ABSTRACT This study aimed to evaluate sago pulp fermentation method and its effect on crude fiber content, digestibility, and utilization of sago pulp as a feed raw material for Nile tilapia. Fermentation was done using three different fermenters, i.e. yeast tapai and baker’s yeast with five doses of 10 g/kg, 20 g/kg, 50 g/kg,70 g/kg,100 g/kg, respectively, and sheep rumen liquid with five doses of 100 mL/kg, 200 mL/kg, 300 mL/kg, 500 mL/kg and 1000 mL/kg. The incubation time was 0, 24, 72, and 96 hours. In the digestibility test, tilapia (25 g) was stocked at a density of 7 fish/aquarium. Three different diets were applied in quadruplicate, i.e. reference diet (100% reference diet), unfermented sago pulp (AS), and fermented sago pulp (ASF). Three different dietary treatments (in quadruplicate) containing different carbohydrate sources were tested, i.e. cassava flour as a comparion (G), unfermented sago pulp (AS), and fermented sago pulp (ASF). Fermentation of sago pulp with tapai yeast at a dose of 50 g/kg at 72 hours incubation time could reduce crude fiber by 35.76%, neutral detergent fiber (NDF) by 32.68%, and hemicellulose by 60.39%. Fermentation with yeast tapai could significantly increase sago pulp dry matter digestibility by 34% and carbohydrate digestibility by 21%, as well as increase glucose absorption. The growth experiment showed that the use of ASF diets resulted in higher specific growth rate (3.31 ± 0.12%/ day), protein retention (47.34 ± 5.23%) and fat retention (85.58 ± 5.44%) than those of AS dietary. In conclusion, fermentation of sago pulp using yeast tapai at a dose of 50 g/kg at 72 hours incubation could reduce crude fiber content and increase dry matter and carbohydrate digestibilities, so that it can be used as a source of carbohydrates in tilapia diet. Keywords : carbohydrate, digestibility, fermentation, fiber, Nile tilapia, sago pulp ABSTRAK Penelitian ini bertujuan mengevaluasi metode fermentasi ampas sagu dan pengaruhnya terhadap kandungan serat kasar, kecernaan, dan pemanfaatan ampas sagu sebagai bahan baku pakan ikan nila. Fermentasi dilakukan dengan penambahan tiga perlakuan bahan fermentor yaitu ragi tape dan ragi roti ditambahkan dengan dosis masing-masing sebanyak 10 g/kg, 20 g/kg, 50 g/kg, 70 g/kg, 100 g/kg, dan cairan rumen domba yang ditambahkan dengan dosis 100 mL/kg, 200 mL/kg, 300 mL/kg, 500 mL/kg, dan 1000 mL/kg. Lama waktu inkubasi 0, 24, 72, dan 96 jam. Pada uji kecernaan digunakan ikan nila (25 g) yang dipelihara dengan kepadatan tujuh ekor per akuarium. Pada uji ini dilakukan tiga perlakuan pakan dengan empat ulangan, yaitu pakan acuan, ampas sagu tanpa fermentasi (AS), dan ampas sagu fermentasi (ASF). Percobaan dilakukan dengan tiga perlakuan pakan (4 ulangan) dengan tiga sumber karbohidrat yang berbeda yaitu gaplek (G) sebagai pembanding, ampas sagu (AS), dan ampas sagu fermentasi (ASF). Fermentasi ampas sagu dengan menggunakan ragi tape sebanyak 50 g/kg dengan lama inkubasi 72 jam dapat menurunkan serat kasar tertinggi sebanyak 35.76%, dan menurunkan fraksi serat neutral detergent fiber (NDF) dan hemisellulosa masing-masing sebanyak 32.68% dan 60.39%. Perlakuan fermentasi ampas sagu dapat meningkatkan nilai kecernaan bahan sebesar 34%, kecernaan karbohidrat sebesar 21%, serta penyerapan glukosa. Hasil uji pertumbuhan menunjukkan bahwa perlakuan ASF memberikan nilai laju pertumbuhan spesifik (3.31 ± 0.12%/hari), retensi protein (47.34 ± 5.23%) dan retensi lemak (85.58 ± 5.44%) yang lebih tinggi dibandingkan perlakuan AS (P