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See detailRefinement of the production of antigen-specific hen egg yolk antibodies (IgY) intended for passive dietary immunization in animals: A review
Marcq, Christopher ULg; Thewis, André ULg; Portetelle, Daniel ULg et al

in Biotechnologie, Agronomie, Société et Environnement = Biotechnology, Agronomy, Society and Environment [=BASE] (2013), 17(3), 483-493

Antibodies have become essential tools in recent decades, with a wide range of applications in the laboratory and in human and veterinary medicine. The use of laying hens, instead of mammals, to obtain ... [more ▼]

Antibodies have become essential tools in recent decades, with a wide range of applications in the laboratory and in human and veterinary medicine. The use of laying hens, instead of mammals, to obtain the necessary antibodies from the eggs is a major advance in terms of animal welfare because it makes blood sampling obsolete. However, the advantages of this technology are numerous, in addition to the animal welfare aspect. With a carefully designed immunization protocol, it is possible to enhance both the hen’s immune response and its welfare during the process. This review puts forward recommendations how to do this and discusses recent approaches on improving the technology. [less ▲]

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See detailControl of Salmonella contamination of shell eggs – preharvest and postharvest methods: a review
Galis, Anca; Marcq, Christopher ULg; Marlier, Didier ULg et al

in Comprehensive Reviews in Food Science and Food Safety (2013), 12

Salmonella Enteritidis is one of the most prevalence foodborne pathogen, its most important reservoir being considered the shell egg. As the concerns related to the increasing human salmonellosis cases ... [more ▼]

Salmonella Enteritidis is one of the most prevalence foodborne pathogen, its most important reservoir being considered the shell egg. As the concerns related to the increasing human salmonellosis cases grow, the need for an application of preventive methods either at the farm level or during the processing steps is crucial for a better control of the foodborne outbreaks due to the consumption of this specific food product. This review focuses on the application of preventive methods at the farm level, on preharvest step, in order to reduce the risk of shell eggs contamination with Salmonella, especially S. Enteritidis, through a better control of the laying hens’ infection with this pathogen. As postharvest methods, a first approach is the egg storage conditions and the prevention of Salmonella spp. growth and multiplication. In addition, shell eggs may be subjected to eggshell decontamination, to reduce the risk of foodborne outbreaks. Several of these latter mentioned methods are already authorized to be put in place in different countries, as it is the case in the United States of America and Canada. Their efficacy has been proven and their use is regarded by some as mandatory for ensuring shell eggs safety for the consumers. [less ▲]

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See detailLes phobies des aliments d'origine animale sont-elles toujours fondées ?
Marcq, Christopher ULg

Conference given outside the academic context (2012)

Quand les productions animales deviennent positives pour la santé humaine… Vache folle, dioxine, toxi-infections alimentaires, maladies cardiovasculaires… Le secteur de l'élevage est depuis plusieurs ... [more ▼]

Quand les productions animales deviennent positives pour la santé humaine… Vache folle, dioxine, toxi-infections alimentaires, maladies cardiovasculaires… Le secteur de l'élevage est depuis plusieurs années décrié et victime d’une forme de phobie. Mais ces craintes véhiculées par les produits issus de l’élevage sont-elles toujours fondées ? Comment la recherche peut-elle œuvrer pour rendre les produits animaux plus sûrs sur le plan sanitaire ? Nous verrons comment l’œuf de poule, régulièrement associé aux toxi-infections alimentaires, pourrait bien devenir dans le futur un alicament, sérieux allié pour lutter contre les infections animales et humaines. [less ▲]

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See detailUsefulness of a Vancomycin pretreatment when challenging chickens in order to evaluate anti-Salmonella preparations
Marcq, Christopher ULg; Cambier, Carole ULg; Thewis, André ULg et al

in Ceylan, Necmettin; Ciftci, Ibrahim; Adabi, Shahram (Eds.) 18th European Symposium on Poultry Nutrition: Proceedings (2011, October)

For many years, Salmonella infection models have been developed in chickens with the aim to study the effects of prophylactic or therapeutic measures on the colonization of the gut. However, although the ... [more ▼]

