Integrated multi-sensor tracking and metabolomics uncover transport environmental stress and metabolic mechanisms in leopard coral grouper (Plectropomus leopardus).

Maintaining the quality and physiological stability of high-value live seafood during transport remains challenging. This study investigated the effects of transport time and temperature on water-quality dynamics, oxidative stress, and serum metabolism in leopard coral grouper (Plectropomus leopardus). Progressive acidification was a major environmental change during transport. Prolonged transport increased MDA and altered serum enzyme activities, whereas 16 °C alleviated oxidative stress and hepatic injury. Integration of continuous water-quality measurements with serum responses identified final-30-min pH and low-level dissolved oxygen (10th percentile) as complementary environmental indicators (R2 = 0.749), while MDA, GSH-Px, and ALT were selected as representative serum indicators (R2 = 0.817). Metabolomic analysis showed that low-temperature transport attenuated metabolic disturbances, whereas prolonged transport altered creatine, histamine, and palmitic acid, mainly involving arginine and proline metabolism and glycerophospholipid metabolism. These results provide a basis for characterizing transport stress and optimizing pre-slaughter handling of high-value live seafood.