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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Neonatal porcine blood derived dendritic cell subsets show activation after TLR2 or TLR9 stimulation
Vreman, Sandra ; Auray, Gael ; Savelkoul, Huub F.J. ; Rebel, Annemarie ; Summerfield, Artur ; Stockhofe-Zurwieden, Norbert - \ 2018
Developmental and Comparative Immunology 84 (2018). - ISSN 0145-305X - p. 361 - 370.
Dendritic cell - Innate immunity - Neonate - Porcine - Toll like receptor ligand
The present study investigated the innate immune response in vitro to determine porcine neonate responses with Toll-like receptor (TLR)2 ligand (Pam3Cys) or TLR9 ligand (CpG) and compared these with adults. We identified the same phenotypically defined dendritic cell (DC) subsets and DC proportions in porcine neonate and adult blood by flow cytometry, which were plasmacytoid DCs (pDCs): CD14−CD4+CD172a+CADM1-) and conventional DCs (cDCs), being further divided into a cDC1 (CD14−CD4−CD172alowCADM1+) and a cDC2 (CD14−CD4−CD172a+CADM1+) subset. With neonatal cells, the TLR2 ligand induced a stronger TNF expression in monocytes and pDCs, and a stronger CD80/86 upregulation in cDC1, when compared to adult cells. Furthermore, in neonatal mononuclear cells TLR9 ligand was more potent at inducing IL12p40 mRNA expression. These results indicate clear responses of porcine neonatal antigen presenting cells after TLR2 and TLR9 stimulation, suggesting that corresponding ligands could be promising candidates for neonatal adjuvant application.
Case studies on genetically modified organisms (GMOs) : Potential risk scenarios and associated health indicators
Santis, Barbara De; Stockhofe, Norbert ; Wal, Jean Michel ; Weesendorp, Eefke ; Lallès, Jean Paul ; Dijk, Jeroen van; Kok, Esther ; Giacomo, Marzia De; Einspanier, Ralf ; Onori, Roberta ; Brera, Carlo ; Bikker, Paul ; Meulen, Jan van der; Kleter, Gijs - \ 2018
Food and Chemical Toxicology 117 (2018). - ISSN 0278-6915 - p. 36 - 65.
Allergenicity - Genetically modified -feed - Health indicators - Horizontal gene transfer - Mycotoxin-reduction - Nutritionally altered geneticalli modified crops
Within the frame of the EU-funded MARLON project, background data were reviewed to explore the possibility of measuring health indicators during post-market monitoring for potential effects of feeds, particularly genetically modified (GM) feeds, on livestock animal health, if applicable. Four case studies (CSs) of potential health effects on livestock were framed and the current knowledge of a possible effect of GM feed was reviewed. Concerning allergenicity (CS-1), there are no case-reports of allergic reactions or immunotoxic effects resulting from GM feed consumption as compared with non-GM feed. The likelihood of horizontal gene transfer (HGT; CS-2) of GMO-related DNA to different species is not different from that for other DNA and is unlikely to raise health concerns. Concerning mycotoxins (CS-3), insect-resistant GM maize may reduce fumonisins contamination as a health benefit, yet other Fusarium toxins and aflatoxins show inconclusive results. For nutritionally altered crops (CS-4), the genetic modifications applied lead to compositional changes which require special considerations of their nutritional impacts.No health indicators were thus identified except for possible beneficial impacts of reduced mycotoxins and nutritional enhancement. More generally, veterinary health data should ideally be linked with animal exposure information so as to be able to establish cause-effect relationships.
Alternatieve vloeren voor vleeskalveren
Heeres-van der Tol, Jetta ; Wolthuis, Maaike ; Bokma, Sjoerd ; Smits, Dolf ; Stockhofe, Norbert ; Vermeij, Izak ; Reenen, Kees van - \ 2017
Wageningen : Wageningen Livestock Research (Wageningen Livestock Research rapport 1056) - 103
dierenwelzijn - dierlijke productie - vleeskalveren - huisvesting - diergedrag - diergezondheid - animal welfare - animal production - veal calves - housing - animal behaviour - animal health
Immunoassay standardisation for "universal" influenza vaccines : Workshop report
Pavlova, Sophia ; Alessio, Flavia D'; Houard, Sophie ; Remarque, Edmond J. ; Stockhofe, Norbert ; Engelhardt, Othmar G. - \ 2017
Influenza and Other Respiratory Viruses 11 (2017)3. - ISSN 1750-2640 - p. 194 - 201.
