title: Effects of birthweight on reproductive system development and onset of puberty in gilts.
abstract: The aim of the present study was to investigate the effects of birthweight on bodyweight development, development of the genital tract, onset of puberty and their associations with insulin-like growth factor (IGF) 1 and leptin concentrations. Pairs of littermate gilts from 51 litters were selected: one piglet with the highest birthweight (HW; 1.5±0.2kg) and the other with the lowest birthweight (LW; 1.0±0.2kg). Gilt pairs were killed at either fixed ages (80.8±1.2 days; AG; 16 pairs), fixed bodyweight (35.2±1.4kg; WG; 16 pairs) or after first oestrus (EG; 19 pairs). In the AG group, HW gilts were 5.6kg heavier at the time of death than LW gilts. In the WG group, LW gilts were 5.9 days older at the time of death (P<0.05). There were no significant differences in the number or size of total antral follicles or in the follicle population among birthweight classes. Age at puberty was similar between the HW and LW gilts, but bodyweight at time of death was greater for HW gilts (P<0.05). Birthweight did not affect the development of the genital tract, ovulation rate or hormone plasma concentrations. These results suggest that birthweight does not affect the development of the genital tract before puberty and puberty onset.
authors.affiliation: Department of Morphology, Federal University of Minas Gerais, Belo Horizonte, MG 31.270-901, Brazil.
authors.forename: F R C L
authors.initials: FRCL
authors.lastname: Almeida
authors.affiliation: Adaptation Physiology Group, Department of Animal Sciences, Wageningen University, P.O. Box 338, 6700 AH, Wageningen, The Netherlands.
authors.forename: B
authors.initials: B
authors.lastname: Laurenssen
authors.affiliation: Department of Morphology, Federal University of Minas Gerais, Belo Horizonte, MG 31.270-901, Brazil.
authors.forename: L X
authors.initials: LX
authors.lastname: Pereira
authors.affiliation: Human and Animal Physiology Group, Department of Animal Sciences, Wageningen University, P.O. Box 338, 6700 AH, Wageningen, The Netherlands.
authors.forename: K J
authors.initials: KJ
authors.lastname: Teerds
authors.affiliation: Adaptation Physiology Group, Department of Animal Sciences, Wageningen University, P.O. Box 338, 6700 AH, Wageningen, The Netherlands.
authors.forename: N M
authors.initials: NM
authors.lastname: Soede
mesh_terms: D000367:Age Factors; D000818:Animals; D001724:Birth Weight / Q000502:physiology*; D005187:Fallopian Tubes / Q000254:growth & development*; D005260:Female; D007334:Insulin-Like Growth Factor I / Q000378:metabolism*; D020738:Leptin / Q000097:blood*; D006080:Ovarian Follicle / Q000502:physiology*; D012741:Sexual Maturation / Q000502:physiology*; D013552:Swine; D014599:Uterus / Q000254:growth & development*
chemical_list: D020738:Leptin; D007334:Insulin-Like Growth Factor I