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151.
Guillaume Pfeuti James Longstaffe Leonid S. Brown Anna K. Shoveller Carol M. Taylor Dominique P. Bureau 《Aquaculture Research》2019,50(8):2081-2095
A digestibility trial was carried to assess the apparent digestibility coefficient (ADC) of crude protein (CP) and amino acids (AA) in two feather meals (FeM) of different origin (FeM1 and FeM2) and in their enzymatically pre‐treated ingredient stream (PTFeM1 and PTFeM2) in rainbow trout. The ADC of CP was 11%–17% higher (p < 0.05) in the PTFeMs than in their FeM counterparts. There was no difference (p > 0.05) of ADC of CP among FeMs and among PTFeMs. The FT‐Raman analysis showed a reduction in concentration and conformational stability of disulphide bonds in the PTFeMs when compared to their FeM counterparts. Moreover, important discrepancies in disulphide concentration were observed between FeMs and between PTFeMs. These observations suggest that the ADC of CP in FeM is not only governed by disulphide bond content and other variables should be considered. Higher concentrations of the cross‐linked amino acids (CLAA) lanthionine, lysinoalanine and β‐aminoalanine were measured in FeM1 and PTFeM1 as compared to FeM2 and PTFeM2 respectively. Previous studies have suggested inverse relationships between CLAAs and the digestibility as well as bioavailability of AAs in feed ingredients. A previous study conducted in our laboratory showed a lower (p < 0.05) bioavailability of arginine in FeM1 and PTFeM1 than in FeM2 and PTFeM2, respectively, in rainbow trout. Our results suggest that (a) the digestibility of AAs in FeM may be affected by disulphide bond content and the presence of CLAAs, and (b) CLAA content may be indicator of bioavailability of AAs in FeM. 相似文献
152.
Véronique Martin-Jézéquel Guillaume Calu Leo Candela Zouher Amzil Thierry Jauffrais Véronique Séchet Pierre Weigel 《Marine drugs》2015,13(12):7067-7086
Over the last century, human activities have altered the global nitrogen cycle, and anthropogenic inputs of both inorganic and organic nitrogen species have increased around the world, causing significant changes to the functioning of aquatic ecosystems. The increasing frequency of Pseudo-nitzschia spp. in estuarine and coastal waters reinforces the need to understand better the environmental control of its growth and domoic acid (DA) production. Here, we document Pseudo-nitzschia spp. growth and toxicity on a large set of inorganic and organic nitrogen (nitrate, ammonium, urea, glutamate, glutamine, arginine and taurine). Our study focused on two species isolated from European coastal waters: P. multiseries CCL70 and P. australis PNC1. The nitrogen sources induced broad differences between the two species with respect to growth rate, biomass and cellular DA, but no specific variation could be attributed to any of the inorganic or organic nitrogen substrates. Enrichment with ammonium resulted in an enhanced growth rate and cell yield, whereas glutamate did not support the growth of P. multiseries. Arginine, glutamine and taurine enabled good growth of P. australis, but without toxin production. The highest DA content was produced when P. multiseries grew with urea and P. australis grew with glutamate. For both species, growth rate was not correlated with DA content but more toxin was produced when the nitrogen source could not sustain a high biomass. A significant negative correlation was found between cell biomass and DA content in P. australis. This study shows that Pseudo-nitzschia can readily utilize organic nitrogen in the form of amino acids, and confirms that both inorganic and organic nitrogen affect growth and DA production. Our results contribute to our understanding of the ecophysiology of Pseudo-nitzschia spp. and may help to predict toxic events in the natural environment. 相似文献
153.
Detection of genetically isolated entities within the Mediterranean species of Bemisia tabaci: new insights into the systematics of this worldwide pest
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155.
