Newcastle disease virus (NDV) is highly contagious, leading to the million loss in the poultry industry per year. Unfortunately, there is unknown treatment for ND but the vaccines. The objective of the present study is to evaluate the effect of Astragalus polysaccharide (APS) on membrane capacity in response to Newcastle disease virus (NDV) infection and the potential mechanism. Chicken embryo fibroblast cells (CEFs) were exposed to 10⁴TCID₅₀/ml NDV, while 150 μg/mL APS were added before/after NDV infection as well as after the mixture. This manner is to mimic preventive, therapeutic, and neutral treatment in clinical practice. Our results shows therapeutic effect of APS was less than preventive effect, while the neutral group was unstable. It shows the significant decrease in silica content, Na⁺/K⁺-ATPase activity and cell membrane fluidity, and the increase in membrane potential during NDV infection compared with the control groups (P<0.05), whereas APS reversed markedly these changes. These suggest APS enhanced the protective effect of CEFs during the early stages of NDV infection. Hence, APS may prevent ND by adding to the feed or nutrition in poultry.

Key words: Astragalus polysaccharide, Cytomembrane disruption, Newcastle disease virus