Development of a chicken egg yolk antibody (IgY) could effectively prevent and treat goose astrovirus infection.

Goose astrovirus (GAstV) is a major threat to the goose industry, with no effective drugs or vaccines available. Developing safe and effective prevention and treatment strategies is essential to reduce its impact. In our study, we used the GAstV GDCS strain as the vaccine antigen and found that a 1 ‰ formaldehyde concentration effectively inactivated the virus after 24 h at 37 °C. The inactivated virus antigen was subsequently emulsified with white oil to formulate the GAstV inactivated vaccine. This vaccine was administered four times to 22-week-old laying hens, and IgY was subsequently purified from the egg yolk using the polyethylene glycol (PEG) precipitation method. After the fourth immunization, IgY concentration was 3.133 mg/mL. SDS-PAGE showed IgY has a 65 kDa heavy chain and a 25 kDa light chain. The IgY effectively neutralized GAstV in vitro with a titer of up to 2^9.67. Administering IgY to goslings effectively prevents and treats GAstV infection by reducing symptoms, mortality, tissue damage, and viral load. These findings offer significant tools for the clinical prevention and management of GAstV infection.