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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Multi-objective decision-making for public health - dietary assessment and advice
Lemmen-Gerdessen, J.C. van; Claassen, G.D.H. ; Veer, P. van 't; Vorst, J.G.A.J. van der - \ 2017
- 4 p.
Alphavirus capsid proteins self-assemble into core-like particles in insect cells: A promising platform for nanoparticle vaccine development
Hikke, M.C. ; Geertsema, C. ; Wu, V. ; Metz, Stefan ; Lent, J.W.M. van; Vlak, J.M. ; Pijlman, G.P. - \ 2016
Biotechnology Journal 10 (2016)2. - ISSN 1860-6768 - p. 266 - 273.
The mosquito-borne chikungunya virus (CHIKV) causes arthritic diseases in humans, whereas the aquatic salmonid alphavirus (SAV) is associated with high mortality in aquaculture of salmon and trout. Using modern biotechnological approaches, promising vaccine candidates based upon highly immunogenic, enveloped virus-like particles (eVLPs) have been developed. However, the eVLP structure (core, lipid membrane, surface glycoproteins) is more complex than that of non-enveloped, protein-only VLPs, which are structurally and morphologically 'simple'. In order to develop an alternative to alphavirus eVLPs, in this paper we engineered recombinant baculovirus vectors to produce high levels of alphavirus core-like particles (CLPs) in insect cells by expression of the CHIKV and SAV capsid proteins. The CLPs localize in dense nuclear bodies within the infected cell nucleus and are purified through a rapid and scalable protocol involving cell lysis, sonication and low-speed centrifugation steps. Furthermore, an immunogenic epitope from the alphavirus E2 glycoprotein can be successfully fused to the N-terminus of the capsid protein without disrupting the CLP self-assembling properties. We propose that immunogenic epitope-tagged alphavirus CLPs produced in insect cells present a simple and perhaps more stable alternative to alphavirus eVLPs.
Groentejuwelen
Verkerke, Wouter - \ 2015
Development and application of a protocol to evaluate herd welfare in Dutch dairy farms
Metz, J.H.M. ; Dijkstra, T. ; Franken, P. ; Frankena, K. - \ 2015
Livestock Science 180 (2015). - ISSN 1871-1413 - p. 183 - 193.
A protocol was developed and applied in a field survey to incorporate evaluation of herd welfare into the existing quality assurance program in Dutch dairy farming. Welfare was derived from the state of the biological needs of cows. Welfare targets and critical control points were selected according to HACCP principles, while restriction was to dairy herds with loose-cubicle housing (>90% of Dutch herds). The feasibility for measurement of the protocol was tested in a pilot study with 52 preselected, medium-sized herds for time needed for the observations (set at ~1 h to 2 h ), robustness of parameters (threshold of 80% true cases for repeated scores), and opinions from inspectors and farmers, which were variable but positive on average. The final protocol consisted of 16 animal-based and 14 environment-based parameters. From a random sample of 240 dairy herds (1% of Dutch farms), 164 herds (12,267 cows) with median herd size of 67 cows (SD=38) participated in the field survey, on a voluntary basis. The time needed for scoring averaged 78 min (SD=22) per herd. Animal-based parameters included leg disorders, normal and abnormal locomotion, external lesions, skin and teat problems, poor body condition, and fearfulness of the herd. Herd prevalence averaged highest for abnormal locomotion (43.8%), swollen hocks and knees (25.2%), dermatophytosis (24.2%), scabies (20.1%), and filthiness (17.4%). However, herd prevalence was lowest (96% of herds). Overall, our results indicate various directions for welfare improvement in practice, both at the individual farm and sector level.
