| Popis: |
The gray catfish known as Surubim-do-Paraíba (Steindachneridion parahybae), which is endemic to the Paraíba do Sul river basin, is on the red list of Brazilian fauna threatened with extinction and the cryopreservation of germ cells of this fish is needed in support of conservation.We aimed to assess the effect of storage temperature on S. parahybae mature and immature oocytes.Two trials were carried out. Trial I (TI.1-3) used 30 mature oocytes (diameter1.8 mm) placed in cryoprotectant solutions and submitted to three different techniques. Trial II (TII.1-3) used 30 immature oocytes (diameter1.6 mm) placed in cryoprotectant solutions and submitted to three storage temperatures (i.e., TII.1 at room temperature for 120 min; TII.2 in the freezer for 120 min; TII.3 in liquid nitrogen for 24 hours.The mature oocytes were sensitive to every protocol used, including at room temperature. In contrast, the immature oocytes had increased sensitivity according to the temperature reduction to which they were submitted, with the treatment in liquid nitrogen causing greater damage.The immature stages exhibit more promising results, encouraging further studies using the combination of different CPSs, mainly penetrating ones, in oocyte cryopreservation protocols. |
