Staff Publications

Staff Publications

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    'Staff publications' is the digital repository of Wageningen University & Research

    'Staff publications' contains references to publications authored by Wageningen University staff from 1976 onward.

    Publications authored by the staff of the Research Institutes are available from 1995 onwards.

    Full text documents are added when available. The database is updated daily and currently holds about 240,000 items, of which 72,000 in open access.

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Jan Willem van Groenigen: What would the world look like without earthworms? | WURcast
Groenigen, Jan-Willem van - \ 2017
helminths - soil fertility
Valorisation of waste streams from by-product to worm biomass
Laarhoven, Bob - \ 2017
Wageningen University. Promotor(en): Cees Buisman, co-promotor(en): Hardy Temmink; Hellen Elissen. - Wageningen : Wageningen University - ISBN 9789463438117 - 141
biomass - residual streams - animal nutrition - fisheries - organic wastes - helminths - biomassa - reststromen - diervoeding - visserij - organisch afval - wormen

There is a global demand for more feed resources to keep up with the increasing production of livestock. The hunger for resources is most urgent in the aquaculture sector, which to a large degree depends on the non-sustainable use of fish oil/ meal from wild fish. Aquatic macro invertebrates such as the freshwater worm Lumbriculus variegatus (Oligochaeta, Lumbriculidae, common name blackworms, further abbreviated as Lv) are rich in proteins, lipids, vitamins and minerals. When cultivated on safe and low-grade organic wastes they can provide a sustainable fishmeal alternative for most freshwater and marine fish.

Chapter 1 introduces the concept of aquatic worm production on waste streams. Worm biomass composition and relevant research lines are explained. Organic waste sludges from food industries are a rich source of bio-molecules and can be upgraded to (fish) feed when fed to aquatic worms. For valorisation of waste streams by aquatic worms, as proposed in this thesis, these streams preferably are free from contaminants such as organic micro pollutants, heavy metals and pathogens. For example, this would not be the case when sewage (municipal) sludge is used as a substrate for the worms. However, such contaminated sludges may still be applied for non-food applications. Thus, the quality of the waste stream that is used as a substrate for the worms determines the application potential of the worm biomass as well as the options for downstream processing and refinery.

Previous research showed that Lv can be used for reduction and compaction of sewage sludge. The consumption of (suspended) sludge particles results in a dry matter reduction of 25 - 50 % and in worm faeces that are 60 % more compact than the original waste sludge. This contributes to a significant reduction in sludge processing costs. Sludge reduction by aquatic worms is mainly studied by research groups in The Netherlands and in China. Unfortunately, it is generally accepted free swimming worms in full-scale wastewater treatment plants is extremely difficult, mainly because of large (seasonal) population fluctuations. A controlled reactor concept applying the sessile (crawling, sediment dwelling) species Lv already was developed in earlier research. The key characteristic of this reactor is a carrier material for the worms, which also functions as a separation layer between the waste stream (worm food) and a water phase used for aeration, worm harvesting and worm faeces collection. This concept also was the starting point for the development of the improved reactor concept that is described in this thesis.

The two main objectives of this thesis were: (1) to assess the potential of organic waste streams and by-products for Lv production for fish feed and (2) to develop a (cost and resource) effective bioreactor for this purpose.

In Chapter 2 a new, standardized method is described and tested that can be used for a quantitative and qualitative assessment of the effect of different substrates on worm growth. This method not only can be used to select waste streams suitable for worm production, but also is proposed as a tool is ecotoxicology studies.

The test method consists of beaker experiments with a combination of agar and sand to optimize food uptake by and growth of the worms. The effects of agar gel, sand, and food quantity were studied and evaluated for different food sources. Agar gel addition ameliorated growth conditions by reducing microbial food hydrolysis and by improving the sediment structure. This guaranteed that substrate ingestion and worm growth in the first place were the result of the food quality and the effect of other (environmental) factors was reduced. A final test with secondary potato starch sludge demonstrated the test method is appropriate for the evaluation of solid and suspended organic feedstuffs/waste streams.

In Chapter 3 the standardized method of chapter 2 was used for worm growth studies, focussing on the effect of carbon to nitrogen (C/N) ratios of diets on worm growth and reproduction. Growth and reproduction of Lv on different combinations of wheat based derivatives like gluten and gray starch was studied at fixed isoenergetic levels (expressed as chemical oxygen demand (COD) of the food), but at different C/N ratios. Growth and reproduction rates were compared to those on Tetramin, a substrate known to result in excellent worm growth. Growth was mainly controlled by the C/N ratio of the single and mixed wheat fraction diets. Lower C/N ratios of around 6-7 gave a much better performance than high C/N ratios of around 20. This probably was caused by Lv relying on the presence of proteins as carbon and energy source. Although growth and reproduction rates were not as high as on the control diet, the results were promising for development of a worm biomass production reactor, operating on by-products from wheat processing industries.

