This study aims to determine the effect of using sago dregs fermented with Pleurotus ostreatus as a complete feed mixture for rabbits. This research uses experimental methods and analysis using variance with a Randomized Group Design (RAK). The ration treatment consisted of 5 levels which were repeated in 3 body weight groups, each experimental unit was filled with 2 male rabbits so that the number of rabbits used was 30. The treatment given is the level of use of fermented sago dregs in complete feed. The ration is made in pellet form with the following arrangement: R0 = Ration without using fermented sago dregs; R1 = Ration using 5% Pleurotus ostreatus fermented sago dregs; R2 = Ration using 10% Pleurotus ostreatus fermented sago dregs; R3 = Ration using 15% Pleurotus ostreatus fermented sago dregs and R4 = Ration using 20% ​​Pleurotus ostreatus fermented sago dregs. The variables observed were feed consumption, body weight gain and feed conversion. The research results showed that the highest feed consumption was in the R2 treatment, namely 59.70 g ind^-1 d^-1. The R2 treatment was statistically significantly higher (P<0.05) than the R3 and R4 treatments with values ​​of 56.22 g ind^-1 d^-1 and 53.10 g ind^-1 d^-1 respectively but not significantly different (P>0, 05) compared to treatments R0 and R1 with values ​​of 56.11 g ind^-1 d^-1 and 57.15 g ind^-1 d^-1. The results of the analysis of variance for the treatments showed that there were significant differences (P<0.05) in the increase in body weight of rabbits. The highest increase in body weight was in treatment R2, namely 15.91 g ind^-1 d^-1. The R2 treatment produced higher PBB (P>0.05) than the R0 and R3 treatments with values ​​of 13.00 g ind^-1 d^-1 and 13.10 g ind^-1 d^-1 respectively and were much higher (P<0.05) compared to treatments R1 and R4 with values ​​of 14.49 g ind^-1 d^-1 and 11.20 g ind^-1 d^-1. average feed conversion of 4.32; 3.97; 3.75; 4.29 and 4.74. Treatment R2 showed the lowest conversion value compared to other treatments in this study. This shows that R2 treatment is more efficient than other treatments. The conclusion of this research is that the administration of 10% fermented Pleurotus ostreatus sago dregs in a complete feed mixture showed the best results in terms of consumption parameters with a value of 59.70 g ind^-1 d^-1, body weight gain with a value of 15.91 g ind^-1 d^-1 and produced feed conversion of 3.75.

Keywords: Sago dregs, fermentation, Pleurotus ostreatus, complete feed, rabbits.