A sensitive epitope-blocking ELISA for the detection of Chikungunya virus-specific antibodies in patients
Goh, L.Y.H. ; Kam, Y.W. ; Metz, S.W.H. ; Hobson-Peters, J. ; Prow, N.A. ; McCarthy, S. ; Smith, D.W. ; Pijlman, G.P. ; Ng, L.F.P. ; Hall, R.A. - \ 2015
Journal of Virological Methods 222 (2015). - ISSN 0166-0934 - p. 55 - 61.
west-nile-virus - linked-immunosorbent-assay - valley encephalitis-virus - monoclonal-antibodies - diagnostic-accuracy - universal detection - reunion island - insect cells - ns1 protein - pcr assay
Chikungunya fever (CHIKF) has re-emerged as an arboviral disease that mimics clinical symptoms of other diseases such as dengue, malaria, as well as other alphavirus-related illnesses leading to problems with definitive diagnosis of the infection. Herein we describe the development and evaluation of a sensitive epitope-blocking ELISA (EB-ELISA) capable of specifically detecting anti-chikungunya virus (CHIKV) antibodies in clinical samples. The assay uses a monoclonal antibody (mAb) that binds an epitope on the E2 protein of CHIKV and does not exhibit cross-reactivity to other related alphaviruses. We also demonstrated the use of recombinant CHIK virus-like particles (VLPs) as a safe alternative antigen to infectious virions in the assay. Based on testing of 60 serum samples from patients in the acute or convalescent phase of CHIKV infection, the EB-ELISA provided us with 100% sensitivity, and exhibited 98.5% specificity when Ross River virus (RRV)- or Barmah Forest virus (BFV)-immune serum samples were included. This assay meets the public health demands of a rapid, robust, sensitive and specific, yet simple assay for specifically diagnosing CHIK-infections in humans.
Groentejuwelen : waarom zie je alleen knappe groente in de supermarkt? (interview Wouter Verkerke)
Metz, M. ; Verkerke, W. - \ 2015
Quest 2015 (2015)135. - p. 32 - 35.
The effect of temperature on the folding of vertebrate glycoproteins in insect cells
Oers, M.M. van; Xin, L. ; Hikke, M.C. ; Metz, S.W.H. ; Vlak, J.M. ; Braakman, I. ; Pijlman, G.P. - \ 2015
Insects are poikilothermic organisms able to survive in fluctuating ambient temperatures. As their body temperature varies with the temperature of the environment, it is likely that these invertebrates have properties that allow correct folding of glycoproteins within a broad temperature range. To test this concept, we studied the folding ability of the influenza virus hemagglutinin (HA) expressed in Sf9 insect cells growing at 27°C and compared with human HeLa cells growing at 37°C, the optimal temperature for HA. HA folding was demonstrated to be more efficient in insect cells than in HeLa cells and remained fast over a broad temperature range, from 24°C to 45°C. An HA mutant that only folds below 27°C, however, showed identical temperature-sensitivity for folding in insect cells: it did not fold at 37°C. We also tested a protein with a low natural optimal temperature. Therefore, we expressed the structural polyprotein of salmonid alphavirus (SAV) in Sf9 cells, using a baculovirus vector. A similar strategy had previously resulted in immunogenic and correctly processed enveloped virus-like particles (eVLPs) of the SAV-related chikungunya virus. However, at 27°C, no SAV eVLPs were formed. The SAV envelope glycoprotein E2 was not transported from the endoplasmic reticulum (ER) to the Golgi due to incorrect folding, despite the presence of E1. SAV normally replicates between 10°C and 15°C. We therefore lowered the temperature during the glycoprotein production phase to 15°C and found that E2 transport to the cell surface recovered and eVLPs were secreted into the culture fluid. We concluded that protein-intrinsic properties may limit the temperature range for correct folding, but that insect cells — in contrast to mammalian cells — have the ability to fold glycoproteins at a broad temperature range. This quality makes insect cells highly suitable for expression of both mammalian and fish virus glycoproteins.
Prospects for Agroforestry in REDD+ landscapes in Africa
Minang, P.A. ; Duguma, L.A. ; Bernard, F. ; Metz, O. ; Noordwijk, M. van - \ 2014
Current Opinion in Environmental Sustainability 6 (2014). - ISSN 1877-3435 - p. 78 - 82.
carbon sequestration - forest degradation - intensification - deforestation - conservation - challenges - systems - area
Agroforests and agroforestry can be direct targets of Reduced Emissions from Deforestation and Forest Degradation (REDD+) programs, or indirect parts of the necessary conditions for success. Whether or not it becomes a core element of REDD+ depends on the country's forest definition. We review these dimensions of agroforestry in REDD+, with supporting examples, mostly from Africa, and highlight the implications and challenges for enhancing the contributions of agroforestry to REDD+ and corresponding sustainable benefits. Where carbon stocks in agroforestry cannot be directly targeted in REDD+, agroforestry still can be included in REDD+ strategies, as ways to (1) shift demand for land (land sparing) and (2) provide alternative sources of products otherwise derived from forest over-exploitation or conversion, thereby avoiding leakage from forest protection efforts.
