Resistance to temperature change, handling stress, and disease in small sea cucumbers Apostichopus japonicus in different color morphs

The selection of sea cucumbers characterized by resilience to temperature changes, handling stress, and disease is the key to enhancing the efficiency of Apostichopus japonicus production. Color morphs were devised to distinguish the resilience of A. japonicus. The objective of the present study was to evaluate the behavioral and physiological differences of seeds of A. japonicus in different colored under the condition of acute drop of temperature, seawater washing, and Vibrio infection. The dark-colored individuals showed significantly higher food consumption, fecal output, and glycogen phosphorylase activity under the condition of acute temperature drop. This connotates that dark-colored seeds demonstrate a swifter resumption of feeding activities and exhibit superior adaptability in rapidly cooling environments. Significantly longer foraging distance and foraging time, as well as faster foraging speed, and higher cortisol concentration were found in dark-colored individuals after seawater washing. This indicates that dark-colored individuals exhibit a swift responsiveness to handling stress, enabling prompt resumption of foraging activities. Dark-colored seeds have more survived number and higher catalase activity after Vibrio infection. This indicates that dark-colored individuals manifest a heightened resistance to Vibrio infection. In conclusion, dark-colored seeds of A. japonicus have a stronger ability to resist temperature changes, handling stress, and disease.