Abstract
With increasing regulations restricting antibiotic use in animal feed, the need for alternative strategies to prevent and manage necrotic enteritis (NE) has become imperative. As a result, developing effective vaccines has emerged as a top priority for broiler chicken health management. Coccidial infections are a well-established predisposing factor for NE, underscoring the importance of controlling coccidiosis to help mitigate NE outbreaks. This research aimed to investigate the protective efficacy of vaccine preparations containing Eimeria maxima elongation factor-1α and a multicomponent antigen cocktail of Clostridium perfringens, including a single collagen adhesion protein (CpCna) and two chimeric proteins: CpNA (NetB-Alpha-toxin) and CpFZ (Fructose-1,6-bisphosphate aldolase-Zinc metalloprotease). Two vaccine preparations-recombinant subunit vaccines and DNA vaccines-were developed to assess their immunoprotective effects, determined by relative body weight gain rate, lesion scores, survival rates, and antigen-specific IgY levels using a dual-infection NE challenge model involving E. maxima and C. perfringens. Broilers were administered two subcutaneous immunizations with either adjuvanted proteins or eukaryotic expression plasmids on Days 7 and 17. Chickens vaccinated with the five antigens exhibited significantly higher serum antigen-specific IgY levels, improved weight gains, zero mortality, and reduced lesion scores following the lethal dual-infection challenge. These results indicated that vaccine preparations targeting both C. perfringens and E. maxima represent a promising approach for controlling and preventing coccidiosis-induced NE in chickens.