Immunoassay - Influenza - Standardisation - Universal - Vaccine - Workshop

The development of broadly reactive influenza vaccines raises the need to identify the most appropriate immunoassays that can be used for the evaluation of so-called universal influenza vaccines and to explore a path towards the standardisation of such assays. More than fifty experts from the global influenza vaccine research and development field met to initiate such discussion at a workshop co-organised by the EDUFLUVAC consortium, a European Union funded project coordinated by the European Vaccine Initiative, and the National Institutes of Health/National Institute of Allergy and Infectious Diseases, USA. The workshop audience agreed that it was not possible to establish a single immunoassay for "universal" influenza vaccines because the current approaches differ in the vaccines' nature and immunogenicity properties. Therefore, different scientific rationales for the immunoassay selection are required. To avoid dilution of efforts, the choice of the primary evaluation criteria (eg serological assays or T-cell assays) should drive the effort of harmonisation. However, at an early phase of clinical development, more efforts on exploratory assessments should be undertaken to better define the immune profile in response to immunisation with new vaccines. The workshop concluded that each laboratory should aim towards validation of the appropriate immunoassays used during the entire process of vaccine development from antigen discovery up to establishment of correlates of protection, including the different steps of quality control (eg potency assays), animal studies and human clinical development. Standardisation of the immunoassays is the ultimate goal, and there is a long way to go.

Study of potential health effects of electromagnetic fields of telephony and Wi-Fi, using chicken embryo development as animal model
Woelders, H. ; Wit, A.A.C. de; Lourens, A. ; Stockhofe, N. ; Engel, B. ; Hulsegge, B. ; Schokker, D. ; Heijningen, P. van; Vossen, S. ; Bekers, D. ; Zwamborn, P. - \ 2017
Bioelectromagnetics 38 (2017)3. - ISSN 0197-8462 - p. 186 - 203.
The objective of this study is to investigate possible biological effects of radiofrequency electromagnetic fields (RF-EMF) as used in modern wireless telecommunication in a well-controlled experimental environment using chicken embryo development as animal model. Chicken eggs were incubated under continuous experimental exposure to GSM (1.8 GHz), DECT (1.88 GHz), UMTS (2.1 GHz), and WLAN (5.6 GHz) radiation, with the appropriate modulation protocol, using a homogeneous field distribution at a field strength of approximately 3 V/m, representing the maximum field level in a normal living environment. Radiation-shielded exposure units/egg incubators were operating in parallel for exposed and control eggs in a climatized homogeneous environment, using 450 eggs per treatment in three successive rounds per treatment. Dosimetry of the exposure (field characteristics and specific absorption rate) were studied. Biological parameters studied included embryo death during incubation, hatching percentage, and various morphological and histological parameters of embryos and chicks and their organs, and gene expression profiles of embryos on day 7 and day 18 of incubation by microarray and qPCR. No conclusive evidence was found for induced embryonic mortality or malformations by exposure to the used EMFs, or for effects on the other measured parameters. Estimated differences between treatment groups were always small and the effect of treatment was not significant. In a statistical model that ignored possible interaction between rounds and exposure units, some of the many pairwise comparisons of exposed versus control had P-values lower than 0.05, but were not significant after correction for multiple testing
Proper Timing of Foot-and-Mouth Disease Vaccination of Piglets with Maternally Derived Antibodies Will Maximize Expected Protection Levels
Dekker, A. ; Chénard, G. ; Stockhofe, N. ; Eble, P.L. - \ 2016
Frontiers in Veterinary Science 3 (2016). - ISSN 2297-1769
We investigated to what extent maternally derived antibodies interfere with foot-and-mouth disease (FMD) vaccination in order to determine the factors that influence the correct vaccination for piglets. Groups of piglets with maternally derived antibodies were vaccinated at different time points following birth, and the antibody titers to FMD virus (FMDV) were measured using virus neutralization tests (VNT). We used 50 piglets from 5 sows that had been vaccinated 3 times intramuscularly in the neck during pregnancy with FMD vaccine containing strains of FMDV serotypes O, A, and Asia-1. Four groups of 10 piglets were vaccinated intramuscularly in the neck at 3, 5, 7, or 9 weeks of age using a monovalent Cedivac-FMD vaccine (serotype A TUR/14/98). One group of 10 piglets with maternally derived antibodies was not vaccinated, and another group of 10 piglets without maternally derived antibodies was vaccinated at 3 weeks of age and served as a control group. Sera samples were collected, and antibody titers were determined using VNT. In our study, the antibody responses of piglets with maternally derived antibodies vaccinated at 7 or 9 weeks of age were similar to the responses of piglets without maternally derived antibodies vaccinated at 3 weeks of age. The maternally derived antibody levels in piglets depended very strongly on the antibody titer in the sow, so the optimal time for vaccination of piglets will depend on the vaccination scheme and quality of vaccine used in the sows and should, therefore, be monitored and reviewed on regular basis in countries that use FMD prophylactic vaccination.
