Fractionation of the reference inoculum of epizootic rabbit enteropathy in discontinuous sucrose gradient identifies aetiological agents in high density fractions

Szalo, Ioan Mihai; Lassence, Cédric; Licois, Dominique; Coudert, Pierre; Poulipoulis, Anastassios; Vindevogel, Henri; Marlier, Didier

doi:10.1016/j.tvjl.2005.12.013

Cited by 27 publications

(40 citation statements)

References 3 publications

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“…However, several histological and ultrastructural lesions and haematological profiles observed in this present study at the same time corroborate an infectious aetiology and suggest a bacterial origin as mentioned by Szalo et al (2006). It is possible that ERE is a multifactorial disease.…”

Section: Discussionsupporting

confidence: 87%

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Experimentally induced epizootic rabbit enteropathy: clinical, histopathologicaI, ultrastructural, bacteriological and haematological findings

Dewrée

Meulemans²,

Lassence

et al. 2010

World rabbit sci.

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Epizootic rabbit enteropathy is an emerging disease that has appeared in French intensive enclosed rabbit farms since the beginning of 1997. Common clinical signs are mild watery diarrhoea with considerable distension of the abdomen. At necropsy, a significant dilation of the stomach and small intestine without gross evidence of acute or chronic enteric lesions (inflammation or congestion) was observed. The purpose of this study was to describe the anatomopathologic changes concerning the small intestine and those concerning the blood profile, in experimentally infected rabbits. In a first part of the experiment, thirty animals were inoculated with a reference inoculum and five were kept as controls for clinical signs examination and histopathological study. In a second part, 17 out of the inoculated rabbits and the 5 controls animals were randomly assigned to blood testing. Microscopic lesions were studied in sections from the different parts of the small intestine (duodenum, jejunum and ileum) by light microscopy, scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The histological findings revealed only limited inflammation in inoculated animals. Major villous changes were atrophy, fusion, destruction and loss of epithelial cells. In inoculated rabbits, the congestion and dilation of blood vessels of jejunal lamina propria were significantly higher than in control animals (P<0.005). There was significantly more (P<0.05) apoptosis of cells of the jejunal epithelium in inoculated rabbits than in control animals. Infiltration of polymorphonuclear neutrophiles was observed into the jejunal or ileal tunica muscularis. SEM performed on the intestinal tract of 15 inoculated rabbits revealed blankets and globular particles of mucus associated with numerous bacteria on jejunum and ileum villi. This was not observed in the intestinal tract of control rabbits. Bacteria were found adhering to the epithelial surface and inside intestinal epithelial cells in a few animals by TEM and by light microscopy after Warthin-Starry staining. None of the bacteria isolated from the intestinal mixed contents and cultivated on usual media, are commonly known as rabbit's pathogens. Regarding the haematological profile, neutrophil counts significantly increased (P<0.05) and lymphocyte counts significantly decreased (P<0.01), in inoculated rabbits compared to those of the control group.

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Section: Discussionsupporting

confidence: 87%

“…The neutrophilia and lymphopenia observed in inoculated animals could be a response of the immune system to inflammation and this could reinforce the hypothesis of an infectious cause such as bacterial invasion. The same conclusion about a bacterial aetiology in the ERE syndrome has recently been mentioned by Szalo et al (2006).…”

Section: Discussionsupporting

confidence: 71%

Experimentally induced epizootic rabbit enteropathy: clinical, histopathologicaI, ultrastructural, bacteriological and haematological findings

Dewrée

Meulemans²,

Lassence

et al. 2010

World rabbit sci.

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“…Presently, the most common disorder in rabbit production is the occurrence of a complex enteritis (Epizootic Rabbit Enteropathy, ERE) which is the first cause of mortality in the European rabbit industry (Dewree et al, 2003). However, no pathogenic agent has been identified to date (Licois et al, 2000;Marlier et al, 2006;Szalo et al, 2007;Huybens et al, 2009). To prevent post-weaning digestive disorders, prophylactic antimicrobial medication is normally used in growing rabbits.…”

Section: Introductionmentioning

confidence: 99%

Effect of mannan oligosaccharides on rabbit performance, digestibility and rectal bacterial anaerobic populations during an episode of epizootic rabbit enteropathy.

Bovera¹,

Nizza²,

Marono³

et al. 2010

World Rabbit Sci.

