Abstract: Objective: To optimize the colony count of IgY against F. nucleatum in oral simulation environment. Methods: The final colony count was used as the evaluation index. On the basis of single factor test, response surface methodology was employed with three factors and three levers such as number of colonies at different dose of IgY, initial inoculation concentrations of F. nucleatum, and culture time in the artificial saliva. The experiment was repeated three times under the optimal conditions to verify the accuracy of the model. Results: The optimum culture conditions were as follows: culture time was 6 h, dose of IgY was 181 mmol/L, and F. nucleatum initial inoculation concentration was 2×10⁶ CFU/mL. Under these conditions, the final number of colonies was 4.52×10⁴ CFU/mL, and relative error with the theoretical value was less than 5%. The variance analysis showed that the P value of the model was significant, the missing value was not significant, and the theoretical value was in good agreement with the measured value. Conclusion: The number of colonies of F. nucleatum in the simulated oral env-ironment was significantly decreased, which indicated that the regression model could be a good predictor of the response of F nucleatum in the oral cavity.

Key words: Response surface optimization, Fusobacterium nucleatum, Immunoglobulin of yolk Proliferation