Characterization of embryos derived from calf oocytes: Kinetics of cleavage, cell allocation to inner cell mass, and trophectoderm and lipid metabolism

Abstract

Embryos derived from calf oocytes were compared with adult cow oocyte‐derived embryos (1) by studying the kinetics of embryo development using time‐lapse cinematography (2) by evaluating the ratio between inner cell mass (ICM) and trophectoderm (TE) cells in blastocysts (3) by measuring the triglyceride content of the blastocysts. The rate of calf oocyte‐derived embryos reaching the blastocyst stage was reduced (26 vs. 46% for adult derived embryos). Calf oocyte‐derived embryos preferably arrested their development before the 9‐cell stage. Those that developed into blastocysts had cleaved earlier to reach the 2‐cell or 3‐cell stages than embryos that arrested before the 9‐cell stage. The 9‐cell stage tended to appear later in calf oocyte‐derived embryo that reached the blastocyst stage than in adult‐derived embryos. This difference became significant at the morula stage. Accordingly, the fourth cell cycle duration was longer for calf oocyte‐derived embryos. Day 8 blastocysts from both sources had similar total cell numbers (calf: 89 ± 20; cow: 100 ± 30) and cell distribution between TE and ICM. The triglyceride content of day 7 blastocysts was similar for both sources (64 ± 15 vs. 65 ± 6 ng/embryo, respectively). In conclusion, calf oocyte‐derived embryos are characterized by a higher rate of developmental arrest before the 9‐cell stage and by a longer lag phase preceding the major onset of embryonic genome expression. These changes might be related to insufficient “capacitation” of the calf oocyte during follicular growth. Despite these differences, modifications in the quality of the resulting blastocysts were not detected. Mol. Reprod. Dev. 57:346–352, 2000. © 2000 Wiley‐Liss, Inc.

The <i>In Vitro</i> Developmental Competence of Oocytes from Juvenile Calves is Related to Follicular Diameter

“…Those oocytes underwent maturation, fertilization, and cleavage at rates no different from those in cows [19]. However, the time of first cleavage was delayed [45] and embryo yields were reduced [19]. Similar patterns of in vitro development were observed in this study, but only with calf oocytes from 2-3 and 4-8 mm follicles, suggesting that the deficiencies described previously are restricted to these size categories.…”

“…T h i s d i f f e r e n c e i n d e v e l o p m e n t a l competence of oocytes derived from calves and cows is also highlighted by slower cell division rates in calf oocytes, which is evident from the low proportion of 4-cell embryos at 46 h p.i. It has been shown that early dividing embryos are more developmentally competent than delayed cleaving embryos [2,45].…”

Brilliant Cresyl Blue stain selects largest oocytes with highest mitochondrial activity, maturation-promoting factor activity and embryo developmental competence in prepubertal sheep

“…In prepubertal goat oocytes, Romaguera et al (2010Romaguera et al ( , 2011 did not find differences in blastocyst quality, assessed by blastomere ploidy and cryotolerance, between oocytes coming from different diameter follicles and between oocytes from adult and prepubertal goats, concluding that oocyte quality was positively related to blastocyst production but not to blastocyst quality. In cattle, Majerus et al (2000) observed that the percentage of blastocysts obtained from calf oocytes was reduced in comparison with those from adult animals (26 vs 46%); however, the number of blastocyst cells was not different (89 and 100 respectively) and the ICM:TE ratio was similar (1:2.70 and ) within a column are significantly different (Fisher test; P!0.05). MII, metaphase II; 2PN, one sperm tail and 2 pronuclei; PS (polyspermic), two or more sperm tails or more than 2 pronuclei; AS (asynchronous), only one pronucleus.…”

“…Blastocyst viability is related to the timing of blastocyst formation (Majerus et al 2000), embryo cryotolerance assessed by blastocyst re-expansion rates post-warming (Leoni et al 2009) and the number of blastomeres at a given age and their allocation to the inner cell mass (ICM) and the trophectoderm (TE; Papaioannou & Ebert 1988). The blastocyst is composed of two different cell lineages: TE and the ICM.…”

Laparoscopic ovum pick-up for in vitro embryo production from dairy bovine and buffalo calves

“…In general, this seems to be the common procedure from what is found in the literature. Indeed, most articles show littleto-no deviations in the procedures respect of those in use for oocytes from adult cows and heifers (Revel et al, 1995;Armstrong et al, 1997;Khatir et al, 1998;Majerus et al, 2000;Taneja et al, 2000;Kauffold et al, 2005b;Currin et al, 2017).…”