aplikasi protein sel tunggal dan “spent grains” dalam FORMULASI PAKAN untuk pemeliharaan kerapu hibrid (Epinephelus fuscoguttatus x Epinephelus polypekadion)

Abstract

Sumber protein alternatif berupa protein sel tunggal (PST) dari sisa produksi bumbu penyedap dan “spent grains” dari sisa produksi minuman bir memiliki kandungan protein yang tinggi. Penelitian ini bertujuan untuk mendapatkan dosis terbaik dari penggunaan dua sumber bahan tersebut terhadap pertumbuhan dan sintasan ikan kerapu hibrid (kerapu cantik). Empat pakan uji diformulasikan dengan menambahkan kombinasi tepung spent grains dan PST untuk menggantikan protein dari tepung ikan sebesar (A) 0%, (B) 30%, (C) 40%, dan (D) 50%. Uji pakan dilakukan di keramba jaring apung menggunakan 12 jaring berukuran 2 m x 2 m x 2 m. Bobot awal ikan kerapu cantik yang digunakan adalah 63 ± 0,6 g dan ditebar dengan kepadatan 253 ekor/jaring. Pakan uji diberikan dua kali sehari secara satiasi. Data yang diamati adalah pertumbuhan (bobot dan panjang), sintasan, dan konversi pakan. Hasil penelitian menunjukkan bahwa perlakuan pakan A (0%) menghasilkan berat akhir sebesar 299,6 ± 27,0 g lebih baik dan berbeda nyata (P<0,05) dari perlakuan C (40%) dan D (50%), namun tidak berbeda nyata (P>0,05) dengan perlakuan pakan B (30%), yaitu 287,4 ± 5,3 g. Hasil ini menunjukkan bahwa substitusi protein tepung ikan dengan campuran protein dari PST dan spent grains pada pakan pembesaran kerapu hibrid dapat dilakukan sampai level 30%.

Single cell protein left-over from seasoning factory and spent grains from brewery waste are potential as high protein sources for animal feed. This study was aimed to obtain an optimal supplementation dose of the two ingredients in relation to the growth and survival rate of hybrid grouper (Cantik grouper). Four test feeds were formulated by mixing different combinations of single cell protein and spent grains to replace fishmeal protein content in the feed at 0%, 30%, 40%, and 50%. The feeding trials were conducted at a floating net cage consisted of 12 netpens sized 2 m x 2 m x 2 m. The initial mean weight of hybrid grouper was 63 ± 0.6 g. The fish were stocked at a density of 253 fish/netpen. Feed treatments were given at satiation two times a day. Parameters of growth (final body weight and length), survival rate, and feed conversion were observed. The results showed that fish in treatment A (0%) gained the final body weight of 299.6 ± 27.01 g which was significantly different (P<0.05) with that of treatment C and D, but not significantly different with fish in treatment B (30%), with the mean weight gain of 287.4 ± 5,3 g. Fish in treatment B (30%) showed better growth response and survival rate than that of treatment C (40%) and D (50%). The result also indicated that fish fed with treatment B feed (30%) had not different a mean final body weight with the control feed. This study suggested that a combination of single cell protein and spent grains to substitute fish meal in grow-out feed for hybrid grouper could be applied up to 30%.