Monitoring oxidative stress, immune response, Nrf2/NF-κB signaling molecules of Rhynchocypris lagowski living in BFT system and exposed to waterborne ammonia.

ABSTRACT

The present study was implemented to evaluate oxidative stress, immune response, Nrf2 and NF-κB signaling molecules related genes expression of Rhynchocypris lagowski living in biofloc technology (BFT) system and exposed to waterborne ammonia. According to the differences of CN ratios, the experiment was divided into four groups CN 10.81 (control group), CN 151, CN 20 1 and CN 251. The results demonstrated that BFT can effectively regulate water quality and promote growth, and the CN 201 group has the most significant effect (P < 0.05). Besides, significant increases in immune enzymes (lysozyme, complement C3, C4, immunoglobulin M and nitric oxide synthase) and anti-inflammatory factor (IL-2) activity of R. lagowski were emerged in the treatment CN 201 after the 56-d growth experiment and the challenging trial (P < 0.05). Comparing the antioxidant status of R. lagowski in liver and gut before and after ammonia stress superoxide dismutase, total antioxidant capacity and catalase activity in treatments CN 201 were significant increased (P < 0.05), while the level of malondialdehyde was marked lower than that in control. Meanwhile, treatment CN 201 considerably upregulated Nrf2 signaling molecules related genes and significantly down-regulated the expression of pro-inflammatory factor gene in NF-κB signaling pathway compared with the control (P < 0.05). These results indicated that BFT could enhance growth, antioxidant and immune response and regulate Nrf2 and NF-κB related genes expression in R. lagowski, with most excellent effects in fish given CN 201 group.