Anthropometric, biochemical, dietary, morbidity and well-being assessments in women and children in Indonesia, India and Senegal: a UKRI GCRF Action Against Stunting Hub protocol paper.

INTRODUCTION: Child stunting has a complex aetiology, especially in the first 1000 days of life. Nutrition interventions alone have not produced expected impacts in reducing/preventing child stunting, indicating the importance of understanding the complex interplay between environmental, physiological and psychological factors influencing child nutritional status. This study will investigate maternal and child nutrition, health and well-being status and associated factors through the assessment of: (1) anthropometry, (2) biomarkers of nutrition and health status, (3) dietary intakes, (4) fetal growth and development, (5) infant morbidity, (6) infant and young child feeding (IYCF) and (7) perinatal maternal stress, depression and social support. METHODS: This study will be conducted in a prospective pregnancy cohort in India, Indonesia and Senegal. Pregnant women will be recruited in the second (Indonesia, Senegal) and third (India) trimester of pregnancy, and the mother and infant dyads followed until the infant is 24 months of age. During pregnancy, anthropometric measures will be taken, venous blood samples will be collected for biochemical assessment of nutrition and health status, dietary intakes will be assessed using a 4-pass-24-hour dietary recall method (MP24HR), fetal ultrasound for assessment of fetal growth. After birth, anthropometry measurements will be taken, venous blood samples will be collected, MP24HR will be conducted, infant morbidity and IYCF practices will be assessed and a sample of breastmilk will be collected for nutrient composition analyses. Perinatal maternal stress, depression, social support and hair cortisol levels (stress) will be measured. The results from this study will be integrated in an interdisciplinary analysis to examine factors influencing infant growth and inform global efforts in reducing child stunting. ETHICS AND DISSEMINATION: Ethical approval was granted by the Ethics Committee of the London School of Hygiene and Tropical Medicine (17915/RR/17513); National Institute of Nutrition (ICMR)-Ministry of Health and Family Welfare, Government of India (CR/04/I/2021); Health Research Ethics Committee, University of Indonesia and Cipto Mangunkusumo Hospital (KET-887/UN2.F1/ETIK/PPM.00.02/2019); and the Comité National d'Ethique pour la Recherche en Santé, Senegal (Protocole SEN19/78); the Royal Veterinary College (URN SR2020-0197) and the International Livestock Research Institute Institutional Research Ethics Committee (ILRI-IREC2020-33). Results will be published in peer-reviewed journals and disseminated to policy-makers and participating communities

Nematodes, indicators of the origin of the soil used by termites to construct biostructures

In Sahelian savannas, fungus-growing termites form biogenic structures made of soil or sheetings, on the soil surface and inside the soil, to protect themselves against heat, desiccation and predators while collecting food. The purpose of this study was to determine if analysis of the nematofauna can show differences in the way termites construct sheetings according to termite species or organic material harvested. In this study, soil nematodes, which were inactive during the experiment, were passively transported in soil. pellets by termites when they built sheetings. Composition of the soil nematofauna was analyzed in sheetings produced when harvesting the four different types of different organic matter and in the soil around which these structures were produced. Three of the four organic materials were applied on soil as mulch whereas wood Logs were inserted in the soil. Nematode density and diversity in sheetings produced by the three different termite species present (Ancistrotermes guineensis, Ondontotermes nilensis and Macrotermes subhyalinus) were similar in the four organic treatments except for sheetings constructed within the wood by A. guineensis. Nematode densities in sheetings were about ten-fold lower than in the 0-10 cm upper soil layer. Moreover, the composition of the nematofauna in sheetings was very different from that of the upper 10cm, except for the sheetings built on wood. A finer comparison of the soil nematofauna in the top 7cm of soil (separated in 0-0.25, 0.25-3.0 and 3.0-7.5cm), and of fresh surface sheetings (produced within 24h) showed that nematode composition of sheetings was very similar to that of the soil. in the superficial strata (0-3 cm). Analysis of the nematofauna led us to conclude that the soil. used by termites to construct biogenic structures when harvesting organic matter originates from soil layers as close as possible to the area where the organic resource is located. Moreover, there were no differences in the soil or the three type of surface-applied organic matter used for the three fungus-growing termites

Changes in nematode communities following cultivation of soils after fallow periods of different length

The composition of the nematofauna was studied in four soils that differed in length of fallow restoration period since previous cultivation. The longest fallow period was 21 years. Plots were sampled for 2 years after starting cultivation of the fallow soils. The treatments were ranked following a restoration-exploitation gradient depending on fallow duration and the number of years of millet cultivation after fallow clearing ; components of the nematofauna were analysed for correlation with this ranking. The nematode community structures at the first date of sampling during cultivation clearly reflected the length of the fallow period. Nematode community structures in the fallow soils rapidly approached those in the continuously cultivated soil ; they were hardly distinguishable during the second year of cultivation. One-third of the recorded nematode taxa exhibited pronounced responses to the cultivation. Mononchidae, Anatonchidae, Tylencholaimoidea, #Acrobeles, #Pseudacrobeles, Tylenchidae and #Helicotylenchus preferred sites of more mature successional status, while Dorylaimoidea, #Tylenchorhynchus and Rhabdolaimidae dominated the cultivated sites. The maturity index (MI) did not distinguish the management regimes. The plant parasite index (PPI) tended to decrease with higher restoration status linked to greater abundance of the Tylenchidae in these situations. The decrease of fungal to bacterial feeders reflected a decreasing importance of the fungal decomposition pathway after resuming cultivation. (Résumé d'auteur

