DOI: 10.1016/j.wdp.2022.100393.

Burkina Faso hosts the fourth highest number of conflict-related internal displaced persons (IDPs) in the world. These people have to cope simultaneously with the full spectrum of environmental, social and health-related stresses in the long, medium and short term, respectively. We seek to compare the living conditions of IDPs before and during the lockdown implemented by the authorities (27.3.-5.5.2020) to contain the spread of the virus. 84.9% of the IDPs surveyed had no income-generating activities during the lockdown and the activities of the remaining 15.1% were greatly scaled-down. For a large majority of them, their living conditions, already described as difficult under ‘normal’ circumstances (insufficient food, insignificant financial assistance, or difficult access to health care), further deteriorated. In addition, IDPs were unable to leave the camps or regions where they were located to search for better living conditions or to return home. These IDPs, like many in the sub-region and around the world, therefore require urgent assistance from the authorities and humanitarian NGOs, as the slightest new stress is likely to considerably worsen their already vulnerable state.

Preferred routes of cholera in RDC

Kayembe HCN, Bompangue D, Linard C, Muwonga J, Moutschen M, Situakibanza H, Ozer P. 2022. Modalities and preferred routes of geographic spread of cholera from endemic areas in eastern Democratic Republic of the Congo. PLOS ONE 17:e0263160. DOI: 10.1371/journal.pone.0263160.

Cholera is endemic along the Great Lakes Region, in eastern Democratic Republic of the Congo (DRC), but outbreaks spread to other areas, also due to perpetual conflicts. This study explores the modalities and main routes of this geographic spread. Historical reconstruction of major outbreak expansions of cholera since its introduction in eastern DRC, maps of distribution and spatiotemporal cluster detection analyses of cholera data from passive surveillance (2000–2017) were used to describe the spread dynamics. Four modalities of geographic spread and their likely main routes from the source areas of epidemics to other areas were identified: in endemic eastern provinces, and in non-endemic provinces of eastern, central and western DRC. The higher the number of conflict events reported in eastern DRC, the greater the geographic spread of cholera across the country. Thus, the dynamics of the spread of cholera follow a fairly well-defined spatial logic and can therefore be predicted. These results could contribute to the development of a plan to build resilience in health zones iteratively affected by epidemic waves spreading from endemic areas to achieve the 2030 goals of reducing cholera as a major public health threat.

Plant extracts for striped catfish

Nhu PN, Hang BTB, Phuong NT, Kestemont P, Huong DTT. 2022. Effects of plant extracts on selected haematological parameters, digestive enzymes, and growth performance of striped catfish, Pangasianodon hypophthalmus (Sauvage, 1878) fingerlings. AACL Bioflux 15:1790–1806.

This study examined the effects of dietary supplementation with selected plant extracts on the haematology, enzymatic activities, and growth of striped catfish fingerlings. The enhancement of haematological parameters in conjunction with increased digestive enzyme activity may contribute to the improved health of catfish following the intake of a diet supplemented with plant extracts at different doses and feeding durations. A diet including Psidium guajava 0.2 and Phyllanthus amarus 0.2 extracts administered for 60 days has the potential to modify hematology, enzymatic activity as well as the growth of P. hypophthalmus. Hence, the preference of fish for various plant extract-based diets should be assessed, as these results could demonstrate high use and intake of aquafeed which may lead to improve growth performance of fish.

Immune responses and acute inflammation in common carp

Nguyen TM, Agbohessou PS, Nguyen TH, Tran Thi NT, Kestemont P. 2022. Immune responses and acute inflammation in common carp Cyprinus carpio injected by E.coli lipopolysaccharide (LPS) as affected by dietary oils. Fish & Shellfish Immunology 122:1–12. DOI: 10.1016/j.fsi.2022.01.006.

