Maturation Status, Protein Synthesis and Developmental Competence of Oocytes Derived from Lambs and Ewes

Abstract

The efficacy of oocyte selection for in vitro embryo production depends on the abundance and diameter of follicles, cumulus layers around the oocytes and subsequent fertilization. Application of 'ovum pick-up' technique allows us to utilize partially matured oocytes for embryo production even from juvenile subjects. To compare their developmental competence, oocytes derived from lambs and ewes and cultured in maturation medium for up to 26 h were assessed at 2 h intervals by confocal microscopy after chromatin and microtubulin-specific fluorochrome labelling. Lamb oocytes reached second meiotic metaphase (MII) at lower numbers at 24 h (60.0%) and 26 h (28.6%) whereas 85.7% of adult-derived oocytes attained MII status by 24 h of maturation. Radiolabelling of oocyte proteins revealed higher incorporation of [(35)S-]-methionine and [(35)S]-cysteine in adult-derived oocytes compared to lamb oocytes. Although the cleavage rate of lamb oocytes was similar to that of ewe oocytes, the proportion reaching blastocyst stage was significantly lower (p < 0.05) in the lamb-derived oocytes. However, blastocysts from both types of oocytes displayed similar cell lineage allocations to inner cell mass and trophectoderm.

Effects of the Presence and the Numbers of Corpora Lutea in Non-Delivered and Delivered Pigs on In Vitro Oocyte Maturation and Embryonic Development

“…The developmental competences of oocytes recovered from these ovaries are different [1,6,8,[14][15][16][17][18]. In addition, it is noteworthy that pigs are multi-ovulatory animals.…”

“…Dev. 55: [655][656][657][658][659][660] 2009) o date, in vitro production (IVP) of embryos has been attempted in many species including pigs [1][2][3][4][5][6][7][8][9][10][11], cattle [12][13][14][15] and sheep [16,17]. In these trials, the oocytes used for IVP were obtained from animals in various stages of growth, e.g., sexual maturity.…”

“…The usage of younger oocyte donors enables reduction of the generation interval and rapid expansion of a valuable genotype. In many cases, however, the oocytes obtained from prepubertal animals have had a lower developmental competence than those of postpubertal or aged animals [1,6,8,[14][15][16][17][18]. The low quality of oocytes recovered from prepubertal animals is the principal problem for IVP.…”

Involvement of E-cadherin in early in vitro development of adult and juvenile sheep embryos

“…Moreover prepubertal oocytes showed lower metabolic activity than adult oocytes in relation to protein synthesis (Ledda et al 1996;Gandolfi et al 1998;Kochhar et al 2002), glucose, pyruvate and glutamine metabolism (O'Brien et al 1996;Steeves and Gardner 1999). In sheep, in particular, radiolabelling of oocyte proteins revealed a higher incorporation of 35 Smethionine and 35 S-cysteine into adult oocyte proteins compared with juvenile ones (Kochhar et al 2002). In accordance with these data, we observed a significantly higher relative abundance of some mRNAs, including E-cadherin, in the adult ovine oocytes compared with the prepubertal oocytes (Leoni et al 2007).…”

Single cell transcriptome profiling revealed differences in gene expression during oocyte maturation in Haimen white goats

“…Thus, JIVET promotes embryo production and transplantation for commercial purposes and provides abundant materials and critical research methods for animal cloning, embryonic stem cell research, transgenosis, egg banking, and other embryo biotechnology areas. Offspring have been successfully produced from 4-to 8-week-old kids (O'Brien et al, 1997;Ledda et al, 1999;Ptak et al, 1999;Kochhar et al, 2002;Kelly et al, 2005), calves (Armstrong et al, 1992), and kids (Izquierdo et al, 2002;Koeman et al, 2003) using JIVET (Gou et al, 2009).…”