This product is CEF serum-free medium, a chemically defined medium specifically designed for the in vitro culture of chicken embryonic fibroblasts (CEF). Its core formulation precisely mimics the unique metabolic characteristics of avian cells, optimizing energy supply and cell adhesion factors. This provides a stable and efficient cell proliferation platform for the research, development, and production of avian viral vaccines (such as avian influenza vaccines and Newcastle disease vaccines), while completely eliminating batch-to-batch variability introduced by serum and the risk of avian pathogen contamination.