Verrijkte leefomgeving; gezondere biggen : gevoeligheid voor ziekten en infecties vermindert door verrijkt kraamhok
Stockhofe, Norbert - \ 2016
animal welfare - animal production - pigs - animal housing - animal behaviour - animal health
Enriched Housing Reduces Disease Susceptibility to Co-Infection with Porcine Reproductive and Respiratory Virus (PRRSV) and Actinobacillus pleuropneumoniae (A. pleuropneumoniae) in Young Pigs
Dixhoorn, I.D.E. van; Reimert, I. ; Middelkoop, J.A. ; Bolhuis, J.E. ; Wisselink, H.J. ; Groot Koerkamp, P.W.G. ; Kemp, B. ; Stockhofe, Norbert - \ 2016
PLoS One 11 (2016)9. - ISSN 1932-6203
Until today, anti-microbial drugs have been the therapy of choice to combat bacterial diseases. Resistance against antibiotics is of growing concern in man and animals. Stress, caused by demanding environmental conditions, can reduce immune protection in the host, influencing the onset and outcome of infectious diseases. Therefore psychoneuro-immunological intervention may prove to be a successful approach to diminish the impact of diseases and antibiotics use. This study was designed to investigate the effect of social and environmental enrichment on the impact of disease, referred to as “disease susceptibility”, in pigs using a co-infection model of PRRSV and A. pleuropneumoniae. Twenty-eight pigs were raised in four pens under barren conditions and twenty-eight other pigs were raised in four pens under enriched conditions. In the enriched pens a combination of established social and environmental enrichment factors were introduced. Two pens of the barren (BH) and two pens of the enriched housed (EH) pigs were infected with PRRSV followed by A. pleuropneumoniae, the other two pens in each housing treatment served as control groups. We tested if differences in disease susceptibility in terms of pathological and clinical outcome were related to the different housing regimes and if this was reflected in differences in behavioural and immunological states of the animals. Enriched housed pigs showed a faster clearance of viral PRRSV RNA in blood serum (p = 0.014) and histologically 2.8 fold less interstitial pneumonia signs in the lungs (p = 0.014). More barren housed than enriched housed pigs developed lesions in the lungs (OR = 19.2, p = 0.048) and the lesions in the barren housed pigs showed a higher total pathologic tissue damage score (p<0.001) than those in enriched housed pigs. EH pigs showed less stress-related behaviour and differed immunologically and clinically from BH pigs. We conclude that enriched housing management reduces disease susceptibility to co-infection of PRRSV and A. pleuropneumoniae in pigs. Enrichment positively influences behavioural state, immunological response and clinical outcome in pigs.
Invasive pneumococcal disease leads to activation and hyperreactivity of platelets
Tunjungputri, Rahajeng N. ; Jonge, Marien I. de; Greeff, Astrid de; Selm, Saskia van; Buys-Bergen, Herma ; Harders-Westerveen, Jose F. ; Stockhofe-Zurwieden, Norbert ; Urbanus, Rolf T. ; Groot, Phillip G. De; Smith, Hilde E. ; Ven, Andre J. van der; Mast, Quirijn de - \ 2016
Thrombosis Research 144 (2016). - ISSN 0049-3848 - p. 123 - 126.
