Papers by Fiona Stansfield
Reproduction, Fertility and Development, 2013
This study aimed to determine whether the follicle reserve in the ovary of the African elephant d... more This study aimed to determine whether the follicle reserve in the ovary of the African elephant declines progressively after puberty and whether its depletion constrains the fertility of older females. Elephant ovaries were fixed in 4% neutral buffered formalin and small-follicle counts made using stereological protocols. Excepting a slight rise in small-follicle numbers between 16 and 25 years of age, there was a trend for follicle numbers to fall from puberty to 70 years. Reproductive status did not impact significantly on small-follicle numbers (P = 0.31). The number of early primary follicles, initially higher in number than true primary follicles, fell from post-puberty to nil at 45 years of age. Six of the seven oldest animals in the study showed signs of recent ovarian activity in the form of antral follicles, corpora lutea or large corpora nigra. The four oldest elephants (mean age 69 years) had a median small-follicle count of 11 113. In summary, it appears that the elephant ovary is capable of supplying oocytes for ovulation right up to the time of death at the age of maximum life expectancy, although the follicle reserve becomes depleted in some older elephants.
Human–Wildlife Conflict (HWC) is inevitable where humans and wildlife share the same habitat and ... more Human–Wildlife Conflict (HWC) is inevitable where humans and wildlife share the same habitat and its limited resources. Mitigation packages include HWC reporting, but this is often ineffective as the information conveyed is generally scattered and inadequate. A new coping strategy has been developed with a view to limiting HWC and avoiding incident peaks at certain periods. The booming mobile phone sector and the popular use of text messages have provided an opportunity to assess the impact of real-time communication systems in HWC mitigation strategies. Preliminary tests were conducted in Mozambique and Zimbabwe with FrontlineSMS, a mobile data collection system. The overall system can be improved by using an Android application such as KoBoCollect on a smartphone enabling easier recording of georeferenced data. Once adopted, HWC early warning systems could be deployed at low cost, improving the global management and conservation of flagship species involved in HWC, such as the elephant.
Placenta, Jul 1, 2019
The wildebeest is a populous African ungulate, but despite its wide distribution within that cont... more The wildebeest is a populous African ungulate, but despite its wide distribution within that continent few reports exist on the structure and endocrine functions of its placenta. Methods: The pregnant uteri of 43 Blue Wildebeest estimated to be at less than 70 days of the 8 month gestation period were examined grossly and histologically. Results and discussion: The cervix divided into left and right components which eliminated any connection between the uterine horns and limited conceptus development and placentation to the single ipsilateral horn. The placenta was typically ruminant synepitheliochorial macrocotyledonary with numerous flat placentomes developing in the gravid horn. Appreciable quantities of exocrine secretion were accumulated in the lumen of both gravid and non-gravid uterine horns and proliferation of the trophoblast into presumptive villi was evident between the placentomes. The single corpus luteum of pregnancy persisted unchanged during the period of gestation monitored and the mononuclear trophoblast cells of the intercotyledonary, but not the cotyledonary, allantochorion stained strongly for 3-β hydroxysteroid dehydrogenase indicating their likely secretion of progesterone. The binucleate trophoblast cells stained positively with antisera raised against placenta-associated glycoprotein and bovine placental lactogen. Neither the maternal corpus luteum or the allantochorion showed immunohistochemical staining for cytochrome P450 aromatase.
South African Journal of Wildlife Research, Oct 1, 2013
ABSTRACT Faced with an overabundant elephant population amid the difficult context of the land re... more ABSTRACT Faced with an overabundant elephant population amid the difficult context of the land reform programme in Zimbabwe, Savé Valley Conservancy (SVC) applied for an annual management quota of 60 animals in 2008 with the objectives of controlling an increasing population, attracting goodwill from the surrounding rural communities by providing a protein source and reducing the illegal bushmeat trade. Eighty-nine elephants were cropped in eight separate hunts during 2009 and 2010 providing 41 tonnes of meat. With adequate air-support, the cropping of family herds was feasibly and humanely conducted by skilled professional hunters. The handling of carcasses and the preservation of large quantities of meat were technically challenging on site. Because of the high demand for fresh meat, the processing facilities to extend meat shelf-life could not be tested. Cropping elephants remains a costly exercise at around US$550 per carcass. Cost recovery is possible with the sale of meat, offal and hides, but in this study was only partially achieved due to mismanagement of product delivery and sale. With 2.3 kg purchased per buyer, the production of meat partially satisfied the local population demand but offered an opportunity to the game meat producers to establish social links with their neighbours.To observe long-term impact on the illegal bushmeat trade currently affecting the SVC we suggest careful monitoring of future harvests.
