Reproduction de Bagrus bajad (Fabricius, 1775, Bagridae) du Lac Albert, Bassin du Nil, République Démocratique du Congo (RDC)

Le Bagrus bajad figure parmi les espèces des poissons très pêchées dans les cours d’eau tropicaux d’Afrique dont les informations sur la reproduction sont rares. Quelques paramètres de reproduction de Bagrus bajad du Sud-ouest du Lac Albert ont été étudiés durant cette recherche. Les échantillons ont été collectés entre décembre 2019 et décembre 2020 au moyen des éperviers, des palangres et des filets maillants de maille standard (20,2, 25,4 et 30,5 mm). Au total, 520 spécimens dont 283 femelles et 237 males ont été étudiés. Les informations sur le sex-ratio, le stade de maturité sexuelle, le rapport gonadosomatique, le rapport hepathosomatique, la fécondité et le facteur de condition ont été analysés. L’étude a révélé l’égalité entre les mâles et les femelle parmi les individus, même si les femelles étaient supérieurs aux mâles (1: 0,84; p-value<0.05). Tous les poissons étudiés ont présenté tous les stades de maturité sexuelle (I, II, III, IV, et V). Les matures (III, IV et V) ont une plus grande proportion (III, IV et V) par rapport aux immatures (I et II). Les mâles ont une taille de première maturité sexuelle de 43.5 cm contre 44 cm pour les femelles. Les valeurs mensuelles des indices gonadosomatiques et celles des stades gonadiques macroscopiques prouvent que B. bajad a trois périodes de fraie au cours de l’année : (i) Janvier-Avril ; (ii) Juin-Août et (iii) Octobre-Novembre alternées par une période d’un mois de repos en mai, septembre et décembre. La fécondité absolue est de 525 à 34440 ovocytes mais n’est pas significativement corrélées avec la longueur totale (R2=0,002) et le poids (R2=0,12). Les connaissances de la présente étude constituent une base fondamentale pour assurer la surveillance des risques d’épuisement du stock potentiel cette espèce et orienteront les décideurs à développer des politiques et stratégies efficaces garantissant l’exploitation et la conservation rationnelle de cette espèce.   Bagrus bayad is one of the highly fished fish species in tropical African rivers for which information on reproduction is scarce. Some reproduction parameters of B. bayad from the southwest of Lake Albert were studied. The samples were collected between December 2019 and December 2020 using cast nets, longlines, and standard mesh gillnets (20.2, 25.4, and 30.5 mm). A total of 520 specimens including 283 females and 237 males were examined. Information on sex ratio, stage of sexual maturity, gonadosomatic ratio, hepatosomatic ratio, fecundity, and condition factor was analyzed. The study revealed equality between males and females among individuals, although females were superior to males (1:0.84; p-value<0.05). All fish investigated showed all stages of sexual maturity (I, II, III, IV, and V). The mature (III, IV and V) have a greater proportion (III, IV and V) compared to the immature (I and II). Males have a size at first sexual maturity of 43.5 cm against 44 cm for females. The monthly values of gonadosomatic indices and those of macroscopic gonad stages show that B. bajad has three spawning periods a year: (i) January-April; (ii) June-August and (iii) October-November, alternated by a one-month rest period in May, September, and December. Absolute fecundity varies between 525 and 34440 oocytes but is not significantly correlated with total length (R2=0.002) and weight (R2=0.12). Knowledge from this study constitutes a fundamental basis for ensuring the monitoring of the risks of depletion of the potential stock of this species and will guide decision-makers in developing effective policies and strategies guaranteeing rational exploitation and conservation of this species