Fournier G Boutier M Stalin Raj V Mast J Parmentier E Vanderwalle P Peeters D Lieffrig F Farnir F Gillet L Vanderplasschen A 《Veterinary research》2012,43(1):6
ABSTRACT: Cyprinid herpesvirus 3 (CyHV-3), also known as Koi herpesvirus, is the etiological agent of a mortal disease in common and koi carp. Recently, we investigated the entry of CyHV-3 in carp using bioluminescence imaging and a CyHV-3 recombinant strain expressing luciferase (LUC). We demonstrated that the skin is the major portal of entry after inoculation of carp by immersion in water containing CyHV-3. While this model of infection mimics some natural conditions in which infection takes place, other epidemiological conditions could favour entry of virus through the digestive tract. Here, we investigated whether ingestion of infectious materials mediates CyHV-3 entry through the digestive tract. Carp were fed with materials contaminated with the CyHV-3 LUC recombinant (oral contamination) or immersed in water containing the virus (contamination by immersion). Bioluminescence imaging analyses performed at different times post-infection led to the following observations: (i) the pharyngeal periodontal mucosa is the major portal of entry after oral contamination, while the skin is the major portal of entry after contamination by immersion. (ii) Both modes of inoculation led to the spreading of the infection to the various organs tested. However, the timing and the sequence in which some of the organs turned positive were different between the two modes of inoculation. Finally, we compared the disease induced by the two inoculation modes. They led to comparable clinical signs and mortality rate. The results of the present study suggest that, based on epidemiological conditions, CyHV-3 can enter carp either by skin or periodontal pharyngeal mucosal infection. 相似文献
156.
I.?Urretavizcaya J.?B.?Royo C.?Miranda B.?Tisseyre S.?Guillaume L.?G.?SantestebanEmail author 《Precision Agriculture》2017,18(2):133-144
Source to sink size ratio, i.e.: the relative abundance of photosynthetically active organs (leaves) with regards to photosynthate demanding organs (mainly bunches), is widely known to be one of the main drivers of grape oenological quality. However, due to the difficulty of remote sink size estimation, Precision Viticulture (PV) has been mainly based on within-field zone delineation using vegetation indices. This approach has given only moderately satisfactory results for discriminating zones with differential quality. The aim of this work was to investigate an approach to delineate within-vineyard quality zones that includes an estimator of sink size in the data-set. The study was carried out during two consecutive seasons on a 4.2 ha gobelet-trained cv. ‘Tempranillo’ vineyard. Zone delineation was performed using Normalized Difference Vegetation Index (NDVI), soil apparent electrical conductivity (ECa) and bunch number (BN) data. These variables were considered separately, in pairs, or the three altogether, using fuzzy k-means cluster analysis for combinations. The zones delineated based on single variables did not allow a sufficient discrimination for grape composition at harvest, NDVI being the only variable that by itself resulted in zones that to some extent differed in grape composition. On the contrary, when two variables were combined, discrimination in terms of grape composition improved remarkably, provided the sink size estimation variable (BN) was included in the combination. Lastly, the combination of the three variables yielded the best discriminating zoning, improving slightly on those provided by NDVI + BN and ECa + BN combinations. Thus, the relevance of including a variable related to sink size (in this case the number of bunches per plant) has been confirmed, which makes its consideration highly advisable for any PV work aiming at zone delineation for grape quality purposes. 相似文献
157.
Uber Magdalena Legout Cédric Nord Guillaume Crouzet Christian Demory François Poulenard Jérôme 《Journal of Soils and Sediments》2019,19(9):3255-3273
Journal of Soils and Sediments - Knowledge of suspended sediment provenance in mesoscale catchments is important for applying erosion control measures and best management practices as well as for... 相似文献
158.