Eicosanoids, resolvins, and lipoxins formed from long-chain polyunsaturated fatty acids (LC-PUFAs) are the main lipid mediators in the inflammatory processes explaining the influence of dietary lipid sources on the immune system. This study aimed to determine the effects of dietary plant oils instead of fish oil or LC-PUFA supplementation in these oils on fish immune and inflammatory responses under normal and LPS-stimulated conditions. The use of plant oil did not cause any negative effects on fish growth, feed utilization, and survival. The supplementation of LC-PUFAs in diet did not lead to any change in husbandry variables measured in common carp. LPS was able to stimulate the immune system as well as induce acute inflammation in common carp. The dietary lipid sources have modified the immune responses and some other physiological processes involved in acute inflammatory processes. The fish oil-based diet supported an increase of the pro-inflammatory responses while the plant oil mixture or LC-PUFA supplemented diets led to higher anti-inflammatory responses and cytoprotection.

Antiskarn-hosted strategic metal mineralizationin Morocco

Bouabdellah M, Boukirou W, Jébrak M, Bigot F, Yans J, Mouttaqi A, El Gadarri M, Errami A, Levresse G. 2022. Discovery of antiskarn-hosted strategic metal mineralization in the Upper Cretaceous Twihinate carbonatite intrusion (West African Craton Margin, Moroccan Sahara). Ore Geology Reviews 149:105105. DOI: 10.1016/j.oregeorev.2022.105105.

Although volumetrically insignificant among igneous rocks, carbonatites and their metasomatized and weathered derivatives stand out as the ones most targeted rock types as they provide most of the world’s strategic metals production such as niobium, rare earth elements (REE), tantalum, phosphorous, copper, iron and fluorine. The Twihinate prospect is currently considered as one of the most promising carbonatite-hosted strategic metals discoveries that have been made in the Moroccan Sahara over the last two decades. The Nb-P-Fe ± LREE ± U-Th-rich mineralization and associated base metal sulfides, fluorite and baryte are hosted by an Upper Cretaceous calcite carbonatite and its overlying weathered derivates. Our petrographic, mineralogical and geochemical data indicate that part of the newly discovered mineralization is related to a widespread metasomatic event which resulted in development of the Twihinate antiskarn lithotypes. The ore mineralogy consists predominantly of oxides (vanadiferous titanomagnetite), pyrochlore group minerals, phosphates (apatite, monazite), and REE-fluorcarbonates (bastnäsite-(Ce)) with subordinate amounts of sulfides (chalcopyrite, sphalerite, and galena), fluorite and baryte. In addition to the above-referenced strategic metals, the Twihinate ore is characterized by widespread occurrence of vanadiferous titanomagnetite. This V enrichment could constitute a per value for the explored occurrences through the development of mining of magnetite-bearing carbonatitic rocks and related antiskarn rocks targeting V as a by-product. Petrogenetically, we propose that the calc-silicate antiskarn rocks and related Nb-P-Fe ± LREE ± U-Th-rich mineralization were formed as a result of silica contamination of the residual carbonatite-derived melts by the surrounding Silurian-Devonian granitic rocks.

Goethite record in the High Atlas Foreland (Morocco)

Verhaert M, Gautheron C, Dekoninck A, Vennemann T, Pinna-Jamme R, Mouttaqi A, Yans J. 2022. Unravelling the Temporal and Chemical Evolution of a Mineralizing Fluid in Karst-Hosted Deposits: A Record from Goethite in the High Atlas Foreland (Morocco). Minerals 12:1151. DOI: 10.3390/min12091151.

