Metabolomics-based study on the mechanism of cold-induced stress response in waterless-preserved live Crassostrea hongkongensis

During ecological ice-temperature preservation, the survival rate of Hong Kong oysters fluctuates, leading to a change in quality. This transformation process involves a series of metabolic response mechanisms. Using metabolomics technology, we conducted an in-depth analysis of the entire process's mechanisms through subtle molecular changes. Fresh oysters served as the control group, while the experimental group underwent 24-hour purification before being placed in an ecological ice-temperature environment for 9 days of preservation. Results revealed a declining trend in crude protein content, decreasing from 7.43 % to 6.71 %. After 9 days of preservation,crude fat content decreased by 41.88 % compared to pre-preservation levels, while glycogen content dropped from 19.74 mg/g to 13.51 mg/g. This indicates that fat and glycogen, as primary energy reserves, were depleted first. Differentially expressed metabolites were primarily concentrated in these pathways: amino acid biosynthesis; cysteine and methionine metabolism; arginine and proline metabolism. Useing qRT- PCR experiments validated the accuracy of the metabolomics results. Collectively, these findings indicate that the organism shifts energy acquisition toward amino acid and nucleotide metabolic pathways to sustain normal physiological activities. Concurrently, it activates antioxidant defense systems, regulatory mechanisms protecting against oxidative stress damage during stress exposure, providing theoretical support for waterless live transport of shellfish. • Low temperature and water deficit rapidly deplete fat and glycogen reserves in Crassostrea hongkongensis. • Further metabolomic analysis elucidated how amino acid and energy metabolism regulate these variations. • Differential metabolic genes were validated by qRT-PCR to confirm the omics results. • Visualization of the stress-related physiological regulatory mechanisms was presented in a diagram.