Experimental induction of necrotic enteritis in broiler chickens by clostridium perfringens isolates from the outbreaks in Iran

ABSTRACT

To establish an stable challenge system for induction of necrotic enteritis [NE] in broiler chickens, different potential factors and predisposing conditions were imposed in 6 separate different experiments using 525 day-old chicks in total. Despite the presence of some predisposing factors and using 4 isolates of Clostridium perfringens [CP] from acute and severe NE outbreaks as challenge bacteria, the disease was not successfully reproduced in the first 4 experiments. In the 5th and 6th experiments, the predisposing conditions were changed and each bird was challenged with 3 ml [3_10[8] CFU/ml] of CP live culture via oral route and also the feed mixed with CP suspension 2 times per day and for 5 consecutive days. Clinical signs and mortalities, and lesions associated with NE were observed in the later two experiments. This study showed that by stressful nutritional and management procedures such as increased stocking density and high levels of wheat and fish meal; induction of relative immunosuppression; using sufficient CP concentration and appropriate ways of its multiplication; and applying challenge bacteria isolated from acute outbreaks, NE may be experimentally induced in broiler chickens