Timing and duration of ore deposit formation are crucial to understanding the mineralization process. To address this, the geochronological (U-Th)/He method, geochemical and H- and O-isotope compositions of pure goethite formed in the Imini karst-hosted Mn district (High Atlas, Morocco) were examined in detail. Two main generations of cavity-filling and fracture-filling goethite are identified, and both precipitated prior to the massive Mn oxide ore. The δD and δ18O values reveal that the mineralizing fluid of cavity and fracture-filling goethite is meteoric-derived but enriched in 18O due to fluid–rock interactions with the host rock dolostone or mixing with O2-rich surface water resident in an open karst system. The cavity-filling goethite precipitated between 95 to 80 Ma, whereas fracture-filling goethite formed between 80 to 50 Ma. Ore deposition occurred discontinuously during the early Atlas doming associated with one or more early compressional events in the Atlas tectonism. The increase in δD values and depletion in U content result from a change in the mineralizing fluid within the karst system. At about 50 Ma, the fluid is notably enriched in U, Cu and trace metals.

Isolation of quercetin-3-O-sulfate from guava leaves

Nguyen P-D, Hérent M-F, Le T-B, Bui T-B-H, Bui T-B-H, Do T-T-H, Nguyen T-P, Scippo M-L, Kestemont P, Quetin-Leclercq J. 2023. Isolation of quercetin-3-O-sulfate and quantification of major compounds from Psidium guajava L. from Vietnam. Journal of Food Composition and Analysis 115:104928. DOI: 10.1016/j.jfca.2022.104928.

In Vietnam, Guava, Psidium guajava, has a high economic value, mostly for fresh fruit, but also for products from guava leaves for tea or leave extracts. P. guajava leaves show a wide range of pharmacological activities such as anti-diabetes, anti-oxidant, anti-microbial, anti-cancer, anti-diarrhea, and anti-inflammatory. This study identifies the major phenolic compound of a crude ethanol extract of P. guajava leaves and develops methods for quantification of phenolic and triterpenic components by HPLC-PDA-HRMS. The major phenolic compound was determined as quercetin-3-O-sulfate which is isolated and quantified for the first time in P. guajava. Validated HPLC-DAD quantification methods were developed to quantify the major triterpenic and phenolic derivatives of this extract and found to be accurate in the concentration range of 2–50 μg/mL for phenolic, and 5–100 μg/mL for triterpenic compounds. Four crude ethanol extracts of guava leaves collected at different periods of the year were analyzed using the developed methods and were found to be richer in triterpenic than phenolic derivatives. It is notable that weather or rainfall influenced the richness in bioactive compounds in guava leaves.

Co-management approach & mangrove conservation

Gnansounou SC, Sagoe AA, Mattah PAD, Salako KV, Aheto DW, Glèlè Kakaï R. 2022. The co-management approach has positive impacts on mangrove conservation: evidence from the mono transboundary biosphere reserve (Togo-Benin), West Africa. Wetlands Ecology and Management. DOI: 10.1007/s11273-022-09894-0.

Literature on conservation science has documented the increasing use of the co-management approach to effectively conserve natural resources. Although some studies found the co-management approach as highly effective, others also reported some uncertainties associated with the use of this conservation approach. Using the mono transboundary biosphere reserve (MTBR) as a case study, this work assessed the effectiveness of the co-management approach for mangrove conservation in West Africa. Data was collected in two protected sites of the reserve (one in Togo and the other in Benin). Results showed that the co-management approach has lowered anthropogenic stressors to mangroves in the reserve. Under the co-management approach, all the mangroves located in the Benin side of the reserve are identified as under low risk whereas 42% of the mangrove cover are considered under low risk and 58% under medium risk in Togo. Local perception also portrayed the reduction of mangrove degradation in the study sites following the adoption of the co-management approach in the two countries. However, there are some challenges such as the financial support provision and regular community engagement which need to be thoroughly researched and addressed to achieve the sustainability of the positive impacts of the co-management in the MTBR.

Saline-tolerant striped catfish

Dao Minh H, Duong Thuy Y, Pham Thanh L, Bui Minh T, Vo Nam S, Do Thi Thanh H, Bui Thi Bich H, Nguyen Thi Ngoc T, Dang Quang H, Kestemont P, Nguyen Thanh P, Farnir F. 2022. Selective breeding of saline-tolerant striped catfish (Pangasianodon hypophthalmus) for sustainable catfish farming in climate vulnerable Mekong Delta, Vietnam. Aquaculture Reports 25:101263. DOI: 10.1016/j.aqrep.2022.101263.