For many years, Salmonella infection models have been developed in chickens with the aim to study the effects of prophylactic or therapeutic measures on the colonization of the gut. However, although the literature includes numerous challenge models, few studies investigated the infection rates among the inoculated population. We have implemented an antibiotic pretreatment of the chickens (vancomycin hydrochloride, 25 mg/bird) as an infection promoter. Indeed, vancomycin affects the normal gut microflora and releases sites for Salmonella at the intestinal epithelium. Two experiments were undertaken and a presence/absence cloacal swab method was used to evaluate cecal colonization. In the first experiment, birds were orally inoculated with Salmonella Typhimurium at 21 days of age. Three inoculum doses (3 × 103, 3 × 106, 3 × 109 cfu/bird) and an uninfected control were compared according to whether or not vancomycin had been used. Higher levels of Salmonella colonization (more than 70 %) were achieved in the gut by pretreating birds with vancomycin before inoculation (P < 0.05). In the second experiment, chicks were inoculated at 7 days of age with 108 cfu/bird after a vancomycin pretreatment, leading to an infection rate of 87.5 %. In conclusion, vancomycin promotes efficiently the percentage of colonized birds in the challenged population, with either young animals or olders. [less ▲]

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See detailIn vitro antagonistic activity evaluation of Lactic Acid Bacteria (LAB) combined with cellulase enzyme against Campylobacter jejuni growth in co-culture
Dubois Dauphin, Robin ULg; vandeplas, Sabrina; Didderen, Isabelle et al

in Journal of Microbiology and Biotechnology (2011), 21(1), 62-70

The antibacterial effects of nine Lactic Acid Bacteria (LAB) on Campylobacter jejuni were investigated using agar gel diffusion and co-culture assay. Inhibition potential was not the same between both ... [more ▼]

The antibacterial effects of nine Lactic Acid Bacteria (LAB) on Campylobacter jejuni were investigated using agar gel diffusion and co-culture assay. Inhibition potential was not the same between both techniques. Only two LAB, Lb. pentosus CWBI B78 and E. faecium THT, showed an anti-campylobacter activity in co-culture assay in using dehydrated poultry excreta mixed with ground straw (DPE/GS) as the only growth substrate source. It was observed that the complementation with Cellulase A complex (Beldem S.A.) of this medium enhanced antimicrobial effect of both bacteria. The co-culture medium acidification was correlated with the concentration in supplemented enzyme. The antibacterial effect was characterized by the production of lactic acid by the homofermentative E. faecium THT and the lactic and acetic acids production by the heterofermentative Lb. pentosus CWBI B78. The antagonistic properties from bacteria-enzyme cooperation could reduce the prevalence of Campylobacter consequently the risk of human infection. [less ▲]

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See detailSalmonella Typhimurium oral challenge model in mature broilers: Bacteriological, immunological, and growth performance aspects.
Marcq, Christopher ULg; Cox, Edwin; Szalo, Ioan Mihai ULg et al

in Poultry Science (2011), 90(1), 59-67

In this study, Salmonella enterica serovar Typhimurium challenge models were tested to identify the best conditions under which to perform the experimental infection of 3-wk-old broilers. Such a model ... [more ▼]

In this study, Salmonella enterica serovar Typhimurium challenge models were tested to identify the best conditions under which to perform the experimental infection of 3-wk-old broilers. Such a model would be useful to study the efficiency of therapeutic treatments that could take place at the end of the grow-out period. Salmonella-free chicks were obtained from a breeder flock vaccinated with Salmonella. Intestinal maternal immunity was monitored by ELISA analyses at 2, 9, and 16 d of age. Data indicated that protection of maternal origin was not maintained over time and was drastically reduced at 9 d of age (P < 0.01). At 21 d of age, chickens were orally inoculated with Salmonella Typhimurium. The effects of the oral challenge dose (0, 3 x 10(3), 3 x 10(6), and 3 x 10(9) cfu/bird) and vancomycin pretreatment (no administration or 25 mg/bird) on intestinal immune responses, growth performance, and Salmonella colonization of chickens were investigated. After infection, the mucosal immune response was rapid, with increased (P < 0.01) anti-Salmonella Typhimurium IgA titers measured at 8 d postinfection in intestinal contents. A linear relationship (P < 0.05) existed between specific IgA levels in intestinal and cecal contents and the challenge dose inoculated. None of the challenge protocols caused mortality or clinical symptoms after infection. Nevertheless, the experimental infection induced a significant deterioration of growth performance. The pretreatment with 25 mg of vancomycin at 3 h before Salmonella inoculation was able to establish stable infection rates among the population of 3-wk-old infected chickens. Nevertheless, Salmonella shedding was not stable over the rearing period, and the bacteria seemed to be naturally eliminated from most birds at 22 d postinfection. This natural clearance of the gut, which was related, at least in part, to the intestinal immune response, should limit the usability of the created mature challenge model within 1 to 2 wk after inoculation. [less ▲]

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See detailKeep bacteria under control: Dietary modulation of gut microflora in farm animals by use of hen egg yolk antibodies
Marcq, Christopher ULg; Thewis, André ULg; Portetelle, Daniel ULg et al

E-print/Working paper (2010)

This review article focuses on the use of IgY in therapy or prophylaxis of diseases in veterinary medicine as well as in the context of functional foods to modulate microflora in animal.

