Growth and development of the ovary and small follicle pool from mid fetal life to pre-puberty in the African elephant (Loxodonta africana)

Show simple item record Stansfield, Fiona Jane Nothling, Johan Oliviette Allen, William R. 2012-10-24T07:59:58Z 2012-10-24T07:59:58Z 2012-07-23
dc.description.abstract BACKGROUND Follicle numbers and developing ovarian morphology, particularly with reference to the presence of interstitial tissue, are intimately linked within the ovary of the African elephant during the period spanning mid-gestation to puberty. These have not been previously quantified in any studies. The collection of 7 sets of elephant fetal ovaries between 11.2 and 20.2 months of gestation, and 29 pairs of prepubertal calf ovaries between 2 months and 9 years of age during routine management off-takes of complete family groups in private conservancies in Zimbabwe provided an opportunity for a detailed study of this period. RESULTS The changing morphology of the ovary is described as the presumptive cortex and medulla components of the fetal ovary settled into their adult form. Interstitial tissue dominated the ovary in late fetal life and these cells stained strongly for 3β–hydroxysteroid dehydrogenase. This staining continued postnatally through to 4.5 years of age suggesting continued secretion of progestagens by the ovary during this period. The considerable growth of antral follicles peaked at 28% of ovarian volume at around 16.7 months of fetal age. The numbers of small follicles (primordial, early primary and true primary), counted in the cortex using stereological protocols, revealed fewer small follicles in the ovaries of animals aged 0 to 4.5 years of age than during either late fetal life or prepubertal life. CONCLUSIONS The small follicle populations of the late-fetal and prepubertal ovaries of the African elephant were described along with the changing morphology of these organs. The changes noted represent a series of events that have been recorded only in the elephant and the giraffe species to date. The expansion of the interstitial tissue of the fetal ovary and its continued presence in early post natal life may well contribute to the control of follicle development in these early years. Further research is required to determine the reasons behind the variation of numbers of small follicles in the ovaries of prepubertal calves. en
dc.description.librarian ab2012 en
dc.description.sponsorship This project was kindly funded, in part, by the China Wildlife Conservation Association and The National Research Foundation of South Africa. en
dc.description.uri en
dc.identifier.citation Stansfield, FJ, Nothling, JO & Allen, WR 2012, 'Growth and development of the ovary and small follicle pool from mid fetal life to pre-puberty in the African elephant (Loxodonta africana)', BMC Veterinary Research, vol. 8, no. 119, pp. 1-27. en
dc.identifier.issn 1746-6148
dc.identifier.other 10.1186/1746-6148-8-119
dc.identifier.other 6602528464
dc.identifier.other O-6382-2014
dc.language.iso en en
dc.publisher BioMed Central en
dc.relation.requires Adobe Acrobat Reader en
dc.rights © 2012 Stansfield et al. ; licensee BioMed Central Ltd. This is an open access article distributed under the terms of the Creative Commons Attribution License en
dc.subject Elephants en
dc.subject Oogenesis en
dc.subject Folliculogenesis en
dc.subject Interstitial cells en
dc.subject Ovaries en
dc.subject Reproductive life en
dc.subject Follicle pool en
dc.subject.lcsh African elephant en
dc.subject.lcsh Reproduction en
dc.title Growth and development of the ovary and small follicle pool from mid fetal life to pre-puberty in the African elephant (Loxodonta africana) en
dc.type Article en

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