Metabolic Changes in Scylla paramamosain During Adaptation to an Acute Decrease in Salinity

Hongzhi Yao,Guoling Liang,Xing Li,Chunlin Wang,Gao Gao,Huan Wang,Yuhao Chen,Changkao Mu

doi:10.3389/fmars.2021.734519

Abstract

The mud crab Scylla paramamosain is an important euryhaline mariculture species. However, acute decreases in salinity seriously impact its survival and can result in large production losses. In this study, we evaluated metabolic changes in S. paramamosain exposed to an acute salinity reduction from 23 psu to 3 psu. After the salinity decrease, hemolymph osmolality declined from 726.75 to 642.38 mOsm/kg H2O, which was close to the physiological equilibrium state. Activities of osmolality regulation-related enzymes in the gills, including Na+-K+-ATPase, CA, and V-ATPase all increased. Using LC-MS analysis, we identified 519 metabolites (mainly lipids). Additionally, 13 significant metabolic pathways (P &lt; 0.05) were identified via enrichment analysis, which were mainly related to signal pathways, lipids, and transportation. Our correlation analysis, which combined LC-MS and previous GC-MS data, yielded 28 significant metabolic pathways. Amino acids and energy metabolism accounted for most of these pathways, and lipid metabolism pathways were insignificant. Our results showed that amino acids and energy metabolism were the dominant factors involved in the adaptation of S. paramamosain to acute salinity decrease, and lipid metabolites played a supporting role.

Highlights

Changes in salinity impact the growth (Nurdiani and Zeng, 2007), immunity (Péqueux, 1995), and disease status (Parado-Estepa and Quinitio, 2011) of crustaceans
Na+-K+-ATPase activity in the gills, which is responsible for osmolality regulation, continuously increased from 0 to 6 h to reach 31.53 U/mL and decreased from 24 h to reach the physiological equilibrium state (24.28 U/mL)
Using liquid chromatography-mass spectrometry (LC-MS) technology, we identified 519 differential metabolites, and 63 metabolic pathways were identified by KEGG enrichment analysis of differential metabolites

Summary

Introduction

Changes in salinity impact the growth (Nurdiani and Zeng, 2007), immunity (Péqueux, 1995), and disease status (Parado-Estepa and Quinitio, 2011) of crustaceans. Inorganic ions and amino acids are the main factors that impact osmolality in crustaceans (Pan et al, 2007; Romano and Zeng, 2012; Long et al, 2018). Muscle is the main source of amino acids (Dooley et al, 2000; Mcnamara et al, 2004), which are the main substances responsible for maintaining cellular osmolality. They play an important role in the Metablic Changes During Salinity Adaption process by which crustaceans adapt to changes in salinity (Shinji et al, 2012; Lv et al, 2013). Previous studies have shown that the amino acids produced in muscle supplemented the hemolymph to help maintain the osmolality balance in a hypotonic environment (Lu et al, 2015)

Results

Discussion

Conclusion