title: Ultrastructure and mitochondrial numbers in pre- and postpubertal pig oocytes.
abstract: Prepubertal pig oocytes are associated with lower developmental competence. The aim of this experiment was to conduct an exhaustive survey of oocyte ultrastructure and to use a design-unbiased stereological approach to quantify the numerical density and total number of mitochondria in oocytes with different diameters from pre- and postpubertal pigs. The ultrastructure of smaller prepubertal immature oocytes indicated active cells in close contact with cumulus cells. The postpubertal oocytes were more quiescent cell types. The small prepubertal oocytes had a lower total mitochondrial number, but no differences were observed in mitochondrial densities between groups. Mature postpubertal oocytes adhered to the following characteristics: presence of metaphase II, lack of contact between cumulus cells and oocyte, absence of rough endoplasmic reticulum and Golgi complexes, peripheral location of cortical granules and central localisation of mitochondria, vesicles and lipid droplets. Prepubertal oocytes displayed more variation. The ultrastructure of large pre- and postpubertal oocytes was compatible with higher developmental competence, whereas that of smaller prepubertal oocytes could explain their reduced capacity. The higher number of mitochondria in large pre- and postpubertal oocytes could have an influence on oocyte competence, by increasing the pool of mitochondria available for early embryonic development.
authors.affiliation: Department of Animal Science, Aarhus University, Blichers Allé 20, DK-8830 Tjele, Denmark.
authors.forename: Hanne Skovsgaard
authors.initials: HS
authors.lastname: Pedersen
authors.affiliation: Department of Animal Science, Aarhus University, Blichers Allé 20, DK-8830 Tjele, Denmark.
authors.forename: Henrik
authors.initials: H
authors.lastname: Callesen
authors.affiliation: Department of Molecular Biology and Genetics, Aarhus University, Blichers Allé 20, DK-8830 Tjele, Denmark.
authors.forename: Peter
authors.initials: P
authors.lastname: Løvendahl
authors.affiliation: Stereology and Electron Microscopy Laboratory, Centre for Stochastic Geometry and Advanced Bioimaging, Aarhus University, Nørrebrogade 44, DK-8000 Aarhus C, Denmark.
authors.forename: Fenghua
authors.initials: F
authors.lastname: Chen
authors.affiliation: Stereology and Electron Microscopy Laboratory, Centre for Stochastic Geometry and Advanced Bioimaging, Aarhus University, Nørrebrogade 44, DK-8000 Aarhus C, Denmark.
authors.forename: Jens Randel
authors.initials: JR
authors.lastname: Nyengaard
authors.affiliation: Department of Veterinary Clinical and Animal Science, University of Copenhagen, Dyrlægevej 16, DK-1870 Frederiksberg C, Denmark.
authors.forename: Nanett Kvist
authors.initials: NK
authors.lastname: Nikolaisen
authors.affiliation: Department of Veterinary Clinical and Animal Science, University of Copenhagen, Dyrlægevej 16, DK-1870 Frederiksberg C, Denmark.
authors.forename: Peter
authors.initials: P
authors.lastname: Holm
authors.affiliation: Department of Veterinary Clinical and Animal Science, University of Copenhagen, Dyrlægevej 16, DK-1870 Frederiksberg C, Denmark.
authors.forename: Poul
authors.initials: P
authors.lastname: Hyttel
mesh_terms: D000367:Age Factors; D000818:Animals; D002452:Cell Count; D048429:Cell Size; D002478:Cells, Cultured; D005260:Female; D059471:In Vitro Oocyte Maturation Techniques; D008540:Meiosis; D008677:Metaphase; D046529:Microscopy, Electron, Transmission; D008928:Mitochondria / Q000648:ultrastructure*; D009865:Oocytes / Q000648:ultrastructure*; D012741:Sexual Maturation; D034421:Sus scrofa