الفهرس 
Introduction
The aim of the workOnly 14 pages are availabe for public view
 |  | from | 120 |  |  |
| | | from | 120 | | |
Abstract
A total number of 220 samples were taken from private farms in broiler chickens in Assiut and Sohag Governorates, collected samples were examined for post mortem changes and also bacteriologically for possible recovery of Cl. perfringens.
Evaluation of the effect of probiotic on growth performance, feed conversion ratio (FCR) and mortality rate in broiler chickens, and also the effect of probiotic on inhibiton of Necrotic enteritis (NE).
The current study revealed the following results:
• 107 out of 220 intestinal and liver samples with a percentage of 48.6 % were positive for clostridial infection, 70 out of 130 intestinal samples with a percentage of 53.8 % were positive for clostridial infection, 37 out of 90 liver samples with a percentage of41.1% were positive forclostridial infection. All these isolates were morphologically and biochemically identified.
• The rate of Cl.perfringens isolation from intestines was higher than from liver.
• Clostridial species typing using dermonecrotic test on albino guinea pigs showed that (92) out of (107) isolates (86 %) were proved to be type A, while (15) out of (107) isolates (14 %) were proved as type D. These results revealed that the Cl.perfringes type A was the most common type compared to type D and other types of Cl.perfringes species.
• The usage of probiotic resulted in lowering Cl.perfringensclinical signs and intestinal lesion score where group Ш (infection group) showed more severe lesions than group Π (probiotic+infection group) which had intestinal lesion score (3) compared with lesion score (2) of group Π (probiotic+infection group)
• There was no significant difference of body weight between group Ι (probiotic group) and group ΙѴ (conrol group), however group Ι (probiotic group) had higher body weight value than group ΙѴ (conrol group), while these groups were significantly have higher body weight than group Π (probiotic+infection group) which also significantly higher than group Ш (infection group).
• Values of body weight gain (BWG) and feed intake (FI) were higher for group Ι (probiotic group), followed by group ΙѴ (conrol group), then group Π (probiotic + infection group) and finally group Ш (infection group) which showed the lower values. For feed conversion ratio (FCR); group Ι (probiotic group) showed improved FCR where the lower value occurred, followed by group ΙѴ (conrol group), then group Π (probiotic + infection group) and finally group Ш (infection group) which showed the higher values.