Exploring Inflammation of Infection of Chicken Embryos before 12 days of embryonic development: A Promising Experimental Model

Abstract

The chicken embryo (CE) has emerged as a valuable in vivo model for investigating immune development, infection, and inflammation. This review outlines the biological and practical advantages of the CE model, emphasizing its phylogenetic proximity to mammals, well-characterized development, and accessibility for experimental manipulation. The ontogeny of the immune system is discussed, including the formation of primary and secondary lymphoid organs and the early appearance of innate and adaptive immune responses. Special attention is given to the suitability of the CE for modeling inflammatory responses, particularly in studies using live pathogens such as Salmonella Pullorum. Several studies have successfully employed the CE to assess bacterial virulence and host–pathogen interactions, demonstrating its relevance for infection biology. Furthermore, we highlight ethical considerations related to animal welfare, noting that the use of embryos before the development of nociception aligns with the principles of the 3Rs. Together, these findings support the CE as a robust and ethically responsible model for studying early host responses to infection and inflammation.