Levels of Salmonella and Campylobacter in organic and conventional chicken fillets in the Netherlands
Gkogka, E. ; Aryani, D. ; Metz, A. ; Telgmann, S. ; Reij, M.W. - \ 2014
In: Abstract book ICFMH Conference Food Micro. - - p. 460 - 460.
Chikungunya virus-like particles are more immunogenic in a lethal AG129 mouse model compared to glycoprotein El or E2 subunits
Metz, S.W.H. ; Martina, B.E. ; Doel, P. van den; Geertsema, C. ; Osterhaus, A.D. ; Vlak, J.M. ; Pijlman, G.P. - \ 2013
Vaccine 31 (2013)51. - ISSN 0264-410X - p. 6092 - 6096.
insect cells - expression
Chikungunya virus (CHIKV) causes acute illness characterized by fever and long-lasting arthritic symptoms. The need for a safe and effective vaccine against CHM/infections is on the rise due to on-going vector spread and increasing severity of clinical complications. Here we report the results of a comparative vaccination-challenge experiment in mice using three different vaccine candidates produced in insect cells by recombinant baculoviruses: (i) secreted (s)E1 and (ii) sE2 CHIKV glycoprotein subunits (2 mu g/immunization), and (iii) CHIKV virus-like particles (VLPs) (1 mu g E2 equivalent/immunization). These experiments show that vaccination with two subsequent administrations of 1 mu g of Matrix M adjuvanted CHIN VLPs completely protected AG129 mice from lethal CHIN challenge. Vaccination with El and E2 subunits provided partial protection, with half of the mice surviving but with significantly lower neutralizing antibody titres as compared to the VLP vaccinated mice. This study provides evidence that even a modest neutralizing antibody response is sufficient to protect mice from CHM/infections. Neutralization was the prominent correlate of protection. In addition, CHIKV VLPs provide a superior immune response and protection against CHIICV-induced disease in mice as compared to individual CHIKV-sEl and -sE2 subunits. (C) 2013 Elsevier Ltd. All rights reserved.
Salmonid alphavirus low-temperature dependent glycoprotein processing and trafficking are important for virus-like particle formation
Hikke, M.C. ; Metz, S.W.H. ; Feenstra, F. ; Villoing, S. ; Vlak, J.M. ; Pijlman, G.P. - \ 2013
In: Abstract book of the 32nd Annual Meeting of the American Society for Virology. - - p. 315 - 315.
Electrochemical phosphate recovery from nanofiltration concentrates
Kappel, C. ; Yasadi, K. ; Temmink, B.G. ; Metz, S.J. ; Kemperman, A.J.B. ; Nijmeijer, K. ; Zwijnenburg, A. ; Witkamp, G.J. ; Rijnaarts, H. - \ 2013
Separation and Purification Technology 120 (2013). - ISSN 1383-5866 - p. 437 - 444.
amorphous calcium-phosphate - municipal waste-water - aqueous-solution - precipitation - hydroxyapatite - magnesium - struvite - removal - substitution - experiences
The high total phosphorus content of raw domestic wastewater with its significant eutrophication potential offers an excellent possibility for phosphate recovery. Continuous recirculation of NF concentrate to an MBR and simultaneous phosphate recovery from the NF concentrate can be applied to produce reusable water, recovering phosphates, while at the same time decreasing the scaling potential of the recirculated NF concentrate, prolonging the retention times of slowly biodegradable soluble compounds (e.g. micropollutants) and recirculating multivalent cations to promote the bio-flocculation. Here we introduce an electrochemical system to recover phosphates. An electrochemical cell was divided into an anode and a cathode compartment separated by a cation exchange membrane. Precipitation of phosphates from nanofiltration concentrate was induced by locally increasing the pH at the cathode surface by water electrolysis and thereby creating supersaturated conditions at the cathode. 70–95% recovery of total phosphate was achieved at a pH of 8–10 near the cathode. Ion analysis, XRD and ATR-FTIR spectra indicated that the precipitate consisted of amorphous calcium phosphate (ACP) and minor proportions of amorphous calcium carbonate (ACC). The amount of ACC was dependent on the pH. Calcium phosphate scaling at the cathode surface did not occur due to H2-gas formation preventing nucleation and growth at the cathode.
