Effects of dietary selenium on growth performance, antioxidative status and tissue selenium deposition of juvenile Chu's croaker (Nibea coibor)

Selenium (Se) is an essential antioxidative trace element for animals. Proper dietary Se supplementation could promote growth and antioxidative ability of fish species, especially for those under oxidative stress caused by high-density aquaculture model. However, the narrow safety rage between deficiency and toxicity doses of Se complicates its use for supplementation purpose. Here, we reported the effects of dietary Se supplementation with sodium selenite (0.21, 0.53, 0.79, 1.11, 1.45 and 1.72 mg Se/kg diet, P1?P6) on the growth performance, antioxidative status and tissue Se deposition of an important marine economic fish, Chu?s croaker (Nibea coibor). After an 8-week feeding trial, it was demonstrated that the dietary Se supplementation (P1?P3) significantly improved the weight gain of the fish, while a decreased trend of weight gain was observed at higher Se sup-plementation levels (P4?P6). The activities of glutathione peroxidase (GPx) in serum and liver significantly increased with the increasing Se levels. While, the activities of superoxide dismutase (SOD) and catalase (CAT) firstly increased and then decreased with the increasing Se levels, with highest value presented in P4 and P3 group, respectively. The trends of malondialdehyde (MDA) content in serum and liver were opposite to those of CAT, with lowest value in P3 group. Similar to their enzyme activity counterparts, the mRNA expression of GPx1, SOD1 and SOD2 in liver were also significantly affected by the dietary Se levels. Furthermore, it was shown that Se contents in liver, muscle and swim bladder linearly increased with the dietary Se levels, with the Se accu-mulation efficiency of liver > muscle > swim bladder. It can be concluded that a dietary Se supplementation of 0.74 mg/kg is suggested for the aquaculture of juvenile N. coibor, based on the weight gain, antioxidative enzyme activities/expression and tissue Se accumulation.