Effects of Taurine and Vitamin C on the Improvement of Antioxidant Capacity, Immunity and Hypoxia Tolerance in Gibel Carp (Carrassius auratus gibeilo)

To investigate the effects of taurine and vitamin C on gibel carp (<i>Carrassius auratus gibeilo</i>), fish (41.85 ± 0.03 g) were fed three diets with 0% taurine + 0% vitamin C (D0), 0.1% taurine + 0% vitamin C (D1), and 0.1% taurine + 0.1% vitamin C (D2) for 8 weeks. Then 12-hour hypoxic stress test was conducted. The results showed that weight gain rate (WGR), specific growth rate (SGR), and sustained swimming time (SST) were significantly increased in the D2. CAT, SOD, T-AOC, and GSH were increased. GSH-Px and <i>il-6</i> were decreased in D1 and D2. In hypoxia, CAT and T-AOC were decreased, while GSH, <i>sod</i>, and <i>nrf2</i> were the highest in D1. Compared to normoxia, GSH-Px was increased, while SOD and MDA were decreased. <i>Il-10</i> and <i>nf-κb</i> were increased. <i>Vegf</i>, <i>epo</i>, and <i>ho-1</i> were increased and they all were higher than that in normoxia. The number of gill cell mitochondria and survival rate (SR) of gibel carp had an increasing trend but no significant difference among groups. In conclusion, taurine with vitamin C improved the growth and SST of gibel carp, and taurine and taurine with vitamin C improved antioxidant capacity, immunity, and hypoxia tolerance.