Chikungunya virus-like particle vaccine
Metz, S.W.H. - \ 2013
University. Promotor(en): Just Vlak, co-promotor(en): Gorben Pijlman. - S.L. : s.n. - ISBN 9789461735652 - 139
chikungunyavirus - virusachtige deeltjes - virusziekten - aedes albopictus - vectoren, ziekten - vaccins - vaccinontwikkeling - genexpressie - baculovirus - insecten - celcultuur vaccins - chikungunya virus - virus-like particles - viral diseases - disease vectors - vaccines - vaccine development - gene expression - insects - cell culture vaccines

Chikungunya virus (CHIKV) is an arthropod-borne alphavirus (family Togaviridae) and is the causative agent of chikungunya fever. This disease is characterised by the sudden onset of high fever and long-lasting arthritic disease. First identified in Tanzania in 1952, CHIKV has re-emerged in the last decade causing large outbreaks throughout Africa, Asia and Southern Europe. Increased CHIKV spread is mainly caused by its adaptation to a new mosquito vector, the Asian tiger mosquito Ae. albopictus, which is able to colonize more temperate regions. Currently, there are no antiviral treatments or commercial vaccines available, to prevent CHIKV infections. However, increased vector spread and clinical manifestations in humans, have triggered vaccine development. A broad range of vaccine strategies have been proposed and described, including inactivated virus formulations, live-attenuated virus, chimeric virus vaccines, DNA vaccines, adenoviral vectored vaccines, subunit protein vaccines and virus-like particle (VLP) formulations. However, these vaccination strategies have specific limitations in manufacturing, immunogenicity, safety, recombination and large scale production. Many, if not all safety problems do not apply for subunit or VLP based vaccines, except for the recombinant origin of the vaccine.

Recently, a CHIKV VLP-based vaccine was developed and provided protection in both mice and non-human primates. Even though this VLP approach is a safe, efficient and promising alternative to other vaccine strategies, large scale DNA plasmid transfection into mammalian cells and VLP yield of transfected cells remains challenging in terms of industrial production. These problems are alleviated by using the recombinant baculovirus-insect cell expression system.

In this thesis, recombinant baculoviruses were constructed to produce CHIKV glycoprotein E1 and E2 subunits and VLPs.For the production of CHIKV-E1 and E2 subunits, both protein genes were cloned downstream the polyhedrin gene (polh) promoter of in an Autographica californica multiple nucleopolyhedrovirus backbone, together with their authentic signal peptides 6K(E1) and E3(E2). Deletion of the C-terminal transmembrane domain, generated secreted versions of E1 (E1ΔTM or sE1) and E2 (E2ΔTM or sE2). A substantial amount of recombinant protein was glycosylated and processed by furin. The secreted CHIKV subunits were purified from the medium and were able to induce neutralizing antibodies in rabbits. For the production of the VLPs, the complete structural polyprotein (capsid, E3, E2, 6K, E1) was cloned downstream the AcMNPV polh promoter. E3E2 precursor processing and glycosylation appeared to be more efficient when E3E2 were expressed as part of the whole structural polyprotein cassette, compared to the individually expressed E3E2. The VLPs were isolated from the medium fraction and were morphologically similar to wild type CHIKV. A similar strategy was used to produce VLPs from another alphavirus, the salmonid alphavirus (SAV). Here, however, the normal baculovirus expression temperature of 27°C appeared to be detrimental for SAV-E3E2 furin cleavage and SAV-VLP production. E2-glycoprotein processing was shown to be temperature dependent and a tailored temperature-shift regime was designed in which Sf9-cells were infected with a recombinant baculovirus expressing the SAV structural proteins, and incubated at 27°C for 24 h, followed by a processing phase of 72 h at 15°C. Using this temperature regime, SAV-VLPs were produced that were morphologically indistinguishable from wild type SAV and underscores the flexibility of the baculovirus-insect cell expression system.

