Objective This study aims to investigate the effects of temporary depuration on the body composition, oxidative stress, the structure and function of bacterial communities of Crassostrea hongkongensis.

Methods This study carried out a 96-hour depuration treatment on shelled C. hongkongensis. Subsequently, the changes of survival rate, body composition, and oxidative stress enzyme activities were analyzed during depuration. 16Sribosomal RNA gene (16S rRNA) sequencing was employed to analyze the structure and functions of bacterial communities.

Results The results indicated that the crude protein content of C. hongkongensis exhibited significant fluctuations during depuration. Meanwhile, the crude fat content remained at a relatively high level, and the ash content decreased. During depuration, the superoxide dismutase (SOD) activity reached its peak value (442 U/g) at 24 h, whereas the catalase (CAT) activity reached the minimum value (55 μmol/min/g) at 72 h, the glutathione peroxidase (GSH-Px) activity and malondialdehyde (MDA) content reached their maximum values (167 μmol/min/g, 242 nmol/g) at 96 h. The analysis of bacterial communities demonstrated that the depuration time had a significant influence on the bacterial community structure of C. hongkongensis, and 48 h was the critical time point for the change in bacterial community structure. Proteobacteria and Bacteroidetes were the dominant phyla, accounting for over 85% of the total bacterial abundance. The Kyoto encyclopedia of genes and genomes (KEGG) signaling pathway enrichment results revealed that the functions of bacterial-mediated environmental adaptation, immune system, protein folding, sorting and degradation, and nucleotide metabolism were significantly higher in C. hongkongensis at 24, 48, and 72 h compared to 0 h and 96 h.

Conclusion Based on the above findings, the appropriate depuration duration for C. hongkongensis is 48−72 h. This result offers a scientific reference for the enhancement of C. hongkongensis quality.