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Assessment of drivers of antimicrobial usage in poultry farms in the Mekong delta of vietnam: A combined participatory epidemiology and Q-sorting approach
No full textIn the Mekong Delta of Vietnam, poultry farmers use high amounts of antimicrobials, but little is known about the drivers that influence this usage. We aimed to identify these drivers using a novel approach that combined participatory epidemiology (PE) and Q-sorting (a methodology that allows the analysis of the subjectivity of individuals facing a common phenomenon). A total of 26 semi-structured collective interviews were conducted with 125 farmers representative of the most common farming systems in the area (chickens, meat ducks, and mobile grazing ducks), as well as with 73 farmers' advisors [veterinarians, veterinary drug shop owners, and government veterinarians/commune animal health workers (CAHWs)] in five districts of Dong Thap province (Mekong Delta). Through these interviews, 46 statements related to the antimicrobials' perceived reliability, costs, and impact on flock health were created. These statements were then investigated on 54 individuals (28 farmers and 26 farmers' advisors) using Q-sorting interviews. Farmers generally indicated a higher propensity for antimicrobial usage (AMU) should their flocks encounter bacterial infections (75.0-78.6%) compared with viral infections (8.3-66.7%). The most trusted sources of advice to farmers were, in decreasing order: government veterinarian/CAHWs, their own knowledge/experience, veterinary drug shop owners, and sales persons from pharmaceutical and feed companies. The highest peak of AMU took place in the early phase of the production cycle. Farmers and their advisors showed considerable heterogeneity of attitudes with regards to AMU, with, respectively, four and three discourses representing their views on AMU. Overall, farmers regarded the cost of AMU cheaper than other disease management practices implemented on their farms. However, they also believed that even though these measures were more expensive, they would also lead to more effective disease prevention. A key recommendation from this finding would be for the veterinary authorities to implement long-term sustainable training programs aiming at reducing farmers' reliance on antimicrobials
Unexplained hydrogen isotope offsets complicate the identification and quantification of tree water sources in a riparian forest
No full textWe investigated plant water sources of an emblematic refugial population of Fagus sylvatica (L.) in the Ciron river gorges in south-western France using stable water isotopes. It is generally assumed that no isotopic fractionation occurs during root water uptake, so that the isotopic composition of xylem water effectively reflects that of source water. However, this assumption has been called into question by recent studies that found that, at least at some dates during the growing season, plant water did not reflect any mixture of the potential water sources. In this context, highly resolved datasets covering a range of environmental conditions could shed light on possible plant–soil fractionation processes responsible for this phenomenon. In this study, the hydrogen (δ2H) and oxygen (δ18O) isotope compositions of all potential tree water sources and xylem water were measured fortnightly over an entire growing season. Using a Bayesian isotope mixing model (MixSIAR), we then quantified the relative contribution of water sources for F. sylvatica and Quercus robur (L.) trees. Based on δ18O data alone, both species used a mix of top and deep soil water over the season, with Q. robur using deeper soil water than F. sylvatica. The contribution of stream water appeared to be marginal despite the proximity of the trees to the stream, as already reported for other riparian forests. Xylem water δ18O could always be interpreted as a mixture of deep and shallow soil waters, but the δ2H of xylem water was often more depleted than the considered water sources. We argue that an isotopic fractionation in the unsaturated zone and/or within the plant tissues could underlie this unexpected relatively depleted δ2H of xylem water, as already observed in halophytic and xerophytic species. By means of a sensitivity analysis, we found that the estimation of plant water sources using mixing models was strongly affected by this δ2H depletion. A better understanding of what causes this isotopic separation between xylem and source water is urgently needed
An overview of the models available for simulating human food digestion : mythe or reality?
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Health risks assessment in three urban farms of Paris Region for different scenarios of urban agricultural users: A case of soil trace metals contamination
No full textWithin the context of a worldwide emergence of various forms of urban agriculture, there is a growing awareness concerning the health risks associated to the presence of different pollutants influencing the urban products safety. Among the most common pollutants found in soils and vegetables grown in the city, Trace Metals (TM’s) are of major concern. This paper deals with risks assessment associated with the presence of TM’s in soil, via two main exposure path ways: soil and vegetables ingestions. Risks assessments were conducted for various types of real scenarios encountered in three forms of urban farms near Paris (Ile-de-France Region). The farms have soil TM’s levels in abnormally high concentrations (Pb (Lead), Cd (Cadmium), Hg (Mercury), Cu (Copper) and Zn (Zinc) contents higher than geochemical backgrounds and threshold values for sludge spreading, often used as reference values in France). The results of the Hazard Quotient (HQ)-based risk assessment approach (HQ defined as the ratio of estimated daily intake/tolerable daily intake) show that the most risky scenarios concern urban farmers (HQtot = 1.02, because of the on-site working on a daily basis all year round), children gardeners (HQtot = 1.29) and regular children consumers (HQtot = 1.6 in maximalist scenario, where the consumer would exclusively consume the vegetables of the farm). Next would be the adult gardener scenario (HQtot= 0.9), while the least risky are adult consumer scenarios (HQtot = 0.62) and the farm workers (HQtot = 0.45). For the highest risk scenarios (urban farmers and children), specific and drastic measures may be considered, such as reducing the site frequentation by sensitive populations (child and pregnant women) or proceeding to control analysis of TM’s levels in blood for the most exposed peoples. The choice of parameters used in HQ-based method must be appropriated to the specificities of urban agricultural activities. The uncertainties in the choice of some parameters such as soil ingestion, vegetable intake and exposure frequency could result in an over- or under-estimation of the risk