Infection - Myocardial infarction - Platelet activation - Platelets - Pneumonia - Streptococcus pneumoniae

Using a novel porcine model of intravenous Streptococcus pneumoniae infection, we showed that invasive pneumococcal infections induce marked platelet activation and hyperreactivity. This may contribute to the vascular complications seen in pneumococcal infection.

Characterization of immune responses following homologous reinfection of pigs with European subtype 1 and 3 porcine reproductive and respiratory syndrome virus strains that differ in virulence
Weesendorp, Eefke ; Stockhofe-Zurwieden, Norbert ; Nauwynck, Hans J. ; Popma-De Graaf, D.J. ; Rebel, Johanna M.J. - \ 2016
Veterinary Microbiology 182 (2016). - ISSN 0378-1135 - p. 64 - 74.
Genetic subtypes - Homologous reinfection - Immune response - Porcine reproductive and respiratory syndrome virus - Protection

Porcine reproductive and respiratory syndrome virus (PRRSV) causes significant economic losses to the pork industry worldwide. Vaccination results often in limited protection. Understanding host immune responses elicited by different PRRSV strains could help to develop more efficacious vaccines. In the current study we characterized immunological responses and viral kinetics in pigs after primo infection and homologous challenge of the highly virulent European subtype 3 strain Lena, and the moderate to low virulent subtype 1 strain LV. Eighteen pigs were infected per strain, and 18 non-infected pigs served as control. Post mortem analysis was performed at days 7, 46 and 60 p.i. At day 46, pigs were challenged with the homologous strain. After the first inoculation, pigs infected with Lena developed fever and clinical symptoms, while this was not observed in pigs infected with LV. Virus titres in serum were about 100-fold higher in pigs infected with Lena than in pigs infected with LV. An inflammatory response was observed in pigs after primo infection with Lena with significantly higher levels of IL-12, IL-1β and TNF-α in the bronchoalveolar lavage. IFN-γ ELISPOT assay showed comparable responses between Lena and LV. Neutralizing antibodies were detected earlier in serum of pigs infected with Lena than in pigs infected with LV. After the challenge, a boost in antibody levels in both groups was observed. Challenge infection resulted in both groups in complete protection and sterile immunity, with no viraemia, clinical symptoms or viral RNA in tissues. In conclusion, although there were clear differences in immunological, clinical and virological responses to the primo infection, there were no differences observed in protection against homologous challenge.

Increased B and T cell responses in M. bovis bacille Calmette-Guérin vaccinated pigs co-immunized with plasmid DNA encoding a prototype tuberculosis antigen
Bruffaerts, Nicolas ; Pedersen, Lasse E. ; Vandermeulen, Gaëlle ; Préat, Véronique ; Stockhofe, Norbert ; Huygen, Kris ; Romano, Marta - \ 2015
PLoS One 10 (2015)7. - ISSN 1932-6203

The only tuberculosis vaccine currently available, bacille Calmette-Guérin (BCG) is a poor inducer of CD8+ T cells, which are particularly important for the control of latent tuberculosis and protection against reactivation. As the induction of strong CD8+ T cell responses is a hallmark of DNA vaccines, a combination of BCG with plasmid DNA encoding a prototype TB antigen (Ag85A) was tested. As an alternative animal model, pigs were primed with BCG mixed with empty vector or codon-optimized pAg85A by the intradermal route and boosted with plasmid delivered by intramuscular electroporation. Control pigs received unformulated BCG. The BCG-pAg85A combination stimulated robust and sustained Ag85A specific antibody, lymphoproliferative, IL-6, IL-10 and IFN-γ responses. IgG1/IgG2 antibody isotype ratio reflected the Th1 helper type biased response. T lymphocyte responses against purified protein derivative of tuberculin (PPD) were induced in all (BCG) vaccinated animals, but responses were much stronger in BCG-pAg85A vaccinated pigs. Finally, Ag85A-specific IFN-γ producing CD8+ T cells were detected by intracellular cytokine staining and a synthetic peptide, spanning Ag85A131-150 and encompassing two regions with strong predicted SLA-1∗0401/SLA-1∗0801 binding affinity, was promiscuously recognized by 6/6 animals vaccinated with the BCG-pAg85A combination. Our study provides a proof of concept in a large mammalian species, for a new Th1 and CD8+ targeting tuberculosis vaccine, based on BCG-plasmid DNA co-administration.

