Transcriptomic analysis of the effects of dietary chitosan on the molting process in Procambarus clarkii

Molting is a critical physiological process for growth and development in arthropods. After molting, Procambarus clarkii (red swamp crayfish) exhibits a distinctive behavior of ingesting its exuviae. However, the functional significance of this behavior during the molting process remains unclear. Histological analysis revealed distinct intestinal remodeling during molting, characterized by the sequential detachment of the peritrophic membrane (PM) and the sloughing of the degenerating intestine (DI) into the lumen. To simulate the physiological effects of exuviae ingestion, chitosan, a key bioactive derivative of the exoskeleton, was administered via oral gavage. Transcriptomic analysis was performed to identify key events in the intestine and hemocytes following chitosan supplementation. The results showed that chitosan supplementation upregulates the expression of genes associated with immune responses and enzyme inhibitors in the intestine. Meanwhile, transcriptomic analysis of hemocytes reveals the enrichment of pathways involved in cell motility and exoskeleton hardening-related processes. This process is potentially linked to the enhanced expression of immune-related genes and shapes the microbial community during molting, thereby providing a novel foundation for investigating disease management strategies in crayfish during the molting cycle.