In Chapter 4 a new reactor concept for Lv cultivation on waste streams was developed and tested. In a vertical tubular reactor a centralized food compartment was surrounded by a gravel layer that mimicked the natural habitat of Lv. Secondary (biological) sludge from a potato starch processing industry was used as a clean and low value food source. The results with respect to worm growth rate, density and production and nutrient recovery were compared to the previous reactor design. Much higher worm densities were achieved (6.0 compared to 1.1 kg ww m-2 carrier material) as well as much faster Lv growth rates (4.4 - 12 compared to 1.2 % d-1). As a result the areal worm production rate was no less than 40 times higher (560 compared to 14 g ww m-2 d-1). The higher worm density, which was found to be independent of gravel size in a range of 2.4 to 8.0 mm, allowed for a significantly shorter food retention time in the reactor (~ 2.2 days compared to > 10 days for the previous reactor design). This restricted microbial mineralization of the food, making high nutrient recoveries from waste to worm biomass possible: 16-30 % COD, 19-22 % N and 9-11 % P. The high biomass density also limited the release of ammonium, which at large concentrations is toxic for the worms. However, even shorter food retention times (e.g. higher loading rates) are not recommended as a minimum microbial activity is needed for conversion of the original substrate into compounds that can be taken up by the worms.

In Chapter 5 worm growth, reproduction and biomass quality were evaluated on several waste streams and by-products of bacterial, animal and plant origin. The effect of 26 different diets, all applied at high food levels, on Lv growth, reproduction and fatty acid (FA) content and profile were investigated. For this purpose the standardized test method of Chapter 2 was used. In addition, it was discussed which diet composition and food sources would be most suitable for large scale production of Lv.

Diets consisting of single cell biomass from bacterial or plant origin with a high protein content (C/N ratio < 8.8), high P content (C/P < 50) and low in total ammonia nitrogen (TAN) (< 20 g N/kg) gave the highest growth rates and vital worms without signs of mortality. Besides the C/P ratio of the diet, worm conditions related with the difference between test and pre-culture conditions. The starting weight of the worms seemed to have an effect on the total fatty acid content of the worms. The growth potential of a diet rich in proteins and P depends on how much TAN is associated with the diet. By blending different food sources these factors to a certain extent can be manipulated. Lv seemed to have a distinct and very stable FA composition, irrespective of the diet’s FA composition. The worms were rich in poly unsaturated FAs (PUFAs), including several w3 and w6 FAs, and contained relatively high levels of C18 and C20 PUFAs. This makes them suitable as fish feed, in particular for freshwater fish.

In order to serve aquaculture feed markets with an attractive alternative to fish meal, such as aquatic worm biomass, a continuous and secure bulk production needs to be realized. In Chapter 6 the performance parameters established in chapter 4 (worm growth rate, density and biomass production rate) were used as the input for a feasibility assessment of large scale worm production on secondary sludge from the potato industry. In addition, in chapter 6 future value chains and lines of research were discussed.

A hypothetical worm production system treating the surplus secondary sludge from a potato processing factory can reduce excess sludge production by 50 % in solids and 62 % in volume. This is accompanied by a daily production of 1.6 metric ton of fresh worm biomass. With a very conservative estimation of the worm density of 1.6 kg ww/m2 carrier material a footprint of the system of 217 m2 can be realized, which is at least two times smaller than with a previous reactor design without a gravel layer. With reduced sludge processing costs and a conservative market price of 1.4 €/kg dry worm biomass, worm production can already be realized at an annual rate of return of 3 years. However, the costs are highly sensitive for worm biomass stocking, reactor construction and operation. A more accurate economic assessment should be based on the results of pilot-scale research.

Two general product types, whole biomass (as fish feed) and refined products can be distinguished and applied in two application areas (feed and non-food), depending on the quality of the organic (waste) sludge that the worms have been produced from. Valorisation for potential bulk markets needs further refinery of crude worm biomass into a lipid (worm oil) and a protein fraction (protein isolate). This can result in several new and unique business models in aquaculture, feed, chemical and agriculture sectors. Obviously, an assessment of economical and legislative boundary conditions needs to be part of such business models.

