Oxidative stress in juvenile tambaqui (Colossoma macropomum) after different periods of air exposure

This study evaluated the response of juvenile Colossoma macropomum to oxidative stress when exposed to air for different periods of time. Fifty-four juveniles weighing 74.8 ± 17.4 g were randomly transferred to nine 30-L tanks in a recirculating aquaculture system and acclimatized to experimental conditions for 15 days. The fish were subsequently fasted for 24 h, after which a group of animals (n = 6) was sampled immediately at the beginning of the experiment to determine baseline levels (without air exposure). Another group (n = 24) was exposed to air for 30 min (30E) and the rest of the fish (n = 24) were exposed to air for 60 min (60E). Oxidative damage and antioxidant defenses were determined immediately after air exposure (IAE; n = 6) and at 1, 24 and 48 h after air exposure (1hAE, 24hAE, and 48hAE; n = 6 animals/per exposure time) by euthanizing fish and immediately removing the gills, liver, kidney, and brain. The interaction between factors (air exposure time x collection time) had an effect on reduced glutathione in the liver (P