Reproduction, Jun 1, 2012
The ovaries of eight African elephant foetuses and their mothers between 2 and 22 months of gesta... more The ovaries of eight African elephant foetuses and their mothers between 2 and 22 months of gestation, and those of two cycling and two lactating elephants, were examined grossly, histologically and immunocytochemically, with emphasis on the development and regression of accessory corpora lutea (CL) of pregnancy and the steroidogenic capacities of the accessory CL and the foetal ovaries. The results supported recent findings that the accessory CL form as a result of luteinisation, with and without ovulation, of medium-sized follicles during the 3-week inter-luteal period of the oestrous cycle. They enlarge significantly and become steroidogenically active around 5 weeks of gestation, probably in response to the placental lactogen which is secreted by the implanting trophoblast of the conceptus. The large luteal cells stained strongly for 3b hydroxysteroid dehydrogenase (3bHSD) activity throughout the 22-month gestation period although they showed vacuolation and other degenerative changes in the final months of gestation coincident with hypertrophy and hyperplasia of 3bHSD-positive interstitial cells in the foetal gonads. It is proposed that the progestagens secreted by the enlarged gonads of the elephant foetus may function both to assist the maternal ovaries in supporting the pregnancy state and to induce torpor and intrauterine immobility of the rapidly growing foetus.
Reproduction, Nov 1, 2012
The follicular reserve and its ontogeny in the elephant are of interest because elephants have th... more The follicular reserve and its ontogeny in the elephant are of interest because elephants have the longest reproductive life of all landbased mammals. They also have the longest recorded pregnancy, which allows a protracted view of the series of significant events involved in the development of the embryonic and fetal gonads. The large elephant population of Zimbabwe provided the opportunity to collect conceptuses from elephants culled for management reasons and hunted professionally. Five embryos aged 76-96 days and the ovaries of four fetuses aged 4.8-11.2 months were fixed in 4% buffered formalin and studied by conventional histological sectioning and a stereological protocol to calculate the follicle reserve of each fetus. These observations enabled the conclusion that the migration of primordial germ cells into the indifferent gonad terminates at around 76 days of gestation while entry of oogonia into meiosis along with first follicle formation starts at around 5 months. Peak numbers of follicles are present by mid-gestation towards the end of the 6-month mitotic-meiotic transition period. It appears that the cortex of the elephant fetal ovary at mid-gestation (11 months) has already reached a developmental stage exhibited by the ovaries of many other mammals at full term.
Animal Reproduction Science, 2011
Information on the ovarian follicle reserve in the African elephant (Loxodonta africana) is lacki... more Information on the ovarian follicle reserve in the African elephant (Loxodonta africana) is lacking. This study set out to determine the ratios of early preantral follicles and their relative dimensions in the ovaries of 16 African elephant aged 10 to 34 years. The ovaries were sectioned histologically. Follicles were counted and classified according to expansion of the pre-granulosa cells. Early primary follicles were the most common (75.8% ± 11.8%), followed by true primary follicles (23.8% ± 11.8%), whereas primordial follicles were the most rare (< 2%). Measurements made on at least 100 early preantral follicles from each animal (n = 1464) indicate that growth in oocyte and nuclear diameters started with transition to the true primary stage P < 0.01. This, together with the observed ratios between the three types of early preantral follicles suggest that both classical primordial and early primary follicles contribute to the ovarian reserve in the African elephant.
