Physiological Stress and Tissue Damage Response of Ctenopharyngodon idella to Artificial and Automated Injection

This study evaluated the responses of physiological stress and tissue damage of Ctenopharyngodon idella through artificial and automated injection. Wound recovery, gene expression, serum immune parameters, and cortisol levels were analyzed post-injection. Histopathological analysis revealed active wound recovery in all groups, with the automated injection group showing a faster epithelial regeneration rate compared to the artificial injection group. Gene expression and serum immune parameters exhibited similar changes in response to both injection methods. Gene expression data indicated significant upregulation of pro-inflammatory genes (TNFα) and healing-related genes (GRHL1), while anti-inflammatory genes (IL10) and epithelial markers (KRT1) were downregulated. Serum analyses showed increased peroxidase, protease, and IgM levels in stressed fish, suggesting prolonged immune activation. Plasma and head kidney cortisol levels significantly increased in both injection groups, with higher elevations noted in the automated injection group. These findings suggest that while both methods induce similar molecular responses, automated injection may cause less tissue trauma and offer a quicker recovery trajectory. Overall, automated injection appears to be a preferable method for minimizing tissue damage and promoting faster recovery in grass carp, potentially leading to improved outcomes in aquaculture practices. Further research should explore long-term effects and broader applications of automated injection technologies.