Replacements of Antibiotics in the Control of Necrotic Enteritis: A Review
Aayesha Riaz*, Sajid Umar, Muhammad Tanveer Munir, Muzammil Tariq
Department of Patho-Biology, Faculty of Veterinary and Animal Sciences, University of Arid Agriculture, Murree Road, Rawalpindi, Pakistan
Necrotic enteritis (NE) is an emerging economic problem of the broiler industry, which is caused by the bacterium Clostridium perfringens (C. perfringens). Under the normal physiological conditions, C. perfringens may be present in the gut asymptomatically but drastic changes of the gut environment result in damage to the intestinal mucosa, which can lead to a rapid proliferation of C. perfringens and the development of NE. Factors associated with the development of NE include parasitism (coccidiosis), high fiber diets and poor hygienic housing conditions. Moreover, excessive use of antibiotic growth promoters (AGP) enhances the capability of C. perfringens to induce the disease. The key virulence factors in the pathogenesis of NE of C. perfringens are the novel toxins, such as NetB and alpha toxins. Therefore, a toxoid vaccine using the alpha toxin, capable of generating an antibody response can be transferred to the progeny thus achieving partial protection from NE. However, these toxoid vaccines are still under experimentation and an insight of the mechanism which involves the role of alpha toxin in the development of immunity and pathogenesis is desired. This review has three aims: firstly, it intends to summarize the current available information about NE in chickens; secondly, it aims to elaborate the pathogenesis of NE at the molecular level and finally, future prospects of vaccination against NE and other possible novel methods for the control of disease are suggested.