Acute stress response in gill of Pacific white shrimp Litopenaeus vannamei to high alkalinity

As a multifunctional organ, the gill plays a key role in the regulation of homeostasis. Excessive alkalinity in water can seriously threaten the survival of aquatic animals, however, the studies on the mechanism of alkalinity stress and adaption of crustacea are still limited. In this study, we aimed to investigate the mechanisms of acute alkalinity stress in the gill of Pacific white shrimp Litopenaeus vannamei by integrating physiological, histological, transcriptome, and metabolome analyses, which is an important aquaculture species of crustaceans. The physiological parameters related to homeostasis regulation, oxidative stress, material metabolism, and ammonia detoxification were significantly changed under acute alkalinity stress. There were a considerable number of genes and metabolites that were significantly changed in expression and level, which related to glycolysis/gluconeogenesis, fatty acid metabolism, amino acid metabolism, antioxidation, ammonia metabolism, and glycerophospholipid metabolism, In addition, the local structure of the gill was damaged and accompanied by cell apoptosis. The above results indicate that acute alkalinity stress can lead to damage to the gill structure, and affect its ion transport function, and the genes related to ion transport protein were upregulated. The antioxidant capacity in the gill was strengthened under acute alkalinity stress, at the same time, acute alkalinity stress would induce apoptosis in the gill. The glycogen catabolism in gill was significantly enhanced under acute alkalinity stress, while the lipid anabolism was inhibited, and the mechanism of the ornithine-urea cycle has been further mobilized to alleviate the inhibition of ammonia excretion and the accumulation of metabolic ammonia in the internal environment. In addition, the glycerophospholipid metabolism in the gill was disturbed under acute alkalinity stress. The current study will provide important clues for understanding the alkalinity stress mechanism of crustaceans, and provide an important theoretical basis for the optimization of shrimp aquaculture in saline-alkaline waters.