Host-pathogen interaction at the intestinal mucosa correlates with zoonotic potential of Streptococcus suis
Ferrando, Maria Laura ; Greeff, Astrid De; Rooijen, W.J.M. Van; Stockhofe-Zurwieden, Norbert ; Nielsen, Jens ; Wichgers Schreur, P.J. ; Pannekoek, Yvonne ; Heuvelink, Annet ; Ende, Arie Van Der; Smith, Hilde ; Schultsz, Constance - \ 2015
The Journal of Infectious Diseases 212 (2015)1. - ISSN 0022-1899 - p. 95 - 105.
clonal complex - intestinal translocation - piglets. - serotype - Streptococcus suis - tight junctions - zoonotic infections

Streptococcus suis has emerged as an important cause of bacterial meningitis in adults. The ingestion of undercooked pork is a risk factor for human S. suis serotype 2 (SS2) infection. Here we provide experimental evidence indicating that the gastrointestinal tract is an entry site of SS2 infection. Methods. We developed a noninvasive in vivo model to study oral SS2 infection in piglets.We compared in vitro interaction of S. suis with human and porcine intestinal epithelial cells (IEC). Results. Two out of 15 piglets showed clinical symptoms compatible with S. suis infection 24-48 hours after ingestion of SS2. SS2 was detected in mesenteric lymph nodes of 40% of challenged piglets. SS2 strains isolated from patients showed significantly higher adhesion to human IEC compared to invasive strains isolated from pigs. In contrast, invasive SS9 strains showed significantly higher adhesion to porcine IEC. Translocation across human IEC, which occurred predominately via a paracellular route, was significantly associated with clonal complex 1, the predominant zoonotic genotype. Adhesion and translocation were dependent on capsular polysaccharide production. Conclusions. SS2 should be considered a food-borne pathogen. S. suis interaction with human and pig IEC correlates with S. suis serotype and genotype, which can explain the zoonotic potential of SS2.

Pathogenesis of European subtype3 and subtype 1 PRRSV strains in pigs
Weesendorp, E. ; Stockhofe, N. ; Rebel, J.M.J. - \ 2015
In: Proceedings International PRRS Congress. -
Vaccination against porcine reproductive and respiratory syndrome virus (PRRSV) results often in limited protection. Understanding host immune responses and pathogenesis elicited by different PRRSV strains could help to develop more efficacious vaccines. Differences in host response between the European subtype 3 strain Lena and subtype 1 strains Belgium A and Lelystad-Ter Huurne (LV) were examined in several studies and “meta-analyses” results across studies will be presented. Characteristic of infections with strain Lena, compared to strains Belgium A and LV, are fever, clinical symptoms, a systemic inflammatory response, higher virus titres in serum, differences in leukocyte populations in blood, lower numbers of IFN-γ secreting cells in blood, and a delayed antibody response against a non-related immunization. In the lungs, infection with strain Lena induce more severe acute pathology with an proinflammatory response and an influx of neutrophils and monocytes in bronchoalveolar lavage fluid (BALF). However, after a few weeks, all strains induce an increased percentage of cytotoxic T cells and higher levels of IFN-γ producing cells in BALF. We hypothesized that the stronger early inflammatory response of the Lena strain contributed to the observed faster clearance of virus after infection and better protection against reinfection. In a comparative study, this hypothesis was tested. Pigs were infected with strains Lena or LV and homologous challenged after 46 days. Challenge infection resulted in both groups in complete protection , with no viraemia, clinical symptoms or viral RNA in tissues. After the challenge, a boost in antibody levels in pigs infected with homologous strains mounted rapidly and IFN-γ ELISPOT assays showed comparable responses between Lena and LV, when cells were homologous stimulated. However, clear differences between the strains in levels of neutralizing antibodies and IFN-γ SC were observed when the assays were performed with heterologous virus. In conclusion, although, there are clear differences in immunological, clinical and virological responses after infection, with stronger inflammatory response for strain Lena-infected pigs, there were no differences observed in protection against homologous challenge. Whether this is also true for heterologous challenges needs further research.
