Yolk immunoglobulin (IgY), a polyclonal antibody, has garnered considerable attention for its role in conferring passive immunity against bacterial and viral diseases. This paper comprehensively reviews the current research on the fundamental structure and physicochemical properties of IgY. Additionally, the paper emphasize the diverse applications of IgY in preventing and treating bacterial and viral diseases, offering valuable insights for future research and the broader utilization of IgY in aquaculture.

Gracilaria tenuistipitata var.liui Zhang et Xia,commonly known as Gracilaria crinale, is one of the major marine economic algae cultivated in coastal areas of China.In order to obtain the best enzymolysis conditions for the isolation of protoplasts from Gracilarla tenuistipitata var.liui Zhang et Xia,the isolation conditions of protoplasts were optimized from the factors of enzymolysis solution composition,enzymolysis temperature and enzymolysis time.The optimum enzymatic hydrolysis conditions were as follows:1) Enzymatic hydrolysis solution components:salinity 25 sterilized natural seawater with 10 mmol·L^-1 CaCl₂,0.8 mol/L D-Mannitol,2% Cellulase R-10,1% Maecrozyme R-10,0.5% pectinase Y-23,10 U/mL agarase,pH 6.3;2) Enzymolysis conditions:28℃,80 r·min^-1,dark enzymolysis for 8 h.This study would provide a powerful tool for the genetic improvement of Gracilaria varieties.