Compound Inhibitors Mitigate Skin Ulceration Induced by UVA and Vibrio splendidus in the Sea Cucumber Apostichopus japonicus

The sea cucumber (Apostichopus japonicus) is highly susceptible to environmental stress during aquaculture, storage, and transportation, often resulting in autolysis and considerable economic losses. UVA irradiation and Vibrio splendidus infection were used to induce skin ulceration in A. japonicus. In this study, UVA irradiation and V. splendidus infection were used to induce skin ulceration, and the effectiveness of a compound inhibitor in delaying its onset was evaluated. The degree of skin ulceration in A. japonicus was evaluated. Body wall tissues were collected to measure the activities of self-digesting enzymes, AchE, cathepsin L, SOD, and CAT. Caspase-3 expression was also analyzed to assess apoptosis and tissue damage. The results indicated that soaking A. japonicus in the inhibitor composition significantly delayed the onset of skin ulceration. After 72 h of UVA irradiation, the skin ulceration in group Eg was 0.55%, which was significantly lower than that in groups Cg and Wg. In the V. splendidus infection model, group Eg showed a 4-day delay in the onset of skin ulceration, compared to group Cg. Enzyme activity and gene expression analysis revealed that the inhibitor composition significantly reduced self-digesting enzyme expression in the A. japonicus body wall, increased SOD and CAT activities, and inhibited Caspase-3 expression. This study provides valuable theoretical insights into controlling skin ulceration in A. japonicus during aquaculture, preservation, and transportation.