Stage-Dependent Heat-Stress Mechanisms in Chinese Sturgeon (Acipenser sinensis) Early Life-Stages Under Simulated Thermal-Lag Effect.

Hydraulic engineering-driven thermal lag disturbs natural water temperature and induces thermal stress in early-life-stage Chinese sturgeon (Acipenser sinensis), yet stage-specific molecular stress mechanisms remain unclear. This study assessed phenotypic, proteomic and metabolomic responses of endogenous-nutrition embryos and exogenous first-feeding larvae under 16 °C, 19 °C and 22 °C. Phenotypic results showed optimal embryo survival at 16 °C (hatching rate 64.6%), maximum larval growth at 19 °C (specific growth rate 6.79%/d), and severe developmental suppression at 22 °C (with the hatching rate dropping by 49.6 percentage points relative to 16 °C). Multi-omics uncovered distinct injury pathways: high temperature disrupted amino-acid and fatty-acid catabolism and triggered organic-acid accumulation and energy deficiency in embryos; in first-feeding larvae, it activated ferroptosis, polyunsaturated fatty-acid peroxidation and lysosomal pathways to produce oxidative damage. These findings demonstrate that a 1-3 °C temperature rise exceeds stage-specific thermal tolerance, with embryos succumbing to "metabolic suppression-energy deficiency" and larvae to "oxidative stress-ferroptosis". This study provides the first integrative proteomic and metabolomic evidence of stage-dependent thermal injury mechanisms in sturgeon, offering mechanistic insights critical for conservation physiology and informing conservation actions for this endangered sturgeon species.