Samira Faramarzpour - Fisheries Department, Faculty of Natural Resources, University of Guilan, Sowmeh Sara, Iran
Bahram Falahatkar - Fisheries Department, Faculty of Natural Resources, University of Guilan, Sowmeh Sara, Iran

Atresia is a result of degeneration oocytes in the ovary, which can occur at differentstages of ovarian development. In this study, 18 female Sterlet broodstocks with anaverage weight of 1120.2 ± 240.4 g were considered in the three differentexperimental groups consisted of non-overripe, beginning of overripe and completelyoverripe. Blood was sampled to find changes in stress indices (cortisol, glucose andlactate) at those stages. Cortisol level was determined by RIA, while glucose andlactate were analyzed with colorimetric method. Components analysis showedsignificant differences in the levels of cortisol, glucose and lactate (P<0.05) whichthe maximum levels of cortisol and lactate were 68.66 ± 10.93 ng/ml and 30.66 ±5.32 mg/dl, respectively in completely overripe fish, while the maximum plasmaglucose concentrations (68.83 ± 5.92 mg/dl) were observed in non-overripetreatment. The present study revealed physiological changes in atresia process as wellas fluctuation of stress indices during overriping period.

Oocyte, Sterlet sturgeon, Stress, Atresia