Aquaculture Reports, Vol 49 Art 103705, 2026
C. F. Benevente, M. R. de Abreu, Q. C. Ameno Alves, G. Caló, A. S. Mechaly, S. R. Batlouni
Highlights
- In vitro ovulation of lambari follicles was standardized without CO₂ incubation.
- A single dose of 1 µg DHP/mL efficiently induced oocyte maturation and ovulation.
- Partial culture medium exchanges did not improve in vitro ovulation outcomes.
- PGF₂α alone induced ovulation in a dose-dependent manner in lambari follicles.
- Combining DHP and PGF₂α did not enhance ovulation beyond DHP alone.
Abstract
This study aimed to evaluate the in vitro ovulation in lambari (Astyanax altiparanae) by 17α,20β-dihydroxy-4-pregnen-3-one (DHP) and prostaglandin F2α (PGF2α). Five experiments were carried out to: (1) test different DHP concentrations (0.01–100 μg/mL), (2) assess the influence of pH (7.1 vs. 9.0) with medium exchange, (3) compare responses between isolated follicles and ovarian fragments, (4) analyze the effect of medium replacement during induction, and (5) examine ovulation induced by DHP alone or combined with varying PGF2α doses (50–5000 ng/mL). The results showed that DHP promotes ovulation in lambari, but its efficacy is hindered when using ovarian fragments instead of individualized follicles. Both pH 7.1 and 9.0 supported ovulation similarly when using 1 μg DHP/mL, and medium exchange was not necessary for successful induction. Additionally, PGF2α combined with DHP did not enhance ovulation compared to DHP alone, though PGF2α alone induced ovulation in a dose-dependent manner, with 5000 ng/mL being sufficient. These findings confirm that both DHP and PGF2α are potent inducers of final maturation and ovulation in lambari in vitro. Moreover, the potential synergistic effect observed at higher PGF2α doses underscores the importance of dose standardization when using hormonal combinations to prevent spawning failure in captive females. Prostaglandins are used as a complement to hypophysation to enhance ovulation in farmed fish species. A dose-dependent effect of PGF2α observed here suggests potential for improving lambari in vivo ovulation rates that nowadays are reported to be around 40–60% using the best protocols.
