Research Progress on Egg Yolk Antibodies (IgY) in Poultry and Swine with Implications for Other Livestock: Precise Immunoregulation and Detection Technologies

Against the backdrop of reducing antibiotic use and promoting green farming worldwide, the search for safe and efficient alternatives to antibiotics has become an urgent need in the field of animal nutrition and disease prevention and control. IgY, as a natural passive immunoglobulin derived from the yolk of poultry. It has received extensive attention due to its multiple functions, such as broad-spectrum antipathogen, regulation of intestinal microecology and enhancement of mucosal immunity. However, IgY still faces a series of challenges in practical applications, including biological stability and <i>in vivo</i> delivery efficiency, functional detection and immune effect evaluation. This article focuses on the precise immune regulatory mechanism of IgY in poultry and swine. The latest research progress in maintaining intestinal homeostasis, neutralizing pathogens, feed delivery technology and related functional detection methods is systematically reviewed. Ultimately, the focus of future research on IgA is analyzed.