2024 |
Cowl VB, Comizzoli P, Appeltant R, Bolton RL, Browne RK, Holt WV, et al., 'Cloning for the Twenty-First Century and Its Place in Endangered Species Conservation.', Annu Rev Anim Biosci, 12 91-112 (2024) [C1]
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Nova |
2023 |
Perera TRW, Gibb Z, Bromfield EG, Rupasinghe T, Skerrett-Byrne DA, Swegen A, 'Early pregnancy associated changes in systemic lipid profiles of mares revealed by high resolution mass spectrometry', Journal of Equine Veterinary Science, 125 104780-104780 (2023) [C1]
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Nova |
2023 |
Appeltant R, Hermes R, Holtze S, Modina SC, Galli C, Bjarkadottir BD, et al., 'The neonatal southern white rhinoceros ovary contains oogonia in germ cell nests.', Commun Biol, 6 1049 (2023) [C1]
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2023 |
Lawson EF, Griffin RA, Ghosh A, Gibb Z, Baker MA, Tanwar PS, Swegen A, 'Deciphering the influence of mare oviductal organoid secretions on equine spermatozoa', Journal of Equine Veterinary Science, 125 104657-104657 (2023) [C1]
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Nova |
2023 |
Gibb Z, Clulow JR, Maclellan LJ, Morris LHA, Aitken RJ, Swegen A, 'Storing stallion sperm in SpermSafe at 17°C may improve fertility by reducing mPTP formation', Journal of Equine Veterinary Science, 125 104589-104589 (2023) [C1]
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Nova |
2023 |
Waugh SJ, Lawson EF, Gibb Z, Skerrett-Byrne DA, Swegen A, 'Embryo-maternal interactions revealed by phosphoproteomic analysis of endometrial organoids exposed to embryo secretome', Journal of Equine Veterinary Science, 125 104794-104794 (2023) [C1]
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Nova |
2023 |
Griffin RA, Harrison N, Swegen A, Miller K, DeIuliis G, Rebourcet D, et al., 'Age-related DNA damage in stallions: an ongoing investigation', Journal of Equine Veterinary Science, 125 104590-104590 (2023) [C1]
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Nova |
2023 |
Swegen A, Appeltant R, Williams SA, 'Cloning in action: can embryo splitting, induced pluripotency and somatic cell nuclear transfer contribute to endangered species conservation?', Biol Rev Camb Philos Soc, 98 1225-1249 (2023) [C1]
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Nova |
2022 |
Pollard C-L, Younan A, Swegen A, Gibb Z, Grupen CG, 'Insights into the NAD(+) biosynthesis pathways involved during meiotic maturation and spindle formation in porcine oocytes', JOURNAL OF REPRODUCTION AND DEVELOPMENT, 68 216-224 (2022) [C1]
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Nova |
2022 |
Pollard C-L, Gibb Z, Swegen A, Grupen CG, 'NAD plus , Sirtuins and PARPs: enhancing oocyte developmental competence', JOURNAL OF REPRODUCTION AND DEVELOPMENT, 68 345-354 (2022) [C1]
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Nova |
2022 |
Perera TRW, Skerrett-Byrne DA, Gibb Z, Nixon B, Swegen A, 'The Future of Biomarkers in Veterinary Medicine: Emerging Approaches and Associated Challenges', ANIMALS, 12 (2022) [C1]
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Nova |
2022 |
Lawson EF, Grupen CG, Baker MA, Aitken RJ, Swegen A, Pollard CL, Gibb Z, 'Conception and early pregnancy in the mare: lipidomics the unexplored frontier', Reproduction and Fertility, 3 R1-R18 (2022) [C1]
Lipids are dynamic biological molecules that play key roles in metabolism, inflammation, cell signalling and structure. They are biologically significant in the physiology of conc... [more]
Lipids are dynamic biological molecules that play key roles in metabolism, inflammation, cell signalling and structure. They are biologically significant in the physiology of conception and reproduction. Many of the mechanisms surrounding equine conception and the early feto-maternal dialogue are yet to be understood at a biochemical level. Recently, lipidomic technologies have advanced considerably and analytical strategies have been enhanced and diversified. Consequently, in-depth lipidomic exploration now has the potential to reveal new lipid biomarkers and biochemical relationships that improve our understanding of the processes leading to efficient and successful reproduction. This review considers the role of lipids in conception and establishment of pregnancy, providing new insights into the enigmatic pathways governing early reproductive physiology of the mare.
