Developmental Characteristics of the Embryonic Liver Tissue and Long‐Term Culture of Primary Hepatocytes in Duck

The liver serves as an excellent model for studying body development. Numerous studies have been conducted on mammalian liver development, whereas research focusing on duck liver remains limited, particularly regarding the embryonic stage. Additionally, hepatocytes from duck embryos exhibit limited in vitro proliferation and are prone to undergoing the epithelial‐mesenchymal transition (EMT), which hinders the maintenance of hepatocyte characteristics and functions. In this study, hematoxylin‐eosin (HE) staining, Oil red O staining, and transmission electron microscopy (TEM) were performed on liver tissues from 5 to 26 days of embryonic ages to investigate their developmental characteristics. The results revealed that liver development was characterized by increasing hepatocyte numbers, extending hepatocyte cords, rising number, and decreasing area of liver sinusoids, the formation of diverse blood vessels, the progressive accumulation of lipid droplets, and alterations in the types, and quantities of organelles. Simultaneously, cell morphology, biochemical indicators, function indicators, and growth curves were assessed in hepatocyte culture. Among the 5 candidate media selected, Medium 1 and Medium 9 were found to be most suitable for hepatocyte proliferation and characteristic maintenance. Furthermore, it was found that serum significantly enhanced hepatocyte proliferation efficiency, whereas high concentrations could induce EMT. Notably, Medium 9‐a promoted hepatocyte proliferation without EMT. Finally, a comparison of growth curves across eleven media revealed that Medium 9 and Medium 9‐a showed superior performance. Therefore, these findings provide valuable insights and a powerful cellular tool for subsequent studies on liver functions and nutritional metabolism in ducks.