Phenotypic characterization and hepatopancreatic transcriptomics reveal the regulatory mechanisms of precocious...

Precocious maturation is a challenge in Macrobrachium nipponense culture, leading to reduced yields and germplasm degradation. However, the regulatory mechanisms underlying this phenomenon remain uncharacterized. In this study, precocious individuals were identified during a five-month culture encompassing broodstock selection and larval rearing. The precocious group exhibited significantly lower body length, body weight, and fecundity (P < 0.05), with the precocious individuals accounting for approximately 13.56% of the population. Comparative transcriptomic analysis of the hepatopancreas identified 373 differentially expressed genes (DEGs), comprising 201 upregulated and 172 downregulated genes. Functional enrichment analysis highlighted three key reproductive development-related pathways: MAPK, estrogen, and Wnt signaling. Within these pathways, AP-1 was consistently downregulated, while MKNK1-like and HSP70-like exhibited pathway-specific expression patterns (downregulated and upregulated, respectively). These findings, validated by qRT-PCR, suggest a cross-pathway "transcription-translation dual-gate" suppression mechanism. This mechanism likely facilitates the physiological transition from a high-biosynthesis state before precocity to a state of homeostatic maintenance. The results provide a valuable reference for future research on the reproductive regulation of M. nipponense.