Abstract: The inhibition of immunoglobulin G from different sources on Escherichia coli, Staphylococcus aureus and Bacillus subtilis was studied respectively in this article. The qualitative inhibition of IgG on the three germs determined by tubes serial dilution test and quantitative newcombe experiment was made respectively after 12h and 24h of the fluid culture. Under 30℃, it showed that bovine colostrum IgG, bovine serum IgG and swine serum IgG inhibited respectively the three germs to some extent, and the antibacterial effect of those IgG in 12h culture was more remarkable. But chicken IgY did not inhibit any germ under the experiment condition. Under 37℃, it was observed that bovine colostrum IgG had only low inhibiting rate on St. aureus at 80mg/ml concentration.

Key words: antibacterial effect in vitro, bovine colostrum IgG, bovine serum IgG, swine serumIgG, chicken IgY