African queens find mates when males are rare

This is the final version. Available from Wiley via the DOI in this record. DATA AVAILABILITY STATEMENT: Sex ratio, spermatophore numbers and Rcode: Figshare doi:10.6084/ m9.figshare.21947729.In butterflies and moths, male-killing endosymbionts are transmitted from infected females via their eggs, and the male progeny then perish. This means that successful transmission of the parasite relies on the successful mating of the host. Paradoxically, at the population level, parasite transmission also reduces the number of adult males present in the final population for infected females to mate with. Here we investigate if successful female mating when males are rare is indeed a likely rate-limiting step in the transmission of male-killing Spiroplasma in the African Monarch, Danaus chrysippus. In Lepidoptera, successful pairings are hallmarked by the transfer of a sperm-containing spermatophore from the male to the female during copulation. Conveniently, this spermatophore remains detectable within the female upon dissection, and thus, spermatophore counts can be used to assess the frequency of successful mating in the field. We used such spermatophore counts to examine if altered sex ratios in the D. chrysippus do indeed affect female mating success. We examined two different field sites in East Africa where males were often rare. Surprisingly, mated females carried an average of 1.5 spermatophores each, regardless of male frequency, and importantly, only 10-20% remained unmated. This suggests that infected females will still be able to mate in the face of either Spiroplasma-mediated male killing and/or fluctuations in adult sex ratio over the wet-dry season cycle. These observations may begin to explain how the male-killing mollicute can still be successfully transmitted in a population where males are rare.National Geographic SocietyRoyal Societ

Assessment of aflatoxin and fumonisin contamination levels in maize and mycotoxins awareness and risk factors in Rwanda

Mycotoxins are secondary metabolites of fungi that are toxic to humans and animals when consumed in contaminated food and feed. The Rwandan climate conditions like steady temperature and sufficient rainfall favor the growth of fungi leading to high probability of mycotoxins contamination. Mycotoxins get into maize throughout the value chain from the field to processed products. Maize is  promoted in Rwanda under the Crop Intensification Program (CIP), for nutrition and food security. The aim of the study was to evaluate mycotoxins (Aflatoxin and fumonisin) levels in maize and assess awareness and factors associated with mycotoxin contamination in Rwanda. Maize samples (227 kg) from season B 2019 were collected in 15 Districts in five provinces of Rwanda after an interview with a representative of the household or cooperative using a structured questionnaire. The samples were analyzed for aflatoxin and  fumonisin using Reveal Q+ and AccuScan Gold Reader. From the interview, most of the respondents were not aware about aflatoxin (59.7 %) and 99 % did not know the effect of mycotoxins on human health. The average of aflatoxin contamination in surveyed districts was 6.69±13 μg/kg. In general, 90.4 % of samples scored below the limit of aflatoxin level regulated in East Africa/Kenya regulation standards (10 μg/kg). The levels of aflatoxin ranged between 0 and 100.9 μg/kg. The means aflatoxin levels within districts ranged between 1.36±0.5 μg/kg and 13.75±25 μg/kg. Among 9.6 % of the samples containing aflatoxins above the EU and Kenyan regulations standard limit, 5.7 % were above the US standards of 20 μg/kg. Within clusters, the level of aflatoxin more than 10 μg/kg was 5 %, 7 % and 18 % for stores, household and market samples, respectively. From the study, as mechanical damage of grains, moisture content of grains and the temperature of the store house increased, Aflatoxin level also increased. Fumonisin analyzed in maize ranged from 0 to 2.3 μg/g and only one sample from market showed a slightly higher level of fumonisin than the EU and US limit of 2 μg/g. More effort for aflatoxin mitigation is needed at the market level. Farmers need to be aware and taught how they can improve their agricultural system and more knowledge on mycotoxin control is needed. The results point to appropriate measures to recommend for control ofmycotoxins in Rwanda and awareness creation. Key words: AccuScan, Aflatoxin, Fumonisin, Fungal, Maize, Mycotoxins, Reveal Q+, Rwand

Response to the Novel Corona Virus (COVID-19) Pandemic Across Africa: Successes, Challenges, and Implications for the Future

