Based on metabolomics analysis: metabolic mechanism of intestinal tract of Scylla paramamosain under low-salt saline-alkali water aquaculture environment.

Background: In recent years, the total production of mud crab Scylla paramamosain has been declining, and the breeding areas are faced with land shortage and shortage of breeding production, which needs to be solved urgently. S. paramamosain can survive and grow in a wide range of salinities is an excellent variety suitable for saline-alkali water aquaculture. As a species with high economic value and strong adaptability to the environment, its cultivation under low salt conditions can not only improve the utilization efficiency of saline-alkali land, but also provide new possibilities for the sustainable development of aquaculture.

Results: A total of 248 different metabolites were identified by LC/GC-MS in the intestinal tract of S. paramamosain. These different metabolites were mainly concentrated in 'Lipids and lips-like molecules'. Among them, 112 metabolites are upregulated, and among these upregulated metabolites are mainly 'Fatty Acyls' and 'Glycerophospholipids'. The upregulation of these metabolites indicates an increase in lipid storage of S. paramamosain, which may increase the resistance of S. paramamosain to adverse environmental stress. Among them, 136 metabolic differentiates were down-regulated, mainly 'Carboxylic acids and derivatives'. The down-regulation of these organic acids may indicate that organic acids are used as energy sources for the immune response to long-term environmental stress.

Conclusion: Under long-term chloride type low-salt saline-alkali water stress, S. paramamosain will shift to another homeostasis for development.