T A Niewold

University of Leuven, Louvain, Flanders, Belgium

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Publications (115)173.68 Total impact

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    ABSTRACT: Most commonly, salivary cortisol is used in pig stress assessment, alternative salivary biomarkers are scarcely studied. Here, salivary cortisol and two alternative salivary biomarkers, haptoglobin and chromogranin A were measured in a pig stress study. Treatment pigs (n = 24) were exposed to mixing and feed deprivation, in two trials, and compared to untreated controls (n = 24). Haptoglobin differed for feed deprivation vs control. Other differences were only found within treatment. Treatment pigs had higher salivary cortisol concentrations on the mixing day (P < 0.05). Chromogranin A concentrations were increased on the day of refeeding (P < 0.05). Haptoglobin showed a similar pattern to chromogranin A. Overall correlations between the salivary biomarkers were positive. Cortisol and chromogranin A were moderately correlated (r = 0.49, P < 0.0001), correlations between other markers were weaker. The present results indicate that different types of stressors elicited different physiological stress responses in the pigs, and therefore including various salivary biomarkers in stress evaluation seems useful.
    Research in veterinary science. 06/2014;
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    ABSTRACT: One of the major challenges in pig production is managing digestive health to maximize feed conversion and growth rates, but also to minimize treatment costs and to warrant public health. There is a great interest in the development of useful tools for intestinal health monitoring and the investigation of possible prophylactic/ therapeutic intervention pathways. A great variety of in vivoand in vitro intestinal models of study have been developed in the recent years. The understanding of such a complex system as the intestinal system (IS), and the study of its physiology and pathology is not an easy task. Analysis of such a complex system requires the use of systems biology techniques, like proteomics. However, for a correct interpretation of results and to maximize analysis performance, a careful selection of the IS model of study and proteomic platform is required. The study of the IS system is especially important in the pig, a species whose farming requires a very careful management of husbandry procedures regarding feeding and nutrition. The incorrect management of the pig digestive system leads directly to economic losses related suboptimal growth and feed utilization and/or the appearance of intestinal infections, in particular diarrhea. Furthermore, this species is the most suitable experimental model for human IS studies. Proteomics has risen as one of the most promising approaches to study the pig IS. In this review, we describe the most useful models of IS research in porcine and the different proteomic platforms available. An overview of the recent findings in pig IS proteomics is also provided.
    Current Protein and Peptide Science 02/2014; · 2.33 Impact Factor
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    ABSTRACT: Health is a key element in pig welfare and steady weight gain is considered an indicator of good health and productivity. However, many diseases such as diarrhoea cause a substantial reduction in food intake and weight gain in pigs. Therefore, continuous weight monitoring is an essential method to ensure pigs are in good health. The purpose of this work was to investigate the feasibility of an automated method to estimate weight of individual pigs by using image processing. This study comprised measurements on four pens of grower pigs, each consisting of 10 pigs. At the start of the experiments, pigs weighed on average 23 ± 4.4 kg (mean ± SD) while at the end their average weight was 45 ± 6.5 kg. Each pen was monitored by a top-view camera. For validation purposes, the experiment was repeated once. Individual pigs were automatically identified by their unique painting patterns using shape recognition techniques. The weight estimation process developed as follows: First, to localized pigs in the image, an ellipse fitting algorithm was employed. Second, the area the pig occupying in the ellipse was calculated. Finally, the weight of pigs was estimated using dynamic modelling. The developed model was then validated by comparing the estimated weight against manual twice weekly actual weight measurements of each individual pig. In addition, to monitor the weight of pigs individually, the pigs were marked on their back with basic unique paint patterns and were identified automatically using shape recognition techniques. In this way, the weight of each individual pig could be estimated. This method can replace the regular weight measurements on farms that require repeated handling and thereby causing stress to the pigs. Overall, video imaging of fattening pigs appeared promising for real-time weight and growth monitoring. In this study pig weight could be estimated with an accuracy of 97.5% at group level (error of 0.82 kg) and 96.2% individually (error of 1.23 kg). This result is significant since the existing automated tools currently have a maximum accuracy of 95% (error of 2 kg) in practical setups and 97% (error of 1 kg) in walk-through systems (when pigs are forced to pass a corridor one by one) on average. Future work should focus on developing specific algorithms to account for the effect of gender and genotype on body surface area and body weight since these factors affect the model parameters for weight estimation.