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Nova |
2022 |
Klein EK, Swegen A, Gunn AJ, Stephen CP, Aitken RJ, Gibb Z, 'The future of assessing bull fertility: Can the 'omics fields identify usable biomarkers? .', Biol Reprod, 106 854-864 (2022) [C1]
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Nova |
2022 |
Pollard CL, Gibb Z, Clulow J, Ruiz A, Sheridan A, Bahrami M, et al., 'NAD(+) precursor concentrations are elevated in the follicular fluid of mares following oral supplementation of nicotinic acid', JOURNAL OF EQUINE VETERINARY SCIENCE, 113 (2022)
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2022 |
Pollard C-L, Gibb Z, Clulow J, Ruiz A, Sheridan A, Bahrami M, et al., 'Supplemental Nicotinic Acid Elevates NAD(+) Precursors in the Follicular Fluid of Mares', ANIMALS, 12 (2022) [C1]
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Nova |
2022 |
Pollard C-L, Gibb Z, Swegen A, Lawson EF, Grupen CG, 'Nicotinic acid supplementation at a supraphysiological dose increases the bioavailability of NAD + precursors in mares (vol 105, pg 1154, 2021)', JOURNAL OF ANIMAL PHYSIOLOGY AND ANIMAL NUTRITION, 106 720-720 (2022)
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2022 |
Griffin RA, Swegen A, Baker MA, Ogle RA, Smith N, Aitken RJ, et al., 'Proteomic analysis of spermatozoa reveals caseins play a pivotal role in preventing short-term periods of subfertility in stallions .', Biol Reprod, 106 741-755 (2022) [C1]
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Nova |
2021 |
Medica AJ, Aitken RJ, Nicolson GL, Sheridan AR, Swegen A, Iuliis GND, Gibb Z, 'Glycerophospholipids protect stallion spermatozoa from oxidative damage in vitro', Reproduction and Fertility, 2 199-209 (2021) [C1]
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Nova |
2021 |
Hildebrandt TB, Hermes R, Goeritz F, Appeltant R, Colleoni S, de Mori B, et al., 'The ART of bringing extinction to a freeze History and future of species conservation, exemplified by rhinos', Theriogenology, 169 76-88 (2021) [C1]
The ongoing mass extinction of animal species at an unprecedented rate is largely caused by human activities. Progressive habitat destruction and fragmentation is resulting in acc... [more]
The ongoing mass extinction of animal species at an unprecedented rate is largely caused by human activities. Progressive habitat destruction and fragmentation is resulting in accelerated loss of biodiversity on a global scale. Over decades, captive breeding programs of non-domestic species were characterized by efforts to optimize species-specific husbandry, to increase studbook-based animal exchange, and to improve enclosure designs. To counter the ongoing dramatic loss of biodiversity, new approaches are warranted. Recently, new ideas, particularly the application of assisted reproduction technologies (ART), have been incorporated into classical zoo breeding programs. These technologies include semen and oocyte collection, artificial insemination, and in-vitro embryo generation. More futuristic ideas of advanced ART (aART) implement recent advances in biotechnology and stem-cell related approaches such as cloning, inner cell mass transfer (ICM), and the stem-cell-associated techniques (SCAT) for the generation of gametes and ultimately embryos of highly endangered species, such as the northern white rhinoceros (Ceratotherium simum cottoni) of which only two female individuals are left. Both, ART and aART greatly depend on and benefit from the rapidly evolving cryopreservation techniques and biobanking not only of genetic, but also of viable cellular materials suitable for the generation of induced pluripotent stem cells (iPSC). The availability of cryopreserved materials bridges gaps in time and space, thereby optimizing the available genetic variability and enhancing the chance to restore viable populations.
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2021 |
Pollard CL, Gibb Z, Hawdon A, Swegen A, Grupen CG, 'Supplementing media with nad
In vitro maturation (IVM) is an important reproductive technology used to produce embryos in vitro. However, the developmental potential of oocytes sourced for IVM is markedly low... [more]
In vitro maturation (IVM) is an important reproductive technology used to produce embryos in vitro. However, the developmental potential of oocytes sourced for IVM is markedly lower than those matured in vivo. Previously, NAD+-elevating treatments have improved oocyte quality and embryo development in cattle and mice, suggesting that NAD+ is important during oocyte maturation. The aim of this study was to examine the effects of nicotinic acid (NA), nicotinamide (NAM) and nicotinamide mononucleotide (NMN) on oocyte maturation and subsequent embryo development. Porcine oocytes from small antral follicles were matured for 44 h in a defined maturation medium supplemented with NA, NAM and resveratrol or NMN. Mature oocytes were artificially activated and presumptive zygotes cultured for 7 days. Additionally, oocytes were matured without treatment then cultured for 7 days with NMN. Supplementing the IVM medium with NA improved maturation and blastocyst formation while NAM supplementation improved cleavage rates compared with untreated controls. Supplementing the IVM or embryo culture media with NMN had no effect on maturation or embryo development. The results show that supplementing the maturation medium with NA and NAM improved maturation and developmental potential of porcine oocytes.
