Effects of transport in water and waterless transport on physiological stress and flesh quality of turbot (Scophthalmus maximus)

In order to investigate the changes of physiological and biochemical indexes and flesh quality of turbot (Scophthalmus maximus) during transportation in water and without water to provide reference for the preservation and transportation of S. maximus, in this study, turbots were placed under water and waterless conditions for simulated transportation experiments to compare the changes of physiological and biochemical indexes and muscle quality of S. maximus in different transportation environments and to provide reference for the preservation of S. maximus in transportation. In the experiment, the purchased S. maximus was temporarily reared, cooled, oxygenated and packed for transport, and samples were taken from S. maximus at different times of transport to test the physiological and biochemical indexes and muscle indexes of S. maximus. The results showed that after 18 hours of simulated transportation, the survival rate of S. maximus in the water transport group and the waterless transport group remained 100%. The water content, crude fat, pH, glycogen, adenosine triphosphate (ATP) and adenosine monophosphate (AMP) contents in S. maximus muscle decreased significantly, lactate and inosine monophosphate (IMP) contents increased. Among them, the AMP content of S. maximus in the group transported in water decreased by 38.65% and the IMP content increased by 29.1%, while the AMP content of turbot in the group transported without water decreased by 12.83% and the IMP content increased by 28.47%; among the blood biochemical indexes of S. maximus, blood glucose (GLU), blood urea nitrogen (BUN) and cortisol levels increased significantly. After transportation, the changes of physiological stress and energy metabolism indexes of turbot in the waterless transportation group were smaller than those in the water transportation treatment group. In addition, the content of flavorful nucleotides IMP and AMP in the muscle of turbot in the low-temperature anhydrous transportation group was significantly higher than that of S. maximus in the water transportation group, indicating that the low-temperature anhydrous transportation increased the flavorful substances of turbot and improved the flavor of fish flesh. The results of the study indicate that the application of low-temperature waterless keep-alive technology for live fish transportation has broad prospects.