Effects of O2 supersaturation on metabolism and growth in juvenile turbot (Scophthalmus maximus L.)

Abstract

Effects of O2 supersaturation on metabolism and growth were studied in juvenile turbot (Scophthalmus maximus L.). When fish were reared for 30 days in water containing O2 at 147% or 223% air saturation, there were no significant differences in food intake, growth, food conversion or protein utilization compared to fish exposed to normoxia (100% air saturation in water outlet). Exposure to hyperoxia resulted in increased body fat deposition. Daily rates of O2 consumption of resting fish were not affected by O2-concentrations, and there were no significant differences in rates of nitrogenous excretion among fish exposed to the different O2-concentrations. Turbot tolerated severe hyperoxia, 350% air saturation, for 10 days. There were changes in acid-base balance that compensated for the respiratory acidosis resulting from O2 supersaturation. Blood pH was regulated within 24 h (it averaged 7.69 over the 30-day experiment) by significant increases in plasma CO2 content and pCO2. Plasma CO2 was dose dependent averaging 11.3 and 18.9 mmol l−l under 147% and 224% O2 saturation, respectively, compared to 6.7 mmol l−l under normoxia. Over the 30-day experiment, the only change in hydromineral balance was a slight, but non-significant decrease in plasma chloride content in fish exposed to hyperoxia (137 mmol l−l compared to 139 under normoxia). There were no changes in haematocrit, haemoglobin and red blood cell counts (they averaged 18.3%, 3.7 g dl−1 and 1.37×106 mm−3, respectively) and no signs of stress (plasma cortisol averaged 3.8 ng ml−1) related to exposure to O2-supersaturation for 30 days.

Effects of repeated hypoxic shocks on growth and metabolism of turbot juveniles

“…The present work provides additional data on the growth performance of turbot reared under moderate hypoxic conditions, as previous studies focused either on higher oxygen depletion or hyperoxic conditions (Pichavant et al, , 2001Person-Le Ruyet et al, 2002). It showed that the threshold concentration for significant reduced growth is about 5-5.5 mg O 2 l -1 in juveniles of turbot.…”

Environmental variability in seagrass meadows: effects of nursery environment cycles on growth and survival in larval red drum Sciaenops ocellatus

“…In fishes, hyperoxia causes transient acid-base imbalances (Wood & LeMoigne 1991) as the fishes hypoventilate. However, there is no evidence in the literature that DO levels above saturation result in significant growth impairment (Caldwell & Hindshaw 1994, Person-Le Ruyet et al 2002, Foss et al 2003. In the present study, the cumulative amount of time that fish were exposed to hypoxia in the laboratory was probably the cause of growth reduction in the laboratory experiments.…”

Growth rate, catalase and superoxide dismutase activities in rock carp (Procypris rabaudi Tchang) exposed to supersaturated total dissolved gas

“…Gunnarsli et al (2008b) indicated, however, that no effects of nitrogen gas supersaturation were found on the growth of Atlantic cod (Gadus morhua L.) reared for seven weeks. The report discribed by Person-Le Ruyet et al (2002) also demonstrated that no substantial increase in growth of turbot occurred when the turbot were reared for 30 d in O 2 -supersaturated and saturated water. However, in the study by Krise (1993), growth rate reductions were obvious when lake trout were exposed to gas supersaturation for more than 252 d with a gas pressure ΔP=17 mmHg.…”