Comparison of immune defense and antioxidant capacity between broodstock and hybrid offspring of juvenile shrimp (Macrobrachium nipponense): Response to acute ammonia stress

Abstract

Ammonia is a major environmental pollutant in the aquatic system that poses a great threat to the health of shrimp. Macrobrachium nipponense, as one of the large‐yield farmed shrimp, is facing germplasm degradation. Genetic improvement through hybridization is one of the effective methods to solve this problem. However, there are few studies on the effects of ammonia nitrogen on the germplasm resources of M. nipponense. In this study, the broodstock populations (Dianshan, DS) and hybrid offspring (DS ♀ × CD [Changjiang, CJ ♂ × Dongting, DT ♀], SCD) were exposed to 0, 5, or 20 mg/L of ammonia for 96 h. The survival rate of the SCD group was greater than the DS group, although there were no significant differences in weight gain rate and length gain rate (p > 0.05). The number of positive cells and apoptosis rates in the DS group were significantly greater than in the SCD group after ammonia exposure (p < 0.05). As the ammonia concentration increased, the antioxidant enzyme activities in the SCD group were significantly higher than DS group, while the hepatotoxicity enzyme activities in the SCD group were significantly lower than DS group (p < 0.05). The trends in the expression of antioxidant‐ and immune‐related genes were generally consistent with the activities of antioxidant enzymes. Our study found that the hybrid population had stronger stress resistance than their parent populations at the same ammonia concentration. This study confirms our speculation that hybrid population has a greater advantage in antioxidant immunity, which also provides reference for the follow‐up study of chronic ammonia toxicity.

Comparison of detoxification capacity between broodstock and hybrid offspring in the gills of juvenile shrimp ( Macrobrachium nipponense ): Response to chronic ammonia stress

“…The pre‐experiment results showed that the 96‐h ammonia LC50 values in the DS and SCD juvenile shrimp groups were 27.758 and 30.958 mg/L, and the 95% confidence intervals were 12.784–48.602 and 16.943–51.462 mg/L, respectively (Li et al, 2022). Hence, the TAN concentrations were set at 0, 1 and 10 mg/L for the chronic experiments.…”