Physiology and Molecular Response Mechanisms in the Gills of Macrobrachium rosenbergii Under Acute NaHCO3 Alkaline Stress

As an important freshwater economic shrimp, Macrobrachium rosenbergii (M. rosenbergii) possesses a certain tolerance to saline/alkaline conditions. Analyzing the damage mechanism and stress response of M. rosenbergii in saline/alkaline environments will provide a scientific basis for promoting ecological restoration through the utilization of saline/alkaline water resources for aquaculture. In the first experiment, the 96 h median lethal concentration (LC50) of NaHCO3 was determined for juvenile M. rosenbergii. A second experiment then exposed the shrimp to a control group and an alkaline water group set at 60% of the established LC50. After 96 h of exposure, gill tissue samples were collected from both groups for analysis. The aim was to clarify both the damage mechanisms induced by NaHCO3 and the response mechanisms. The current results indicated that acute NaHCO3 exposure reduced antioxidant enzyme activity and induced gill tissue damage in M. rosenbergii. In response to the stress caused by NaHCO3, M. rosenbergii activated immune-related enzymes as well as immune-related differentially expressed genes involved in endocytosis, autophagy, and the toll-like receptor signaling pathway. In summary, the current research provided reference information for understanding the adverse effects caused by saline/alkaline water stress and for the breeding of M. rosenbergii in saline/alkaline water environments.