Post-cooling survival, growth and deformity rates in zebrafish embryos (Danio rerio)

Abstract

This study investigated and analysed survival, growth and macro- and microscopic damage during the development of zebrafish embryos up to the adult stage after undergoing cooling. The embryos at 50% epiboly stage were selected, submerged in cryoprotectant solution of methanol and sucrose, cooled gradually to 0 ± 2°C temperature, and divided into two groups with different storage times (6 and 18 h). Subsequently, the embryos were reheated, rehydrated and incubated normally. The experiment lasted 5 months and, from hatching onward, the larvae were examined, collected and processed at pre-established time intervals. The hatching rate was significantly higher for the larvae stored for 18 h compared with the 6-h group. However, embryos from this group gave rise to a larger number of malformations, and these were much more severe compared with those in the 6 h group, which led to a higher mortality in the long term. Regarding larval length, the animals of the 6 h group had higher mean total length compared with the 18 h group, but both treatments were inferior to the control. Numerous macro- and microscopic malformations were observed and, in both treatments, only the morphologically normal individuals were able to develop to the adult stage, with organ development similar to the control, except for the gonads that were still undifferentiated in treated animals.

Effect of methanol-based vitrification solutions on the survival rate of cryopreserved common carp (Cyprinus carpio) embryos

“…The molecular weight of PG is lower than that of DMSO (76.09 g/mol vs. 78.03 g/mol), so its degree of permeability through the cellular membrane is higher, which favors its cryoprotective action (Smith et al 2001;Adams et al 2004). The current results also showed that the combination of MeOH and PG had a lower degree of toxicity and a stronger capability to prevent ice crystal formation, which is consistent with previous studies ( It was reported that the storage period negatively in uenced hatchability and survival rates in Cyprinus carpio (Ahammad et al 2003), Brycon orbignyanus (Paes et al 2014), and Danio rerio (Paes & Nakaghi 2018). In the current study, as expected, the increasing storage time considerably decreased the hatching and survival rates, mainly in embryos that were vitri ed with solutions containing DMSO (V1 and V2).…”

Phenotypic plasticity induced using high ambient temperature during embryogenesis in domesticated zebrafish, Danio rerio

“…Cooling exposure at 50% epiboly stage for 6 and 18 hr in zebrafish embryos also resulted in a considerably reduced embryonic survival ability (control: 67.50% vs. 18 hr: 39.80% and 6 hr: 18.75%) during hatching process (Paes & Nakaghi, 2017 TA B L E 2 (Continued) inability of the emerging larvae to break down the eggshell along with malformations such as pericardial and yolk-sac oedema, tail deformity and spinal curvature (Aksakal & Ciltas, 2018).…”