Performance of food–feed maize and cowpea cultivars under monoculture and intercropping systems: Grain yield, fodder biomass, and nutritive value

Livestock feeding in Burkina Faso is characterized by a recurrent deficit in both the quality and the quantity of fodder during the dry season, which affects animal performance. To overcome this, quality fodder/forage production is an alternative. Therefore, this study evaluated food- and feed-improved cultivars of maize and cowpea in intercropping trials using the “mother and baby trials” approach with crop–livestock farmers. The mother trial comprised a randomized block design with eight treatments and four replicates: two cowpea (KVx745-11P and Tiligré) and two maize cultivars (Barka and Espoir), and grown under two cropping systems (monoculture and intercropping). Baby trials were established on-farm and involved 30 farmers during two seasons (2019 and 2020) in four villages in the South Sudan zone of Burkina Faso. Data were collected on (1) weed density and biomass, (2) grain yield and fodder biomass, (3) intercropping efficiency, and (4) fodder nutritive value. Data were analyzed using ANOVA and the least significant difference (LSD) means separation at a 5% threshold. The results revealed that maize and cowpea intercropping significantly reduced weed biomass (p ≤ 0.05). In monoculture, the maize cultivar Barka produced a greater grain yield (4980 kg/ha) and fodder biomass [6259 kg dry matter (DM)/ha] than the cultivar Espoir, which produced a grain yield of 2581 kg/ha and fodder biomass of 4952 kg DM/ha. The cowpea cultivars, KVx745-11P and Tiligré, were similar (p ≥ 0.05) in terms of fodder biomass (2435–2820 kg DM/ha) and grain yield (1152–1163 kg/ha). For the intercropping system, land equivalent ratios for fodder biomass (1.18:1.41) and grain yield (1.02:1.44) were greater than 1; intercropping also had better productivity system indexes than the monoculture cropping system. The crude protein concentration of fodder was greater for Barka maize (9.5%–9.8%) than for Espoir maize (8.5%–8.7%). The crude protein concentration was greater for cowpea KVx745-11P (19%–21.8%) than for cowpea Tiligré (15%–17%). Intercropping both Barka maize and cowpea KVx745-11P was the most productive cropping system for maximizing grain and fodder production for crop–livestock farmers in the South Sudan zone of Burkina Faso

The positive impact of red palm oil in school meals on vitamin A status: study in Burkina Faso

BACKGROUND: Vitamin A (VA) deficiency is widespread in sub-Saharan Africa and school-age children are a vulnerable group. In Burkina Faso, the production and consumption of red palm oil (RPO) is being promoted as a food supplement for VA. The objective of the study was to assess the impact on serum retinol of adding RPO to school lunch in two test zones of Burkina Faso. METHODS: Over one school year, 15 ml RPO was added to individual meals 3 times a week in selected primary schools in two sites. Serum retinol was measured with HPLC at baseline and exactly 12 months later to take account of seasonality. A simple pre-post test design was used in the Kaya area (north-central Burkina), where 239 pupils from 15 intervention schools were randomly selected for the evaluation. In Bogandé (eastern Burkina), 24 schools were randomised for the controlled intervention trial: 8 negative controls (G1) with only the regular school lunch; 8 positive controls (G2) where the pupils received a single VA capsule (60 mg) at the end of the school year; and 8 schools with RPO through the school year (G3). A random sample of 128 pupils in each school group took part in the evaluation. RESULTS: In Kaya, serum retinol went from 0.77 ± 0.37 μmol/L at baseline to 1.07 ± 0.40 μmol/L one year later (p < 0.001). The rate of low serum retinol (<0.7 μmol/L) declined from 47.2% to 13.1%. In Bogandé, serum retinol increased significantly (p < 0.001) only in the capsule and RPO groups, going from 0.77 ± 0.28 to 0.98 ± 0.33 μmol/L in the former, and from 0.82 ± 0.3 to 0.98 ± 0.33 μmol/L in the latter. The rate of low serum retinol went from 46.1 to 17.1% in the VA capsule group and from 40.4% to 14.9% in the RPO group. VA-deficient children benefited the most from the capsule or RPO. Female sex, age and height-for-age were positively associated with the response to VA capsules or RPO. CONCLUSION: RPO given regularly in small amounts appears highly effective in the reduction of VA deficiency. RPO deserves more attention as a food supplement for VA and as a potential source of rural income in Sahelian countries

Modulation of innate immune responses at birth by prenatal malaria exposure and association with malaria risk during the first year of life.

BACKGROUND: Factors driving inter-individual differences in immune responses upon different types of prenatal malaria exposure (PME) and subsequent risk of malaria in infancy remain poorly understood. In this study, we examined the impact of four types of PME (i.e., maternal peripheral infection and placental acute, chronic, and past infections) on both spontaneous and toll-like receptors (TLRs)-mediated cytokine production in cord blood and how these innate immune responses modulate the risk of malaria during the first year of life. METHODS: We conducted a birth cohort study of 313 mother-child pairs nested within the COSMIC clinical trial (NCT01941264), which was assessing malaria preventive interventions during pregnancy in Burkina Faso. Malaria infections during pregnancy and infants' clinical malaria episodes detected during the first year of life were recorded. Supernatant concentrations of 30 cytokines, chemokines, and growth factors induced by stimulation of cord blood with agonists of TLRs 3, 7/8, and 9 were measured by quantitative suspension array technology. Crude concentrations and ratios of TLR-mediated cytokine responses relative to background control were analyzed. RESULTS: Spontaneous production of innate immune biomarkers was significantly reduced in cord blood of infants exposed to malaria, with variation among PME groups, as compared to those from the non-exposed control group. However, following TLR7/8 stimulation, which showed higher induction of cytokines/chemokines/growth factors than TLRs 3 and 9, cord blood cells of infants with evidence of past placental malaria were hyper-responsive in comparison to those of infants not-exposed. In addition, certain biomarkers, which levels were significantly modified depending on the PME category, were independent predictors of either malaria risk (GM-CSF TLR7/8 crude) or protection (IL-12 TLR7/8 ratio and IP-10 TLR3 crude, IL-1RA TLR7/8 ratio) during the first year of life. CONCLUSIONS: These findings indicate that past placental malaria has a profound effect on fetal immune system and that the differential alterations of innate immune responses by PME categories might drive heterogeneity between individuals to clinical malaria susceptibility during the first year of life

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

Effect of thermal ageing on the mechanical properties and cracking behaviour of asphalt concrete

International audienceThis article assesses the impact of ageing on the properties of asphalt concrete (AC) by combining experiments and numerical simulations. Rheological tests were performed at four thermal ageing duration (0, 3, 6 and 9 days). The results show an increase in the complex modulus and a decrease in phase angle with ageing time. For each ageing time, semi-circular bending tests were carried out under two loading rates (1. mm/min and 5. mm/min) and three temperatures (-20˚C, 0˚C and 20˚C). The results shown an increase of the peak load when the loading rate increases for each thermal ageing time and temperature. No meaningful variation of the peak load with respect to the ageing time was observed at low temperatures. However, it was found that at 20˚C, the peak load increases with ageing duration. A finite element modelling was implemented to simulate the force-deflexion curve, coupling viscoelastic behaviour and crack growth criterion. The results show a similarity between numerical and experimental results