    Computers and Electronics in Agriculture 01/2014; 107:38–44. · 1.77 Impact Factor
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    ABSTRACT: Abstract Weaned piglets are very susceptible to diarrhea caused by enterotoxigenic Escherichia coli. In the past, various natural components were proposed to have beneficial effects by reducing the effects of diarrheal infectious diseases in humans and animals, and thus may represent an alternative for the use of (prophylactic) antibiotics. Alternatives may inactivate enterotoxigenic Escherichia coli heat-labile toxin (LT) by interfering with toxin binding to the cellular receptor GM1. In this study, various plants and other natural substances were tested for inhibitory properties, in the GM1 binding assay, and in the LT-induced cAMP production in Vero cells. The toxic dose of each compound was determined in a cell viability assay, and the highest nontoxic concentrations were used in the GM1 and cAMP assays. Results demonstrated that only d-(+)-galactose, lactose, N-acetyl-d-galactosamine, and two tea extracts were able to inhibit the binding of LT to its GM1 receptor. In the cAMP assay, only the two tea extracts showed inhibitory activity. This shows that d-(+)-galactose, lactose, and N-acetyl-d-galactosamine can indeed inhibit LT binding to GM1 based on structural homology with GM1 in the absence of living cells. However, in the cAMP assay, d-(+)-galactose, and lactose, N-acetyl-d-galactosamine are apparently metabolized to below their effective inhibitory concentration, likely predicting limited practical applicability in vivo. Both tea extracts maintained their activity in the presence of cells. The active compounds in both are probably polyphenols, which are not easily metabolized, and most likely work by aggregating the toxin. In conclusion, the combination of methods used here is a convenient and fast method for preselecting natural substances containing potentially toxin-binding compounds. Furthermore, if antidiarrhea activity is attributed to compounds found inactive here, their activity is unlikely based on interference with toxin binding.
    Foodborne Pathogens and Disease 05/2013; · 2.28 Impact Factor
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    ABSTRACT: BACKGROUND: The aim of this study was to identify transcription factors/regulators that play a crucial role in steering the (innate) immune response shortly (within a few hours) after the first contact of the intestinal mucosa with an inflammatory mediator, and to test whether the processes regulated by these factors/regulators can be modulated by chemical substances of natural origin. METHODS: We experimentally induced inflammation by perfusion of surgically applied jejunal loops with Salmonella enterica subspecies enterica serovar Typhimurium DT104 in three pigs. Segments of mock and Salmonella treated loops were dissected after 2, 4 and 8 hours of perfusion. IL8 and IL1-beta mRNA expression levels were measured in mucosal scrapings of all segments. Furthermore, intra-animal microarray comparisons (isogenic) between Salmonella and mock treated segments after 8 hours, and inter-animal comparisons between similar Salmonella-treated loops of each pig at 2 and 4 hours, were performed. RESULTS: IL-1beta and IL8 mRNA levels, and intra-animal microarray comparisons at 8 hours between Salmonella and mock treated segments showed that the response-time and type of response to Salmonella was different in all three pigs. This plasticity allowed us to extract a comprehensive set of differentially expressed genes from inter-animal comparisons at 2 and 4 hours. Pathway analysis indicated that many of these genes play a role in induction and/or tempering the inflammatory response in the intestine. Among them a set of transcription factors/regulators known to be involved in regulation of inflammation, but also factors/regulators for which involvement was not expected. Nine out of twenty compounds of natural origin, which according to literature had the potential to modulate the activity of these factors/regulators, were able to stimulate or inhibit a Salmonella-induced mRNA response of inflammatory-reporter genes IL8 and/or nuclear factor of kappa light polypeptide gene enhancer in B-cells inhibitor alpha in cultured intestinal porcine epithelial cells. CONCLUSIONS: We describe a set of transcription factors/regulators possibly involved in regulation of "very early" immune mechanism which determines the inflammatory status of the intestine later on. In addition, we show that these mechanisms may be modulated by chemical substances of natural origin.
