EFFECT OF SUBSTITUTION AMTABIS FERMENTED WITH Aspergillus niger ON THE WEIGHT AND THE PERCENTAGE OF CARCASS BROILER BY: RIFKI MARZANI ABSTRACT The purpose of this study was to obtain information about the effect of substitution amtabis fermented with Aspergillus niger (A.niger) on broiler weight and the percentage of carcass. This research was conducted at the Field Laboratory of Animal Husbandry Department, Agricultural Faculty, Syiah Kuala Universtiy Darusslam, Banda Aceh from December 4, 2015 to January 9, 2016. Totally 100 day old chickens (DOC), strain CP 707 produced from PT. Charoen Pokphand Jaya Farm Medan, were used in this study. This study was designed by using completely randomized design (CRD) consisting of 4 treatments and 5 replications. Each replication is experimental unit with the total of 25 experimental units for the whole experiment. Treatments in this study consists of P0 (control diet without Amtabis), P1 (commercial diet substituted with 2% of Amtabis), P2 (commercial diet substituted with 4% of Amtabis), and P3 (commercial diet substituted with 6% of Amtabis). Data were analyzed by using Analysis of Variance (ANOVA). Parameters measured in this study were live weight, carcass weight, carcass percentage, pieces of carcass weight, carcass percentage cuts. The results showed that the substitution of Amtabis in commercial rations significant effect (P0,05) on carcass percentage. Substitution of Amtabis at the level of 6% on commercial feed tended to increase live weight, carcass weight and percentages but still not above control weight. Effect of substitution Amtabis on weight and cut-up pieces of broiler carcass showed significantly influenced on the weight of the wings, tights and drum sticks. Key words: Broiler chicken, Amtabis, substitution, commercial feed and carcass.