Adipose tissue (AT) was reported to influence reproductive functions through regulation of the hy... more Adipose tissue (AT) was reported to influence reproductive functions through regulation of the hypothalamus-pituitary-gonadal axis, and infertility in captive African elephants has been correlated to obesity. Next generation sequencing was utilised to generate transcriptomes of peri-renal AT from culled wild adults. RNA was extracted using Qiagen RNeasy Mini Kit, followed by quality evaluation with Agilent 2100 Bioanalyzer. RNA transcription was quantified using RNA-Seq (Illumina HiSeq). A total of 63,041,074 (F1), 83,963,786 (F2), and 56,783,624 (M1) paired reads were obtained. Differential gene expressions (DGE) were analysed using edgeR (www.bioconductor.org/packages/release/bioc/html/edgeR.html). Statistically significant DGE related to adipogenesis, lipogenesis and energy homeostasis were validated using qRT-PCR (ELOVL5, FASN, LEP, NR2F2, PPARγ, RXRα, SCD). DGE were also evaluated between sexes and ages (adult-juveniles) through qRT-PCR. Hierarchical clustering of gene expressions in adults revealed that genes expressed by the non-pregnant female (F2) was closer to those of the young growing bull, compared to the lactating female (F1). Furthermore, pregnant or lactating females showed a higher energy expenditure and lower lipogenesis level compared to young growing males. This may be due to high energy requirement for maintenance of pregnancy and lactation. However, energy homeostasis of the juveniles appeared to be more comparable between sexes, as mRNA expression failed to show a clear pattern of differential expression. This is indicative of similar growth rate in these juveniles. Results from this study provides baseline data on the dynamics of AT in wild African elephants. Ultimately, knowledge generated will be used to improve management and fertility of captive African elephants.
Reproduction in Domestic Animals, Jul 9, 2017
Elephant ovaries contain multiple corpora lutea (CLs) throughout pregnancy. Two CLs (P-1 and P-2)... more Elephant ovaries contain multiple corpora lutea (CLs) throughout pregnancy. Two CLs (P-1 and P-2) collected from a pregnant African elephant were used to investigate their origin and physiological state in this study. The mRNA expressions of prolactin receptor, CYP11A and inhibin betaB subunit were higher in P-2 than in P-1, while LHCGR and inhibin betaA subunit mRNA were higher in P-1 than in P-2. Protein expression of cleaved caspase-3 was detected in P-1 but not in P-2. These results suggest different origins for the two CLs in this one pregnant elephant, and we also demonstrated the production of bioactive prolactin by the elephant placenta.
<p>Dark brown staining indicates leptin. Leptin was expressed exclusively in the cytoplasm ... more <p>Dark brown staining indicates leptin. Leptin was expressed exclusively in the cytoplasm of adipocytes. The top panel shows micrographs of leptin staining at 10× magnification and the lower panel shows micrographs at 40× magnification; N = nucleus, L = lipid droplet, C = cytoplasm.</p
<p>Hierarchical clustering (A) and principal component analysis (B) shows that samples clus... more <p>Hierarchical clustering (A) and principal component analysis (B) shows that samples cluster according to age and sex. Two differentially expressed genes identified by array analysis (A), <i>DGAT</i> and <i>FHL1</i> were selected for validation by qRTPCR in male (N = 3) and female (N = 3) elephants.</p
BMC Veterinary Research, 2012
Background: Follicle numbers and developing ovarian morphology, particularly with reference to th... more 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 midgestation 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.
<p>Green squares indicate the seventh lamellae (L7). <b>A</b>) three molars at ... more <p>Green squares indicate the seventh lamellae (L7). <b>A</b>) three molars at stage M4L7 (molar 4 lamella 7), <b>B</b>) three molars at M5L7, and <b>C</b>) three molars at M6L7. All show similar development, but not necessarily wear, in each tooth at each stage.</p
<p>The white arrow/red dot marks the Age Reference Point (ARP) and the yellow line marks th... more <p>The white arrow/red dot marks the Age Reference Point (ARP) and the yellow line marks the Age Reference Line (ARL). The remnant of the tooth in the right mandible had rotated as shown. Grid = 1cm<sup>2</sup>.</p
<p><sup>1</sup> ARL class as allocated to all jaws in the study</p><p&... more <p><sup>1</sup> ARL class as allocated to all jaws in the study</p><p><sup>2</sup> ARL age allocated based on a best fit with the Laws [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0124980#pone.0124980.ref012" target="_blank">12</a>] and Lee et al. [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0124980#pone.0124980.ref003" target="_blank">3</a>] data</p><p><sup>3</sup> The Laws [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0124980#pone.0124980.ref012" target="_blank">12</a>] age class was allocated to photographs of the occlusal surface of all jaws in the study</p><p><sup>4</sup> The Lee et al. [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0124980#pone.0124980.ref003" target="_blank">3</a>] median age as allocated to Laws [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0124980#pone.0124980.ref012" target="_blank">12</a>] criteria. Some of the classes are inverted</p><p>* No difficulty in molar identification from birth to this age. There is little difficulty in identifying molar types 1, 2, and 3 which makes ageing relatively easy up to when M4 occupies the mesial position at 10 years of age and the ARL = M4L6.