Background: Soybean milk dregs (SMD) are one of the potential feed ingredients for quail, however improving their nutritional value and utilization requires a biotechnological approach. This investigation was performed on the percentage and effect of using fermented soybean milk dregs (FSMD) inoculated with Aspergillus ficuum in quail rations.Methods: 200 quails (Coturnix japonica), aged 20 weeks, were used in this study. They were kept in 20 battery cage units, each with 10 quails inside. The analysis was carried out using a completely randomized design with 5 treatment rations and 4 replications. The treatment rations were R1, R2, R3, R4, and R5 using 0, 10, 15, 20, and 25% FSMD respectively, which were prepared based on 20% iso-protein and 2800 kcal/kg iso-calorie. Feed consumption, egg production, egg mass, feed conversion, egg weight, shell thickness, and quail yolk color were among the variables that were observed.Results: According to the results of the analysis of variance, feed consumption, egg production, egg mass, feed conversion, egg weight, and shell thickness were all unaffected by the use of FSMD (P >0.05). Additionally, there was a strong correlation between parameters under the treatment effect, with the exception of egg thickness.Conclusion: The optimum level of fermented soybean milk dregs was 25% level in quail rations.Keywords: Soybean milk dregs; Aspergillus ficuum; Fermentation; Quail performance