Striped catfish (Pangasianodon hypophthalmus), a freshwater species cultured mainly in the Mekong Delta region in Southern Vietnam, is facing a significant challenge due to salinity intrusion as a result of climatic changes. Given these evolving environmental conditions, selecting new strains with a higher salinity tolerance could make production of striped catfish economically feasible in brackish environments. In this study, a selection program aimed at developing a striped catfish strain able to survive and grow fast in a saline environment. The results from this study demonstrate that a selective breeding for increased saline tolerance of striped catfish can already be effective after one generation of selection under saline environment. The improved salinity tolerance of striped catfish developed in the present study is of practical significance in the context of Mekong Delta aquaculture, where the striped catfish breeding activities are projected to be greatly affected by salinity intrusion due to climate change. The selected animals originating from this study also constitute a valuable genetic resource for subsequent studies targeting a better understanding of the physiology and genomic characteristics of this improved strain as well as the mechanisms of osmoregulatory adaptation to salinity in striped catfish.

Salinity affects intestinal microbiota & gene expression

Hieu DQ, Hang BTB, Lokesh J, Garigliany M-M, Huong DTT, Yen DT, Liem PT, Tam BM, Hai DM, Son VN, Phuong NT, Farnir F, Kestemont P. 2022. Salinity significantly affects intestinal microbiota and gene expression in striped catfish juveniles. Applied Microbiology and Biotechnology. DOI: 10.1007/s00253-022-11895-1.

Inland aquaculture with striped catfish (Pangasianodon hypophthalmus) is important in Southeast Asia, particularly in Mekong Delta in Vietnam. Currently, it faces climatic challenges, especially extensive salinity intrusion. Saline water is observed up to 40 km far from the river mouth and increased salinity levels in striped catfish farms rise up to 9 psu (practical salinity units). In teleost fish, the gut is important to regulate water balance in marine environments but less so in freshwater fish. Here, juvenile striped catfish, have been chronically exposed to a salinity gradient from freshwater to 20 psu and were sampled at the beginning (D20) and the end (D34) of exposure. Results revealed that the intestinal microbial profile of striped catfish reared in freshwater conditions were dominated by the phyla Bacteroidetes, Firmicutes, Proteobacteria, and Verrucomicrobia. Alpha diversity decreased as salinity increased. Furthermore, the beta diversity between groups was significantly different. It is likely that the fish intestine contributed to osmoregulation by modifying the expression of osmoregulatory genes. In conclusion, the fish intestinal microbiota was significantly disrupted in salinities higher than 10 psu and these effects were proportional to the exposure time. The modifications of intestinal gene expression related to ion exchange and stressful responses may help the fish to adapt hyperosmotic environment.


Contamination of Water, Sediment and Fish

Douny C, Zoumenou YMBG, Aïna M, Toko II, Igout A, Guedegba L, Chabi SK, Kestemont P, Scippo M-L. 2021. Contamination of Water, Sediment and Fish with Residues of Pesticides Used in Cotton Production in Northern Benin. Archives of Environmental Contamination and Toxicology. DOI: 10.1007/s00244-021-00888-2. shareable link

In Northern Benin, insecticides are used for cotton production. These insecticides can be easily transferred to water ponds close to cotton fields. To monitor insecticides levels in water, sediments and fish samples from water ponds, a GC–MS analytical method was developed to detect residues of endosulfan, DDT and its parent compounds, isomers of HCH, pyrethroids and chlorpyrifos. In addition, the influence of storage conditions of water sample on pesticides determination performance has been studied. Concentrations of insecticide residues in sediment for all water ponds ranged from non-detected to 101 µg/kg and from non-detected to 36 µg/kg in fish. Preliminary risk assessment for consumers of the North of Benin showed that the Estimated Daily Intakes were lower than the Acceptable Daily Intakes and Acute Reference Doses for all consumers. However, as one fish can be contaminated by five pesticide residues at the same time, it is not possible to exclude a risk for the consumer due to his exposure to mixtures of pesticides.

