Changes of sex steroids and blood biochemical indices in cultured Sterlet sturgeon (Acipenser ruthenus) during overriping period

This investigation was carried out to assess the over-ripening phenomenon and its relationships with sex steroids levels including testosterone (T), progesterone (P), 17-beta estradiol (E2) and some important liver enzymes such as alanine aminotransferase (ALT) and aspartate aminotransferase (AST), as well as to determine the levels of stress indices and blood biochemical parameters including cortisol, glucose, lactate total fat, total protein and calcium in cultured Sterlet sturgeon (Acipenser ruthenus) broodstocks. For this study, 18 fish with an average weight of 1120.2 ± 240.4 g were selected. Blood samples were taken from three groups (each group with six fish) in three stages including non-overripe, beginning the overriping, and completely–overripe process. Comparing the three groups showed significant differences in plasma levels of T, E2, AST, cortisol, glucose and lactate, with the highest levels of AST, cortisol, and lactate with values in completely-overripe stage, and the lowest levels of in non-overripe stage. The highest levels of glucose, T, and E2 were found in non-overripe stage (P0.05). This study showed that steroid hormones and biochemical indices could be more reliable indicators for forecasting and assessment of ripening stage of sturgeon and these factors can be used as biomarkers to control reproduction and ripening times in cultured Sterlet sturgeon broodstocks.