DIEL RHYTHM OF OXYGEN CONSUMPTION ON ADULT COMMON CARP Cyprinus carpio WITH CONTINUOUS 24-HOURS PHOTOPERIOD Some external factors could affect the metabolism rate of fish. One of them is photoperiod which related to the length of day and night in a day. Based on that correlation, the experiment was conducted to determine the effects of photoperiod manipulation to the diel rhythm of oxygen consumption on adult common carp Cyprinus carpio. The experimental fish (total length: 29.2 ± 0.4 cm, total weight: 1295.8 ± 56.1 g) was observed in respirometer which connected in a closed recirculation system. The study was conducted with three replications with one individu in each replication. The water temperature and closed recirculation system was maintained at 20.2 ± 0.3oC. The photoperiod was set to 24 hours light : 0 hours of dark by using fluorescent lamp which lit continuously. The results showed that during 24 hours observation at 24 hours light: 0 hours dark condition, adult common carp has an oxygen consumption range of 24.5 - 29.1 mg O2/kg/h at 20oC. The average value of the lowest oxygen consumption occurred at 02.00 and 17.00 (24.5 ± 1.9 mg O2/kg/h). Meanwhile, the highest oxygen consumption value was recorded at 06.00 (29.1 ± 1.7 mg O2/kg/h). Based on data of oxygen consumption obtained from this study, no significant difference found between oxygen consumption of adult common carp during day and night with photoperiod manipulation. The activity and metabolism of adult common carp have changed with the change of photoperiod.Keywords: Common carp, Cyprinus carpio, oxygen consumption, photoperiod. ABSTRAK Beberapa faktor eksternal dapat mempengaruhi laju metabolisme pada ikan. Salah satu diantaranya adalah fotoperiode yang berkaitan dengan lamanya siang dan malam dalam satu hari. Berdasarkan korelasi tersebut, maka dilakukan penelitian untuk mengetahui pengaruh manipulasi fotoperiode terhadap ritme harian konsumsi oksigen pada induk ikan mas Cyprinus carpio. Ikan uji (panjang total 29,2 ± 0,4 cm; bobot total 1295,8 ± 56,1 g) diamati di dalam respirometer yang terhubung dalam sistem resirkulasi tertutup. Penelitian dilakukan dengan tiga ulangan dengan masing-masing jumlah induk ikan sebanyak satu ekor. Suhu air dan sistem resirkulasi tertutup diatur pada suhu 20,2 ± 0,3oC. Fotoperiode diatur pada kondisi 24 jam terang : 0 jam gelap dengan menggunakan lampu fluorescent yang dinyalakan secara kontinyu. Hasil penelitian menunjukkan bahwa selama pengamatan 24 jam kondisi 24 jam terang : 0 jam gelap, induk ikan mas memiliki kisaran konsumsi oksigen sebesar 24,5 - 29,1 mg O2/kg/jam di 20oC. Nilai rata-rata konsumsi oksigen terendah terjadi pada jam 02.00 dan 17.00, yaitu 24,5 ± 1,9 mg O2/kg/jam. Sedangkan nilai konsumsi oksigen tertinggi tercatat pada jam 06.00, yaitu 29,1 ± 1,7 mg O2/kg/jam. Berdasarkan data konsumsi oksigen yang diperoleh dari penelitian ini, tidak ditemukan adanya perbedaan nyata antara konsumsi oksigen induk ikan mas saat siang dan malam hari dengan adanya manipulasi fotoperiode. Aktivitas dan metabolisme induk ikan mas mengalami perubahan dengan adanya perubahan fotoperiode.Kata kunci: Ikan mas, Cyprinus carpio, konsumsi oksigen, fotoperiode.
The utilization of rapeseed expeller for carp (Cyprinus carpio) diets