Clay-based refractory materials in Tunisia

Grine O, Moussi B, Hajjaji W, Pilate P, Yans J, Jamoussi F. 2021. Low-cost northern Tunisian kaolinitic clay-based refractory materials and effect of a rich alumina clay addition. Arabian Journal of Geosciences 14:1595. DOI: 10.1007/s12517-021-08099-8. shareable link

The addition of various quantities of raw materials could be used in order to improve the physical and pyroscopic performances of silica-alumina refractories manufacturing. This work deals with the valorisation of the Sidi Bader (area of Tabarka, North West Tunisia) kaolinitic clay in refractory silica alumina bricks. The chemical and mineralogical composition of the investigated raw materials shows alumina content between 20 and 35% and silica content less than 65%, while the mineralogical composition consists mainly of kaolinite associated with illite, quartz, and anatase. Commercial alumina-rich clay (AS) is added to the Sidi Bader clay. The characterization and optimization results of the chamotte grog provide a less dense and more porous chamotte, but mineralogically stable by sintering the Sidi Bader clay for 6 h at 1500 °C. The obtained results are highly encouraging, but further investigation is necessary to refine this potential valorisation. Adding more than 20% of alumina-rich clay will possibly yield better results.


Numidian clay for ceramic tiles

Moussi B, Hajjaji W, Hachani M, Hatira N, Labrincha JA, Yans J, Jamoussi F. 2020. Numidian clay deposits as raw material for ceramics tile manufacturing. Journal of African Earth Sciences 164:103775. DOI: 10.1016/j.jafrearsci.2020.103775.

Tunisia has a growing industry of ceramic tiles. Several clays collected in the Numidian Flysch Formation (Upper Oligocene) at Tabarka, and Sejnane (Northern part of Tunisia) were tested for their potential use in ceramic manufacturing to provide a database that could be used by investors. The mineralogy composition of raw clays is dominated by kaolinite and illite and shows relatively high quartz content for the two sites of Tabarka and Sejnane. Chemical analyses highlight a significant richness in SiO2 which can be explained by the presence of clays and silica sand. Technological tests confirm the aptitude of these clays to be used in the manufacture of ceramic tiles on an industrial scale.

Fish production in Benin

Pèlèbè ROE, Imorou Toko I, Ouattara IN, Attakpa EY, Montchowui EH, Kestemont P. 2019. Fish production in cages and pens in the northern Benin water reservoirs. Livestock Research for Rural Development 31.

This study aims at assessing the production of Clarias gariepinus and Oreochromis niloticus reared for 120 days in cages and pens installed in the Batran water reservoir in the cotton basin and Songhaï water reservoir outside the cotton basin in northern Benin. For C. gariepinus, the final biomass and the production values are significantly higher in Batran-caged fish while the lowest values are obtained with the same infrastructure in Songhaï. Differences are significant between the two infrastructures only in Batran. With regard to O. niloticus, values obtained for these two parameters are about twice as high in Songhaï compared to Batran in both cages and pens. They are similar between the two infrastructures in each water reservoir. However, cages that do not promote fish contact with aquatic sediment would be more appropriate to avoid the health risks associated with agricultural pesticides in the water reservoir located at the cotton basin.

Deadly effect of insecticides on fish

Guedegba NL, Toko II, Agbohessi PT, Zoumenou B, Douny C, Mandiki SNM, Schiffers B, Scippo M-L, Kestemont P. 2019. Comparative acute toxicity of two phytosanitary molecules, lambda-cyhalothrin and acetamiprid, on Nile Tilapia (Oreochromis Niloticus) juveniles. Journal of Environmental Science and Health, Part B 54:580–589. DOI: 10.1080/03601234.2019.1616986.

