A respirometer system to measure critical and recovery oxygen tensions of fish under simulated diurnal fluctuations in dissolved oxygen

作者：Mamun Shamsuddin Mohammed^*; Focken Ulfert; Becker Klaus

来源：Aquaculture International, 2013, 21(1): 31-44.

DOI：10.1007/s10499-012-9529-1

• Dissolved oxygen-controlled respirometer system
• Critical oxygen tension (P-c)
• Recovery oxygen tension (P-r)
• Diurnal dissolved oxygen fluctuations

We describe a computer-operated recirculating respirometer system (ca. 140 L water) with six respirometer chambers and a reference chamber (L x W x H: 26 cm x 12 cm x 20 cm; volume 6.24 L) that simulates diurnal dissolved oxygen (DO) fluctuations normally occur in aquaculture ponds. A gas-mixing device, "Digamat" proportionately dissolves gaseous nitrogen and oxygen (and if desired, carbon dioxide) in water to achieve DO levels from 1.0 to 40.0 kPa (0.3-14.0 mg L-1) at different temperatures. A series of computer-operated valves sequentially allow water from respirometer chambers to a single oxygen probe to measure DO concentration. Oxygen consumptions of fish as the differences in DO concentrations between respirometer and reference chamber are used to calculate different metabolic rates (standard, routine, and active), and critical (P (c)) and recovery (P (r)) oxygen tensions of individually reared unfed and fed fish. An experiment was conducted to evaluate the ability of the system to measure metabolic parameters for individually reared Nile tilapia (Oreochromis niloticus L.) at three temperatures (low: 22.5, optimum: 27.5 and high: 33.5 A degrees C). The fed fish had significantly higher P (c) and P (r) values at optimum and high temperatures than unfed fish. At low and high temperatures, both fed and unfed fish had higher P (c) and P (r) than at optimum temperature. The standard metabolic rate was significantly higher at higher temperatures (44.9, 51.7, and 77.7 mg O-2 kg(-0.8) h(-1) at 22.5, 27.5, and 33.5 A degrees C, respectively).

• 出版日期2013-2