    Journal of Inflammation 04/2013; 10(1):18. · 2.55 Impact Factor
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    ABSTRACT: The purpose of this work was to investigate feasibility of an automated method to identify marked pigs in a pen in experimental conditions and for behaviour-related research by using image processing.This study comprised measurements on four groups of piglets, with 10 piglets per group in a pen. On average, piglets had a weight of 27 ± 4.4 kg at the start of experiments and 40 kg ± 6.5 at the end. For the purpose of individual identification, basic patterns were painted on the back of the pigs. Each pen was monitored by a top-view CCD camera.Ellipse fitting algorithms were employed to localise pigs. Consequently, individual pigs could be identified by their respective paint pattern using pattern recognition techniques. Taking visual labelling of videos by an experienced ethologist as the gold standard, pigs could be identified with an average accuracy of 88.7%. It was also shown that behaviours such as resting can be monitored using the presented technique.
    Computers and Electronics in Agriculture 04/2013; 93:111–120. · 1.77 Impact Factor
  • R Verhelst, M Schroyen, N Buys, T A Niewold
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    ABSTRACT: Recently, polyphenol extracts were suggested to inhibit binding of Escherichia coli heat labile enterotoxin (LT) to its intestinal receptor GM1. Therefore, polyphenols are promising feed or food supplements to combat enterotoxigenic infections. Little is known of the precise mechanism, or the type of polyphenol required. Here, seven different polyphenols were tested in vitro (1) for inhibition of LT binding to GM1 (GM1-ELISA), (2) for LT inhibitory activity in the cAMP Vero-cell assay, and (3) by testing the aggregating properties of polyphenols with LT using molecular weight exclusion membrane filters, and by centrifugation techniques. Results showed only three out of seven polyphenols, pentagalloylglucose (PGG), epigallocatechingallate (EGCG) and gallocatechingallate (GCG), to effectively inhibit binding of LT to GM1, and to inhibit induction of cAMP in Vero cells, and that PGG is the most effective. Blocking of the GM1 receptor is unlikely as a mechanism because pre-incubation of GM1 with polyphenols had no effect. Co-incubation of polyphenols with forskolin did not interfere with cAMP production in Vero cells, showing that polyphenol activity is not directly related to cAMP. It is concluded that the inhibitory activities of these three polyphenols may coincide with the formation of large (>100kDa) LT-polyphenol aggregates. Enterotoxin inactivation appears to require a minimum of two galloyl moieties in polyphenol structure and the pentagalloyl PGG is the most effective.
    Veterinary Microbiology 01/2013; · 3.13 Impact Factor
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    ABSTRACT: The purpose of this study is to investigate the feasibility and validity of an automated image processing method to detect the locomotion of pigs in a group housed environment and under experimental conditions. Topview video images were captured for forty piglets, housed ten per pen. On average, piglets had a weight of 27 kg (SD=4.4 kg) at the start of experiments and 40 kg (SD=6.5) at the end. Each pen was monitored by a topview CCD camera. The image analysis protocol to automatically quantify locomotion involved localising pigs through background subtraction and tracking them over a set period of time. To validate the accuracy of detecting pigs “In Locomotion” or “Not In Locomotion”, they were compared to offline manually labelled behavioural data ('In Locomotion' versus 'Not In Locomotion'). This is the first study to show that the locomotion of pigs in a group can be determined using image analysis with an accuracy of 89.8%. Since locomotion is known to be associated with issues such as lameness, careful monitoring can give an accurate indication of the health and welfare of pigs.
    Livestock Science. 01/2013;
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    ABSTRACT: Automated collection of continuous activity data of pigs can be performed easily using video analysis. In welfare and health research, this technique can be economically advantageous over manual observations. However, the relationship between activity measures by automated video analysis and manually scored behavioural activity has never been established. We correlated automated activity measures through video analysis to ethological scores of pig activity, using off-line video recordings of four pens with grower pigs. Human observations (HO) of different behavioural activities were carried out by 2-min scan sampling during four 30-min sessions on 6 observation days. HO of pig activity was expressed as a mean proportion per session. Automated observations (AO) of pig activity were calculated by the relative number of moving pixels between two consecutive image frames (1 frame/second) and expressed as a mean image activity index per session. The overall correlation between pig activity data from AO and HO was strong and positive (Rs=0.92, P<0.0001). When comparing AO and HO data at session level, the correlation coefficients for the two afternoon sessions were lower. Both static activities and activities involving locomotion had a significant effect on the activity index of AO (P<0.05), but activities that included locomotion had a 3 times higher effect than static activities. Further validation research is necessary, but it can be concluded that automated video analysis is a promising technique to continuously monitor behavioural activity level of pigs at pen level.