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See detailAntibodies Dynamics in the Broiler Digestive Tract after Salmonella Typhimurium Oral Challenge
Marcq, Christopher ULg; Cox, Edwin; Thewis, André ULg et al

in Duclos, Michel; Nys, Yves (Eds.) XIIIth European Poultry Conference: Program & Book of Abstracts, World's Poultry Science Journal, Volume 66, Supplement (2010, August)

This study aimed to provide directions for Salmonella challenge experiment conception by offering a better understanding of the relationship between age and mucosal immune responsiveness of chicken ... [more ▼]

This study aimed to provide directions for Salmonella challenge experiment conception by offering a better understanding of the relationship between age and mucosal immune responsiveness of chicken. Intestinal maternal immunity of Salmonella-free chicks was monitored by ELISA analyses at 2, 9 and 16 days of age. At 21 days of age, chicks were orally inoculated with Salmonella Typhimurium. Three inoculum doses (3 x 10E3, 3 x 10E6, 3 x 10E9 cfu/bird) and an uninfected control were then compared concerning mucosal immune status of the small intestine and cecum. Results suggest that difficulties encountered to infect very young chicks can be related, at least partly, to maternal immunity. The relatively low level of intestinal immune defences observed thereafter could indicate a right time to perform an experimental infection of birds and to maximize the spreading of the pathogen during challenge experiment. After infection of 3-week-old chickens, the mucosal immune response was rapid with increased anti-Salmonella Typhimurium IgA titers. There was a linear relationship between specific IgA levels in intestinal and cecal secretions and the challenge dose initially inoculated. [less ▲]

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See detailImmunisation passive du poulet de chair vis-à-vis des salmonelles à l'aide d'anticorps du jaune d'oeuf
Marcq, Christopher ULg; Thewis, André ULg; Portetelle, Daniel ULg et al

in Impacts de l'alimentation sur la santé animale : nouveaux développements (2009, October 14)

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See detailInterview (télévision locale Canal Zoom, émission "C'est l'Heure") dans le cadre de l'organisation de la 9ème Journée des Productions Porcine et Avicole
Marcq, Christopher ULg

Diverse speeche and writing (2009)

Reportage diffusé dans l'émission "C'est l'heure" sur Canal Zoom et relatif à la 9ème Journée des Productions Porcine et Avicole - La 9ème Journée des Productions Porcine et Avicole organisée ... [more ▼]

Reportage diffusé dans l'émission "C'est l'heure" sur Canal Zoom et relatif à la 9ème Journée des Productions Porcine et Avicole - La 9ème Journée des Productions Porcine et Avicole organisée conjointement par le Centre wallon de Recherches agronomiques et la Faculté des Sciences agronomiques de Gembloux s'intéressera à l'impact de l'alimentation sur la santé animale. Il faut notamment trouver des alternatives aux farines animales et aux antibiotiques. Les chercheurs gembloutois se sont intéressés à de nouvelles substances nutritionnelles que l'on peut trouver dans le jaune d'œuf ou le colostrum bovin… (Reportage réalisé le 25/09/09) [less ▲]

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See detailPotential of Dried Egg Yolk as a Source of Immunoglobulins to Control Salmonella in the Gastrointestinal Tract of the Broiler Chicken
Marcq, Christopher ULg; Portetelle, Daniel ULg; Chalghoumi, RAJA ULg et al

in 17th European Symposium on Poultry Nutrition : Proceedings & Abstracts (2009, August)

Egg yolk immunoglobulins (IgY) are considered as a promising tool of establishing passive immunity against enteric pathogens (e.g. Salmonella) in poultry (Kovacs-Nolan and Mine, 2005). In our previous ... [more ▼]

