TY - JOUR

T1 - Effect of stage of follicular growth during superovulation on developmental competence of bovine oocytes.

AU - Humblot, P

AU - Holm, P

AU - Lonergan, P

AU - Wrenzycki, C

AU - Lequarré, a-S

AU - Joly, C Guyader

AU - Herrmann, D

AU - Lopes, a

AU - Rizos, D

AU - Niemann, H

AU - Callesen, H

PY - 2005/3/1

Y1 - 2005/3/1

N2 - The final steps of oocyte capacitation and maturation are critical for embryonic development but detailed information is scarce on how the oocyte is affected during this period. In this study, 2033 oocytes were collected from 106 superovulated cattle at four different time points before ovulation. Follicular characteristics were measured and oocyte quality was assessed by morphology, mRNA expression of eight marker genes or developmental ability after in vitro/in vivo maturation and subsequent in vitro fertilization and culture. Approaching ovulation, expected increases in follicular size and cumulus expansion suggested progression of oocyte maturation. No differences were found in the expression patterns of analyzed genes, except for heat-shock-protein (Hsp) that was lower in in vivo matured oocytes collected shortly before ovulation. Oocytes collected at this time also had higher developmental ability measured as blastocyst rates (57.6 after in vitro production while no differences were found between oocytes recovered earlier at the first three time points (39.3-41.5. We conclude that oocytes recovered late in the preovulatory period are more developmentally competent than oocytes recovered at the pre-capacitation and the capacitation period, probably due to the former having matured in vivo. However, a precisely defined time for aspirating immature oocytes for subsequent in vitro development seems not to be crucial.

AB - The final steps of oocyte capacitation and maturation are critical for embryonic development but detailed information is scarce on how the oocyte is affected during this period. In this study, 2033 oocytes were collected from 106 superovulated cattle at four different time points before ovulation. Follicular characteristics were measured and oocyte quality was assessed by morphology, mRNA expression of eight marker genes or developmental ability after in vitro/in vivo maturation and subsequent in vitro fertilization and culture. Approaching ovulation, expected increases in follicular size and cumulus expansion suggested progression of oocyte maturation. No differences were found in the expression patterns of analyzed genes, except for heat-shock-protein (Hsp) that was lower in in vivo matured oocytes collected shortly before ovulation. Oocytes collected at this time also had higher developmental ability measured as blastocyst rates (57.6 after in vitro production while no differences were found between oocytes recovered earlier at the first three time points (39.3-41.5. We conclude that oocytes recovered late in the preovulatory period are more developmentally competent than oocytes recovered at the pre-capacitation and the capacitation period, probably due to the former having matured in vivo. However, a precisely defined time for aspirating immature oocytes for subsequent in vitro development seems not to be crucial.

KW - Animals,Cattle,Embryo Culture Techniques,Embryo Culture Techniques: veterinary,Female,Fertilization in Vitro,Fertilization in Vitro: veterinary,Growth Differentiation Factor 9,Heat-Shock Proteins,Heat-Shock Proteins: genetics,Intercellular Signaling Pepti

U2 - 10.1016/j.theriogenology.2004.06.002

DO - 10.1016/j.theriogenology.2004.06.002

M3 - Journal article

C2 - 15710200

VL - 63

SP - 1149

EP - 1166

JO - Theriogenology

JF - Theriogenology

SN - 0093-691X

IS - 4

ER -