Development of an Immunoglobulin Y (IgY)-Based Vaccine for Salmonella Control in Poultry

Salmonella infections in poultry represent a significant threat to public health and contribute to substantial economic losses within the agricultural sector. In response to these challenges, this study explored an innovative dual control strategy integrating the use of indigenous plant-based bacterial attenuation with targeted immunotherapy using egg yolk-derived immunoglobulin Y (IgY) antibodies. Garlic (Allium sativum) and onion (Allium cepa) extracts were employed to attenuate virulent strains of Salmonella enterica, resulting in a notable reduction in bacterial viability during in vitroassays. Following oral vaccination with the attenuated strains, chickens mounted a robust immune response, characterised by the production of high titres of anti-Salmonella IgY antibodies, as measured by ELISA. Functional assays demonstrated that these antibodies possessed strong agglutination activity against homologous Salmonella strains, highlighting their utility in passive immunisation protocols. Safety assessments confirmed the vaccine’s non-pathogenic profile, while immunogenicity trials showed consistent antibody production across vaccinated flocks. This dual modality—combining natural antimicrobial agents with specific IgY-based immunotherapy—offers a sustainable, low-cost alternative to antibiotics, with the potential to reduce zoonotic transmission, enhance poultry welfare, and support antimicrobial stewardship in animal husbandry.