High percentages of larval tetraploids in the yellowtail tetra Astyanax altiparanae induced by heat-shock: The first case in Neotropical characins

Return temperature after heat shock affects the production of tetraploids in the yellowtail tetra Astyanax altiparanae

“…After heat shock, lower survival rates were observed for all treatments, which was expected and described in other studies (Piferrer et al, 2009;do Nascimento et al, 2020b). Several factors have been described to explain lower survival in tetraploids, including genetic factors such as mosaicism, aneuploidy, asynchronous development or high homozygosity (Zhang and Onozato, 2004;Fujimoto et al, 2013) and also physiological or developmental problems caused by extreme conditions such as the temperatures or the high pressures used for tetraploidization.…”

“…Other studies have also shown that triploid females are sterile (do Nascimento et al, 2017a) and present increased carcass yield (do Nascimento et al, 2017b). Therefore, we standardized a protocol for tetraploid induction in A. altiparane using heat shock (do Nascimento et al, 2020b). Such study showed that tetraploid males could produce viable and diploid spermatozoa for mass production of triploid fish (100%).…”

“…However, protocols for tetraploid induction are difficult to establish, limited to a few species and generally result in low survival (Yoshikawa et al, 2008;Piferrer et al, 2009). In the Neotropical region, studies on the production of tetraploid fish have been restricted to only two species, the silver catfish Rhamdia quelen (Garcia et al, 2018) and the yellowtail tetra Astyanax altiparanae (do Nascimento et al, 2020b).…”

“…Among such species, the A. altiparanae has recently been considered a model organism for basic and applied studies (Pereira-Santos et al, 2016;do Nascimento et al, , 2020ados Santos et al, 2018), especially for chromosome set manipulation, such as induction (Adamov et al, 2017;Piva et al, 2018) and rearing of triploid fish (Bertolini et al, 2018). Other studies have also shown that triploid females are sterile (do Nascimento et al, 2017a) and present increased carcass yield (do Nascimento et al, 2017b).…”

Triploidization in the streaked prochilod Prochilodus lineatus inferred by flow cytometry, blood smears and karyological approaches

“…Unfortunately, in this study, the rise of triploids was not 100% effective, as observed in previous works within other species (Adamov et al, ; Piferrer et al, ). This suggests that triploids must be produced using other strategies, such as gametes from tetraploid individuals in order to achieve 100% efficacy (do Nascimento et al, ). Nevertheless, for ploidy confirmation, several tools were used, including erythrocyte diameter, flow cytometry and three types of karyological analysis including conventional Giemsa staining, Ag‐NOR staining and fluorescence in situ hybridization (FISH).…”