Effects of solid feed level and roughage-to-concentrate ratio on ruminal drinking and passage kinetics of milk replacer, concentrates, and roughage in veal calves
Berends, H. ; Borne, J.J.G.C. van den; Stockhofe-Zurwieden, N. ; Gilbert, M.S. ; Zandstra, T. ; Pellikaan, W.F. ; Reenen, C.G. van; Bokkers, E.A.M. ; Gerrits, W.J.J. - \ 2015
Journal of Dairy Science 98 (2015)8. - ISSN 0022-0302 - p. 5621 - 5629.
Effects of solid feed (SF) level and roughage-to-concentrate (R:C) ratio on ruminal drinking and passage kinetics of milk replacer, concentrate, and roughage were studied in veal calves. In total, 80 male Holstein-Friesian calves (45 ± 0.2 kg of body weight) were divided over 16 pens (5 calves per pen). Pens were randomly assigned to either a low (LSF) or a high (HSF) SF level and to 1 of 2 R:C ratios: 20:80 or 50:50 on a dry matter (DM) basis. Roughage was composed of 50% corn silage and 50% chopped wheat straw on a DM basis. At 27 wk of age, measurements were conducted in 32 calves. During the measurement period, SF intake was 1.2 kg of DM/d for LSF and 3.0 kg of DM/d for HSF, and milk replacer intake averaged 2.3 kg of DM/d for LSF and 1.3 kg of DM/d for HSF. To estimate passage kinetics of milk replacer, concentrate, and straw, indigestible markers (CoEDTA, hexatriacontane C36, Cr-neutral detergent fiber) were supplied with the feed as a single dose 4, 24, and 48 h before assessment of their quantitative recovery in the rumen, abomasum, small intestine, and large intestine. Rumen Co recovery averaged 20% of the last milk replacer meal. Recoveries of Co remained largely unaffected by SF level and R:C ratio. The R:C ratio did not affect rumen recovery of C36 or Cr. Rumen fractional passage rate of concentrate was estimated from recovery of C36 in the rumen and increased from 3.3%/h for LSF to 4.9%/h for HSF. Rumen fractional passage rate of straw was estimated from Cr recovery in the rumen and increased from 1.3%/h for LSF to 1.7%/h for HSF. An increase in SF level was accompanied by an increase in fresh and dry rumen contents. In HSF calves, pH decreased and VFA concentrations increased with increasing concentrate proportion, indicating increased fermentation. The ratio between Cr and C36 was similar in the small and large intestine, indicating that passage of concentrate and straw is mainly determined by rumen and abomasum emptying. In conclusion, increasing SF level introduces large variation in passage kinetics of dietary components, predominantly in the rumen compartment. The SF level, rather than the R:C ratio, influences rumen recovery of concentrate and roughage. Our data provide insight in passage kinetics of milk (Co representing the milk replacer) and SF (Cr and C36 representing roughage and concentrate, respectively) and may contribute to the development of feed evaluation models for calves fed milk and SF.
Effects of solid feed level and roughage-to-concentrate ratio on ruminal drinking and passage kinetics of milk, concentrates, and roughage in veal calves
Berends, H. ; Borne, J.J.G.C. van den; Stockhofe, N. ; Gilbert, M.S. ; Zandstra, T. ; Pellikaan, W.F. ; Reenen, K. van; Bokkers, E.A.M. ; Gerrits, W.J.J. - \ 2015
In: Book of abstracts of 2015 Joint Annual Meeting of ADSA-ASAS. - - p. 869 - 869.