</p><p>** No difficulty in molar identification from here onward. To obtain further information with regard to <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0124980#pone.0124980.t001" target="_blank">Table 1</a>, refer to the Notes below and Figure references in Column 5. <b>Note 1</b>. It is usually not difficult to differentiate between M3 and M4. If there is any doubt, this can be substantiated by measuring the distance from the ARP to the crest, and the inter ramus width (see <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0124980#pone.0124980.g002" target="_blank">Fig 2</a>, Tables <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0124980#pone.0124980.t002" target="_blank">2</a> and <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0124980#pone.0124980.t003" target="_blank">3</a>). In addition, it is useful to look at the first lamella of the molar in question, the first lamellae on M3 tends to fill the full width of the tooth whereas in M4 it tends to form a pillar on the lateral side. <b>Note 2</b>. Note how much smaller M4 is compared to M5 despite there being a difference of only 1 lamellae (<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0124980#pone.0124980.g010" target="_blank">Fig 10F</a>). M4s are narrower and shallower and tend to have thinner enamel ridges. The base of the root in M5 is also much longer and the gap between the roots of L3 and L4 much wider. See Fig <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0124980#pone.0124980.g010" target="_blank">10G</a> and <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0124980#pone.0124980.g010" target="_blank">10H</a> for further development of M4. <b>Note 3</b>. The Rank M4L10 rarely occurs as this lamellae is usually very small and if present becomes eroded by the mesial end of M5. None were found in this study and therefore there is no photograph. If the ARP to crest is <25 cm then it is suggestive of this being an M4. If ARP to crest >25 cm this suggests it is an M5. <b>Note 4</b>. By this stage the M5 molar is unlikely to be confused with M4 and the alveolus of M6 is usually visible, indicating that this is M5, not an M6 (this cannot be completely relied upon as 7<sup>th</sup> molars do occur in a small percentage of mandibles). See <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0124980#pone.0124980.g009" target="_blank">Fig 9</a> of the development of M5 and M6 at this ARL (M5 and M6 at L stage 2 [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0124980#pone.0124980.g009" target="_blank">Fig 9A</a>] and L stage 3 [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0124980#pone.0124980.g009" target="_blank">Fig 9B</a>]). <b>Note 5</b>. The distal end of M5 is much rounder than the distal end of M6, which is more tapered throughout development. <b>Note 6.</b> From here on, male mandibles and molars are noticeably larger than females. <b>Note 7.</b> M5L11 may rarely occur, none were recorded in this study. <b>Note 8.</b> From the age of 35 (M6L6), packing bone can be seen developing behind the M6 alveolus, indicating that this is M6. If an M7 is developing they can usually be seen to be truncated and irregular in shape.</p><p>Molar progression table relating age to Age Reference Line.</p
<p><b>A)</b> Four jaws at rank M5L8, i and iv are females and ii and iii males.... more <p><b>A)</b> Four jaws at rank M5L8, i and iv are females and ii and iii males. <b>B)</b> Four jaws at rank M6L5, i and ii are male mandibles, ii and iv are female mandibles. NB The L1 of M6 is often not visible in early occlusal wear (just visible in ‘iv’) but can be identified on tooth extraction. <b>C)</b> Two jaws (i male and ii female) at M6L8, and two jaws (iii male and iv female) at M6 + 1cm. Yellow line = ARL.</p
<p>Significant differences (<0.001) were found between all molar male groups, all molar ... more <p>Significant differences (<0.001) were found between all molar male groups, all molar female groups and molar groups including totals of both male and female.</p><p>*Molars relates to the ARLs for each molar, so for example, from M1L1 to M1L5 for Molar 1. For molar 2, M2L1 to M2L7, and so on for the other molars.</p><p><sup>#</sup> Data in this group is biased due to the low number of older male samples.</p><p>Mandible width of African elephants within Zimbabwe.</p
<p>RT-PCR confirms expression of leptin in elephant visceral fat (A) and identified an exon... more <p>RT-PCR confirms expression of leptin in elephant visceral fat (A) and identified an exon-exon boundary (B), derived amino acid sequence (C), structure of human leptin (1AX8) (D) and molecular model of elephant leptin (E). Residues conserved in all human and elephant leptin amino acid sequences are displayed as white text on black. Helices are color coded (C, D,E).</p
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Papers by Fiona Stansfield