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.…”

Differential Toxicity Responses between Hepatopancreas and Gills in Litopenaeus vannamei under Chronic Ammonia-N Exposure

“…The most common dissolved inorganic nitrogen ions include ammonia-N, nitrite-N, and nitrate-N, which are interrelated via the nitrification cycle [4]. A previous study reported that ammonia-N was usually converted to nitrite-N and then to nitrate-N by aerobic chemoautotrophic bacteria, such as Nitrosomonas and Nitrobacter [5], and finally to N 2 via aerobic denitrification [6]. Ammonia is an essential and low-life-sustaining nutrient for marine phytoplankton [7].…”

“…High concentrations of ammonia lead to the pollution of aquatic water, reducing growth rates [11], affecting osmoregulation [2], causing cellular toxicity [12], increasing the susceptibility of aquatic organisms to infection [13], and even resulting in mortality. Additionally, ammonia affects the profusion and physiological conditions of different aquatic animals; among them, the decapod crustaceans are particularly vulnerable to it due to the toxic effect of ammonia, which can influence survival, metabolism, immune function, and oxidative stress [5,14,15].…”

“…At the same time, Zhang et al also pointed out that the hepatopancreas could reserve lipids and synthesize and secrete digestive enzymes [25]. Li et al suggested that chronic exposure to ammonia-N damaged the structure and disturbed the lipid metabolism of the hepatopancreas in shrimp [5]. Zhu et al reported that the hepatopancreas contained superoxide dismutase (SOD) and catalase (CAT), which are related to physiological metabolism and immune reactions in the antioxidant defense system [26].…”