Oxidative Stress and Antioxidant Defenses after Long-term Fasting in Blood of Chinese Sturgeon (Acipenser sinensis)

The effects of long-term fasting on the oxidative stress and antioxidant defenses in juvenile Chinese sturgeon (Acipenser sinensis) were studied. The oxidative stress biomarkers included lysozyme (LSZ), the ability of inhibiting hydroxyl radicals (AIHR), and total antioxidant capacity (T-AOC). The juvenile Chinese sturgeon were fasted for 24 hours at first. Blood samples were taken from fish a total of 8 times, upon sampling every 6 days during the remaining 48-day starvation period. The LSZ activity of juveniles generally increased as the starvation time increased. Furthermore, a significant difference in the LSZ activity of juveniles starved for 43 days was found compared with four groups starved for 1–19 days. In addition, the AIHR of juveniles first increased and subsequently decreased over the course of starvation. Specifically, the AIHR of juveniles was significantly higher in fish after 19 days of starvation than in fish sampled after 37 days of starvation, although there were no other significant differences among the levels for the other groups. The variation of the T-AOC levels of juveniles was higher during the earlier stage of starvation, and was decreased after 19 days of starvation. However, there were no significant differences among the T-AOC groups, except the T-AOC of juveniles starved for 13 days was significantly higher than that of fish starved for 37 days. It's concluded that long-term fasting influenced the antioxidant capability of juvenile Chinese sturgeon.