Evaluation of Different IgY Preparation Methods and Storage Stability as Potential Animal Feed Supplement

Egg yolk can be used as feed additives to improve the immune status of animals and as passive therapy for veterinary diseases, and the egg yolk has proved to be a promising source of antibodies. However, the extraction methods and storage stability of IgY antibodies from egg yolk for feed supplements remain major problems in mass production. Based on Based on IgY antibody titer, IgY thermostability, IgY acid and alkali resistance, resistance to trypsin and pepsin, four different IgY purification methods (PEG extraction, water dilution method, the effect of liquid egg yolk and egg yolk powder preparations) on the activity of IgY antibodies was investigated. The results showed that IgY was stable below 70 oC, and the activity was significantly lost when it exceeded 70 degrees C; IgY was relatively stable in the range of pH 4-10, and the activity was significantly lost beyond this range; IgY had certain resistance to pepsin and trypsin. Among all four purification methods, the IgY antibody titer in liquid egg yolk and egg yolk powder was significantly higher than the other two methods. Moreover, egg yolk powder can prevent bacterial contamination and inactivation due to the formation of sediment. This study provide basic data for IgY application in animal feed supplements.