Comparison propofol and eugenol anesthetics efficacy and effects on general health in Nile Tilapia

Abstract Propofol is increasingly used as a fish anesthetic and pain management tool. However, studies concerning its effect on fish health biomarkers are lacking. Therefore, we aimed to investigate the propofol anesthetic efficacy and its effect on the health biomarkers in Nile tilapia compared to eugenol, an efficient and safe fish anesthetic commonly used in daily aquaculture practices. Nile tilapia were exposed to 2.5 mg/L propofol (PR) and 30 mg/L eugenol (EU). Induction, recovery times, and opercular movements (OM) were recorded. Blood and tissue samples were collected at time 0 (control) after anesthesia was achieved, and after a full recovery for each anesthetic agent, to assess the health biomarkers of the Nile tilapia. Results demonstrated extended induction and anesthetic duration along with rapid recovery in the propofol group compared to eugenol. OM showed a similar trend in both groups, with a significant frequency decrease during anesthesia that was restored during the recovery phase. The PR-group showed a significant transient increase of hematological indices in contrast to the EU group. However, TLC (total leukocytic count) and heterophils showed no statistical changes in the PR group compared to the EU group. A significant transient increase of glucose, cortisol, reduced glutathione (GSH), and catalase (CAT) levels compared to their baseline levels was observed during anesthesia in PR and EU groups with full reversal during recovery. No significant changes were noticed in liver function enzymes, Malondialdehyde (MDA), Superoxide dismutase (SOD), and mRNA tumor necrosis factor- ɑ (tnf-ɑ) expression level in fish exposed to both anesthetics at any stage. The head kidney mRNA interleukin-8 (il-8) level was upregulated significantly during recovery compared to the baseline level in the PR group. However, during anesthesia, it showed no significant changes in the PR group compared to its control and recovery level, in contrast to the EU group. The spleen mRNA il-8exhibited no significant changes in the PR group during anesthesia and recovery compared to the control, contrary to the EU group during recovery. However, splenic il-8was upregulated during recovery compared to anesthesia in the PR group, in contrast to the EU group. Overall, propofol showed advantages in different scenarios compared to eugenol and vice versa. Eugenol appears better suited for use during minor procedures, while propofol may be used when smoother induction and deeper anesthesia are of interest, with a lack of alterations on cytokines expressions during anesthesia.