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ABSTRACT:The effect of three levels of mannan oligosaccharides (MOS at 0.5, 1.0 and 1.5 g/kg diet) compared to dietary antibiotic supplementation (ANT, colistin sulphate 144, tylosin 100 and oxytetracycline 1000 ppm) and to a diet without MOS or medication (control group) were studied on 5 groups of rabbits (n=342 cages/group and 2 rabbits/ cage) from weaning (35 d) to 60 d of age in a farm with an anamnestic history of Epizootic Rabbit Enteropathy (ERE). Mortality rate was recorded daily. Thirty two cages per group were randomly chosen to record growth performance and rectal anaerobic microbial population. Live weight and feed intake were recorded weekly. At 49 d of age rectal swabs were collected with cotton swabs from 8 rabbits per group and the anaerobic microbial population was counted. Feed digestibility was determined per cage using acid insoluble ash as an internal marker, collecting faeces from 57 to 59 d of age. An episode of ERE occurred during the second and the third week of the trial. The control group showed a high mortality rate during the fattening period (78%) and was not considered for further measurements. Total mortality rate was higher (P<0.05) for rabbits fed antibiotics (34.2%) than for those fed MOS (17.7, 7.75 and 17.1 %, for MOS at 0.5, 1.0 and 1.5 g/kg diet, respectively), with the lowest mortality rate being for those with a 1.0 g MOS/kg diet. Medicated rabbits showed similar growth rates compared to the average of those fed MOS diets (38.6 g/d on average), but impaired feed conversion ratio (FCR) and nutrient digestibility (P≤0.003). Rabbits fed MOS at 1.0 g/kg showed better growth rates, FCR and nutrient digestibility (P≤0.01) than those fed 1.5 g/kg MOS. Total anaerobic and Clostridium spp. counts were higher in medicated animals compared to those fed MOS, with those fed 1 g/kg MOS showing the lowest value (P<0.001). Under critical conditions due to an episode of ERE, a concentration of 1.0 g/kg MOS in the diet, could reduce rabbit mortality and improve growth performance.

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“…Approximately 50 mL of intestinal content was taken from the small intestine, caecum and colon of each selected animal, pooled per animal, diluted 1:3 in PBS (if dry), filtered, and stored at −20±2°C. A sample of 134 out of 263 pooled intestinal contents was examined to detect rotavirus antigen with an ELISA test (Cypress Diagnostics ® , Belgium), used in similar studies by Marlier et al (2006) and Szalo et al (2007).…”

Section: Microbiologymentioning

confidence: 99%

Clinical, pathological and microbiological profiles of spontaneous enteropathies in growing rabbits

Badagliacca

Letizia²,

Candeloro

et al. 2010

World rabbit sci.

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ABSTRACT:In a rabbit production facility, health monitoring for enteropathies was performed in 15 production cycles for 20 mo. For each cycle, up to a hundred 35 d old rabbits weaned the same day were randomly selected, reared in the same fattening unit, but separately from the source batch and fed with the same feed except for antimicrobial supplementation. Clinical symptoms and enteric lesions of the selected group were recorded, using two checklists with binomial response (yes/no answer to a list of 54 clinical and enteric variables). The day after weaning, one week later, at the beginning of the enteric symptoms and 4-5 d after the start of the symptoms, inocula from the small intestine and caecum of selected animals were subjected to microbiological, C. spiroforme, Eimeria oocyst and rotavirus antigen detection tests. Representative samples of E. coli and C. perfringens isolates were tested, respectively, for serotype, biotype, eae, afr/2 genes and for a, b1, b2, e, i and enterotoxin toxin genes. The answers to the clinical-pathological variables were subjected to statistical analysis with a cluster analysis programme in order to obtain homogeneous, statistically signifi cant groups of diseased animals (clusters). Then, the clusters were statistically associated with the laboratory outcomes. The cluster to which the enterotyphlitis lesions signifi cantly contributed was associated with E. coli detection, E. coli O103 serotype detection and C. spiroforme ("several elements" variable). C. spiroforme ("rare elements" variable) was signifi cantly associated with a cluster, characterised by a pathological profi le consisting of bloating/rumbling noise and liquid content in stomach and caecum, without enteric infl ammation. C. perfringens was signifi cantly associated with a cluster, characterised by a pathological profi le consisting of dilation/liquid content of small intestine, caecal impaction and mucoid content in the colon. Eighteen out of twenty-fi ve C. perfringens strains, examined for their toxin genotypes, proved to be toxin type A, while 7 out of 25 strains showed the a and b2 toxin genes in combination. The rotavirus antigen and Eimeria oocysts were detected from healthy rabbits (specimens of the day after weaning and one week later) in about 15% of specimens examined, but their presence in the sick animals was not signifi cantly associated with any cluster.

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Fractionation of the reference inoculum of epizootic rabbit enteropathy in discontinuous sucrose gradient identifies aetiological agents in high density fractions

Cited by 27 publications

References 3 publications

Experimentally induced epizootic rabbit enteropathy: clinical, histopathologicaI, ultrastructural, bacteriological and haematological findings

Experimentally induced epizootic rabbit enteropathy: clinical, histopathologicaI, ultrastructural, bacteriological and haematological findings

Effect of mannan oligosaccharides on rabbit performance, digestibility and rectal bacterial anaerobic populations during an episode of epizootic rabbit enteropathy.

Clinical, pathological and microbiological profiles of spontaneous enteropathies in growing rabbits

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