<p>Demand of "dumbo" catfish is going to increase every year so that fry production should be increased in order to support intensification culture system to meet market demand. Intensification in fish culture system may cause decreasing of dissolved oxygen content and producing high level waste in the pond culture. The effort to control inorganic nitrogen in intensive culture system can be performed by adding wheat powder into fish culture media. This can support metabolic process of nitrogen by microbe and then produce protein in terms of bacteria biomass production, so that inorganic nitrogen in the water decreases. Fish can utilize protein from microbe efficiently. This study was conducted to examine effect of rearing density on "dumbo" catfish fry production in the culture system by controlling nitrogen content in water through addition of wheat powder. "Dumbo" catfish fry of 12-day old in average body weight of 0.046±0.006 gram and length of 1.7±0.9 cm were reared for 28 days in density of 400, 800 and 1200 fish/m<sup>2</sup>. The results of study showed that weight and body length of fry reached 1.35 gram and 5.1 cm, respectively. Average of daily growth and production were 10.47 - 11.48% and 2.49 - 3.54 g per day, respectively. Increased of rearing density was insignificantly (<em>p</em>>0.05) affected growth rate and daily production. Average growth in absolute length, survival rate and feed efficiency was about 2.7-3.2 cm, 36.20 - 53.88% and 147 - 172%, respectively. Increased in rearing density was followed by decreased growth in length (<em>p</em><0.05), survival rate and feed efficiency.</p> <p>Keywords: "dumbo" catfish, <em>Clarias</em>, nitrogen, wheat, rearing density</p> <p> </p> <p>ABSTRAK</p> <p>Permintaan ikan lele dumbo terus meningkat setiap tahunnya sehingga diperlukan peningkatan produksi benih untuk mendukung intensifikasi usaha budidaya dalam rangka memenuhi permintaan pasar. Budidaya ikan secara intensif dapat menyebabkan menurunnya kadar oksigen air, sedangkan limbah yang dihasilkan tinggi. Upaya untuk mengendalikan nitrogen anorganik pada budidaya intensif dapat dilakukan melalui pemberian tepung terigu ke dalam media budidaya. Hal ini akan mendukung proses metabolisme nitrogen oleh mikroba dan akan menghasilkan protein dalam bentuk bakteri sehingga nitrogen anorganik dalam air menjadi berkurang. Protein mikroba yang dihasilkan dapat dimanfaatkan sebagai sumber protein yang efisien bagi ikan. Penelitian ini bertujuan untuk mengetahui pengaruh tingkat kepadatan terhadap produksi benih ikan lele dumbo pada sistem budidaya dengan pengendalian nitrogen melalui penambahan tepung terigu. Benih ikan lele dumbo (<em>Clarias sp</em>.) umur 12 hari dengan bobot rata-rata 0,046±0,006 gram dan panjang 1,7±0.9 cm dipelihara selama 28 hari dengan kepadatan 400 ekor/m<sup>2</sup>, 800 ekor/m<sup>2</sup>, 1200 ekor/m<sup>2</sup>. Hasil penelitian menunjukkan bahwa benih ikan mengalami peningkatan ukuran berat (1,35 gram) dan panjang (5,1 cm). Nilai rata-rata pertumbuhan dan produksi harian masing-masing berkisar 10,47 - 11,48% dan 2,49 - 3,54 gr/hari. Peningkatan kepadatan tidak berpengaruh nyata (p>0,05) terhadap laju pertumbuhan dan produksi harian. Nilai rata-rata pertumbuhan panjang mutlak, kelangsungan hidup dan efisiensi pakan masing-masing berkisar 2,7-3,2 cm, 36,20 - 53,88% dan 147 - 172%. Peningkatan kepadatan diikuti dengan penurunan pertumbuhan panjang (p<0,05), kelangsungan hidup dan efisiensi pakan.</p> <p>Kata kunci: lele dumbo, <em>Clarias</em>, nitrogen, terigu, padat penebaran</p>
Study on impacts of direct supplementation of choline into semi-intensive fish culture system based on haematopoietic alterations
