Oxygen consumption of barred loach Nemacheilus fasciatus (Valenciennes, 1846) on different temperatures

Abstract

This study aims to investigate the effects of temperature regimes on oxygen consumption of barred loach Nemacheilus fasciatus. Three experimental groups were set to measure oxygen consumption (OC) of the rearing fish (Length: 6.14 0.4 cm; Weight: 1.46 0.05 g) on different temperatures (21.5, 26.5, and 31.5C) with six replicates. Fish were adapted in an aquarium before stocked and observed in a closed respirometer system (Stocking density: 10 fish/L; Respirometer volume: 1.4 L). Barred loach consumed 365.9, 320.9, and 298.4 mg O2/kg/h at 21.5, 26.5, and 31.5C indicating that the OC decreased gradually with increasing water temperature. However, oxygen consumption of barred loach did not change significantly within the temperature range from 21.5 to 31.5C. The ventilation rate of barred loach increased from 115.0 8.9 to 265.2 42.5 times/min between 21.5 and 31.5C. Oxygen consumption per breath of barred loach was higher at a lower temperature (3.18 0.63, 2.11 1.22, and 1.13 0.57 mg O2/kg/breath at 21.5, 26.5, and 31.5C) (P<0.05). In terms of Q10, the lowest value was found between 26.5 - 31.5C with a value of 1.16. The thermal range was a comfort zone for barred loach to maintain their metabolic efficiency.