Modulation of rainbow trout (Oncorhynchus mykiss) cutaneous mucosal immune responses following anesthesia: A comparative study on different anesthetic agents

The present study investigated the possible effects of different anesthetic agents including MS222 (50 ppm), 2-Phenoxyethanol (2-PE) (0.2 mL L−1) and clove oil (25 ppm), on cutaneous mucosal immune parameters in rainbow trout (Oncorhynchus mykiss). The induction and recovery times for each anesthetic agent were assessed. Also, the immune parameters were measured in skin mucus, 1 and 24 h post anesthesia. No significant difference was observed among treatments at 1 h post-anesthesia except for bactericidal and alkaline phosphatase (ALP) activities which was significantly enhanced in fish exposed to 2-PE compared to other anesthetics. At 24 h post-anesthesia, most of the skin mucosal immune parameters were increased upon exposure to clove oil but decreased following exposure to 2-PE. However, no significant change was noticed after MS222 exposure. These results demonstrated that the anesthetics type should be considered to avoid possible immunosuppression in farmed fish. Furthermore, the present results could be useful for better understanding of alterations in cutaneous mucosal immunity in response to chemical stressors such as anesthetic agents.