Quantification of gut lesions in a subclinical necrotic enteritis model

Abstract

Currently Clostridium perfringens-induced necrotic enteritis is a major problem in broiler flocks. In the present study, broilers were inoculated with a combination of Eimeria maxima or overdose coccidial vaccine (one inoculation) with C. perfringens (repeated inoculations). Single C. perfringens, E. maxima or an overdose of live coccidial vaccine inoculations did not result in grossly visible necrotic gut lesions, while combined inoculation resulted in typical necrotic lesions at approximately 4 days after inoculations with C. perfringens in approximately one-half of the inoculated animals. Semi-quantitative histological lesion scoring was done to evaluate gut damage in gut sections of animals in which no gross necrotic lesions were detected. This included scoring of hyperaemia, haemorrhages, the amount of red blood cells and protein precipitate in the lumen, villus fusion and epithelial defects. The villus length and the villus length/crypt depth ratio were also analysed. This approach proved to be discriminative between single E. maxima infection, overdose of coccidial vaccine or C. perfringens inoculations and the non-inoculated control group, and between the double-inoculated and single-inoculated groups. In general, the highest histological scores for gut lesions were observed in the double-inoculated groups, but the single-inoculated groups had higher scores than the control group. It was concluded that oral inoculation of broilers with an overdose of live coccidial vaccine in combination with multiple oral C. perfringens inoculations is a suitable model for necrotic enteritis without inducing mortality of the animals. C. perfringens and Eimeria act synergistically in inducing grossly visible gut damage.

The role of an attenuated anticoccidial vaccine on the intestinal ecosystem and on the pathogenesis of experimental necrotic enteritis in broiler chickens

“…The experimental model used in the present study for the reproduction of NE is a well-established and reproducible model that has been used in many research studies (Gholamiandehkordi et al, 2007;Timbermont et al, 2009;Lanckriet et al, 2010). It is a multifactorial model, using not only a specific diet formulation and a Gumboro vaccination, but also an oral inoculation of broilers with E. maxima and multiple oral inoculations with a specific strain of C. perfringens.…”

“…It belongs to toxinotype A (no b 2 or enterotoxin genes) and, in vitro, produces moderate amounts of alpha-toxin. The strain carries the netB gene and has been used previously to induce NE (Gholamiandehkordi et al, 2007;Lanckriet et al, 2010). To facilitate the detection of the inoculated strain in experimental birds, rifampicin-resistant mutants were isolated with the gradient technique as described by Pedersen et al (2008) using Brain Heart Infusion broth (02Á599; Scharlau Chemie S.A., Barcelona, Spain) containing rifampicin in a gradient concentration from 0 to 100 mg/ml (R 3501-1G; Sigma Aldrich Chemie GmbH, Steinheim, Germany).…”

“…Broilers in all groups were fed a specially formulated three-phase ration (starter 1 to 9 days, grower 10 to 16 days and finisher 17 to 24 days), which included large quantities of wheat and rye (Gholamiandehkordi et al, 2007). From day 17 onwards, the same isocaloric ration (finisher) was used with the exception that fishmeal replaced the soybean meal as the protein source, in order to predispose to NE.…”

Effects of Glycyrrhizic Acid on Productive and Immune Parameters of Broilers

“…The bursa, spleen and thymus were separated and fixed in 10% buffered formalin, processed, and stained with hematoxylin-eosin for histopathology under light microscopy to determine the degree of injury and thickness of each of these lymphoid organs in terms of maturity of lymphoid cells found, as suggested by Gholamiandehkordi et al (2007). Briefly, bursa evaluation was based on visual injury scores on 0-4 analog scale, the highest degree of injury and adding to the degree of injury the value of the dissemination of such injury and the number of bursas with similar lesions, in a given group.…”

The effect ofArtemisia annuaon broiler performance, on intestinal microbiota and on the course of aClostridium perfringensinfection applying a necrotic enteritis disease model

“…disrupting the integrity of the intestinal wall during formation, as well as high dietary concentrations of animal protein (e.g. fish meal), are important predisposing factors that support intestinal C. perfringens proliferation (Dahya et al, 2006;Gholamiandehkordi et al, 2007;Pedersen et al, 2008).…”