Protective effect of dietary dandelion (Taraxacum officinale) extract on common carp under acute ammonia stress

Abstract

This study examined the remedial effect of dandelion extract (DE) on acute ammonia stress in common carp. The experiment involved supplementing the common carp diet with five DE dozes, including 0 (control), 2%, 4%, 6%, and 8% DE to the basic feed for 56 days. Then, all the fish were exposed to semile thal ammonia stress (1.65 mg/L) for 96 h, followed by detections the indexes of mortality, blood biochemistry, antioxidation, immunity, stress, and inflammation. The results showed that dietary DE increased the serum protein content and antioxidant enzyme activity of common carp ( P < 0.05). However, DE did not significantly affect the contents of stress hormone, HSP70 and HSP90 (p > 0.05). Exposure to ammonia significantly decreased the activities of immune and antioxidant enzymes in the control group. The serum protein content and immune enzyme activity of each DE group were significantly higher than the control group. After ammonia exposure, IL-1β, IL-6, IL-8, TNF-α, and IFN-γ activities in DE groups were significantly lower then the Ctrl group，and IL-10 and antioxidant enzyme activities in 4% DE, 6% DE, and 8% DE groups was significantly higher compared to the Ctrl ( P < 0.05). Ammonia stress caused pathological damage to the liver tissue in control, 2% DE, 4% DE, and 8% DE groups, but the liver tissue of the 6% DE group showed normal tissue characteristics. Therefore, DE has a protective effect on common carp under acute ammonia exposure. Optimal doses of DE can improve the survival rate, antioxidant capacity, and nonspecific immunity, while can reduce the stress and inflammatory reaction of common carp caused by acute ammonia exposure. The second-order multiple regression analysis of TP, COR, LZM, T-AOC, mortality, and immune protection after ammonia stress showed 4.62–6.82% as the optimal level of dietary DE supplementation for carp under acute ammonia stress.