Cover crops alter the soil nematode food web in banana agroecosystems

Cover crops are increasingly being used in agriculture, primarily for weed or erosion management. The addition of cover crops increases the primary productivity of the system and diversifies basal resources for higher trophic levels. How increases in the quality and quantity of basal resources affect bottom-up and top-down control remains a key question in soil food web ecology. We evaluated the response of the nematode community to the introduction of cover crops between rows of a banana plantation. We measured changes in nematode food web structure and inferred the prevalence of bottom-up and top-down effects on the abundance of phytophagous nematodes (i.e., plant-feeding and root-hair-feeding species) 1.5 years after plots with cover crops (Poaceae or Fabaceae species) or bare soil were established. The addition of a cover crop greatly affected the structure and the abundance of the soil nematode community 1.5 years after planting. The abundance of all trophic groups except for plant-feeding nematodes tended to increase with the addition of cover crops. The Shannon Weaver diversity index and the enrichment index increased with the addition of cover crops, indicating that opportunistic, bacterivorous and fungivorous nematodes benefited from the added resources. Plant-feeding nematodes were least abundant in plots with Poaceae cover crops, while bacterivorous, omnivorous, and root-hair-feeding nematodes were more abundant with Fabaceae cover crops than with bare soil, indicating that cover crop identity or quality greatly affected soil food web structure. Bottom-up effects on all trophic groups other than plant-feeding nematodes were evident with Poaceae cover crops, suggesting an top-down control of plant-feeding nematodes by omnivorous nematodes. Conversely, plant-feeding nematodes were evidently not suppressed in Fabaceae cover crops, perhaps because bottom-up effects on omnivorous nematodes were weaker (hence, top-down control by omnivorous nematodes was weaker), and because Fabaceae cover crops probably served as good hosts for some plant-feeding nematodes

Impact of direct seeding mulch-based cropping systems on soil nematodes in a long-term experiment in Madagascar

The objective of this work was to assess the effects of conventional tillage and of different direct seeding mulch-based cropping systems (DMC) on soil nematofauna characteristics. The long-term field experiment was carried out in the highlands of Madagascar on an andic Dystrustept soil. Soil samples were taken once a year during three successive years (14 to 16 years after installation of the treatments) from a 0-5-cm soil layer of a conventional tillage system and of three kinds of DMC: direct seeding on mulch from rotation soybean-maize residues; direct seeding of maize-maize rotation on living mulch of silverleaf (Desmodium uncinatum); direct seeding of bean (Phaseolus vulgaris)-soybean rotation on living mulch of kikuyu grass (Pennisetum clandestinum). The samples were compared with samples from natural fallows. The soil nematofauna, characterized by the abundance of different trophic groups and indices (MI, maturity index; EI and SI, enrichment and structure indices), allowed the discrimination of the different cropping systems. The different DMC treatments had a more complex soil food web than the tillage treatment: SI and MI were significantly greater in DMC systems. Moreover, DMC with dead mulch had a lower density of free-living nematodes than DMC with living mulch, which suggested a lower microbial activity

Nutrition on bacteria by bacterial-feeding nematodes and consequences on the structure of soil bacterial community

Bacterial-feeding nematodes are, with protozoa, the main grazers of soil bacteria. Interactions between bacteria and nematodes have important repercussions on soil functioning and particularly on nutrient availability. We assessed the influence of the bacterial strains ingested on bacterial-feeding nematodes population development and also the consequences of nematode feeding behaviour on the structure of the soil microbial community with a special attention to different soil micro-habitats for nematode and bacteria. In vivo studies conducted in the presence of single bacterial strains showed that the type of ingested bacteria conditioned the development of the different bacterial-feeding Cephalobidae nematode species tested and that the effect of bacteria differed between nematode species. The spatial distribution of soil nematodes between three soil habitats (fresh organic matter, interaggregates pores and aggregates) depended of the trophic behaviour of nematodes. Bacterial-feeding nematodes and fungalfeeding nematodes showed comparable distribution: being preferentially located in the fresh organic matter and in the interaggregate pores. Besides, the activity of inoculated bacterial-feeding nematodes modified the genetic structure of the soil microbial community. Bacterial community of the macroporosity was significantly influenced by the nematodes. On the contrary, no modification of the structure of the bacterial community linked with nematode activity was measured in the bulk soil