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Nova |
2021 |
Pollard C-L, Gibb Z, Swegen A, Lawson EF, Grupen CG, 'Nicotinic acid supplementation at a supraphysiological dose increases the bioavailability of NAD(+) precursors in mares', JOURNAL OF ANIMAL PHYSIOLOGY AND ANIMAL NUTRITION, 105 1154-1164 (2021) [C1]
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Nova |
2021 |
Swegen A, 'Maternal recognition of pregnancy in the mare: Does it exist and why do we care?', Reproduction, 161 R139-R155 (2021) [C1]
Maternal recognition of pregnancy (MRP) is a process by which an early conceptus signals its presence to the maternal system and prevents the lysis of the corpus luteum, thus ensu... [more]
Maternal recognition of pregnancy (MRP) is a process by which an early conceptus signals its presence to the maternal system and prevents the lysis of the corpus luteum, thus ensuring a maternal milieu supportive of pregnancy continuation. It is a fundamental aspect of reproductive biology, yet in the horse, the mechanism underlying MRP remains unknown. This review seeks to address some of the controversies surrounding the evidence and theories of MRP in the equine species, such as the idea that the horse does not conform to the MRP paradigm established in other species or that equine MRP involves a mechanical, rather than chemical, signal. The review examines the challenges of studying this particularly clandestine phenomenon along with the new tools in scientific research that will drive this quest forward in coming years, and discusses the value of knowledge gleaned along this path in the context of clinical applications for improving breeding outcomes in the horse industry.
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Nova |
2020 |
Griffin RA, Swegen A, Baker M, Aitken RJ, Skerrett-Byrne DA, Rodriguez AS, et al., 'Mass spectrometry reveals distinct proteomic profiles in high- And low-quality stallion spermatozoa', Reproduction, 160 695-707 (2020) [C1]
The horse breeding industry relies upon optimal stallion fertility. Conventional sperm assessments provide limited information regarding ejaculate quality and are not individually... [more]
The horse breeding industry relies upon optimal stallion fertility. Conventional sperm assessments provide limited information regarding ejaculate quality and are not individually predictive of fertilizing potential. The aim of this study was to harness mass spectrometry to compare the proteomic profiles of high- and low-quality stallion spermatozoa, with the ultimate goal of identifying fertility biomarker candidates. Extended stallion semen (n = 12) was fractionated using Percoll density gradients to isolate low-quality and high-quality sperm populations. Motility and morphological assessments were carried out, and proteomic analyses was conducted using UHPLC-MS/MS. High-quality spermatozoa recorded higher total (95.2 ± 0.52% vs 70.6 ± 4.20%; P = 0.001) and progressive motilities (43.4 ± 3.42% vs 27.3 ± 4.32%; P = 0.05), and a higher proportion of morphologically normal cells (50.2 ± 4.34% vs 38.8 ± 2.72%; P = 0.05). In total, 1069 proteins were quantified by UHPLC-MS/MS, of which 22 proteins were significantly more abundant in the high-quality sperm population (P = 0.05). A-kinase anchor protein 4 (AKAP4) and Hexokinase 1 (HK1) were considered possible biomarker candidates and their differential expression was confirmed by immunoblot. Protein expression was significantly correlated with total (AKAP4 R2 = 0.38, P = 0.01; HK1 R2 = 0.46, P = 0.001) and progressive motilities (AKAP4 R2 = 0.51, P = 0.001; HK1 R2 = 0.55, P = 0.01), percentage rapid (AKAP4 R2 = 0.29, P = 0.05; HK1 R2 = 0.58, P = 0.001), straight-line velocity (HK1 R2 = 0.50, P = 0.01) and straightness (HK1 R2 = 0.40, P = 0.01). Furthermore, AKAP4 was highly susceptible to adduction by 4-hydroxynonenal (4HNE), which resulted in a global reduction in the phosphorylation profiles following capacitation. In conclusion, the proteomic profiles of high- and low-quality stallion spermatozoa differ substantially, and proteins such as AKAP4 and HK1 could serve as biomarkers of ejaculate quality.
