Developmental dynamics of cloned Mexican bighorn sheep embryos using morphological quality standards

Abstract

The developmental dynamics of cloned Mexican bighorn sheep ( Ovis canadensis mexicana ) embryos were evaluated based on morphological quality standards. Categories determined by standards were correlated with the embryonic development stage, number of nuclei and viability. The results showed no differences in the blastocyst rate between the experimental (cloned Mexican bighorn sheep embryos) and control (parthenogenetic domestic sheep embryos) groups ( p > .05), while type IV fragmentation was higher in clones ( p < .05). The standards allowed for the identification of embryos that divided at least once or fragmented after 24 hr of culture. The highest percentage of morulae appeared at 96 hr, the final stages of development: nonsegmented, blocked, fragmented and blastocysts appeared at 192 hr. Embryonic quality decreased over time, making 96 hr the ideal time point to predict the final morphological quality of embryos. Nuclear staining of the morulae and blastocysts showed that higher embryo quality was associated with a higher percentage of normal and viable blastomeres. The evaluated criteria allowed for descriptions of the dynamics, stage and quality of cloned Mexican bighorn sheep embryos with a high degree of reliability. In addition, developmental anomalies, including fragmentation, multinucleation and blocking, were identified.

Folate receptor‐1 is vital for developmental competence of goat embryos

“…Despite effective knockdown, 5.87% of embryos was able to develop into blastocysts, possibly due to the presence of maternally contributed FOLR1 which may eventually exhausted until blastocyst stage. Our results are in line with a previous study (Strandgaard et al, 2017), which demonstrated the compromised ability of mouse embryos to develop to blastocyst stage after TA B L E 1 Effect of FOLR1 knockdown on the rate of blastocyst production injection (Kharche et al, 2016;Magata et al, 2019;Menéndez-Blanco et al, 2020;Shirazi et al, 2018) and cloning by somatic cell nuclear transfer (Gorczyca et al, 2021;Hernández Martínez et al, 2020;Samiec et al, 2019;Skrzyszowska & Samiec, 2020Wiater et al, 2021).…”

“…The future studies at our laboratory may decipher some of these questions in order to thoroughly elucidate the importance of FOLR1 as a pivotal biomarker suitable for prediction of augmented susceptibility of embryonic genomes to efficient epigenetic reprogramming of their transcriptional activities. The latter could enable the embryologists to estimate the increased developmental competences and molecular quality of caprine and other mammalian species embryos produced by such modern assisted reproductive technologies as microsurgical IVF by intracytoplasmic sperm injection (Kharche et al., 2016; Magata et al., 2019; Menéndez‐Blanco et al., 2020; Shirazi et al., 2018) and cloning by somatic cell nuclear transfer (Gorczyca et al., 2021; Hernández Martínez et al., 2020; Samiec et al., 2019; Skrzyszowska & Samiec, 2020, 2021; Wiater et al., 2021).…”

Resveratrol Reduces ROS by Increasing GSH in Vitrified Sheep Embryos

“…Hernández et al [47] reported a low number of nuclei (44.2 ± 9.9) present in parthenogenetic blastocysts of O. aries and in interspecies cloned blastocysts of O. aries and Ovis canadensis mexicana (46.7 ± 8.1 nuclei). Lorenzo-Torres et al [48] reported 122 nuclei in good-quality blastocysts produced by IVF.…”