Physiological and adaptive aspects of post-winter resistance in the hybrid of Russian sturgeon and Lena sturgeon (Acipenser gueldenstaedtii × A. baeri) and Russian sturgeon (Acipenser gueldenstaedtii) under cage aquaculture conditions

The present study provides a comparative analysis of hematological and physiological-biochemical blood parameters in females of the hybrid of Russian sturgeon (Acipenser gueldenstaedtii) and Lena sturgeon (Acipenser baeri) designated as RsLs and the pure species Russian sturgeon (Acipenser gueldenstaedtii) during the post-winter period under cage rearing conditions in a fish farm located in the Astrakhan region. The objects of the study were 14-year-old females of the RsLs hybrid and the pure Russian sturgeon. The research material comprised blood samples collected from specimens after the completion of wintering. In the blood samples, hematological parameters (hemoglobin concentration, erythrocyte sedimentation rate) and biochemical parameters (total protein, glucose, cholesterol, and albumin content) were determined using standard analytical methods. Statistically significant intergroup differences (p < 0.05) were established for two key parameters: erythrocyte sedimentation rate in the RsLs hybrid was lower (3.3 ± 0.2 mm/h vs. 4.5 ± 0.4 mm/h in Russian sturgeon), while glucose level was higher (7.3 ± 0.3 g/L vs. 6.3 ± 0.3 g/L), reflecting differentiated stress reactivity of the compared groups (hybrid and pure species). For the remaining parameters studied (hemoglobin, total protein, albumin, cholesterol), the revealed intergroup differences did not reach statistical significance. All studied parameters in both groups remained within the physiological reference ranges established for sturgeon species. The revealed differences are interpreted as evidence of enhanced adaptive plasticity of the RsLs hybrid, presumably conditioned by the genetic contribution of the Lena sturgeon, which is characterized by high tolerance to temperature fluctuations and variations in oxygen regime.