SDS-PAGE analysis of IgY among different preparations and storages. A, B, C and D represent four different IgY preparations (PEG-extraction, WD, liquid yolk, yolk power) against E. coli; E, F, G, and H represent four different IgY preparations (PEG-extraction, WD, liquid yolk, yolk power) against Kanamycin, respectively. M, Marker; Lane 1: Fresh antibody preparation; Lane 2 to 7: every month storage monitoring for 6 months period (liquid yolk preparation only 4 months).