Multi-omics dissection of large-size formation in Eriocheir sinensis: Insights from RNA, metabolite profiling, and ceRNA regulatory networks.

Eriocheir sinensis (Chinese mitten crab) is a key economic species in China's freshwater aquaculture industry. Individual body size is a critical trait that determines both market price and production profitability. Large-sized crabs exhibit substantial commercial advantages; however, the underlying molecular mechanisms regulating size formation remain poorly understood. In this study, we conducted an integrative multi-omics analysis combining whole-transcriptome data (mRNA, miRNA, and lncRNA) and untargeted metabolomics across two aquaculture cohorts (cohort2023 and cohort2024). Our results revealed a systemic downregulation of glycolysis, the tricarboxylic acid (TCA) cycle, fatty acid oxidation, and glycerol metabolism in large-sized crabs, suggesting a "low consumption-high storage" metabolic strategy. In contrast, pathways related to organismal development, exoskeleton reconstruction, steroid hormone biosynthesis, and nutrient absorption were significantly upregulated, indicating enhanced growth potential and nutrient assimilation efficiency. ceRNA network modeling and cis-acting lncRNA analysis identified multiple core regulatory genes (e.g., PTGS1, TPI1, POR) as targets of complex non-coding RNA interactions involved in body size regulation. Enzyme activity assays for key rate-limiting steps in carbohydrate and lipid catabolism, along with extensive qPCR validation, further corroborated the transcriptomic findings. Taken together, our study provides the first comprehensive multi-omics perspective on the molecular basis of body size differentiation in E. sinensis, proposing a tripartite mechanism involving suppressed catabolism, stimulated growth and morphogenesis, and improved nutrient acquisition. These findings offer theoretical insight into crustacean growth regulation and provide molecular targets to support selective breeding of high-value, large-sized mitten crab strains.