The effect of anesthetic (2-phenoxyethanol) application on some biochemical and hematological parameters in Russian sturgeon (Acipenser gueldenstaedtii) and Siberian sturgeon (Acipenser baerii) during transport

Abstract

Experiments were carried out to determine the effect of 2-phenoxyethanol to reduce stress response during the transportation of Russian and Siberian sturgeons. In transportation experiment 1 (TE$_{1}$), Siberian sturgeons (687.2 ± 17.41 g) were stocked in tanks and transported for 90 min (stocking density = 65 ± 0.71 kg/$m^{3}$). Before transport, 0.5 mg/L 2-phenoxyethanol was applied to the first group (TE$_{1-A}$, n = 285) but not to the second group (TE$_{1-B}$, n = 287). In transportation experiment 2 (TE2), Russian sturgeons (1873 ± 159 g) were divided into two groups and stocked in tanks as they have a density of 60 ± 0.23 kg/m3 water. Before transport, 0.6 mg/L of 2-phenoxyethanol was applied to the first group (TE$_{2-A}$, n = 99), the second group (TE$_{2-B}$, n = 101) was left without application. During the 10 h of transport period (at the 2, 4, 6, and 8 h), 0.6 mg/L 2-phenoxyethanol was applied to the fish in the first group (TE2-A) every 2 h. The results revealed that plasma glucose and cortisol reached their highest level in the anesthetic-free groups (TE$_{1-B}$ and TE$_{2-B}$) during transportation in both experiments. There was no difference in the protein levels between anesthetic and anesthetic-free groups. In the TE$_{1-B}$ and TE$_{2-B}$, red blood cells and hematocrit decreased, neutrophils and white blood cells increased. However, no changes were observed in eosinophils and mean corpuscular volume between groups in both experiments. Lymphocyte increased in TE1-B in comparison to TE$_{1-A}$ and TE$_{1-BT}$, (before transport anesthetic-free fish in TE1). In addition, there was no change in levels of monocyte, hemoglobin, mean hemoglobin concentration (MCH) and mean corpuscular hemoglobin concentration (MCHC) between TE$_{1-BT}$, TE$_{1-A} $, and TE$_{1-B.}$ Monocyte, hemoglobin, MCH, and MCHC increased in TE2-B compared with TE2-BT (before transport anesthetic-free fish in TE$_{2}$) and TE$_{2-A}$ but the lymphocyte count did not change. The results indicated that the use of anesthetic agent 2-phenoxyethanol during transfer reduced mortality rate (0% and 12.89% in TE$_{1-BA}$ and TE$_{1-B}$, respectively, and 2.02% and 15.84% in TE$_{2-A}$ and TE$_{2-B}$, respectively) and physiological stress in sturgeons.