La pepsine hydrolyse aussi bien les caséines à pH 5 qu’à pH 2, contrairement aux protéines du blanc d’œuf et du standard hémoglobine
No full textIntroduction et but de l’étude: La pepsine, sécrétée dans l’estomac, est la première protéase rencontrée par les protéines alimentaires au cours de la digestion. L’estomac acidifie lentement les bols alimentaires et il a été montré que le pH gastrique a un impact majeur sur les cinétiques de protéolyse 1.En effet, il est généralement admis que la pepsine n’est active qu’à pH acide, pour pH ≤ 5, avec un maximum d’activité autour de pH 2 pour beaucoup de substrats 2.Elle est également représentée comme un diacide 3, ce qui semble vrai lorsqu’elle agit sur l’hémoglobine, substrat de référence pour mesurer son activité. Ce comportement en fonction du pH n’a pas été validé sur des mélanges de protéines alimentaires telles que les caséines, principales protéines du lait, ou les protéines du blanc d’œuf. L’objectif principal de cette étude est de comparer les profils d’activité de la pepsine en fonction du pH sur les caséines du lait de vache (CA) et les protéines du blanc d’œuf (BO).Matériel et méthodes: Les cinétiques d’hydrolyse de protéines de BO entier et de micelles de CA par la pepsine, à différents pH compris entre 1 et 8, ont été suivies au pH-stat pendant 2h, avec quantification du degré d’hydrolyse final (DH) par la méthode OPA. Les vitesses initiales ont été calculées à partir de ces cinétiques entre 0 et 5 minutes. Les concentrations en substrat et en pepsine étaient les mêmes pour chaque expérience, et l’environnement salin était celui du protocole INFOGEST 4. Les CA se présentent en structures supramoléculaires, les micelles, qui précipitent à pH acide. Une étape d’acidification à pH 4 des CA a permis d’étudier des suspensions d’agrégats tous formés dans les mêmes conditions. L’aspect et la taille de ces agrégats ont été observés par microscopie confocale et par morpho-granulométrie.Résultats et Analyse statistique: Les cinétiques d’hydrolyse obtenues suivent, dans leur majorité, des profils de type loi de puissance en fonction du temps. Pour les protéines de BO, le DH final est maximal à pH1 (14,4%) et diminue de manière linéaire en fonction du pH,jusqu’à atteindre des valeurs négligeables pour les pH ≥6. A l’inverse, les valeurs de DH finaux sur les CA ne sont pas significativement différentes sur la gamme de pH 1 à 5 (7,5 ± 1,4 %) puis diminuent à partir de pH 6 et atteignent des valeurs négligeables à pH 8.Le rapport entre la vitesse d’hydrolyse initiale et le DH final des CA est supérieur à celui des protéines du BO quel que soit le pH, suggérant une cinétique d’hydrolyse plus rapide pour les CA.Ces résultats montrent que les caséines du lait,dont le pH se situe un peu au-dessus de 6, n’ont pas besoin d’être longuement acidifiées pour que l’hydrolyse par la pepsine puisse commencer dans l’estomac, atteignant une activité quasi optimale de la pepsine dès pH 5.Conclusion: Les cinétiques d’hydrolyse par la pepsine en fonction du pH diffèrent donc entre un substrat de type protéines globulaires comme l’œuf, et les caséines du lait. Le profil d’activité de la pepsine en fonction du pH est également différent de celui du standard hémoglobine. En outre, contrairement à ce qui est généralement admis, la pepsine peut hydrolyser certains substrats à des pH plus hauts que pH 5
Dataset on potential environmental impacts of water deprivation and land use for food consumption in France and Tunisia
No full textThe dataset concerns the environmental impacts of water consumption and land use caused by 1 kg of food item supplied to two Mediterranean countries: France and Tunisia. The dataset takes into account the food items available in France and Tunisia (identified in two national dietary surveys) and their origin. Water consumption and land use surfaces were extracted from existing databases and from national data for animal feed description. Up-to-date available evaluation methods were used to assess the associated impacts. The origin of ingredients was considered to compute impacts on all countries of the world. These data were used in Perignon et al., 2019.[1][br/]
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[1] M. Perignon, C. Sinfort, J. El Ati, P. Traissac, S. Drogue, N. Darmon, M.-J. Amiot (2019), the Medina Study Group How to meet nutritional recommendations and reduce diet environmental impact in the Mediterranean region? An optimization study to identify more sustainable diets in Tunisia
Global Food Security, 23, pp. 227-235, 10.1016/j.gfs.2019.07.00
Analyse des effets d'échelle, d'organisation spatiale et de structuration géomorphologique pour la modélisation des débits et de flux hydrochimiques en bassins non jaugés
No full textGenome-wide analysis of Cushion willow provides insights into alpine plant divergence in a biodiversity hotspot
No full textThe Hengduan Mountains (HDM) biodiversity hotspot exhibits exceptional alpine plant diversity. Here, we investigate factors driving intraspecific divergence within a HDM alpine species Salix brachista (Cushion willow), a common component of subnival assemblages. We produce a high-quality genome assembly for this species and characterize its genetic diversity, population structure and pattern of evolution by resequencing individuals collected across its distribution. We detect population divergence that has been shaped by a landscape of isolated sky island-like habitats displaying strong environmental heterogeneity across elevational gradients, combined with population size fluctuations that have occurred since approximately the late Miocene. These factors are likely important drivers of intraspecific divergence within Cushion willow and possibly other alpine plants with a similar distribution. Since intraspecific divergence is often the first step toward speciation, the same factors can be important contributors to the high alpine species diversity in the HDM