    Livestock Science. 01/2013;
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    ABSTRACT: Every year over 59 billion animals are slaughtered for worldwide food production. The increasing demand for animal products has made mass animal breeding more important than ever. Satisfying the needs of the market, farmers will have to use automatic tools to monitor the welfare and health of their animals since manual monitoring is expensive and time consuming. Literature has shown that water use of pigs relates to important variables such as inside temperature, food intake, food conversion, growth rate and health condition. So, water use might be an interesting indicator for automatic monitoring pigs’ health or productivity status. Therefore, we tried to find a cheap and elegant way to monitor continuous water use in a group of pigs in a farm pen. This study comprised four groups of piglets, each group of ten animals in a pen. On average, in the beginning of experiments pigs had a weight of 27 kg and in the end they gained weight up to 40 kg. Using a water-meter for each pen, water use rate was measured and monitored minutely. The pig house was also equipped with Charge-coupled device (CCD) cameras. Each pen was monitored for 13 days using a camera which was installed above the pen to generate top-view images. There was a water outlet in the corner of each pen. Employing image processing algorithms, drink nipple visits were monitored automatically. Using data of a performed experiment comprising three weeks of data recordings, the relationship between water use and drink nipple visits was investigated. Results showed that by developing a data-based dynamic model of the visits to the drink nipple observed in videos, half-hourly water use could be estimated with an accuracy of 92%.
    Computers and Electronics in Agriculture 01/2013; 90:164–169. · 1.77 Impact Factor
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    ABSTRACT: Earlier, we showed that some commercial plant derived polyphenol extracts can inactivate heat labile toxin (LT) of enterotoxigenic Escherichia coli (ETEC) in vitro (Omnivin, and ALSOK), whereas others do not (Omnicoa). In this study, based on 40 three week weaned piglets, these three extracts were added to feed and tested for in vivo efficacy in a post-weaning diarrhea model. Piglets were divided in four treatment groups, and given a control diet or a diet supplemented with 1% of one of the three extracts. Half of each treatment group was infected with ETEC on days 6 and 7 post-weaning. Post-infection, rectal feces was assessed daily for diarrhea (as % fecal dry matter (DM)), ETEC excretion. Average daily gain (ADG), average daily feed intake (ADFI), and feed conversion ratio (FCR) were determined. Post-infection, ETEC excretion was reduced by all three extracts compared to control feed, and significantly by Omnivin (p<0.004). Diarrhea was abolished by Omnivin and ALSOK, but not by Omnicoa. No differences were found for ADG, ADFI, and FCR, except for Omnicoa which depressed ADG post-infection significantly (p<0.005). The latter suggests Omnicoa to contain an anti-nutritional factor. The overall results for the different polyphenol extracts were consistent with the respective in vitro activities in the LT-inhibition assay. It is concluded that polyphenol extracts do widely differ in properties, some may have deleterious effects, but others can indeed reduce ETEC induced diarrhea most likely by inactivating LT in vivo.
