Study on Tolerance and Immune Response of Pacific Abalone Haliotis discus hannai during Simulated Air Exposure of Live Transportation

Pacific abalone (Haliotis discus hannai) is an economically important species of sea snails found in China. Live abalones sold in domestic markets are sealed in insulated containers for transportation over extended periods of time (6–24 h), during which this species may experience stressful conditions and spoil. This study assessed the survival rate and weight loss rate (WLR) of abalone under various treatments to determine the optimal packaging transport conditions. Specifically, temperature, supplemental humidity and oxygen, and air exposure during simulated live transport were investigated. Results revealed that the survival rate increased significantly after cold-water shock and humidity control, whereas oxygen supplements did not have a significant effect. In addition, WLR significantly increased over time (P < 0.05). An additional experiment was conducted to investigate the stress response caused by air exposure. Hemocyte parameters, including total hemocyte count (THC), hemocyte mortality, and reactive oxygen species (ROS), were estimated for 2, 6, 12, 24, and 30 h after air exposure at different temperatures. Results revealed that THC significantly decreased after 30 h of air exposure at 5 and 10°C, and after 24 h of air exposure at 20°C. Hemocyte mortality and ROS significantly increased, peaking after 30 h at 5 and 10°C, followed by a gradual decrease over the subsequent 24 h recovery period. THC and ROS levels remained higher than the control levels by the end of the recovery period. The parameters investigated in this study could serve as indicators for the effects on the functional immune response and physiological stress of abalone during live transportation.