Evaluation of chronic and acute hypoxia stress on the immune and antioxidant system of Common carp in biofloc system

Hypoxia stress is an unfavorable environmental condition for fish that can have several effects on immunity and antioxidant. The aim of the present study investigated the impact of hypoxia stress (Chronic; 2 to 2.5 mg/L for 36 hours) and (acute; 0.013 and 0.017 mg/L for 1.5 hours) compared to control (6 to 7 mg/L) on survival, immune and oxidative status Common carp (Cyprinus carpio) in biofloc conditions. In the first stage, the fish (21.90 ± 0.75 g) were stored in 9 tanks (50 liters) in the biofloc system for 7 weeks. In the second stage, the fish were subjected to hypoxia stress (chronic and acute) and control (normoxia). After hypoxia stress, serum lysozyme, total immunoglobulin, and ACH50 activities were significantly lower, and red blood cells (RBC), hemoglobin, and hematocrit were higher in chronic and acute stress treatments. The activity of SOD, CAT, and GPX in the fish serum exposed to hypoxic stress was significantly reduced compared to the control. In general, the results show that both chronic and acute hypoxic stress weakened the blood parameters of common carp in the biofloc system.