Heat-shock technology for mass-fry production of bullfrog Rana catesbeiana

• Published in: Jurnal Penelitian Perikanan Indonesia (Jakarta) Vol. 8; no. 3
• Main Authors: Wiadnya, D.G.R, Hariati, A.M, Mahendra, A.P.,Universitas Brawijaya, Malang (Indonesia), Suryanti, Y
• Format: Journal Article
• Language: English
• Published: 2002
• Subjects: FROGS; GROWTH RATE; HEAT STRESS; LARVAE; METAMORPHOSIS; SHOCK; WATER QUALITY
• ISSN: 0853-5884; 2502-6542

An investigation was held in the laboratory of aquaculture, Faculty of Fisheries, Brawijaya University on September-December 1998, in order to increase growth and metamorphoses of tadpole of bullfrog, Rana catesbeiana (Shaw). The research was done in two recirculation units, consisted of 12 aquaria each. Nearly-hatched eggs and hatched-larvae were treated with different heat-shocks (temperature of 27.5; 30.0; 32.5; 35.0; 37.5 deg. C; and control, as well), during a period of two minutes. The larvae were then incubated in each aquarium (first recirculation for eggs, and larvae for the second, respectively). After 10 days, 300 larvae were selected from each treatment and incubated within the recirculation system, randomly. During the rearing period, larvae was fed with commercial BF-1 (equal protein of approx. 40 percent). Every 10 days, total tadpole-biomass was measured to estimate growth. Metamorphoses was determined when the fry come out from water (lay within stereofoam on the water level), which were then removed. Data analysis was elaborated to find the treatment that gave the best result on growth and metamorphoses. In the second experiment, investigation was continued using shock-period as treatments (control, 1.0; 2.0; 3.0; 4.0; and 5.0 minutes), while shock temperature was 35.0 deg. C with the same procedure (as in the first experiment), growth, mortality, and metamorphoses of the tadpole were measured. During research period, water quality of each aquaria were monitored. At the end, proximate analysis (protein, fat, DM, and ash) of the resulted fry was measured. The result showed that shock temperature of 35 deg. C within a period of two minutes was able to increase growth and metamorphoses of the tadpole (compared to control group). The temperature shock can be applied, either, on nearly-hatched eggs, or hatched larvae as well, with no significant impact on growth and metamorphoses of the larvae. Shock temperature of 35.0 deg. C during two minutes give the best growth of the tadpole, and increased metamorphoses approach 18 days earlier than that of the control (without temperature shock). Based on the observation, there was no abnormalities (morphologically) found during the rearing period (of tadpole, and fry, respectively). Body composition (protein, fat, and ash) of the resulted fry was relatively similar to that in control group. Treating nearly-hatched eggs or hatched larvae with temperature shock gave no significant influence on their survival rate Penelitian ini dilakukan di Laboratorium Budidaya Perikanan Fakultas Perikanan UNIBRAW Malang, pada bulan September sampai dengan Desember 1998. Tujuan penelitian ini adalah untuk mempercepat pertumbuhan dan metamorfosis kecebong katak benggala, Rana catesbeiana (Shaw). Penelitian dilakukan dalam dua unit resirkulasi sistem biofilter, masing-masing dilengkapi dengan 12 akuarium. Telur dan larva katak benggala diberi perlakuan kejut suhu masing-masing pada 27,5; 30,0; 32,5; 35,0; dan 37,5 derajat Celsius selama dua menit, dengan perlakuan kontrol (tanpa kejut suhu). Setelah larva berumur 10 hari, 300 larva diseleksi dari masing-masing perlakuan (dengan 2 x ulangan) dan didederkan pada masing-masing sistem resirkulasi. Selama masa pendederan, larva kecebong diberi pakan BF-1 (setara protein lebih kurang 40 persen). Setiap 10 hari dilakukan penimbangan bobot biomassa kecebong dan pengamatan terhadap mortalitas dan kelainan bentuk tubuh. Perhitungan metamorfosis dilakukan setelah kecebong keluar kaki belakang dan depan. Analisis data dilakukan untuk mendapatkan perlakuan terbaik terhadap laju pertumbuhan dan kecepatan metamorfosis kecebong menjadi percil. Dari hasil seri penelitian pertama, suhu terbaik dijadikan konstan dan periode kejut suhu (1, 2, 3, 4, dan 5 menit dengan perlakuan kontrol) dijadikan perlakuan. Penerapan perlakuan ini dilakukan pada stadia telur dan larva. Dengan cara yang sama seperti pada seri penelitian pertama, pengamatan dilakukan terhadap laju pertumbuhan, kecepatan metamorfosis, sintasan, konversi pakan, dan abnormalitas bentuk tubuh kecebong maupun percil. Perlakuan kejut suhu 35.0 derajat Celsius selama dua menit menghasilkan laju pertumbuhan tertinggi. Persentase metamorfosis terjadi lebih cepat 18 hari dibandingkan dengan pada perlakuan kontrol. Selama pemeliharaan, kualitas air masih dalam kisaran normal untuk pertumbuhan