Abstract

Necrotic enteritis (NE) is a common worldwide poultry disease caused by the bacterium of Clostridium perfringens (C. perfringens) which has significant economic losses in the poultry industry as well as the cost of treatment and preventive measures. The current study was conducted to evaluate the incidence of NetB toxin positive in C. perfringens on different farms in Egypt. In the years 2020 and 2021, on industrial broiler farms (15-45 days-old), 100 intestinal samples were collected consisting of 30 healthy Ross broiler chickens and 70 unhealthy Ross broiler chickens. Culture and biochemical characterization (Catalase, urease, sugar fermentation, gelatin liquefaction, nitrate reduction, and lecithinase reaction tests) confirmed that C. perfringens was isolated at a rate of 10 (3/30) from apparently healthy broiler chickens and 40 from unhealthy broiler chickens. Thirty-one isolates were tested for toxigenicity and typing by ELISA kits and the results showed that 80 of the isolates from unhealthy broiler chickens were C perfringens type A alpha-toxin (toxigenic), 20 were non-toxigenic, and 66.7 isolates from apparently normal broiler chickens were toxigenic. The same thirty-one (44) C. perfringens isolates were detected by PCR to investigate the presence of the NetB toxin gene in apparently healthy and unhealthy broilers and subsequently detect the role of NetB toxin in inducing NE. Of the samples, 82 of the isolates from unhealthy chicks were found to incode NetB gene, while none of the isolates from healthy broiler chickens had NetB. Clostridium perfringens showed sensitivity to amoxicillin, amoxicillin with clavulanic acid and ampiclox, intermediate for ofloxacin, and high resistance to cephalexin, streptomycin, colistin sulfate, erythromycin, sulfa trimethoprim, gentamycin, and oxytetracycline. The present study revealed the importance of NetB gen in the appearance of clinical signs of NE in broiler chickens. © 2023,Journal of World''s Poultry Research. All Rights Reserved.