Integrated Transcriptomic and Metabolomic Analysis Reveals the Regulatory Mechanisms of Macrobrachium rosenbergii in Response to Acute High-Salinity Stress.

Salinity fluctuations pose a severe threat to the survival and physiological homeostasis of freshwater crustaceans. Here, an integrated transcriptomic and metabolomic approach was utilised to characterise the dynamic regulatory responses in the hepatopancreas of adult Macrobrachium rosenbergii subjected to acute high-salinity stress (20‱). The number of differentially expressed genes (DEGs) and metabolites (DMs) increased from 24 to 48 h, signalling a transition from an initial acute stress reaction to systemic homeostatic remodelling. At the molecular level, M. rosenbergii activated autophagy (Atg8a) and p53 (TP53INP) signalling, alongside the reprogramming of lipid and nucleotide metabolism. Pathway analysis identified "alanine, aspartate, and glutamate metabolism" as a central regulatory node. Notably, the downregulation of the glutamate dehydrogenase gene (Gdh) alongside the accumulation of L-glutamate suggests a potential transcriptional-metabolic decoupling phenomenon, wherein the organism appears to prioritise the conservation of critical osmoregulatory effectors over their oxidative degradation. These findings detail the systemic adaptive responses of M. rosenbergii to salinity fluctuations, providing candidate targets for the selective breeding of stress-resilient crustacean strains.