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Nova |
2020 |
Pollard CL, Gibb Z, Swegen A, Lawson E, Grupen CG, 'Niacin as a dietary supplement for improving mare fertility: A preliminary pharmacokinetic study', Journal of Equine Veterinary Science, 89 103092-103092 (2020)
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2019 |
Swegen A, Smith ND, Gibb Z, Curry BJ, Aitken RJ, 'The serine protease testisin is present on the surface of capacitated stallion spermatozoa and interacts with key zona pellucida binding proteins', Andrology, 7 199-212 (2019) [C1]
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Nova |
2019 |
Clulow J, Swegen A, Aitken J, Gibb Z, 'Preliminary insemination trial to determine the fertility of stallion sperm stored for 3 and 7 days at 17ºC in a long term liquid storage medium', Clinical Theriogenology, 11 461-461
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2019 |
Griffin RA, Baker M, Aitken RJ, Swegen A, Gibb Z, 'What makes a fertile sperm? Unique molecular attributes of stallion fertility.', Reproduction (Cambridge, England), 158 R125-R137 (2019) [C1]
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Nova |
2018 |
Griffin RA, Swegen A, Aitken JR, Gibb Z, 'Investigation Into Predictors of Stallion Fertility and Associations With Oxidative Damage', Journal of Equine Veterinary Science, 66 63-63 (2018)
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2018 |
Swegen A, Clulow JR, Baker M, Aitken RJ, Tram QT, Gibb Z, 'Unraveling Infertility: Deciphering the Molecular Basis of Idiopathic Infertility in a Thoroughbred Stallion', Journal of Equine Veterinary Science, 66 90-90 (2018)
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2018 |
Lawson EF, Gibb Z, de Ruijter-Villani M, Smith ND, Stout TA, Clutton-Brock A, et al., 'Proteomic Analysis of Pregnant Mare Uterine Fluid', Journal of Equine Veterinary Science, 66 171-172 (2018)
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2018 |
Gibb Z, Clulow JR, Aitken RJ, Swegen A, 'First Publication to Describe a Protocol for the Liquid Storage of Stallion Spermatozoa for 7 Days', Journal of Equine Veterinary Science, 66 37-40 (2018)
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2017 |
Swegen A, Grupen CG, Gibb Z, Baker M, de Ruijter-Villani M, Smith ND, et al., 'From Peptide Masses to Pregnancy Maintenance: A Comprehensive Proteomic Analysis of The Early Equine Embryo Secretome, Blastocoel Fluid and Capsule.', Proteomics, 17 1-13 (2017) [C1]
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Nova |
2016 |
Swegen A, Aitken RJ, 'Prospects for immunocontraception in feral horse population control: exploring novel targets for an equine fertility vaccine', Reproduction, Fertility and Development, 28 853-853 (2016) [C1]
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Nova |
2016 |
Swegen A, Lambourne SR, Aitken RJ, Gibb Z, 'Rosiglitazone Improves Stallion Sperm Motility, ATP Content, and Mitochondrial Function', BIOLOGY OF REPRODUCTION, 95 (2016) [C1]
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Nova |
2015 |
Swegen A, Curry BJ, Gibb Z, Lambourne SR, Smith ND, Aitken RJ, 'Investigation of the stallion sperm proteome by mass spectrometry', Reproduction, 149 235-244 (2015) [C1]
Stallion spermatozoa continue to present scientific and clinical challenges with regard to the biological mechanisms responsible for their survival and function. In particular, de... [more]
Stallion spermatozoa continue to present scientific and clinical challenges with regard to the biological mechanisms responsible for their survival and function. In particular, deeper understanding of sperm energy metabolism, defence against oxidative damage and cell-cell interactions should improve fertility assessment and the application of advanced reproductive technologies in the equine species. In this study, we used highly sensitive LC-MS/MS technology and sequence database analysis to identify and characterise the proteome of Percoll-isolated ejaculated equine spermatozoa, with the aim offurthering our understanding of this cell's complex biological machinery. We were able to identify 9883 peptides comprising 1030 proteins, which were subsequently attributed to 975 gene products. Gene ontology analysis for molecular and cellular processes revealed new information about the metabolism, antioxidant defences and receptors of stallion spermatozoa. Mitochondrial proteins and those involved in catabolic processes constituted dominant categories. Several enzymes specific to ß-oxidation of fatty acids were identified, and further experiments were carried out to ascertain their functional significance. Inhibition of carnitine palmitoyl transferase 1, a rate-limiting enzyme of ß-oxidation, reduced motility parameters, indicating that b-oxidation contributes to maintenance of motility in stallion spermatozoa.
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Nova |
2014 |
Swegen A, Aitken RJ, 'Characterisation of the stallion sperm proteome', Journal of Equine Veterinary Science, 34 35-37 (2014)
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