Main virulence factors in Escherichia coli isolates from swine over two weeks old with edema disease and/or E. coli diarrhea

The OK antigens and the fimbriae F4 of E. coli with haemolysis isolated from 113 cases of oedema disease and/or diarrhoea were identified serologically. The genes for F18 and for enterotoxins LT, STIa and STII as well as Shigatoxin Stx2e were determined by PCR. Fimbrial variants F18ab and F18ac were distinguished by means of indirect immunofluorescence on smears prepared from the intestinal mucosa and from cultures grown under appropriate conditions. Adhesive fimbriae were detected with every case or isolate, respectively, by means of at least one out of the techniques mentioned above. The serogroup O149:K91 with fimbriae F4ac (K88ac) and genes for the enterotoxins LT and STII was most prevalent. Serogroup O139:K12 with fimbriae F18ab and the gene for Stx2e was second, whereas serogroups O141ab and O141ac with fimbriae F18ac and genes for Stx2e, STII and often LT were much less prevalent. The serogroup O147:K89 with fimbriae F18ac, and genes for STIa and STII was detected for the first time in Switzerland.     

Challenging conservation of migratory species: Sahelian rainfalls drive first-year survival of the vulnerable Lesser Kestrel Falco naumanni

In the context of attested global changes, accurate estimation of whether climatic fluctuations impact on population demographic parameters is needed for adequate management, especially for migratory species. We present a capture-recapture analysis linking survival rates of the vulnerable Lesser Kestrel (Falco naumanni) to annual rainfalls in the Sahel region, considered as a proxy of climatic conditions on wintering grounds. Recapture data were obtained from field observations of individuals ringed and sexed as juveniles over a 14-year monitoring period (1994-2007). We addressed a common but problematic situation in birds where: (i) sex is known with certainty for first-summer or older birds but only suspected for juveniles, and (ii) a large proportion of individuals never return to the study population (e.g. transient behavior). Transient behavior and unknown sexes were explicitly integrated considering a two age class in a multistate capture-recapture model. Survival was time-varying for juveniles (geometric mean: 0.499 ± 0.021) but constant - and higher - for adults (0.718 ± 0.013). Yearling survival probabilities were strongly correlated with rainfalls in the Sahel, suggesting a high dependence of juvenile upon the wintering conditions. While taking sex uncertainty into account, we detected no sex-dependence in survival. Incorporating the sensitivity of survival of wintering migratory birds to climatic variables such as precipitations in arid Sahelian ecosystem may allow to model conservation scenarios with a greater realism. Finally, we encourage the development of international management strategies for migratory species on wintering areas in addition to the existing conservation actions on summering Mediterranean grounds.     

Measurement of the Motion of Fertilizer Particles Leaving a Centrifugal Spreader Using a Fast Imaging System

Although mechanically simple, centrifugal spreaders used for mineral fertilization involve complex physics that cannot be fully characterized at the present time. We are developing sensors to evaluate the spatial distribution of the fertilizer on the ground based on the measurement of initial flight conditions of fertilizer granules after their ejection by the spreading disk. The techniques developed are based on the analysis of images of the area around the disk showing the granule ejection. A high resolution – low cost imaging system for the analysis of high speed particle projection developed for this specific purpose is presented in this paper. The system, based on a camera and a sequence of flashes, is used to characterize the centrifugal spreading of fertilizer particles ejected at speeds of approximately 30ms^–1. It automatically computes the direction of ejection and velocity of each granule observed in the image. Multi-exposure images collected with the camera installed perpendicular to the output flow of granules are analyzed to estimate the trajectories of the fertilizer granules, using different motion estimation methods.     

