Abstract

The swamp eel ( Monopterus albus ) is an economically important aquaculture species in China, yet its artificial seed production is severely hindered by unclear optimal dosages and unknown molecular mechanisms of hormone-induced ovulation. To address this bottleneck, this study evaluated the dose-dependent efficacy of human chorionic gonadotropin (hCG) in inducing ovulation and investigated the underlying regulatory network. Sexually mature female swamp eels were injected with graded doses of hCG (1000–8000 IU/kg). Ovarian responses were assessed via ovulation rate monitoring, transcriptomic and metabolomic profiling, and biochemical assays. Results showed that 4000 IU/kg hCG achieved the highest ovulation rate (80%), exhibiting a clear dose–response relationship. Mechanistically, hCG significantly activated the steroid hormone biosynthesis pathway, upregulated key genes including CYP11A1, and elevated serum progesterone levels. Concurrently, hCG triggered metabolic reprogramming in ovarian tissue, enhanced energy metabolism, increased oxidative stress, and activated pyroptosis-related genes (GSDMeb, Caspase-1, IL-1β). These findings demonstrate that hCG orchestrates ovulation in swamp eel through coordinated activation of progesterone signaling, metabolic reprogramming, and pyroptosis. The identified optimal dose and mechanistic insights provide a theoretical basis for developing standardized artificial spawning protocols for swamp eel in aquaculture.