The immunogenicity of purified CHIKV-sE1 and -sE2 subunits and purified CHIKV-VLPs were then tested in a lethal vaccination-challenge mouse model, in IFN α/β, -γ receptor null AG129 mice. The innate immune system of these mice was made dysfunctional. This vaccine-challenge study clearly showed that VLPs provided superior protection, compared to their subunit counterparts. The subunits provided only partial protection and induced low neutralizing antibody titres. Immunization with the VLPs fully protected mice against lethal challenge and induced significant higher neutralizing antibody titress. Even though neutralizing antibody titres were lower after subunit immunization, this study showed that a minor neutralizing antibody response is sufficient to protect mice from lethal CHIKV challenge. Next, the CHIKV VLPs were tested for their ability to induce complete protection in an adult wild-type immune-competent mouse model, in which mice develop arthritic disease after CHIKV infection. The VLPs were able to induce full protection after a single immunization of 1 µg VLPs, without the use of adjuvants. In addition, IgG isotyping revealed a balanced IgG1-IgG2c response, suggesting a role for both humoral and cellular immunity in the protection against CHIKV infection. Mice served as a proxy for primates and vaccination trials in primates are next on the agenda.

This thesis is a typical example of the opportunities for the recombinant baculovirus-insect cell expression system in viral vaccine development, especially in vaccine development for other arboviruses. Although the CHIKV-VLPs produced in insect cells are amenable for large-scale production, the production process and downstream processing need to be carefully designed and optimized before CHIKV VLPs can be produced on an industrial scale. However, the data presented in this thesis show that CHIKV-VLPs produced in insect cells using recombinant baculoviruses represents as a new, safe, non-replicating and effective vaccine candidate against CHIKV infections.

Chikungunya virus (CHIKV) is an arthropod-borne alphavirus (family Togaviridae) and is the causative agent of chikungunya fever. This disease is characterised by the sudden onset of high fever and long-lasting arthritic disease. First identified in Tanzania in 1952, CHIKV has re-emerged in the last decade causing large outbreaks throughout Africa, Asia and Southern Europe. Increased CHIKV spread is mainly caused by its adaptation to a new mosquito vector, the Asian tiger mosquito Ae. albopictus, which is able to colonize more temperate regions. Currently, there are no antiviral treatments or commercial vaccines available, to prevent CHIKV infections. However, increased vector spread and clinical manifestations in humans, have triggered vaccine development. A broad range of vaccine strategies have been proposed and described, including inactivated virus formulations, live-attenuated virus, chimeric virus vaccines, DNA vaccines, adenoviral vectored vaccines, subunit protein vaccines and virus-like particle (VLP) formulations. However, these vaccination strategies have specific limitations in manufacturing, immunogenicity, safety, recombination and large scale production. Many, if not all safety problems do not apply for subunit or VLP based vaccines, except for the recombinant origin of the vaccine.

Recently, a CHIKV VLP-based vaccine was developed and provided protection in both mice and non-human primates. Even though this VLP approach is a safe, efficient and promising alternative to other vaccine strategies, large scale DNA plasmid transfection into mammalian cells and VLP yield of transfected cells remains challenging in terms of industrial production. These problems are alleviated by using the recombinant baculovirus-insect cell expression system.

