Potential application of an in vitro gonadal culture assay to determine fish reproductive response to environmental temperature.

ELISIO M; ZHANG Y; MIRANDA LA; YAMAMOTO Y; STRUSSMANN CA

Austin

Congreso; Joint Meeting of Ichthyologists and Herpetologists; 2017

px; "><Potential Application of an In Vitro Gonadal Culture Assay to Determine Fish ReproductiveResponse to Environmental TemperatureElisio, M., Zhang, Y., Miranda, L. A., Yamamoto, Y., Strüssmann, C. A.Temperature is a key environmental cue controlling gonadal development and spawning in fish.This control appears to be associated with the influence that this physical variable exerts ongonadal steroidogenesis. This study assessed if profiling of steroid synthesis on in vitro gonadalcultures at different temperatures accurately reflects the fish reproductive response toenvironmental temperature. The pejerrey Odontesthes bonariensis was selected as model becauseof its well characterized in vivo reproductive response to temperature changes. Ovarian in vitrocultures of three females were performed at 6 different temperatures between 12 and 27 °C, usingLeivovitz L-15 medium containing 17-hydroxy-progesterone (100 ng/ml). Testosterone (T), estradiol(E2), and relative gene expression of gonadal aromatase (cyp19a1a) were measured after 12 hoursculture. Cyp19a1a relative expression showed an almost linear decrease with temperatureincrease, while both T and E2 levels in culture medium showed a Gaussian relationship withtemperature. On average, the highest level of E2 was obtained between 19 and 20 °C, while for T itwas between 20.5 and 21.5 °C. The optimal temperature range estimated in this study forproduction of E2 (hormone promoting ovarian development) coincided with the optimal temperaturepreviously reported for ovarian maturation in this species (19-20 °C). The optimal temperatureestimated for T production, which was approximately 1.5 °C higher than for E2, could indicate thebest temperature for inducing spawning. In conclusion, this study provides promising evidences forthe development of a relatively easy in vitro assay to determine fish reproductive response toenvironmental temperature.Keyboards: Fish, Reproductive physiology, temperature, ovarian culture