<![CDATA[Feed costs constitute the largest component of poultry production, accounting for 60–70% of the total production cost. The use of cheap and locally available alternative feed ingredients, such as rice bran and corncob, can help reduce production costs. Fermentation with Effective Microorganisms 4 (EM4) is one approach to improve the nutritional quality and digestibility of corncob. This study aimed to evaluate the effect of substituting rice bran with EM4-fermented corncob flour (FCF) on the performance and energy utilization ratio (EUR) of ULU chickens, a composite local chicken breed. EUR represents the proportion of gross dietary energy intake converted into body weight gain, expressed as grams of body weight gain per 100 kcal of gross energy intake (g/100 kcal). The study used 200 day-old chicks (DOC) of ULU chickens reared for 8 weeks. The experiment was arranged in a completely randomized design (CRD) with five treatments and four replications. The treatments consisted of different ratios of rice bran and FCF: T0 (16% rice bran, 0% FCF), T1 (12% rice bran, 4% FCF), T2 (8% rice bran, 8% FCF), T3 (4% rice bran, 12% FCF), and T4 (0% rice bran, 16% FCF). The parameters measured were feed intake, body weight gain, feed conversion ratio, gross energy intake, and energy utilization ratio. Data were analyzed using analysis of variance (ANOVA). Treatments showing significant effects were further analyzed using Duncan's multiple range test (DMRT). The results showed that substituting rice bran with FCF up to 16% had no significant effect (P>0.05) on feed intake (311.06–327.25 g/bird/week), body weight gain (101.97–105.65 g/bird/week), feed conversion ratio (3.10–3.31), gross energy intake (1,465.89–1,562.52 kcal/bird/week), or energy utilization ratio (6.53–6.96 g/100 kcal). Under the conditions of this experiment, rice bran can be replaced with EM4-fermented corncob flour up to 16% in the ration without reducing the performance or energy utilization ratio of ULU chickens.]]>