Worm biomass is a potential high quality fishmeal replacer, with a similar or even better potential than other waste based alternatives such as single cell biomass and insects. A comparison between Lv and fishmeal with respect to crude composition, essential amino acids and FAs learns that Lv is a highly suitable fish feed source. It can provide essential amino acids at sufficiently high levels. Based on its FA composition and (relatively low) fat content, Lv can best be considered a protein source. Still, worm biomass is rich in PUFA, which could be a potential high value product for feed applications. Compared to black soldier fly and bacterial production systems, Lv shows intermediate production efficiencies, while biomass harvesting and processing probably is more easy.

Additional advantages of Lv worm biomass to replace fishmeal are: 1) Lv acts as a strong natural fish attractant, 2) the growth efficiency of fish on worms is high in comparison to regular feeds, 3) the nutritional profile of worms matches that of fishmeal, 4) the worms are a natural feed source for freshwater fish and 5) the worms allow a secure and stable feed production that is independent of natural resources.

Further recommendations for future research as outlined and discussed in chapter 6 are mostly related to the technical upscaling of the reactor technology and obtaining more detailed insight in controlled worm growth in response to food characteristics, reactor design and operational conditions.

Microbes and asthma : Opportunities for intervention
Smits, Hermelijn H. ; Hiemstra, Pieter S. ; Prazeres Da Costa, Clarissa ; Ege, Markus ; Edwards, Michael ; Garn, Holger ; Howarth, Peter H. ; Jartti, Tuomas ; Jong, Esther C. De; Maizels, Rick M. ; Marsland, Ben J. ; McSorley, Henry J. ; Müller, Anne ; Pfefferle, Petra I. ; Savelkoul, Huub ; Schwarze, Jürgen ; Unger, Wendy W.J. ; Mutius, Erika Von; Yazdanbakhsh, Maria ; Taube, Christian - \ 2016
Journal of Allergy and Clinical Immunology 137 (2016)3. - ISSN 0091-6749 - p. 690 - 697.
asthma - helminths - Hygiene hypothesis - immune regulation - microbes - microbiome - sensitization - viruses

The worldwide incidence and prevalence of asthma continues to increase. Asthma is now understood as an umbrella term for different phenotypes or endotypes, which arise through different pathophysiologic pathways. Understanding the many factors contributing to development of the disease is important for the identification of novel therapeutic targets for the treatment of certain asthma phenotypes. The hygiene hypothesis has been formulated to explain the increasing prevalence of allergic disease, including asthma. This hypothesis postulates that decreased exposure at a young age to certain infectious agents as a result of improved hygiene, increased antibiotic use and vaccination, and changes in lifestyle and dietary habits is associated with changes in the immune system, which predispose subjects to allergy. Many microbes, during their coevolution with human subjects, developed mechanisms to manipulate the human immune system and to increase their chances of survival. Improving models of asthma, as well as choosing adequate end points in clinical trials, will lead to a more complete understanding of the underlying mechanisms, thus providing an opportunity to devise primary and secondary interventions at the same time as identifying new molecular targets for treatment. This article reports the discussion and conclusion of a workshop under the auspices of the Netherlands Lung Foundation to extend our understanding of how modulation of the immune system by bacterial, parasitic, and viral infections might affect the development of asthma and to map out future lines of investigation.

Culturing soles on ragworms: growth and feeding behaviour
Ende, S.S.W. - \ 2015
Wageningen University. Promotor(en): Johan Verreth, co-promotor(en): Johan Schrama. - Wageningen : Wageningen University - ISBN 9789462575622 - 128
solea - soleidae - kweekvis - voeropname - groei - prooi - wormen - foerageren - voedingsgedrag - prestatieniveau - vijverteelt - aquacultuur - farmed fish - feed intake - growth - prey - helminths - foraging - feeding behaviour - performance - pond culture - aquaculture

Ende, S.S.W. (2015). Culturing soles on ragworms: Growth and feeding behaviour. PhD thesis, Wageningen University, The Netherlands.

Despite the high market demand and intensive research efforts since the 1960s commercial culture of common sole (Solea solea L.) has been unsuccessful. Problems related to availability and price of suitable raw materials (invertebrates) and the low tolerance to crowding have hampered the development of intensive sole culture. Alternative extensive pond cultures systems are currently explored where common sole can graze on natural food. The general aim of this study was to get insight into which factors limit growth of common sole foraging on ragworms in ponds. The results did not show any nutritional effects that may hamper the growth of common sole. At non-limiting conditions, i.e. when fed chopped ragworms and when housed in sediment free tanks, common sole showed higher food intake, higher growth rates and higher nutrient utilization efficiencies than when fed mussels or a formulated diet. The results however suggest that growth in a pond with ragworms was limited by reduced foraging capabilities of common sole. To explore this hypothesis, the effect of prey size, predator size and prey density were tested. Overall, intake of buried ragworms was reduced by more than half in contrast to intake of unburied ragworms. Intake of buried ragworms was reduced regardless of ragworm size or common sole size. Increasing ragworm density only resulted in satiation intake values in smaller common sole. Our results additionally indicate that the presence of common sole hampers ragworm performance in a pond. Ragworms reduced their feeding activities when receiving water from tanks which contained common sole and ragworms, i.e. when common sole could graze on ragworms. Results from this PhD study suggest that the growth of common sole in ponds is not limited by nutritional but by their foraging abilities. However, the results of this study are too incomplete to fully predict growth performance of common sole in a pond. Factors such as temperature, oxygen supply or feeding activity need to be investigated to make comprehensive growth predictions.

