Stress indicators throughout the reproduction of farmed Siberian sturgeon Acipenser baerii (Brandt) females

Abstract

We compared the profiles of plasma stress indicators (cortisol, lactate and glucose), ions (sodium, calcium, potassium, magnesium and chloride) and the reproductive potential of females’ Siberian sturgeon (Acipenser baerii, B.) under two reproduction procedures. The treatment 1 had three steps: ovarian follicle sampling, further hormonal injection, and reproduction. Ovarian follicle sample and hormonal injection were performed simultaneously in treatment 2. To allow blood sample without handling, fish were cannulated. Basic levels of studied plasma components were established. A cortisol peak (~200 ng/ml) was recorded after the hormone injection without handling and was very similar to that observed post-handling. Surges of lactate (³ 400 mg/l) were similar whatever the handling, ovarian follicle sampling with or without hormonal injection and reproduction. Glucose profiles were similar whatever the treatment. The return time of glucose content to resting level was longer than those for cortisol and lactate. Glucose profiles together with reproductive potential suggest that, in our experimental conditions, confinement did not have any detrimental consequences. Calcium content did not change. Potassium and magnesium decreased only slightly but significantly, so did sodium and chloride in a higher range. This leads us to suggest that the plasma lost in sodium and chloride might have been transferred to the coelomic fluid. The observed variations in all ion contents simultaneously with those of cortisol, suggest a correlation between cortisol and hydromineral balance. Reproductive potential of females were close to each other for both reproduction treatments (68.8% & 71.3%) but were significantly higher than those recorded in non-cannulated fish (42%).