Triploid Induction in the Yellowtail Tetra, Astyanax altiparanae, Using Temperature Shock: Tools for Conservation and Aquaculture

Abstract

Triploidization is an interesting tool to produce sterile fish. In the yellowtail tetra, Astyanax altiparanae, this can be applied for aquaculture and surrogate technologies. In this study, we compared the efficacy of cold (2 C) or heat shock (38 C, 40 C, and 42 C) on triploid induction in the yellowtail tetra. The eggs were treated with cold or heat shock, 2 min postfertilization (30 min in cold shock or 2 min in heat shock). Intact embryos served as the control group. Ploidy status was confirmed by karyotyping, flow cytometry, and nuclear diameter of erythrocytes. The hatching rate decreased after cold shock (12.69 ± 15.76%) and heat shock at 42 C (0.35 ± 0.69%) in comparison with the control group (63.19 ± 16.82%). At 38 C and 40 C, hatching rates (61.29 ± 17.73% and 61.75 ± 22.1%, respectively) were not decreased. Only one triploid arose at 38 C (1/80). At 40 C, a high number of triploids arose (72/78). At 42 C, very few embryos developed into the hatching stage. A large number of haploid individuals arose after cold shock (61/75), with only one triploid. Our results indicate that heat shocking of embryos at 40 C is optimum for triploid production in the yellowtail tetra.

Environmental manipulation on Astyanax altiparanae out of season spawning

“…Its current production is primarily destined for commercialization as live bait and human consumption (Ferreira et al, 2014). Besides, it has also been used as a fish model (Gomes et al, 2013;Yasui et al, 2014;Adamov et al, 2017;Nascimento et al, 2017) due to characteristics as rapid growth, simple handling, acceptance of artificial feeding and high prolificacy (Gonçalves et al, 2014). A. altiparanae females and males reach gonadal maturation at the fifth month of life, approximately (Garutti, 2003), and show partial spawning from September to March (Porto-Foresti et al, 2010); this restriction of spawning season limits the product offer throughout the year.…”

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

“…In this study, an effective protocol for induction of triploids in the streaked prochilod Prochilodus lineatus was established using heat shock (40°C) at 2 min post‐fertilization. In the south American region, triploids were induced on very few species such as Rhamdia quelen (Huergo & Zaniboni‐Filho, ; Silva, Moreira, Orozco‐Zapata, & Hilsdorf, ; Vozzi, Sánchez, & Permingeat, ), Piaractus mesopotamicus (Foresti, Oliveira, & Carvalho, ) and in the yellowtail tetra Astyanax altiparanae (Adamov et al, ; do Nascimento, de Siqueira‐Silva, et al, ; do Nascimento, Pereira‐Santos, et al, ) what emphasize the innovation and importance of our data.…”

First feeding of diploid and triploid yellowtail tetra Astyanax altiparanae: An initial stage for application in laboratory studies

“…Previous laboratory protocol (Adamov et al., ) were used for creating triploid fry. Three batch of oocytes were fertilized using sperm from different males and considered as triplicates.…”

“…On the other hand, it is necessary to use adequate feeding in fish development for laboratory studies because exogenous food is not available for those conditions. In a recent work (Adamov et al., ), triploid individuals were produced, but decreased hatching and survival rates were found within triploids. However, the performance of the triploids in later stages, including the first feeding, remains unclear.…”

“…A study regarding gamete ultrastructure, developmental staging, and fertilization was established using such a protocol (Dos Santos et al., ). In addition, a protocol for developing triploid fish was achieved in a recent publication (Adamov et al., ), and the newly hatched larvae were used to confirm the ploidy status by flow cytometry. However, in order to evaluate other parameters in adult fish, additional investigations are then necessary to rear the juveniles until they reach the adult stage.…”