Pitel PH Romand S Pronost S Foucher N Gargala G Maillard K Thulliez P Collobert-Laugier C Tainturier D Fortier G Ballet JJ 《Veterinary parasitology》2003,118(1-2):1-6
Neospora caninum, an apicomplexan protozoan parasite, is recognized as a major cause of abortion in cattle while limited information is presently available on association between equine Neospora infections and abortions. The aim of the present study was to document prevalence of antibodies against Neospora sp. in aborted mares as a clue to the role of N. caninum in mare reproductive failure in Normandy, France. Using an agglutination test, the number of animals with elevated (>80) anti-Neospora sp. antibody titer was higher in a group of 54 aborted mares than in randomly chosen groups of 45 mares and 76 horses sampled for equine arteritis virus and Fasciola hepatica antibodies, respectively (P<0.001). N. caninum DNA was found in 3/91 fetal brains, 2/77 fetal hearts, and 1/1 placenta, and present in both brains and hearts of two fetuses. In 13 cases for which both mare serum and fetus were available, no fetal N. caninum amplification product was present while a large variation of maternal antibody titers was found. Data prompt at additional surveys of association between equine reproductive failure and Neospora sp. infection. 相似文献
159.
"TAGS", a program for the evaluation of test accuracy in the absence of a gold standard 总被引:4,自引:0,他引:4
When a perfect reference test (i.e. "gold standard") is not available, it is possible to obtain estimates of test sensitivity and specificity using "latent-class" methods. However, there are few widely available software programs that allow implementation of these procedures. We describe the development of a program (implemented in R and S-Plus software) for this purpose that yields maximum-likelihood estimates of sensitivity, specificity and prevalence. We also have implemented an HTML form, which submits data to a web-based interface to R. The programs can incorporate data obtained from several populations, results of multiple tests, and can account for data obtained from a reference population in which the true status (infected or non-infected) of each individual is known exactly. Two estimation methods are used: a Newton-Raphson procedure and an expectation-maximisation (EM) procedure. The estimation methods assume test independence conditional on the infection status of the individuals and constant test accuracy in each population. A goodness-of-fit statistic and the residuals of pairwise correlation coefficients are calculated to check the validity of these assumptions. Two examples are used to illustrate application and limitations of the programs. The programs are available at www.afssa.fr/interne/tags.htm (Europe) or www.epi.ucdavis.edu/diagnostictests/ (USA). 相似文献
160.
Helen Metcalfe Jana Bürger Christoph von Redwitz Alicia Cirujeda Silvia Fogliatto Denise F. Dostatny Bärbel Gerowitt Michael Glemnitz José L. González-Andújar Eva Hernández Plaza Jordi Izquierdo Michaela Kolářová Jevgenija Ņečajeva Sandrine Petit Gyula Pinke Matthias Schumacher Lena Ulber Francesco Vidotto Guillaume Fried 《Weed Research》2023,63(1):1-11
Over the last 30 years, many studies have surveyed weed vegetation on arable land. The ‘Arable Weeds and Management in Europe’ (AWME) database is a collection of 36 of these surveys and the associated management data. Here, we review the challenges associated with combining disparate datasets and explore some of the opportunities for future research that present themselves thanks to the AWME database. We present three case studies repeating previously published national scale analyses with data from a larger spatial extent. The case studies, originally done in France, Germany and the UK, explore various aspects of weed ecology (community composition, management and environmental effects and within-field distributions) and use a range of statistical techniques (canonical correspondence analysis, redundancy analysis and generalised linear mixed models) to demonstrate the utility and versatility of the AWME database. We demonstrate that (i) the standardisation of abundance data to a common measure, before the analysis of the combined dataset, has little impact on the outcome of the analyses, (ii) the increased extent of environmental or management gradients allows for greater confidence in conclusions and (iii) the main conclusions of analyses done at different spatial scales remain consistent. These case studies demonstrate the utility of a Europe-wide weed survey database, for clarifying or extending results obtained from studies at smaller scales. This Europe-wide data collection offers many more opportunities for analysis that could not be addressed in smaller datasets; including questions about the effects of climate change, macro-ecological and biogeographical issues related to weed diversity as well as the dominance or rarity of specific weeds in Europe. 相似文献