دانشگاه تهران مجله تحقیقات دامپزشکی (Journal of Veterinary Research) 2008-2525 63 2 2008 06 21 EXPERIMENTAL INDUCTION OF NECROTIC ENTERITIS IN BROILER CHICKENS BY CLOSTRIDIUM PERFRINGENS ISOLATES FROM THE OUTBREAKS IN IRAN ایجاد تجربی بیماری آنتریت در جوجه های گوشتی با استفاده از جدایه های PERFRINGENS CLOSTRIDIUM از موارد حاد بیماری در ایران 128 132 23938 FA بهرام شجاعدوست گروه علوم درمانگاهی دانشکده دامپزشکی دانشگاه تهران سید مصطفی پیغمبری گروه علوم درمانگاهی دانشکده دامپزشکی دانشگاه تهران 0000-0001-9166-1303 Journal Article 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 (3×108 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. 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 (3×108 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. https://jvr.ut.ac.ir/article_23938_ece15b23555793f8ba30f202afc924eb.pdf