Background: The COVID-19 pandemic has already claimed considerable lives. There are major concerns in Africa due to existing high prevalence rates for both infectious and non-infectious diseases and limited resources in terms of personnel, beds and equipment. Alongside this, concerns that lockdown and other measures will have on prevention and management of other infectious diseases and non-communicable diseases (NCDs). NCDs are an increasing issue with rising morbidity and mortality rates. The World Health Organization (WHO) warns that a lack of nets and treatment could result in up to 18 million additional cases of malaria and up to 30,000 additional deaths in sub-Saharan Africa. Objective: Document current prevalence and mortality rates from COVID-19 alongside economic and other measures to reduce its spread and impact across Africa. In addition, suggested ways forward among all key stakeholder groups. Our Approach: Contextualise the findings from a wide range of publications including internet-based publications coupled with input from senior-level personnel. Ongoing Activities: Prevalence and mortality rates are currently lower in Africa than among several Western countries and the USA. This could be due to a number of factors including early instigation of lockdown and border closures, the younger age of the population, lack of robust reporting systems and as yet unidentified genetic and other factors. Innovation is accelerating to address concerns with available equipment. There are ongoing steps to address the level of misinformation and its consequences including fines. There are also ongoing initiatives across Africa to start addressing the unintended consequences of COVID-19 activities including lockdown measures and their impact on NCDs including the likely rise in mental health disorders, exacerbated by increasing stigma associated with COVID-19. Strategies include extending prescription lengths, telemedicine and encouraging vaccination. However, these need to be accelerated to prevent increased morbidity and mortality. Conclusion: There are multiple activities across Africa to reduce the spread of COVID-19 and address misinformation, which can have catastrophic consequences, assisted by the WHO and others, which appear to be working in a number of countries. Research is ongoing to clarify the unintended consequences given ongoing concerns to guide future activities. Countries are learning from each other

Slaughter weight rather than sex affects carcass cuts and tissue composition of Bisaro pigs

Carcass cuts and tissue composition were assessed in Bisaro pigs (n=64) from two sexes (31 gilts and 33 entire males) reared until three target slaughter body-weights (BW) means: 17 kg, 32 kg, and 79 kg. Dressing percentage and backfat thickness increased whereas carcass shrinkage decreased with increasing BW. Slaughter weight affected most of the carcass cut proportions, except shoulder and thoracic regions. Bone proportion decreased linearly with increasing slaughter BW, while intermuscular and subcutaneous adipose tissue depots increased concomitantly. Slaughter weight increased the subcutaneous adipose tissue proportion but this impaired intramuscular and intermuscular adipose tissues in the loin primal. The sex of the pigs minimally affected the carcass composition, as only the belly weight and the subcutaneous adipose tissue proportions were greater in gilts than in entire males. Light pigs regardless of sex are recommended to balance the trade-offs between carcass cuts and their non-edible compositional outcomes.Work included in the Portuguese PRODER research Project BISOPORC – Pork extensive production of Bísara breed, in two alternative systems: fattening on concentrate vs chesnut, Project PRODER SI I&DT Medida 4.1 “Cooperação para a Inovação”. The authors are grateful to Laboratory of Carcass and Meat Quality of Agriculture School of Polytechnic Institute of Bragança ‘Cantinho do Alfredo’. The authors are members of the MARCARNE network, funded by CYTED (ref. 116RT0503).info:eu-repo/semantics/publishedVersio

Données actuelles et perspectives de la tomographie par émission de positrons en oncologie-radiothérapie

Positron emission tomography (PET) is one of the most promising diagnostic procedures in oncology. Using the glucose analogue fluorodeoxyglucose, PET produces whole-body images and is highly sensitive for tumor diagnosis and staging. We review three particular clinical situations in which PET-FDG has proven not only its diagnostic accuracy, but also its impact on patient management, i.e., the staging of non-small cell lung cancer, diagnosis and staging of colo-rectal cancer and head and neck cancer recurrence. Image registration yields anatomo-metabolic images that could be used as additional information for the determination of radiation fields. Tracer and technical issues remain to be solved before PET can be routinely used for that purpose