Necrotic enteritis, caused by Clostridium perfringens (C. perfringens) is a disease
present worldwide and causes major economic losses. The re-emergence of the disease,
in recent years, is mainly due to the ban of the usage of antibiotics as growth promoters
in the EU. The aim of this study was to establish a reliable, robust challenge model.
Ross hybrid broilers were divided into randomized groups: a positive and a negative
control group, a group receiving antibiotic treatment and three groups fed with assorted
feed supplements, all receiving the same basal diet. The birds in the treatment groups
were vaccinated twice using a 10-times dose of an Infectious Bursitis live vaccine
and the animals were challenged four times with a NetB toxin producing C. perfringens
strain. The presence of clinical signs and body weight gain were monitored. At the
end of the study necropsy was performed and the gut lesions were scored. During the
experiment, clinical signs were absent in the negative control group and in the antibiotic
treated group. The other animals displayed diarrhea and feather loss. These symptoms
were the most pronounced in the positive control group. The gut lesion scores showed
significant differences between the negative and positive control groups, with the
former scoring the lowest. Based on these results, the challenge model establishment
was successful and in this setup the assessment of the potency of feed additives is
also possible.