    Livestock Science. 01/2013;
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    ABSTRACT: Serum amyloid A (SAA) is a major acute phase protein in most species, and is widely employed as a health marker. Systemic SAA isoforms (SAA1, and SAA2) are apolipoproteins synthesized by the liver which associate with high density lipoproteins (HDL). Local SAA (SAA3) isoforms are synthesized in other tissues and are present in colostrums, mastitic milk and mammary dry secretions. Of systemic SAA the bulk is monomeric and bound to HDL, and a small proportion is found in serum in a multimeric form with a buried HDL binding site. In most species, systemic SAA could easily be studied by purifying it from serum of diseased individuals by hydrophobic interaction chromatography methods. For years, we were not able to isolate systemic pig SAA using the latter methods, and found that the bulk of pig SAA did not reside in the HDL-rich serum fractions but in the soluble protein fraction mainly as a multimeric protein. Based on these surprising results, we analysed in silico the theoretical properties and predicted the secondary structure of pig SAA by using the published pig primary SAA amino acid sequence. Results of the analysis confirmed that systemic pig SAA had the highest homology with local SAA3 which in other species is the isoform associated with non-hepatic production in tissues such as mammary gland and intestinal epithelium. Furthermore, the primary sequence of the pig SAA N-terminal HDL binding site did differ considerably from SAA1/2. Secondary structure analysis of the predicted alpha-helical structure of this HDL binding site showed a considerable reduction in hydrophobicity compared to SAA1/2. Based on these results, it is argued that systemic acute phase SAA in the pig has the structural properties of locally produced SAA (SAA3). It is proposed that in pig SAA multimers the charged N-terminal sequence is buried, which would explain their different properties. It is concluded that pig systemic SAA is unique compared to other species, which raises questions about the proposed importance of acute phase SAA in HDL metabolism during inflammation in this species.
    Journal of Theoretical Biology 10/2012; · 2.35 Impact Factor
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    ABSTRACT: Diarrhoea due to enterotoxigenic Escherichia coli with fimbriae F4 (ETEC-F4) is an important problem in neonatal and just weaned piglets and hence for the pig farming industry. There is substantial evidence for a genetic basis for susceptibility to ETEC-F4 since not all piglets suffer from diarrhoea after an ETEC-F4 infection. It is assumed that the wild boar was originally ETEC-F4 resistant and that susceptibility towards ETEC arose after domestication. There are different phenotypes in the pig determined by which of the three existing F4 variants (F4ab, F4ac or F4ad) they are susceptible or resistant for. This suggests that several F4 receptors exist, expressed individually or in combination with each other on the brush border of the piglet's small intestine. As such, the mucin-type glycoproteins (IMTGP) are described as F4ab/ac receptors, while the intestinal neutral glycospingolipid (IGLad) is proposed as an F4ad receptor. GP74 is a putative F4ab receptor. However, the specific genes that encode for the susceptibility are not yet known. In the past decades, linkage analyses revealed that the loci encoding for the receptor(s) for the two most frequent variants F4ab and F4ac were mapped to the 13th chromosome of the pig (Sus scrofa 13, SSC13). After fine mapping, the region of interest was mapped between two microsatellite markers, Sw207 and S0075, and interesting candidate genes. Numerous SNP analyses and a few expression studies on the three MUC-genes (MUC4, MUC13 and MUC20) and the transferrin receptor gene (TFRC) as well as on some other positional candidate genes have been performed in order to find the causative mutation for the ETEC-F4ab/ac receptor(s). However, until today, the exact mutation causing susceptibility to ETEC-F4 remains unknown.
    Veterinary Research 10/2012; 43(1):70. · 3.43 Impact Factor
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    ABSTRACT: Diarrhoea in neonatal and early-weaned piglets due to enterotoxigenic Escherichia coli-F4 (ETEC-F4) is an important problem in the pig farming industry. There is substantial evidence for a genetic basis for susceptibility to ETEC-F4 since not all pigs suffer from diarrhoea after an ETEC-F4 infection. A region on SSC13 has been found to be in close linkage to the susceptibility of piglets for ETEC-F4ab,ac. Potential candidate genes on SSC13 have been examined and although some polymorphisms were found to be in linkage disequilibrium with the phenotype, the causative mutation has not yet been found. In this study we are looking at the expression of porcine genes in relation to ETEC-F4ab,ac. With the aid of the Affymetrix GeneChip Porcine Genome Array we were able to find differentially expressed genes between ETEC-F4ab,ac receptor positive (Fab,acR(+)) piglets without diarrhoea and F4ab,acR(+) piglets with diarrhoea or F4ab,acR(-) animals. Since the susceptibility to ETEC-F4ab,ac was described as a Mendelian trait, it is not so surprisingly that only two differentially expressed genes, transferrin receptor (TFRC) and trefoil factor 1 (TFF1), came out of the analysis. Although both genes could pass for functional candidate genes only TFRC also mapped to the region on SSC13 associated with susceptibility for ETEC-F4, which makes TFRC a positional functional candidate gene. Validation by qRT-PCR confirmed the differential expression of TFRC and TFF1. In piglets without diarrhoea, the expression of both genes was higher in F4ab,acR(+) than in F4ab,acR(-) piglets. Similarly, TFRC and TFF1 expression in F4ab,acR(+) piglets without diarrhoea was also higher than in F4ab,acR(+) piglets with diarrhoea. Consequently, although both genes might not play a role as receptor for F4 fimbriae, they could be of great importance during an ETEC-F4 outbreak. An upregulation of TFRC can be a consequence of the piglets ability to raise an effective immune response. An elevation of TFF1, a protein involved in mucin formation, may also affect the piglet's capability to cope with ETEC bacteria, rather than being a receptor for its fimbriae.
