Induction of triploidy in Rhamdia quelen (Siluriformes, Heptapteridae) by double-temperature shock

摘要

This study evaluated sequential double-temperature shock (heat and cold) to induce triploidy in Rhamdia quelen. Fertilized eggs were heat shocked at 37, 39 and 41°C at 2 min post-fertilization and then cold shocked at 1°C for 20 min. Intact eggs were used as controls. Egg viability in control groups was higher (65.5 ± 37.0%) than that at 37°C (58.2 ± 37.7%), 39°C (1.8 ± 0.3%) and 41°C (0%). The survival of control hatchery (64.6 ± 36.8%) was higher compared to treatments at 37°C (24.4 ± 15.5%) and 39°C (0.6 ± 0.07%). Triploid percentages were 98.5% at 37°C and 100% at 39°C. Therefore, while double-temperature shock induced 100% triploidy in R. quelen, it also significantly decreased embryo survival and increased the deformity larvae.