Potential improvement of the immune response of chickens against E. coli vaccine by using two forms of chitosan nanoparticles.

Colibacillosis disease has an important economic impact on poultry production worldwide. It is one of the most common causes of mortality in commercial layer and breeder chickens. Avian pathogenic Escherichia coli (APEC) is the main cause of this disease. Nanoparticles have been widely used in vaccine design as both adjuvants and antigen delivery vehicles. The present study aimed to produce an efficient vaccine from E. coli serogroups O1 and O78 to help in controlling colibacillosis in chicken using two forms of chitosan (CS) and ascorbate chitosan (AsCS) nanoparticles. Nanovaccines has been prepared through loading and encapsulation of outer membrane and flagellar antigen on CS and AsCS nanoparticles with loading efficiency 86, 63,55, 48% for CS-loaded-, Cs-capsulated-, AsCS-loaded- and AsCS-capsulated-E. coli Antigen, respectively. Two hundred specific pathogens free (SPF) 3-weeks old broiler chickens were used and divided into four groups to investigate the immune response of nanovaccines. The immune response was measured by the microagglutination, ELISA, and challenge test. From results, it could be concluded that generally adding chitosan NPs is capable of improving vaccine efficacy via the induction of strong immunity. Moreover, we recommend the production of the nanovaccine CS-capsulated -antigen from E. coli O1 and O78 serotypes to be used as a potent vaccine to aid in controlling colibacillosis. Also, the ascorbate chitosan is a great alternate for the initiation of a potent immune response in critical infection cases.