Cooling of pejerrey Odontesthes bonariensis (Teleostei, Atherinidae) embryos at sub-zero temperatures

MACORETTA, CHRISTIAN LEANDRO; MIRANDA, LEANDRO ANDRÉS

THERIOGENOLOGY

ELSEVIER SCIENCE INC

Año: 2020 vol. 149 p. 123 - 130

0093-691X

Pejerrey fish (Odontesthes bonariensis) is a seasonal multiple spawner with great economic importance and an adequate species for Aquaculture. For these reasons, it is necessary to apply biotechnologies to optimize its reproduction in captivity. In this context, the aim of this work was to develop a coolingprotocol for pejerrey embryos at sub-zero temperatures. Two cryoprotective solutions (CSs: S1 and S2), two cooling curves (a fast and a slow one) and two storage temperatures (14 and 20 C) were evaluated for 1 h. High percentages of embryo survival (80e100%) were obtained in all cases. In particular, for cooling at 14 C, the most suitable protocol was the slow temperature decrease in combination with S1 (2.5 M methanol, 1.4 M Me2SO, 0.3 M sucrose, and 0.08 M NaCl). The hatching rate (86.67 ± 11.55%) and the larval survival observed did not differ from those of the control group, and about 30% of normal-looking larvae were obtained. Besides, the slow cooling was also the best way to reach 20 C, obtaining a hatching rate of around 60%. However, all the larvae had different kind ofmalformations. Finally, in order to improve the results obtained at 20 C, the CSs were incorporated into the embryos by microinjection. In this case, it was observed that the most convenient combination was the microinjection of S2 (same composition as S1 but without Me2SO) in the perivitelline space followedby rapid cooling. Although the hatching rate was not improved (67.93 ± 8.31%), the microinjection allowed to obtain at least 4.5% normal-looking larvae. These results showed that the cooling of pejerrey embryos at zub-zero temperatures was feasible. Moreover, the microinjection of cryoprotectants withinthe pejerrey O.bonariensis embryos was employed for the first time in this species.