Effects of solid feed (SF) level and roughage-to-concentrate (R:C) ratio on ruminal drinking and passage kinetics of milk, concentrate, and roughage in veal calves were studied. Eighty calves (2 wk of age, 45 kg bodyweight) were divided over 16 pens. Pens were randomly assigned to a low (LSF) or a high (HSF) SF level, and to one of 2 R:C ratios; 20:80 or 50:50 on a DM basis. Roughage was composed of 50% corn silage and 50% chopped straw on a DM basis. During the measurement period at 27 wk of age, SF intake was 1.2 kg DM/d for LSF and 3.0 kg DM/d for HSF, and milk (replacer) intake averaged 2.3 kg DM/d for LSF and 1.3 kg DM/d for HSF. To estimate passage kinetics of milk, concentrate, and straw, indigestible markers (respectively CoEDTA, hexatriacontane C36, Cr-NDF) were supplied with the feed as a single dose at respectively 4, 24, and 48 h before slaughter. At slaughter, marker recovery was quantified in the rumen, abomasum, small intestine, and large intestine. Rumen Co recovery averaged 20% of the last milk meal. Recoveries of milk remained largely unaffected by SF level and R:C ratio. Ruminal recovery of C36 and Cr was unaffected by R:C ratio. Rumen fractional passage rate of concentrate was estimated from recovery of C36 in the rumen and increased (P <0.001) from 3.3%/h for LSF to 4.9%/h for HSF. Rumen fractional passage rate of straw was estimated from Cr recovery in the rumen and increased (P <0.01) from 1.3%/h for LSF to 1.7%/h for HSF. A greater SF level increased (P <0.001) fresh and dry rumen contents. In HSF calves, pH decreased (from 6.9 to 6.0; P <0.01) and VFA concentrations increased (P <0.05) with a lower R:C ratio, indicating increased fermentation. The Cr:C36 ratio was similar in the small and large intestine, indicating that passage of concentrate and straw was mainly determined by rumen and abomasum emptying. In conclusion, SF level rather than R:C ratio influences rumen passage of concentrate and roughage. Our data provide insight in passage kinetics of milk and SF and may contribute to the development of feed evaluation models for veal calves
Lung pathogenicity of European genotype 3 strain porcine reproductive and respiratory syndrome virus (PRRSV) differs from that of subtype 1 strains.
Weesendorp, E. ; Rebel, J.M.J. ; Popma-de Graaf, D.J. ; Fijten, H.P.D. ; Stockhofe, N. - \ 2014
Veterinary Microbiology 174 (2014)1-2. - ISSN 0378-1135 - p. 127 - 138.
experimentally infected-pigs - lelystad virus - immunological responses - immune-responses - swine - cells - disease - expression - cytokines - virulence
Porcine reproductive and respiratory syndrome (PRRS) is difficult to control due to a high mutation rate of the PRRS virus (PRRSV) and the emergence of virulent strains. The objective of this study was to analyse early and late pathological responses in the respiratory tract after infection with the European PRRSV subtype 3 strain Lena in comparison to two European PRRSV subtype 1 strains: Belgium A and Lelystad-Ter Huurne (LV). For each virus strain, groups of twelve pigs were inoculated, and four pigs per group were euthanized at days 3, 7 and 35 post-infection (p.i.) for consecutive examination. Infection with strain Lena resulted in a more severe disease than with the subtype 1 strains, an inflammatory response within the first week of infection with expression of IL-1a in the lung and lymph node, and an influx of neutrophils and monocytes in bronchoalveolar lavage fluid (BALF). Infection with strain Belgium A or LV resulted in mild or no pathology within the first week of infection, but inflammatory cell influx in the lung interstititium was increased at the end of the experiment at day 35 p.i. At five weeks p.i., all strains induced a higher percentage of cytotoxic T cells and higher levels of IFN-¿ producing cells in BALF. This might have contributed to clearance of virus. In general, subtype 3 strain Lena induced a stronger early inflammatory response which led to more severe clinical disease and pathology. On the other hand, this may have supported an enhanced or faster clearance of virus in tissues, compared to subtype 1 strains.
Schmallenberg virus detection in bovine semen after experimental infection of bulls.
