Handling stress is a significant challenge in intensive aquaculture, often compromising fish welfare, immunity, and overall productivity. This study investigates the skin transcriptomic responses, blood plasma enzyme activities, and histological changes in the liver, spleen, and head kidney of hybrid grouper ( Epinephelus fuscoguttatus × E. lanceolatus ) subjected to repeated handling stress over 10 consecutive days. RNA‐sequencing of the skin identified 2521 differentially expressed genes (DEGs), showing significant enrichment in oxidative phosphorylation and cardiac muscle contraction pathways. Stress conditions upregulated genes such as NADH ubiquinone oxidoreductase , ATP synthase , cytochrome b-c1 complex , cytochrome c oxidase , succinate dehydrogenase complex subunit B , and troponin T2d cardiac , indicating enhanced mitochondrial activity and energy turnover. These molecular signatures correlated with physiological recovery in stress‐resilient (handling‐resilient HR) fish, as evidenced by elevated alanine transaminase levels and preserved hepatic morphology. In contrast, stress‐sensitive (handling‐sensitive HS) fish exhibited a pronounced reduction in hepatic cytoplasmic area (48.75 ± 0.47 μm 2 ) compared to the control (62.47 ± 0.20 μm 2 ) and HR (67.82 ± 0.24 μm 2 ) groups. Furthermore, HS fish showed severe splenic necrosis (3.15 ± 0.68 μm 2 ) compared to the control (0.27 ± 0.29 μm 2 ), reflecting impaired metabolic and antioxidant capacity. This integrated analysis elucidates the molecular and physiological impacts of handling stress and identifies key pathways linked to stress resilience. Implementing refined handling techniques is essential to mitigate stress‐related health impacts and enhance welfare in hybrid grouper aquaculture.
Matusin et al. (Thu,) studied this question.