In this thesis, recombinant baculoviruses were constructed to produce CHIKV glycoprotein E1 and E2 subunits and VLPs.For the production of CHIKV-E1 and E2 subunits, both protein genes were cloned downstream the polyhedrin gene (polh) promoter of in an Autographica californica multiple nucleopolyhedrovirus backbone, together with their authentic signal peptides 6K(E1) and E3(E2). Deletion of the C-terminal transmembrane domain, generated secreted versions of E1 (E1ΔTM or sE1) and E2 (E2ΔTM or sE2). A substantial amount of recombinant protein was glycosylated and processed by furin. The secreted CHIKV subunits were purified from the medium and were able to induce neutralizing antibodies in rabbits. For the production of the VLPs, the complete structural polyprotein (capsid, E3, E2, 6K, E1) was cloned downstream the AcMNPV polh promoter. E3E2 precursor processing and glycosylation appeared to be more efficient when E3E2 were expressed as part of the whole structural polyprotein cassette, compared to the individually expressed E3E2. The VLPs were isolated from the medium fraction and were morphologically similar to wild type CHIKV. A similar strategy was used to produce VLPs from another alphavirus, the salmonid alphavirus (SAV). Here, however, the normal baculovirus expression temperature of 27°C appeared to be detrimental for SAV-E3E2 furin cleavage and SAV-VLP production. E2-glycoprotein processing was shown to be temperature dependent and a tailored temperature-shift regime was designed in which Sf9-cells were infected with a recombinant baculovirus expressing the SAV structural proteins, and incubated at 27°C for 24 h, followed by a processing phase of 72 h at 15°C. Using this temperature regime, SAV-VLPs were produced that were morphologically indistinguishable from wild type SAV and underscores the flexibility of the baculovirus-insect cell expression system.

The immunogenicity of purified CHIKV-sE1 and -sE2 subunits and purified CHIKV-VLPs were then tested in a lethal vaccination-challenge mouse model, in IFN α/β, -γ receptor null AG129 mice. The innate immune system of these mice was made dysfunctional. This vaccine-challenge study clearly showed that VLPs provided superior protection, compared to their subunit counterparts. The subunits provided only partial protection and induced low neutralizing antibody titres. Immunization with the VLPs fully protected mice against lethal challenge and induced significant higher neutralizing antibody titress. Even though neutralizing antibody titres were lower after subunit immunization, this study showed that a minor neutralizing antibody response is sufficient to protect mice from lethal CHIKV challenge. Next, the CHIKV VLPs were tested for their ability to induce complete protection in an adult wild-type immune-competent mouse model, in which mice develop arthritic disease after CHIKV infection. The VLPs were able to induce full protection after a single immunization of 1 µg VLPs, without the use of adjuvants. In addition, IgG isotyping revealed a balanced IgG1-IgG2c response, suggesting a role for both humoral and cellular immunity in the protection against CHIKV infection. Mice served as a proxy for primates and vaccination trials in primates are next on the agenda.

This thesis is a typical example of the opportunities for the recombinant baculovirus-insect cell expression system in viral vaccine development, especially in vaccine development for other arboviruses. Although the CHIKV-VLPs produced in insect cells are amenable for large-scale production, the production process and downstream processing need to be carefully designed and optimized before CHIKV VLPs can be produced on an industrial scale. However, the data presented in this thesis show that CHIKV-VLPs produced in insect cells using recombinant baculoviruses represents as a new, safe, non-replicating and effective vaccine candidate against CHIKV infections.

Effective Chikungunya Virus-like Particle Vaccine Produced in Insect Cells
Metz, S.W.H. ; Gardner, J. ; Geertsema, C. ; Le, T.T. ; Goh, L. ; Vlak, J.M. ; Suhrbier, A. ; Pijlman, G.P. - \ 2013
PLoS Neglected Tropical Diseases 7 (2013)3. - ISSN 1935-2727
equine encephalitis-virus - envelope proteins - baculovirus vectors - inactivated vaccine - expression system - dna vaccines - immunogenicity - infection - opportunities - glycosylation
The emerging arthritogenic, mosquito-borne chikungunya virus (CHIKV) causes severe disease in humans and represents a serious public health threat in countries where Aedes spp mosquitoes are present. This study describes for the first time the successful production of CHIKV virus-like particles (VLPs) in insect cells using recombinant baculoviruses. This well-established expression system is rapidly scalable to volumes required for epidemic responses and proved well suited for processing of CHIKV glycoproteins and production of enveloped VLPs. Herein we show that a single immunization with 1 µg of non-adjuvanted CHIKV VLPs induced high titer neutralizing antibody responses and provided complete protection against viraemia and joint inflammation upon challenge with the Réunion Island CHIKV strain in an adult wild-type mouse model of CHIKV disease. CHIKV VLPs produced in insect cells using recombinant baculoviruses thus represents as a new, safe, non-replicating and effective vaccine candidate against CHIKV infections.