This study compares the toxicity of two active ingredients for fish, a pyrethroid and a neonicotinoid, that are components of a commercial insecticide (Acer 35 EC) used in cotton crop in many West African countries. For 96 hours, the juveniles of Nile Tilapia (Oreochromis niloticus) were exposed to increasing concentrations of active ingredients or a mixture similar to Acer 35 EC. During the experiments, the behavioural responses (loss of balance, colour change, hyperactivity, etc.) that usually precede death were observed in the exposed fish. Fish mortality and lethal concentrations of each chemical were determined. All insecticides had profound impacts on Nile tilapia behaviour which confirm the neurotoxicity of each single active compound as well as of their mixture.

Reproductive biology of fish

Osombause JS, Mandiki SNM, Ulyel J-P, Micha J-C, Kestemont P. 2019. Ovarian activity and plasma sex steroid levels of Distichodus antonii in relation to environmental conditions in the upper basin of the Congo River. African Journal of Aquatic Science 0:1–10. DOI: 10.2989/16085914.2018.1555511.

 Distichodus antonii is an endemic fish species of the Congo River basin. Its wild populations are threatened due to overfishing. Understanding its reproductive biology helps in conservation and management efforts for the species. Ovarian activity and levels of steroid profiles in wild populations were investigated with respect to temperature and rainfall. These were synchronised in two annual reproductive seasons that correspond to the long (September and October) and short (May) rainy season.

Pesticides & Mekong aquaculture

Nguyen QT, Douny C, Tran MP, Brose F, Nguyen PT, Huong DTT, Kestemont P, Scippo M-L. 2019. Screening of quinalphos, trifluralin and dichlorvos residues in fresh water of aquaculture systems in Mekong Delta, Vietnam. Aquaculture Research 50:247–255. DOI: 10.1111/are.13890.

Pesticides are often used in rice farms in Vietnam, which risk to impact on integrated and alternative productions (rice in combination with shrimp or fish). This study developed and validated a method using gas chromatography & mass spectrometry to determine pesticide residues in water samples. One pesticide could be detected in rice field systems. Its concentration could be high in fish. The other two pesticides tested are banned and could not be found in the samples.

Insecticide & Cotton in Benin

Zoumenou BGYM, Aïna MP, Imorou Toko I, Igout A, Douny C, Brose F, Schiffers B, Gouda I, Chabi Sika K, Kestemont P, Scippo M-L. 2018. Occurrence of Acetamiprid Residues in Water Reservoirs in the Cotton Basin of Northern Benin. Bulletin of Environmental Contamination and Toxicology 102:7–12. DOI: 10.1007/s00128-018-2476-4.

Insecticides, such as Acetamiprid, a neonicotinoid, are frequently used in Benin to protect cotton crops. It is therefore expected that water reservoirs close to cotton fields are contaminated with acetamiprid residues via drift, runoff, leaching or drainage. The authors developed an Ultra performance liquid chromatography (UPLC)–UV method to determine acetamiprid residues in water samples. The levels found do not represent a risk for human consumption of this water nor for aquatic species. However, acetamiprid is often used in combination with other pesticides which could be more harmful.


Euphorbia as natural antioxidant

Bach LT, Dung LT, Tuan NT, Phuong NT, Kestemont P, Quetin-Leclercq J, Hue BTB. 2018. Antioxidant activity against hydrogen peroxide-induced cytotoxicity of Euphorbia hirta L. AIP Conference Proceedings 2049:030018. DOI: 10.1063/1.5082519.

Euphorbia hirta is an important plant in traditional medicine in tropical regions, especially used to treat asthma and diarrhoea. This study aimed to investigate the antioxidant capacities of plant extractions and some isolated compounds from E. hirta. Results showed that the plant can serve as natural antioxidative. Its further pharmacological potential should be tested to treat oxidative stress which may be related to neurodegenerative diseases.