Poel, W.H.M. van der; Parlevliet, J.M. ; Verstraten, E.R.A.M. ; Kooi, E.A. ; Hakze-van der Honing, R.W. van der; Stockhofe-Zurwieden, N. - \ 2014
Epidemiology and Infection 142 (2014)07. - ISSN 0950-2688 - p. 1495 - 1500.
antibodies - cattle
To study Schmallenberg virus (SBV) excretion in bovine semen after experimental infection, two bulls were inoculated subcutaneously with a SBV isolate (1 ml Vero cell culture 106 TCID50). After inoculation (at day 0), semen was collected daily from both animals for 21 days and samples were tested for SBV by qRT–PCR assay. At 24 days post-inoculation both animals were subjected to necropsy and the genital organs and lymph nodes draining these organs were also tested for SBV RNA (qRT–PCR). After SBV infection both animals in the study showed viraemia (qRT–PCR) with fever and diarrhoea. SBV RNA could be detected in semen from both animals. The highest SBV RNA concentrations in semen were found in the first week (days 4–7 post-inoculation) but concentrations were relatively low (Ct values 30–39). Viable SBV was only isolated from blood samples and not from semen or genital tissues.
Letter to the editor: Schmallenberg virus antibodies in adult cows and maternal antibodies in calves
Elbers, A.R.W. ; Stockhofe, N. ; Poel, W.H.M. van der - \ 2014
Emerging Infectious Diseases 20 (2014)5. - ISSN 1080-6040 - p. 901 - 902.
infection
Schmallenberg virus antibody persistence in adult cattle after natural infection and decay of maternal antibodies in calves
Elbers, A.R.W. ; Stockhofe-Zurwieden, N. ; Poel, W.H.M. van der - \ 2014
BMC Veterinary Research 10 (2014). - ISSN 1746-6148 - p. 1 - 4.
netherlands
Background: Schmallenberg virus (SBV) has swept through the major part of Europe in the period 2011–2013. A vaccine against SBV has been developed and may be a possible preventive instrument against infection. Presently, there is no data available to refute the assumption that natural SBV infection results in long-term immunity. In that respect, it is of interest to know how long (protecting) virus-neutralizing antibodies are present in naturally infected animals. New-born calves acquire passive immunity from their dams by ingestion and absorption of antibodies present in colostrum, which can block the production of serum antibodies when vaccine is administered to calves with maternally derived antibodies. In that respect, it is useful to know how long it takes for maternal antibodies against SBV to disappear in young animals born from infected dams. Results: Longitudinal whole-herd serological monitoring using virus neutralization test (VNT) indicated that 80% of adult dairy cows still had measurable antibodies against SBV at least 24 months after the estimated introduction of the virus into the herd. Median 2Log VNT titer of the adult dairy cows (=1 year) dropped from 8.6 to 5.6 in a period of 17 months. Median 2Log VNT maternal antibodies titers of calves sampled within 30 days after birth was 8. Calves lost their maternally-derived antibodies after 5–6 months. There was a definite positive relationship between the VNT titer of the dam and the VNT titer of the corresponding calf (age = 30 days) of dam-calf combinations sampled on the same day: the higher the VNT titer of the dam, the higher the VNT titer (maternal antibodies) of the calf. Conclusions: Our field data support the assumption that natural SBV infection in adult cows results in persistence of specific antibodies for at least two years. Based on the observed decay of maternally-derived antibodies in calves, it is presumed safe to vaccinate calves against SBV at an age of approximately 6 months
Intratypic heterologous vaccination of calves can induce an antibody response in presence of maternal antibodies against foot-and-mouth disease virus
Dekker, A. ; Eble, P.L. ; Stockhofe-Zurwieden, N. ; Chenard, G. - \ 2014
BMC Veterinary Research 10 (2014). - ISSN 1746-6148
Background - Maternal antibodies can interfere with foot-and-mouth disease vaccination. In this study we determined whether intratypic heterologous vaccination could help to improve herd immunity. Results - In unvaccinated calves, a half-life of maternal antibodies of 21 days was determined. At two weeks of age, calves without maternal antibodies showed a good antibody response against both vaccines used in the trial, while in calves with maternal antibodies no antibody response to homologous vaccination (A Turkey 14/98) but a limited antibody response to intratypic heterologous vaccination (A22 Iraq) was observed. Conclusion - Two weeks old calves without maternal antibodies respond well to vaccination, but when emergency vaccination is carried out in a region that uses prophylactic vaccination, using an intratypic heterologous vaccine strain may improve the immunity in calves with maternal antibodies
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