Bruises in culled cows: when, where and how are they inflicted?
Strappini, A.C. ; Metz, J.H.M. ; Gallo, C. ; Frankena, K. ; Vargas, R. ; Freslon, I. de; Kemp, B. - \ 2013
Animal 7 (2013)3. - ISSN 1751-7311 - p. 485 - 491.
pre-slaughter - poor welfare - cattle - behavior - transport - markets - carcass - bulls - farms
In Chile, cow carcasses present the highest bruise prevalence compared with other cattle categories; however, the causes of the bruises are frequently unknown. In this study, 52 cull cows were transported to the slaughterhouse in three batches under identical transport conditions. A combination of direct observation and video analyses was used to determine moment, pre-slaughter stage and cause of potential bruising events during the period from loading on the farm until stunning at the slaughterhouse. After slaughter, number of bruises, location on the carcass and characteristics of the bruises were assessed. Seventy-eight bruises were observed on 37 carcasses. Fifty-two bruises were linked back to their causal event. Results showed that 46% of these bruises were a result of interactions between animal and facility, and most of them were inflicted in the stunning box, 27% of the bruises originated from animal–animal interactions and were mostly inflicted during lairage, another 27% was a result of human–animal interactions and were mostly inflicted during loading and unloading of animals. The percentages of potential bruising events resulting in a bruise were 43%, 9% and less than 1% for animal–facility, human–animal and animal–animal interactions, respectively. Most bruises on the back site were inflicted when the animal was in the stunning box (91.2%), whereas bruises on the pin site were mostly (75%) inflicted during loading at the farm. One may conclude that in relative short journeys (=4 h) directly from farm to the slaughterhouse and long lairage times (>12 h), most bruises are the result of circumstances at the slaughterhouse. A substantial amount of these bruises could be avoided by proper animal handling and adequate stunning facilities.
Apparatus and method for purifying a fluid / appareil et procédé pour purifier un fluide
Bakker, S. ; Metz, S.J. ; Racyte, J. ; Bruning, H. ; Rijnaarts, H.H.M. - \ 2012
Octrooinummer: PCT/NL2011/050685, verleend: 2012.
EN)The present invention relates to a device and method for purifying a fluid such as an aqueous liquid flow. The purifying device herein comprises: - a container for the fluid; - electrodes placed in the container and operatively connected to an alternating current source; and - an ultrasonic wave generator placed in the container.
(FR)L'invention concerne un dispositif et un procédé pour purifier un fluide, par exemple un écoulement liquide aqueux. Le dispositif de purification selon l'invention comprend : - un contenant pour le fluide; - des électrodes placées dans le contenant et connectées de manière fonctionnelle à une source de courant alternatif; et - un générateur d'ondes ultrasonores placé dans le contenant.
Device and method for photocatalytic treatment of a fluid / dispositif et procédé de traitement photocatalytique d'un fluide
Bakker, S. ; Kuipers, J. ; Metz, S.J. - \ 2012
Octrooinummer: PCT/NL2012/050095, verleend: 2012-08-03.
Chikungunya virus; development of a recombinant subunit vaccine.
Metz, S.W.H. ; Geertsema, C. ; Vlak, J.M. ; Pijlman, G.P. - \ 2012
Virus-like-particle vaccine against Salmonid alphavirus – we keep it cool, you get the best.
Metz, S.W.H. ; Feenstra, F. ; Vlak, J.M. ; Pijlman, G.P. - \ 2012
Virus-like-particle vaccine against Salmonid alphavirus – we keep it cool, you get the best.
Metz, S.W.H. ; Feenstra, F. ; Vlak, J.M. ; Pijlman, G.P. - \ 2012
In: Abstract book of the 22nd Annual Meeting of the Society for Virology, Essen, Germany, 14-17 March 2012. - - p. 2 - 2.
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