Abstract: Objective: To compare the effectiveness between three methods for purifying the immunoglobulin of egg yolk(IgY) which are polyethylene glycol (PEG) method, chloroform extraction method and chloroform/PEG method, and to provide basis for obtaining the batch of IgY. Methods: The inactivated vaccine of Vibrio parahemolyticus (V. parahemolyticus) was prepared and the hens were immunized by multi-point intramuscular injection.The eggs were collected and the IgY was purified by PEG method, chloroform extraction method and chloroform/PEG method.The protein extraction rate, the IgY titer and the purity of the antibody which purified by different methods were detected.Furthermore, the operation process, cost and safety of the three methods were analyzed. Results: The protein contents of the extraction belonging three methods from high to low in turn were chloroform extraction method, chloroform/PEG method, and PEG method.There was no significant difference in the antibody titer between three methods, and the tiler of chloroform extraction method was slightly high.The purities of purified antibody from high to low in turn were PEG method, chloroform/PEG method and chloroform method.The PEG method had better security but relatively lower extraction efficiency and higher cost.The chloroform/PEG method had high extraction efficiency and good antibody purity. Conclusion: The PEG method is suitable for a small amount of extraction in the laboratory.The chloroform/PEG method is appropriate for extracting the high quality IgY in a batch as it has high extraction efficiency and good antibody purity.

Key words: immunoglobulin of egg yolk, polyethylene glycol method, chloroform method, Vibrio parahemolyticus