Odorous impact of volatile thiols on the aroma of young botrytized sweet wines: identification and quantification of new sulfanyl alcohols

Specific extraction of volatile thiols using sodium p-hydroxymercuribenzoate revealed the presence of three new sulfanylalcohols in wines made from Botrytis-infected grapes: 3-sulfanylpentan-1-ol (II), 3-sulfanylheptan-1-ol (III), and 2-methyl-3-sulfanylbutan-1-ol (IV). The first two have citrus aromas, whereas the third is reminiscent of raw onion. In addition, 2-methyl-3-sulfanylpentan-1-ol, which has a raw onion odor, was tentatively identified. Like 3-sulfanylhexan-1-ol (I), already reported in Sauternes wines, compounds II, III, and IV were absent from must. They were found in wine after alcoholic fermentation, and their concentrations were drastically higher when Botrytis cinerea had developed on the grapes. In the commercial botrytized wines analyzed, the mean levels of II, III, and IV were 209, 51, and 103 ng/L, respectively. Despite their low odor activity values, sensory tests showed additive effects among I, II, and III, thus confirming their olfactory impact on the overall aroma of botrytized wines.     

Reducing Antimicrobial Usage in Pig Production without Jeopardizing Production Parameters

Antimicrobial usage (AMU) has been described to be high in pig production. Although farmers are aware of the high usage, little is known about intervention to improve the situation. This study evaluated the extent to which AMU could be reduced in pig production by the optimization of herd management, biosecurity status, vaccination strategy, anthelmintic therapy and advice on prudent AMU. Furthermore, the effects of these interventions on the herd production results were explored. This intervention study was conducted on 61 Flemish pig herds and included three visits per herd. During the initial visit, information was gathered on herd management, biosecurity status (quantified by means of the Biocheck.UGent^? risk‐based scoring system), vaccination strategy, anthelmintic therapy and AMU. This info was then translated into a herd‐specific action plan which was discussed with the farmer and herd veterinarian/other advisors during the second visit. In the final herd visit (±8 months later), comparable data were obtained to evaluate the progress. Overall, a significant improvement of 2.4 points external and 7 points internal biosecurity on the herds was obtained, combined with additional vaccination, anthelmintic therapy and prudent AMU. This was accompanied by a significant reduction in the AMU with a decrease of 52% for the pigs from birth till slaughter and 32% for breeding animals, based on treatment incidences (TIs) and included an important reduction in the use of critically important antimicrobials. More importantly, the increased biosecurity levels and decreased AMU were combined with significantly improved technical results such as the number of weaned piglets per sow per year (+1.1), daily weight gain (+5.9 g/day) and mortality in the finisher period (?0.6%). Guided interventions as a team effort of farmer and herd veterinarian/other advisors have shown to be a promising method in the reduction of AMU in pig production.     

Landscape diversity and field border density enhance carabid diversity in adjacent grasslands and cereal fields

Landscape Ecology - Permanent grasslands have declined across Europe since the agricultural intensification. Grassland vicinity, landscape heterogeneity and vicinity of hedgerows are enhancing...     

A survey on biosecurity and management practices in selected Belgian cattle farms

The shift from cure towards prevention in veterinary medicine involves the implementation of biosecurity, which includes all measures preventing pathogens from entering a herd and reducing the spread of pathogens within a herd. In Belgium no studies have considered the implementation of biosecurity measures in the daily management of cattle farms. Therefore the aim of the study was to map the current application of biosecurity measures in Belgian cattle farms in the prevention of disease transmission within and between farms.     

Wild-captive metapopulation viability analysis

We developed an interactive management model for wild and captive populations of the ploughshare tortoise or angonoka, Geochelone yniphora. Interactive management is based on the translocation of individuals between wild and captive populations to simulate a metapopulation. Demographic parameters of one captive and two wild populations of this rare tortoise were used to conduct a metapopulation viability analysis (MVA). The effectiveness of the conservation strategy proposed for this species was then evaluated by modifying the probability of extinction and growth of the metapopulation over a fixed period of time. Several alternative scenarios of interactive management were then tested and ranked in terms of their effect on the viability of the metapopulation. The model predicted that catastrophic events such as bush fires would likely have a negative effect on the future of remaining wild populations. However, the model also predicted that the use of captive-born offspring to establish additional wild populations would decrease the risk of extinction of the metapopulation as a whole. We believe that, when supported by sound knowledge of the demographic parameters of a species, the use of MVA as part of an interactive management program can be an effective conservation tool that allows assessment of the probable response of both captive and wild populations to different management alternatives. One of the most interesting aspects of this interactive management approach is the link between in situ and ex situ conservation.     

