Effects of 2-phenoxyethanol (2-PE) anesthesia on some haematological and biochemical indices of silver carp (Hypophthalmichthys molitrix)

In this study, the anesthetic e?ects of 2-phenoxyethanol (2-PE) on possible primary (cortisol level) and secondary (haematological indices and glucose level) stress responses were studied in silver carp (Hypophthalmichthys molitrix). Fish were ?rst exposed to 0.1, 0.3, 0.5, 0.7 and 0.9 mL L-1 2-PE, and the time of induction (deep anesthesia) and recovery were measured. At concentrations of 0.5, 0.7 and 0.9 mL L-1 2-PE, all ?sh were anaesthetized within 3 min of exposure. For assessing possible stress effects caused by effective concentrations of 2-PE, the haematological indices, serum cortisol and glucose were determined in the deeply anaesthetized ?sh as stress indicators. 2-PE exposure resulted in a significant increase in red blood cell (RBC) amounts at 0.1 and 0.3 mL L-1. A parallel increase in hemoglobin and Haematocrite amounts at 0.1 concentrations (p < 0.05) was observed. The serum cortisol levels had the highest amount in 0.1 mL L-1 of 2-PE. Moreover 2-PE exposure resulted in a significant increase in glucose amounts first at the 0.1 and later in the 0.3 mL L-1 concentrations. This study shows that rapid induction of deep anesthesia with a relatively high concentration of 2-PE (0.5, 0.7 and 0.9 mL L-1) was associated with the lowest effects on the haematological and serum biochemical indices in silver carp and so 0.7 mL L-1 could be suggested as a suitable dose for haematological studies in this species.