Plant Biotechnology meets Immunology : plant-based expression of immunologically relevant proteins
Wilbers, R.H.P. - \ 2015
Wageningen University. Promotor(en): Jaap Bakker, co-promotor(en): Arjen Schots; Geert Smant. - Wageningen : Wageningen University - ISBN 9789462574335 - 229
plantenbiotechnologie - immunologie - planten - eiwitten - farmaceutische eiwitten - interleukine 10 - ontstekingsremmers - biologische activiteit - cytokinen - genexpressie - transforming growth factor - wormen - recombinant eiwitten - glycoproteïnen - plant biotechnology - immunology - plants - proteins - pharmaceutical proteins - interleukin 10 - antiinflammatory agents - biological activity - cytokines - gene expression - helminths - recombinant proteins - glycoproteins

The incidence of inflammatory disorders in industrialized countries has dramatically increased over the last decennia, which is believed to result from a change in life-style. Treatment of these inflammatory disorders relies on the intervention in immune responses thereby restoring homeostasis. For now, many inflammatory disorders are treated with broad-acting immunosuppressive drugs or monoclonal antibodies that specifically target pro-inflammatory molecules of the immune system. An alternative therapeutic approach would be to use immunomodulatory proteins that are naturally involved in re-establishing immune homeostasis. This thesis describes the plant-based expression of a variety of immunomodulatory cytokines that may be used as biopharmaceutical proteins in the future. Furthermore, this thesis contains a pioneering chapter on the plant-based expression of immunomodulatory helminth-secreted glycoproteins.

In Chapter 2 we describe the plant-based expression of the immune-regulatory cytokine human transforming growth factor β1 (TGF-β1). By co-expressing human furin with latent TGF-β1 we were able to engineer the post-translational proteolytic processing of TGF-β1, which enabled the production of biologically active TGF-β1. In Chapter 3 we reveal that aggregation is a major production bottleneck for the anti-inflammatory cytokine interleukin-10 (IL-10). By protein engineering we were able to prevent aggregation and created a biologically active fusion protein of IL-10. In Chapter 4 we express biologically active IL-22 in plants. We reveal that, in contrast to current literature, its activity is independent of the presence of N-glycans or their composition. This chapter further reveals that plants offer a powerful tool to allow investigation into the role of N-glycans in protein folding and biological activity of glycoproteins. In Chapter 5 we further explore the potential of glyco-engineering in plants by engineering helminth-like N-glycans. We produce large quantities of two major egg antigens from Schistosoma mansoni and successfully engineer Lewis X, LDN and LDNF N-glycan structures. These plant biotechnological research lines are a showcase for the potential of engineering proteins as well as post-translational modifications in plants with special emphasis on N-glycan engineering. Altogether, the results presented in the first four chapters reveal the remarkable flexibility of plants as a production platform for recombinant proteins. It showcases the potential of engineering proteins as well as post-translational modifications in plants, but it especially highlights the engineering of tailor made N-glycans in plants. This, combined with the speed of transient expression by means of agroinfiltration, makes transient expression in Nicotiana benthamiana a powerful tool to study the role of N-glycans on glycoprotein function.

In parallel to these plant biotechnological research lines, we also developed an in vitro model system based on mouse bone marrow-derived cells to study immunological responses. We used this model to obtain clues on why IL-10 therapy has not been as successful as previously anticipated. In Chapter 6 we have set-up biological activity assays based on bone marrow-derived cells and reveal that IL-10 activity is dependent on both IL-10R1 and IL-10R2, but not IL-10R2-associated signalling via Tyk2. We also show that interactions between IL-10R1 and IL-10R2 (both intracellular and extracellular) reduce cellular binding of IL-10, but are crucial to initiate IL-10 mediated signalling. Furthermore, we observed that macrophages and dendritic cells respond differently to IL-10. This was further investigated in Chapter 7 where we reveal that GM-CSF (the cytokine used to differentiate dendritic cells) is responsible for negatively regulating early IL-10-mediated responses. Strikingly, GM-CSF does not strongly affect the IL-10-induced activation of the transcription factor STAT3. Instead, GM-CSF induces strong constitutive phosphorylation of GSK-3β, a signalling component downstream of the PI3K/Akt pathway. These immunological chapters give novel insights on the mechanism of initiating IL-10-induced signalling and on the possible integration of signal transduction pathways elicited by different cytokines. Ultimately this knowledge could provide us with new therapeutic strategies to treat inflammatory disorders.

