Non-specific defence mechanisms of Russian sturgeon (Acipenser gueldenstaedti Brandt) reared in cages

Abstract

Studies were performed on healthy Russian sturgeon reared in an open heated water reservoir (near Ostrołęka) from May to October in order to determine non-specific defence reactions. After 1 month adaptation, blood was collected in June, July and October. Temperature changed from 27±2°C in summer to 16±5°C in October. The results showed higher metabolic activity of phagocytes (potential killing activity of about 10.3±2.3 bacterial cells and lisozyme activity of about 95±17 mg/l for June and July, respiratory burst activity - peak in June - of about 0.68±0.07 mg/ml) on the background of higher total counts of granulocytes in sturgeon blood (28.4±5.6%) in warm period. The role of eosinophils in binding free oxygenic radicals is discussed. Ceruloplasmine level in plasma did not change in summer (0.93±0.24 mmol/l) but increased about 42,5 % in the period of temperature downfall. The levels of g-globulins in the plasma gradually increased (from 6±2.4 to 10.4±3.4 g/l), while total protein content decreased and this correlated with the growth of b.w. (r= -0.9825). Our data suggest that dynamic of non-specific immune mechanisms in Russian sturgeon was caused by the change of the environmental impetus and somatic growth. The study points to the future research needs and directions.