Penelitian ini bertujuan untuk mengetahui pemberian kotoran sapi terhadap pertumbuhan cacing sutra (Tubifex sp) serta mengetahui dikonsentrasi berapa yang sesuai dengan pertumbuhan cacing sutra (Tubifex sp). Penelitian ini menggunakan metode eksperimen dengan rancangan acak lengkap (RAL) yang terdiri dari lima perlakuan dan tiga kali ulangan. Media perlakuan terdiri dari perlakuan satu kotoran sapi 20% dan lumpur 80%, perlakuan dua kotoran sapi 30% dan lumpur 70%, perlakuan tiga kotoran sapi 40% dan lumpur 60%, kontrol negatif 100% lumpur, dan kontrol positif kotoran sapi hasil olahan biogas 20% dan lumpur 80%. Parameter yang diamati meliputi biomassa dan populasi cacing sutra, serta kualitas air sebagai penunjang. Hasil penelitian menunjukan bahwa pemberian media kotoran sapi dengan konsentrasi yang berbeda tidak berpengaruh terhadap kepadatan populasi dan biomassa cacing sutra. Nilai populasi dan biomassa yang mengalami penaikan terdapat pada perlakuan 3 menghasilkan cacing sutra sebanyak 0,16 gram dan ±67 individu. Berdasarkan data kualitas air selama penelitian diperoleh kisaran suhu 30-32 °C, nilai pH kisaran 5-7 dan nilai do kisaran 5-9.
Kata kunci: cacing sutra, kotoran sapi, populasi, biomassa

This study aims to determine the application of cow dung to the growth of silkworms (Tubifex sp) and to determine what concentration is suitable for silkworms (Tubifex sp). This study used an experimental method with a completely randomized design (CRD) consisting of five treatments and three replications. The treatment media consisted of treatment of one 20% cow dung and 80% sludge, treatment of two 30% cow dung and 70% sludge, three treatment of 40% cow dung and 60% sludge, 100% negative control of sludge, and positive control of processed cow dung. 20% biogas and 80% sludge. The parameters observed included biomass and silkworm population, as well as supporting water quality. The results showed that the application of cow dung media with different concentrations had no effect on the population density and biomass of silkworms. The highest value on population and biomass found in treatment three produced silk worms as much as 10.16 grams and ± 4.267 individuals. Based on water quality data during the study, it was obtained a temperature range of 30-32 ° C, a pH value of 5-7 and a do value of 5-9. Key words: silk worm, cow dung, population, biomass