The first step consisted of the purification of IgY antibodies from egg yolks in order to obtain the highest yield and purity. Antibodies were separated from other constituents of the egg yolk by the addition of acid water and later precipitated by salting-out (19% sodium sulfate) (Fig. 1A) . Although enriched in IgY antibodies, the water soluble fraction (S1) still presented undesirable low molecular weight proteins after acid water precipitation of pooled egg yolk (Fig. 1B , lane S1) that were eliminated after salting-out step (Fig. 1B, lane P2) , presenting an average protein concentration of 4 mg/mL. We recovered 115 eggs from four STAg-immunized chickens during a 49-day interval. Each egg presented an average of 12 mL of yolk and the mean yield was 48 mg of polyclonal antibody per egg. Precipitated antibodies contained in P2 fraction were further submitted to purification by exclusion-size chromatography (Fig. 1C ), resulting in a protein peak between the 13th and 19th fractions, although elevated purity was detected mainly in the 14th fraction (F14), as it may be observed in its SDS-PAGE profile (Fig. 1D) . Thus, the used protocol was able to retrieve a mean of 4 mg of total IgY from 1 ml of crude egg yolk. Slot-blot assays confirmed IgY in fractions from salting-out and gel filtration purified fractions until the concentration of 110 ng of protein (Fig. 1E ).