De beheersing van wormbesmettingen bij schapen op bedrijven in de praktijk : waardevolle inzichten uit een internetenquête
Ploeger, H. ; Antonis, A.F.G. ; Vellema, P. ; Verkaik, J. ; Bokma, M. - \ 2014
schapenhouderij - wormen - spijsverteringskanaal - haemonchus contortus - nematodirus - parasitosen - anthelmintica - sheep farming - helminths - digestive tract - parasitoses - anthelmintics
Actuele ontwikkelingen in de preventie en bestrijding van maagdarmwormen bij schapen : Kernpunten uit een literatuurstudie
Bokma-Bakker, M.H. ; Antonis, A.F.G. ; Ploeger, H. ; Vellema, P. ; Verkaik, J.C. - \ 2014
Wageningen UR/Universiteit Utrecht
schapenhouderij - maagdarmziekten - wormen - dierparasitaire nematoden - nematodirus battus - haemonchus contortus - teladorsagia circumcincta - schapenziekten - gastheer parasiet relaties - graslandbeheer - ziektebestrijding - dierveredeling - selectief fokken - voedersupplementen - schapenvoeding - sheep farming - gastrointestinal diseases - helminths - animal parasitic nematodes - sheep diseases - host parasite relationships - grassland management - disease control - animal breeding - selective breeding - feed supplements - sheep feeding
De schapensector gaat de parasitaire resistentie-ontwikkeling terugdringen. Ze wil dat doen door verbetering van de preventie en de bestrijding van maagdarmwormen. Experts hebben in 2013 een literatuurstudie uitgevoerd. Hierin zijn de belangrijkste binnen- en buitenlandse innovatieve ontwikkelingen voor verlaging van de infectiedruk opgenomen en vertaald naar toepasbaarheid onder de Nederlandse omstandigheden. Bekeken zijn de gebieden fokkerij, voeding, vaccinatie, beweiding, inzet van natuurlijke middelen en diagnostiek. In deze brochure zijn de belangrijkste bevindingen samengevat.
Innovatieve ontwikkelingen voor beheersing van maagdarmwormbesmettingen bij schapen
Bokma-Bakker, M.H. ; Antonis, A.F.G. ; Ploeger, H.W. ; Verkaik, J.C. - \ 2014
Wageningen : Wageningen UR Livestock Research (Rapport / Wageningen UR Livestock Research 779) - 51
schapenhouderij - maagdarmziekten - wormen - resistentiemechanismen - infectiviteit - dierziektepreventie - literatuuroverzichten - sheep farming - gastrointestinal diseases - helminths - resistance mechanisms - infectivity - animal disease prevention - literature reviews
Deze literatuurstudie geeft een weergave van de actuele kennis op het gebied van innovatieve ontwikkelingen in binnen- en buitenland met betrekking tot terugdringen van resistentievorming, preventie en beheersing van maagdarmwormen bij schapen. Hierbij zijn nationale en internationale (innovatieve) ontwikkelingen met betrekking tot het verlagen van de parasitaire infectiedruk op het gebied van fokkerij, voeding, vaccinatie, beweiding en andere relevante velden meegenomen en vertaald naar toepasbaarheid onder de Nederlandse omstandigheden.
Spoelwormbestrijding bij biologische varkens
Verkaik, J.C. ; Mul, M.F. ; Vermeer, H.M. - \ 2013
Wageningen UR Livestock Research
varkenshouderij - zeugen - biggen - vleesproductie - wormen - anthelmintica - dosering - biologische landbouw - pig farming - sows - piglets - meat production - helminths - anthelmintics - dosage - organic farming
De biologische varkenshouderij wil het gebruik van gangbare chemische geneesmiddelen, waaronder ontwormingsmiddelen, minimaliseren. Voorop staan gezonde dieren voor een rendabele bedrijfsvoering. De gangbare varkenshouderij heeft ook belang bij minder gebruik van ontwormingsmiddelen. Het gezamenlijk belang is het voorkomen van parasitaire resistentieontwikkeling. Vanuit dit oogpunt worden adviezen gegeven voor het ontwormen van vleesvarkens, zeugen en biggen.
Ecologische effecten van het ontwormingsmiddel ivermectine
Lahr, J. ; Kats, R.J.M. van; Hout, A. van der; Lammertsma, D.R. ; Werf, D.C. van der; Zweers, A.J. ; Siepel, A. - \ 2011
Vakblad Natuur Bos Landschap 8 (2011)10. - ISSN 1572-7610 - p. 28 - 31.
paarden - excreten - veterinaire producten - wormen - ziektebestrijding - bodembiologie - grote grazers - natuurgebieden - ecosystemen - horses - excreta - veterinary products - helminths - disease control - soil biology - large herbivores - natural areas - ecosystems
