Histological, Physiological and Transcriptomic Analysis Reveal the Acute Alkalinity Stress of the Gill and Hepatopancreas of Litopenaeus vannamei

The pacific white shrimp (Litopenaeus vannamei) has gradually become a promising economic species in the development of saline-alkali water fishery. The study related to the stress reaction of pacific white shrimp under alkalinity stress is still limited, which is also a critical limiting factor for its saline-alkaline aquaculture. In this study, we aim to analyse the stress reaction of pacific white shrimp under acute alkalinity stress between control group (alkalinity:40 mg/L) and treatment group (alkalinity:350 mg/L) through histological observation, physiological determination and transcriptome. In the present study, during the process of acute alkalinity stress, the activities of Na+-K+-ATPase, carbonic anhydrase, sodium/hydrogen exchanger in gill related to homeostasis were significantly changed, the activities of superoxide dismutase and catalase related to antioxidant were decreased in both gill and hepatopancreas, and the activities of protease, lipase and amylase in hepatopancreas were decreased. At the same time, different degrees of histological damages were occured in the gill and hepatopancreas under acute alkalinity stress. There were 194 and 236 different expressed genes identified in gill and hepatopancreas respectively. Functional enrichment assessment indicated that the alkalinity stress-related genes in both gill and hepatopancreas were primarily involved in fatty acid metabolism, glycolysis/gluconeogenesis, glycerophospholipid metabolism. The results indicated that the functions of homeostasis regulation, antioxidation and digestion of pacific white shrimp were decreased under acute alkalinity stress, at the same time, the energy metabolism in gill and hepatopancreas were modified to cope with alkalinity stress. This work provides important clues for understanding the response mechanism of pacific white shrimp under acute alkalinity stress.