Egg yolk immunoglobulins (IgY) are considered as a promising tool of establishing passive immunity against enteric pathogens (e.g. Salmonella) in poultry (Kovacs-Nolan and Mine, 2005). In our previous works, in-feed incorporation of freeze-dried yolk powder (FYP) improved performances of Salmonella-infected broilers (Marcq et al., 2009). Nevertheless, no extra value could be attributed to the presence of specific IgY when a comparison was done between impact of hyperimmune or non immune FYP both concerning growth performances and Salmonella infection. We hypothesized that these inconclusive in vivo results were related to the sensitivity of IgY to gastrointestinal conditions. Egg yolks with high IgY titers directed against Salmonella Enteritidis and Typhimurium were obtained from laying hens immunized as previously described (Chalghoumi et al., 2008). Three feed additives derived from these eggs were produced: FYP, spray-dried yolk powder (SYP), and freeze-dried water-soluble fraction of yolk powder (WSFP). A force-feeding assay was realized on these additives with 48 five-week-old males Ross broiler chicken (Salmonella spp.-free status). Survival of undigested IgY and bioactive Fab fragments was evaluated in the intestinal tract by ELISA. Statistical analyses were done using GLM procedure of Minitab 15.1. Software. Differences were considered significant when P<0.05. As a result of the digestive process, the levels of total and specific undigested IgY found throughout the intestine were dramatically reduced for the three additives. For FYP, no difference was observed with intestinal contents of control animals (P>0.05) and for WSFP, which correspond to semi-purified IgY, the immunological activity reached the same level than that for SYP (P>0.05) whereas its initial level was almost ten times higher. The results suggest a protective effect of whole yolk on IgY with SYP but such effect was not observed with FYP. High levels of Fab fragments were identified in intestinal contents, highlighting the importance of protein digestion in the digestive tract and especially pepsin digestion. These Fab fragments conserve their immunological functionality and remained detectable in all intestinal segments including the caecum which represents the major site of Salmonella infection in poultry. These results can explain our previous challenge data and reveal that a protection treatment should be applied to dried egg yolk to improve the resistance of IgY to gastrointestinal conditions in broilers. [less ▲]

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See detailLe poulet sans salmonelles : quelles recherches pour y parvenir ?
Marcq, Christopher ULg

Conference given outside the academic context (2009)

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See detailAdhesion and growth inhibitory effect of chicken egg yolk antibody (IgY) on Salmonella enterica serovars Enteritidis and Typhimurium in vitro.
Chalghoumi, Raja; Thewis, André ULg; Beckers, Yves ULg et al

in Foodborne Pathogens and Disease (2009), 6(5), 593-604

The protective effects of powder preparation of egg yolk immunoglobulin Y (IgY), specific to Salmonella Enteritidis and Salmonella Typhimurium outer membrane proteins (OMP), against these two Salmonella ... [more ▼]

The protective effects of powder preparation of egg yolk immunoglobulin Y (IgY), specific to Salmonella Enteritidis and Salmonella Typhimurium outer membrane proteins (OMP), against these two Salmonella sp. serovars were investigated in vitro in two different assays: adhesion-prevention and growth-inhibition. The adhesion-prevention assay was conducted using polarized monolayers of the human intestinal epithelial Caco-2 cell line. First, the conditions of Salmonella adherence to Caco-2 cells were optimized, and interferences of bacteria with the transepithelial electrical resistance (TER) of fully differentiated Caco-2 cell monolayers and the lactate dehydrogenase release upon exposure of the cells to Salmonella were evaluated. Both Salmonella sp. serovars were able to adhere to Caco-2 cells and decreased TER. Results from the adhesion-prevention assay demonstrated that specific IgY reduced the decrease in TER of the infected Caco-2 cell monolayers and blocked the Salmonella sp. adhesion in a concentration-dependent manner (p < 0.05). Nonspecific IgY also exhibited an inhibitory effect on these two parameters, but to a lesser extent than that of the specific IgY (p < 0.05). The protective effect of nonspecific IgY could be attributed to the low-density lipoprotein component of the water-soluble fraction of egg yolks that may not have been eliminated during ultrafiltration. The growth-inhibition assay revealed that specific IgY had an inhibitory effect on the bacterial growth, markedly during the late exponential phase, whereas nonspecific IgY failed to do so. Taken together, these results suggest that the in vitro growth inhibitory effect of specific IgY on Salmonella spp. resulted from the specific binding activity of these IgY to Salmonella sp. OMP. Passive immunization with Salmonella sp. OMP-specific IgY could thus be useful to prevent Salmonella colonization in broiler chickens and the subsequent carcass contamination during processing. [less ▲]

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