Het is inmiddels een bekend feit dat ontwormingsmiddelen die aan vee worden gegeven, giftig kunnen zijn voor de mestfauna, de insecten die zich met mest voeden en er hun eieren in leggen. Het verdwijnen van bepaalde soorten mestfauna kan er in bepaalde gevallen toe leiden dat de afbraak van mest in het veld vertraagd wordt, zo blijkt uit buitenlandse studies. Enquêtes wezen eerder uit dat ontwormingsmiddelen in veel Nederlandse natuurgebieden worden toegediend aan grote grazers. Komen dit soort ecologische effecten dus ook in onze natuurgebieden voor? Dit is de afgelopen jaren door Alterra onderzocht in opdracht van het ministerie van EL&I.
How widespread is resistance to invermectin among gastrointestinal nematodes in sheep in The Netherlands? = Hoe wijd verspreid is resistentie tegen ivermectine van maagdarmwormen bij het schaap in Nederland?
Borgsteede, F.H.M. ; Verkaik, J.C. ; Moll, L. ; Dercksen, D. ; Vellema, P. ; Bavinck, G. - \ 2010
Tijdschrift voor Diergeneeskunde 135 (2010)21. - ISSN 0040-7453 - p. 782 - 785.
ivermectine - schapen - maagdarmziekten - wormen - schapenhouderij - haemonchus contortus - ivermectin - sheep - gastrointestinal diseases - helminths - sheep farming - anthelmintic resistance - teladorsagia-circumcincta - haemonchus-contortus - moxidectin - ostertagia - efficacy - benzimidazole - association - strain
In Autumn 2009, a faecal egg count reduction test (FERCT) was carried out on three sheep farms. Groups of 8-11 lambs were treated with ivermectin or moxidectin, with a 14-day interval between treatment and sampling. Ivermectin resistance was present on all three farms. Treatment with ivermectin resulted in a reduction in faecal egg numbers of 94.6%, 63%, and 59%. On two farms, 14 days after treatment pooled faecal samples yielded predominantly larvae of Hamonchus contortus (100% and 98%, respectively). On the third farm, H. contortus and (probably) Teladorsagia circumcincta were resistant to ivermectin (64% and 36% of the larvae, respectively). Treatment with moxidectin resulted in a 100% reduction in egg output in sheep on all three farms. More sensitive culture techniques failed to detect any larvae in samples taken from two farms, but a few Ostertagia-type larvae, probably of T. circumcincta, were detected in samples from the third farm. It can be concluded that gastrointestinal nematodes in sheep from these three farms were resistant to ivermectin, whereas resistance to moxidectin was not detected.
Kijk lammeren vaker in de ogen
Verkaik, J.C. ; Borgsteede, F.H.M. - \ 2009
[Lelystad] : Wageningen UR, Animal Sciences Group
schapen - lammeren - maagdarmziekten - wormen - behandeling - haemonchus contortus - sheep - lambs - gastrointestinal diseases - helminths - treatment
Ontwormen op basis van de kleur van het ooglid gaat verder dan de huidige behandelrichtlijn. Het uitsluitend ontwormen van lammeren in de koppel die lijden aan haemonchose is daarmee de meest verantwoorde manier van ontwormen. Het minimaliseert de selectie op resistente maagdarmwormen en maximaliseert het behoud van de effectiviteit van het gebruikte middel op het bedrijf. De controle en selectie op kleur kost wel meer tijd
Slibverwerking met wormen: toepasbaar voor RWZI’s?
Hendrickx, T.L.G. ; Temmink, B.G. ; Elissen, H.J.H. ; Buisman, C.J.N. - \ 2009
Afvalwaterwetenschap 8 (2009)4. - ISSN 1568-3788 - p. 284 - 292.
afvalwater - afvalwaterbehandeling - rioolslib - biologische technieken - wormen - lumbricidae - economische haalbaarheid - economische analyse - zuiveringsinstallaties - slibzuivering - aquatische wormen - waste water - waste water treatment - sewage sludge - biological techniques - helminths - economic viability - economic analysis - purification plants - sludge treatment - aquatic worms
