Antioxidant enzyme activities in Pacific white shrimp (Litopenaeus vannamei) in response to environmental hypoxia and reoxygenation

Hypoxia–reoxygenation represents a relevant physiological challenge for shrimp culture. The sudden input of oxygen (O2) after environmental hypoxia increases reactive oxygen species (ROS) production in Pacific white shrimp (Litopenaeus vannamei). It has been postulated that a relatively high activity of the main antioxidant enzymes allows several adapted invertebrate species to survive repetitive cycles of hypoxia–reoxygenation by counteracting ROS production and, thus, preventing oxidative stress. In this study, we evaluated the activity of the antioxidant enzymes superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx) in extracts of muscle and hepatopancreas from white shrimp exposed to short-term (24 h) hypoxic conditions (1 mg L− 1 of dissolved O2), and subsequent reoxygenation cycles (1 to 5 h, in 1 h intervals). Results show differences in antioxidant enzyme activities among tissues, even under control conditions. SOD activity was higher in muscle than in hepatopancreas whereas CAT and GPx activities were higher in hepatopancreas. In muscle, SOD activity was higher during hypoxia and lower after 1 h of reoxygenation. In hepatopancreas, antioxidant enzyme activities were higher during hypoxia and lowest in the first hour of reoxygenation. Significant changes in SOD, CAT and GPx activities were also observed in both tissues after 1 h and 2 h of reoxygenation suggesting that hypoxia–reoxygenation affects the antioxidant enzymes. These changes in antioxidant enzyme activities in response to hypoxia–reoxygenation may be crucial to avoid oxidative damage and to preserve the quality of the aquaculture product.