    Veterinary Immunology and Immunopathology 09/2012; · 1.88 Impact Factor
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    ABSTRACT: Dietary oligosaccharides can influence the composition of the gut microbiota, and some are suggested to improve host resistance against infections. The exact mechanisms involved are largely unknown. The aim of the present study was to determine the response of the porcine small intestinal mucosa to feeding arabinoxylan oligosaccharides (AXOS), and whether it modulated the response to a single bacterial challenge with enterotoxigenic Escherichia coli (ETEC). Group pooled jejunal mRNA was analyzed by microarray. AXOS alone up regulated immune responses, and down regulated ETEC induced responses. Analysis of selected genes by qRT-PCR showed that AXOS had no effect on markers of epithelial differentiation and integrity whilst down regulating the epithelial marker intestinal fatty acid binding protein (IFABP). AXOS up regulates the inflammatory and antibacterial protein pancreatitis associated protein (PAP), independent of ETEC. It is concluded that AXOS may exert its attenuating effect on the ETEC induced small intestinal response by influencing the expression of particular innate response proteins such as PAP.
    Journal of Functional Foods. 07/2012; 4(3):626–635.
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    ABSTRACT: Enterotoxigenic Escherichia coli (ETEC) is one of the most frequently isolated enteropathogens in production animals, especially pigs and calves. Economically, the swine industry is by far the most affected by infections with ETEC because of mortality, morbidity and decreased growth rate of newborn and early-weaned piglets. After ingestion by the animal, these bacteria attach themselves to specific receptors on the small intestinal epithelium by means of proteinaceous surface appendages, the fimbriae. The F4 fimbriae, which attach to the F4 receptor, are the most studied. The aim of our study was to investigate gene expression in the small intestine of piglets of MUC13 and MUC20 in relation to animals with a different treatment towards or a different reaction on ETEC-F4ac by means of quantitative reverse transcription chain reaction (qRT/PCR). MUC13 and MUC20 are positional candidate genes for this F4ac receptor and are located in the region on SSC13q41 that segregates with the susceptibility to ETEC-F4ac. The condition of the small intestine is crucial when examining expression differences between different samples. Therefore, the expression of two genes, fatty-acid binding protein 2, intestinal (FABP2) and pancreatitis-associated protein (PAP), now known as regenerating islet-derived 3 alpha (REG3A) in the small intestine was simultaneously checked. FABP2, a standard for epithelial content, reflects the state of damage, whereas REG3A is a measure for inflammation in the small intestine. The four different substudies presented here suggest that expression of MUC13 and MUC20 is not related to the susceptibility of piglets to ETEC-F4ac.
    Animal Genetics 06/2012; 43(3):324-7. · 2.58 Impact Factor
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    ABSTRACT: Enterotoxigenic Escherichia coli (ETEC) strains that produce heat-stable (ST) and/or heat -labile (LT) enterotoxins are cause of post – weaning diarrhea in piglets. However, the relative importance of the different enterotoxins in host immune responses against ETEC infection has been poorly defined. In the present study, several isogenic mutant strains of an O149:F4ac + , LT + STa + STb + ETEC strain were constructed that lack the expression of LT in combination with one or both types of ST enterotoxins (STa and/or STb). The small intestinal segment perfusion (SISP) technique and microarray analysis were used to study host early immune responses induced by these mutant strains 4 h after infection in comparison to the wild type strain and a PBS control. Simultaneously, net fluid absorption of pig small intestinal mucosa was measured 4 h after infection, allowing us to correlate enterotoxin secretion with gene regulation. Microarray analysis showed on the one hand a non-toxin related general antibacterial response comprising genes such as PAP, MMP1 and IL8. On the other hand, results suggest a dominant role for STb in small intestinal secretion early after post-weaning infection, as well as in the induced innate immune response through differential regulation of immune mediators like interleukin 1 and interleukin 17.