De verwerking van afvalslib uit biologische zuivering van industrieel en huishoudelijk afvalwater is kostbaar en de uiteindelijke verwerkingsmethode is veelal verbranding. Met behulp van aquatische wormen kan de hoeveelheid afvalslib worden gereduceerd, de ontwaterbaarheid ervan worden verbeterd en een gedeelte van de nutriënten worden teruggewonnen door de groei van wormenbiomassa. Een nieuw ontwerp voor een wormenreactor, geschikt voor opschaling, is succesvol getest in het lab. Bij relatief kleine RWZI's is het te verwachten voordeel het grootst, gezien de hoge transportkosten van ingedikt slib naar de centrale slibverwerkingsinstallaties en juist hierin kan veel voordeel behaald worden met een wormenreactor. Het economisch perspectief voor de toepassing van een wormenreactor bij een rioolwaterzuiveringsinstallatie (RWZI) van 35.000 i.e. wordt in dit artikel beschreven en is veelbelovend. Voor een gedetailleerde haalbaarheidsstudie zijn echter de ervaringen met een pilot reactor nodig, zoals optimalisatie van het indikken van wormenkeutels. Het economisch perspectief van een wormenreactor valt nog veel gunstiger uit wanneer de geproduceerde wormenbiomassa een hoogwaardige toepassing heeft, zoals visvoer voor consumptievis. Dit zou echter slechts een optie voor schone slibsoorten kunnen zijn, zoals die uit bepaalde voedingsindustrieën
Ploegen of durven wachten : Interview met Derk van Balen
Tonjes, J. ; Balen, D.J.M. van - \ 2009
Nieuwe oogst / Magazine gewas 5 (2009)17. - ISSN 1871-093X - p. 11 - 11.
grondbewerking - bodembiologie - bodemstructuur - wormen - tillage - soil biology - soil structure - helminths
Wormen verbeteren de structuur en een mooie structuur is goed voor wormen. Onderzoek van Praktijkonderzoek Plant en Omgeving (PPO) moet meer duidelijkheid geven over de mate waarin minimale grondbwerking bijdraagt aan een betere wormenstand en hoe de landbouw daar weer van kan profiteren
Wormenwijzer website
Verkaik, J.C. - \ 2008
ASG veehouderij
schapen - myiase - wormen - maagdarmziekten - informatiesystemen - on-line - adviescentra - professionele dienstverlening - internet - dierziektepreventie - sheep - myiasis - helminths - gastrointestinal diseases - information systems - on line - advisory centres - professional services - animal disease prevention
De Wormenwijzer geeft behandeladviezen voor een verantwoorde aanpak van maagdarmwormen bij schapen. De behandeladviezen krijgt men op maat door het beantwoorden van een aantal vragen over de bedrijfssituatie per samenweidend of aangevoerd koppel dieren. De Wormenwijzer bepaalt vervolgens de kans op een maagdarmwormbesmetting en formuleert een advies afgestemd op de bedrijfshistorie. Het advies is gericht op een minimaal risico op schade door maagdarmwormen. Met extra toelichting bij een aantal belangrijke onderwerpen
Inventarisatie van mogelijke fytotherapeutica met een werking tegen wormen bij pluimvee
Mul, M.F. ; Reuvekamp, B.F.J. - \ 2008
Wageningen : Animal Sciences Group - 21
biologische landbouw - pluimveehouderij - diergezondheid - veterinaire producten - geneeskrachtige kruiden - ascaridia - ascaridia galli - heterakis gallinarum - capillaria - raillietina - wormen - organic farming - poultry farming - animal health - veterinary products - herbal drugs - helminths
Deze literatuurstudie is uitgevoerd naar aanleiding van een inventarisatie naar de meest voorkomende aandoeningen bij biologisch legpluimvee. Uit deze inventarisatie bleek dat de bedrijven vooral last hadden van vogelmijt (17 van de 29 bedrijven), wormen (11 van de 29) en E. coli (10 van de 29). De stuurgroep koos voor de aanpak van wormen omdat bij de bestrijding ervan men vrijwel altijd een allopathisch middel gebruikt. In Nederland is één gangbaar middel beschikbaar tegen wormen, flubendazole. Dit is weliswaar toegestaan in de biologische sector, maar past niet in het biologische gedachtegoed. Het streven is immers geen gebruik te maken van gangbare geneesmiddelen en deze alleen curatief te gebruiken indien behandeling noodzakelijk is. Het toepassen van fytotherapeutica tegen wormen kan het gebruik van allopathische middelen in de biologische pluimveehouderij verminderen.
Gezondheid van biologische leghennen
Fiks-van Niekerk, T.G.C.M. ; Bestman, M.W.P. ; Wagenaar, J.P. ; Krimpen, M.M. van; Mul, M.F. ; Kijlstra, A. ; Reimert, H.G.M. ; Reuvekamp, B.F.J. - \ 2008