Discovery of new lactones in sweet cream butter oil

Sweet cream butter oil was analyzed to identify new volatile compounds that may contribute to its flavor, with an emphasis on lactones. The volatile part of butter oil was obtained by using short-path distillation. As some previously unknown lactones were detected in this first extract, it was fractionated further. The fatty acids were removed, and the extract was fractionated by flash chromatography. Three lactonic fractions possessing a creamy, buttery, and fatty character were investigated in depth by gas chromatography (GC) and mass spectrometry (MS) (EI and CI) and high-resolution GC-time-of-flight MS. Many lactones were identified by their mass fragmentation and by comparison with reference materials synthesized during this work. Six γ-lactones, five δ-lactones, and one ε-lactone were identified for the first time in butter oil, seven of them for the first time in a natural product. The possible contribution of these new lactones to the aroma of butter oil is briefly discussed.     

Decomposition kinetics and organic geochemistry of woody debris in a ferralsol in a humid tropical climate

Large inputs of woody debris to soil can improve the soil. We examined the fate of woody debris buried in soil after fire‐free forest conversion to cropland in French Guiana. We measured the mass loss of woody debris > 4 mm on five sampling dates for 4 years after deforestation. Composition of the organic matter of woody debris was analysed with Rock‐Eval pyrolysis, which enabled us to distinguish a labile carbon pool (C_lab) and a resistant carbon pool (C_res). Decomposition of woody debris followed a first‐order function with a half‐life of 17.6 months. During the decomposition of woody debris > 4 mm, the C:N ratio, hydrogen index (HI) and pyrolysed carbon below 400°C (R400) decreased, suggesting that decarboxylation and dehydrogenation of woody debris occurred. Both C_lab and C_res stocks decreased with time, but the decrease in C_lab was faster. There was little humification of the debris and no long‐term biogeochemical preservation of a woody debris fraction, which accords with the first‐order decay observed. We conclude that the benefits of ligno‐cellulosic inputs for soil organic carbon contents in a tropical humid climate occur during the first year following deforestation. Résumé Les apports massifs de débris de bois au sol peuvent améliorer le sol. Nous avons examiné sur un site en Guyane le devenir de débris de bois enfouis dans le sol, suite à la conversion sans brûlis de forêt en cultures. Nous avons mesuré le stock des débris de bois > 4 mm jusqu'à 4 années après déforestation. Les transformations de la matière organique des débris ont bois ont été analysées par la pyrolyse Rock‐Eval, nous permettant de distinguer un compartiment de carbone labile (C_lab) et un compartiment de carbone résistant (C_res) dans ces débris. La décomposition des débris de bois suit une décroissance exponentielle de premier ordre, avec une demi‐vie de 17,6 mois. Durant la décomposition des débris, le rapport C/N, l'indice d'hydrogène (HI) et le carbone pyrolysé avant 400°C (R400) diminuent, suggérant des processus de décarboxylation et déshydrogénation qui se mettent en place rapidement après l'enfouissement des débris. Les stocks de C_lab et C_res diminuent tous deux au cours du temps, avec une cinétique plus rapide pour C_lab. Ces résultats indiquent une faible polymérisation de la matière organique des débris, et une absence de préservation biogéochimique d'une partie des débris, en accord avec la décroissance exponentielle observée. Cette étude suggère que les bénéfices des amendements ligno‐cellulosiques pour la matière organique des sols sont de courte durée en milieu tropical humide.