    PLoS ONE 01/2012; · 3.73 Impact Factor
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    Marisa M Geens, Theo A Niewold
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    ABSTRACT: The high similarity between pigs and humans makes pigs a good gastrointestinal (GI) model for humans. Recently an epithelial cell line originating from the jejunum of pig (IPEC-J2) became available. Once validated, this model can be used to investigate the complex interactions occurring in the intestine. The advantages of using IPEC-J2 as in vitro model of the GI tract are the high resemblance between humans and pigs, and the ease of extrapolating in vitro to in vivo characteristics. In this study, the IPEC-J2 cells were functionally characterized by measuring the trans-epithelial electrical resistance (TEER), and by histological and ultrastructural studies. IPEC-J2 cells grown on six different permeable support systems, were investigated. The Transwell(®)-COL collagen-coated membrane (1.12 cm(2)) showed the best results concerning time efficiency and TEER values. The optimum seeding density of 12 × 10(5) cells/mL ensured that after 9 days of differentiation a confluent monolayer was formed. The decrease in TEER values after a maximum had been reached, coincided with the ultrastructural development of apical microvilli. We conclude that IPEC-J2 cells grown on collagen-coated membranes represent a valuable in vitro model system for the small intestinal epithelium which can be of great interest for intestinal research.
    Cytotechnology 05/2011; 63(4):415-23. · 1.32 Impact Factor
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    ABSTRACT: The acute-phase serum amyloid A (SAA) protein family comprises two main circulating (systemic) isoforms, SAA1 and SAA2, synthesised in liver and one local isoform, SAA3, produced in extrahepatic tissues. Systemic and local SAA show structural differences, which suggests different functions. In the pig, AA-amyloidosis is extremely uncommon, and the structural protein in swine has characteristics of systemic SAA. The only pig SAA sequences published so far, either derived form hepatic or extrahepatic sites have been designated SAA2, but the translated protein shows the properties of SAA3 proteins. The aim of this study was to characterise all the porcine SAA isoforms by sequencing from cDNA and genomic DNA obtained form multiple porcine tissues. Primer pairs were designed to amplify presumably all isoforms of SAA firstly and then specifically for each isotype. Results show that the only isotype isolated and sequenced both from hepatic and extrahepatic tissues correspond to a SAA3-like amino acid sequence. No SAA1-like sequences were identified, which could be indicative of the gene being very rare and consistent with the observed resistance to AA-amyloidosis. Finally, it is concluded that the pig is unique among other species in that the main circulating hepatic SAA isotype shows the characteristics of local highly alkaline SAA. This likely precludes a function as apolipoprotein.
    Veterinary Immunology and Immunopathology 03/2011; 141(1-2):109-15. · 1.88 Impact Factor
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    Communications in agricultural and applied biological sciences 01/2011; 76(1):53-6.

Publication Stats

1k Citations
173.68 Total Impact Points

Institutions

  • 2009–2014
    • University of Leuven
      • • Faculty of Bioscience Engineering
      • • Division of Livestock-Nutrition-Quality
      • • Department of Biosystems
      Louvain, Flanders, Belgium
  • 2011–2012
    • University of Murcia
      • Department of Animal Medicine and Surgery
      Murcia, Murcia, Spain
  • 2004–2008
    • Wageningen University
      • Department of Human and Animal Physiology
      Wageningen, Gelderland, Netherlands
  • 2001–2004
    • Merck Animal Health Netherlands
      Boksmeer, North Brabant, Netherlands
  • 1986–2004
    • Universiteit Utrecht
      • • Department of Farm Animal Health
      • • Faculty of Veterinary Medicine
      • • Division of Veterinary Pathology
      Utrecht, Provincie Utrecht, Netherlands
  • 1994–1997
    • The University of Tennessee Medical Center at Knoxville
      • Department of Medicine
      Knoxville, Tennessee, United States
  • 1994–1996
    • University of Tennessee
      • Department of Medicine
      Knoxville, TN, United States