Lelystad : Animal Sciences Group (Boek / Animal Sciences Group nr. 5) - 80
biologische landbouw - pluimveehouderij - hennen - diergezondheid - dierenwelzijn - vaccinatie - verenpikken - hennenvoeding - wormen - bacterieziekten - salmonella - escherichia coli - brachyspira - aviaire influenzavirussen - infectieus bronchitisvirus - voedselveiligheid - dioxinen - dierhouderij - pluimvee - organic farming - poultry farming - hens - animal health - animal welfare - vaccination - feather pecking - hen feeding - helminths - bacterial diseases - avian influenza viruses - infectious bronchitis virus - food safety - dioxins - animal husbandry - poultry
Dit boekje bevat een bundeling van reeds eerder uitgegeven artikelen en brochures van ASG en LBI over gezondheid van biologische leghennen. Tevens zijn enkele nieuwe stukken toegevoegd over onderwerpen die voor de biologische leghennenhouderij van belang zijn.
Een nieuw reactorconcept voor slibreductie met aquatische wormen
Hendrickx, T.L.G. ; Elissen, H.J.H. ; Temmink, B.G. ; Buisman, C.J.N. - \ 2007
Afvalwaterwetenschap 6 (2007)1. - ISSN 1568-3788 - p. 45 - 52.
rioolslib - predatie - slib - wormen - afvalwaterbehandeling - afvalverwerking - waterorganismen - lumbricus - sewage sludge - predation - sludges - helminths - waste water treatment - waste treatment - aquatic organisms
De behandeling van afvalwater resulteert in de productie van enorme hoeveelheden zuiveringsslib. In Nederland wordt dit slib voornamelijk verbrand. Een biologische aanpak voor het verminderen van de hoeveelheid slib die moet worden getransporteerd en verwerkt is de predatie door aquatische wormen. Tim Hendrickx, Hellen Elissen, Hardy Temmink en Cees Buisman beschrijven experimenten waarin de toepasbaarheid werd getest van een nieuw reactorconcept voor de reductie van slib met behulp van de aquatische oligochaet Lumbriculus variegatus
Hardnekkige wormen
Borgsteede, F.H.M. - \ 2007
Het Schaap 2007 (2007)3. - ISSN 0165-3156 - p. 18 - 19.
schapenhouderij - dierparasitaire nematoden - wormen - nematodenbestrijding - ziektepreventie - haemonchus - agrarische bedrijfsvoering - sheep farming - animal parasitic nematodes - helminths - nematode control - disease prevention - farm management
De weerstand van maagdarmwormen tegen een wormbehandeling neemt toe. Aandacht voor het onder controle houden van worminfecties, bestrijding en resistentie. Vooral Haemonchus levert problemen op
Drug resistance makes new control measures of stomach parasites in small ruminants necessary = Resistentie maakt nieuwe aanpak van de bestrijding van maagdarmwormen bij kleine herkauwers noodzakelijk
Eysker, M. ; Borgsteede, F.H.M. ; Ploeger, H.W. ; Vellema, P. - \ 2005
Tijdschrift voor Diergeneeskunde 130 (2005)7. - ISSN 0040-7453 - p. 205 - 209.
schapenziekten - dierparasitaire nematoden - wormen - ziektebestrijding - nematodenbestrijding - nematodeninfecties - bestrijdingsmethoden - diergeneeskunde - anthelmintica - sheep diseases - animal parasitic nematodes - helminths - disease control - nematode control - nematode infections - control methods - veterinary science - anthelmintics - parasites
Control of Parasitic gastroenteritis in small ruminants is threatened by the worldwide growing problem of anthelmintic resistance. Therfore, alternativeapproaches for worm control are imperative. Of utmost importance is to slow down selection pressure for anthelmintic resistance by using alternative control measure combined with minimal anthelmintic usage. New control options for the Netherlands are discussed. De bestrijding van maagdarmworminfecties bij het schaap wordt wereldwijd bedreigd door toenemende resistentie van wormen tegen anthelmintica. Dit noopt tot aanpassing van de wormbestrijding. In dit artikel wordt aangegeven welke veranderingen in de wormbestrijding nodig zijn. Dit komt voral neer op het deels onbehandeld laten van ooien of lammeren, optimaal gebruik maken van nieuwe informatie over de beweidingsmogelijkheden en een vermindering van 'blind' gebruik van anthelmintica door via faecesonderzoek vast te stellen of ontwormen wel nodig is.
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