THE EXPERIMENTAL MODEL OF NECROTIC ENTERITIS IN CHICKENS INDUCED BY LIVE COCCIDIOSIS VACCINE ALONG WITH CLOSTRIDIUM PERFRINGENS

Background and Aim:Necrotic enteritis (NE) is one of the most important enteric diseases in poultry and is a high cost to the industry worldwide. The economic impact of the disease is estimated to be US$ 2 billion annually due to mortalities and poor performance and the cost of prevention and treatment. The aim of this research is to design an efficient, applicable and repeatable necrotic enteritis model for therapeutic studies.Methods:78 one-day-old SPF (Ross 308) broilers were divided to 13 groups including control, three B groups for challenging with three CFU clostridium perfringens, three P groups for challenging with 3 doses of coccidiosis vaccine and three BP groups challenged with six dosages of bacteria and parasite vaccine in different days. The B groups challenged by 0.5, 1 and 2×108 at days 17-20 and three times a day. The P groups challenged by 100, 150 and 200-fold of the coccidial vaccine on day 28th. The BP groups were received both bacteria and parasite vaccine. The dose and time of administration were similar to that of B and P groups. Small intestine lesions of all groups were assessed and scored following euthanized of chickens.Results:Scoring showed lesion score 1, 2 and 5 for B, P and BP groups respectively.Conclusion:The results showed that clostridium perfringens alone can’t induce necrotic enteritis and needs predisposing agents like coccidia vaccine for induction of the model. The chickens that administered with coccidial vaccine only, showed moderate ulcer but chickens challenged with both clostridium perfringens and coccidial vaccine, induced the model significantly.

کلیدواژه ها:

necrotic enteritis ، coccidiosis ، Clostridium perfringens ، Eimeria ، vaccine