Pesticides & Benin cotton fields

Gouda A-I, Imorou Toko I, Salami S-D, Richert M, Scippo M-L, Kestemont P, Schiffers B. 2018. Plant protection practices and pesticide exposure levels of Northern Benin cotton producers. Cahiers Agricultures 27. DOI: 10.1051/cagri/2018038.

The level to which cotton producers are exposed to pesticides is alarming. Since the majority never received any education nor instructions of use, 75% apply higher amounts than recommended and 80% do not protect themselves during mixing, loading and spraying. Empty pesticide containers are often left in cotton fields or even worse, used for domestic purposes.

Pikeperch production in the Caspian Sea

Falahatkar, B, Efatpanah, I, & Kestemont, P 2018, ‘Pikeperch Sander lucioperca production in the south part of the Caspian Sea: technical notes’, Aquaculture International, vol. 26, no.1, pp. 391–401, DOI: 10.1007/s10499-017-0222-2

Pikeperch (Sander lucioperca) is a popular food fish in the Caspian Sea basin. However, due to over-fishing in the early 20th century and destruction of natural spawning areas, wild populations have completely collapsed. From 1989, Iranian Fisheries Organization developed the artificial propagation and rearing activities for the rehabilitation of natural populations. This publication summarizes the developments concerning reproduction, stock rehabilitation, on-growing etc. in Iran.

Richelle, L, Visser, M, Bock, L, Walpole, P, Mialhe, F, Colinet, G & Dendoncker, N 2018, 'Looking for a dialogue between farmers and scientific soil knowledge: Learnings from an ethno-geomorphopedological study in a Philippine’s upland village' Agroecology and Sustainable Food Systems, vol 42, no. 1, pp. 2-27. DOI: 10.1080/21683565.2017.1322661

Thinh NQ, Phu TM, Douny C, Phuong NT, Huong DTT, Kestemont P, Scippo M-L. 2018. Bioconcentration and half-life of quinalphos pesticide in rice-fish integration system in the Mekong Delta, Vietnam. Journal of Environmental Science and Health, Part B 53:35–41. DOI: 10.1080/03601234.2017.1371551.


Pezzulo, C, Hornby, GM, Sorichetta, A, Gaughan, AE, Linard, C, Bird, TJ, Kerr, D, Lloyd, CT & Tatem, AJ 2017, 'Sub-national mapping of population pyramids and dependency ratios in Africa and Asia' Scientific Data, vol 4, 170089. DOI: 10.1038/sdata.2017.89

Schmitz, M, Baekelandt, S, Tran Thi, LK, Mandiki, R, Douxfils, J, Nguyen, TQ, Do Thi Thanh, H & Kestemont, P 2017, 'Osmoregulatory and immunological status of the pond-raised striped catfish (Pangasianodon hypophthalmus S.) as affected by seasonal runoff and salinity changes in the Mekong Delta, Vietnam' Fish Physiology and Biochemistry, vol 43, no. 1, pp. 39-49. DOI: 10.1007/s10695-016-0266-7

Schmitz, M, Ziv, T, Admon, A, Baekelandt, S, Mandiki, SNM, L'Hoir, M & Kestemont, P 2017, 'Salinity stress, enhancing basal and induced immune responses in striped catfish Pangasianodon hypophthalmus (Sauvage)' Journal of Proteomics, vol 167, pp. 12-24. DOI: 10.1016/j.jprot.2017.08.005


Bich Hang, BT, Nguyen, PT & Kestemont, P 2016, 'Oral administration of Escherichia coli lipopolysaccharide enhances the immune system of striped catfish, Pangasianodon hypophthalmus (Sauvage)' Aquaculture Research, vol 47, no. 4, pp. 1299-1308. DOI: 10.1111/are.12589