Physiological and Whole Blood Transcriptome Signatures Associated with Post-Release Residence in Female Yangtze Sturgeon (Acipenser dabryanus)

Abstract

Yangtze sturgeon is a rare and endemic sturgeon in China whose population restoration depends heavily on artificial propagation and stock enhancement. However, the physiological status of hatchery-origin broodstock after prolonged residence in natural river environments remains poorly understood. We integrated serum biochemistry, reproductive hormone measurements, and whole blood transcriptomics to compare six wild-recaptured females approximately two years after release with six captive females sampled during the expected breeding season. Compared with captive-reared females, released–recaptured females showed significantly lower serum glucose, triglycerides, albumin, total protein, total cholesterol, and estradiol (E2), but higher total antioxidant capacity (T-AOC). Transcriptomic analysis revealed 197 differentially expressed genes (DEGs), among which 91 were upregulated and 106 were downregulated. Functional enrichment revealed changes in ribosome- and oxidative phosphorylation-related genes, reproductive endocrine-associated pathways including Hedgehog and GnRH signaling, redox-related pathways including ferroptosis and peroxisome, and several immune-related pathways. Marked upregulation of ceruloplasmin, together with altered hemoglobin-related transcripts and ferroptosis-associated enrichment, is consistent with altered iron/redox homeostasis in the blood, rather than direct evidence of ferroptotic injury. Overall, the wild-recaptured females exhibited a distinct physiological profile in serum and blood, characterized by altered energy metabolism, reproductive endocrine status, antioxidant regulation, and immune-related transcriptional profiles. These findings provide candidate blood-based indicators for future non-lethal monitoring of released Yangtze sturgeon, although tissue-specific mechanisms require further validation.