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Howell LG, Mawson PR, Comizzoli P, Witt RR, Frankham R, Clulow S, O'Brien JK, Clulow J, Marinari P, Rodger JC. Modeling genetic benefits and financial costs of integrating biobanking into the conservation breeding of managed marsupials. CONSERVATION BIOLOGY : THE JOURNAL OF THE SOCIETY FOR CONSERVATION BIOLOGY 2023; 37:e14010. [PMID: 36178038 DOI: 10.1111/cobi.14010] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/18/2022] [Revised: 08/10/2022] [Accepted: 08/25/2022] [Indexed: 06/16/2023]
Abstract
Managed breeding programs are an important tool in marsupial conservation efforts but may be costly and have adverse genetic effects in unavoidably small captive colonies. Biobanking and assisted reproductive technologies (ARTs) could help overcome these challenges, but further demonstration of their potential is required to improve uptake. We used genetic and economic models to examine whether supplementing hypothetical captive populations of dibblers (Parantechinus apicalis) and numbats (Myrmecobius fasciatus) with biobanked founder sperm through ARTs could reduce inbreeding, lower required colony sizes, and reduce program costs. We also asked practitioners of the black-footed ferret (Mustela nigripes) captive recovery program to complete a questionnaire to examine the resources and model species research pathways required to develop an optimized biobanking protocol in the black-footed ferret. We used data from this questionnaire to devise similar costed research pathways for Australian marsupials. With biobanking and assisted reproduction, inbreeding was reduced on average by between 80% and 98%, colony sizes were on average 99% smaller, and program costs were 69- to 83-fold lower. Integrating biobanking made long-standing captive genetic retention targets possible in marsupials (90% source population heterozygosity for a minimum of 100 years) within realistic cost frameworks. Lessons from the use of biobanking technology that contributed to the recovery of the black-footed ferret include the importance of adequate research funding (US$4.2 million), extensive partnerships that provide access to facilities and equipment, colony animals, appropriate research model species, and professional and technical staff required to address knowledge gaps to deliver an optimized biobanking protocol. Applied research investment of A$133 million across marsupial research pathways could deliver biobanking protocols for 15 of Australia's most at-risk marsupial species and 7 model species. The technical expertise and ex situ facilities exist to emulate the success of the black-footed ferret recovery program in threatened marsupials using these research pathways. All that is needed now for significant and cost-effective conservation gains is greater investment by policy makers in marsupial ARTs.
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Affiliation(s)
- Lachlan G Howell
- School of Environmental and Life Sciences, University of Newcastle, Callaghan, New South Wales, Australia
- Centre for Integrative Ecology, School of Life and Environmental Sciences, Deakin University, Burwood, Victoria, Australia
- FAUNA Research Alliance, Kahibah, New South Wales, Australia
| | - Peter R Mawson
- Perth Zoo, Department of Biodiversity, Conservation and Attractions, South Perth, Western Australia, Australia
| | - Pierre Comizzoli
- Smithsonian's National Zoo and Conservation Biology Institute, Washington, D.C., USA
| | - Ryan R Witt
- School of Environmental and Life Sciences, University of Newcastle, Callaghan, New South Wales, Australia
- FAUNA Research Alliance, Kahibah, New South Wales, Australia
| | - Richard Frankham
- School of Natural Sciences, Macquarie University, Sydney, New South Wales, Australia
- Australian Museum, Sydney, New South Wales, Australia
| | - Simon Clulow
- Centre for Conservation Ecology and Genomics, Institute for Applied Ecology, University of Canberra, Bruce, Australian Capital Territory, Australia
| | - Justine K O'Brien
- Taronga Institute of Science and Learning, Taronga Conservation Society, Mosman, New South Wales, Australia
| | - John Clulow
- School of Environmental and Life Sciences, University of Newcastle, Callaghan, New South Wales, Australia
- FAUNA Research Alliance, Kahibah, New South Wales, Australia
| | - Paul Marinari
- Smithsonian's National Zoo and Conservation Biology Institute, Front Royal, Virginia, USA
| | - John C Rodger
- School of Environmental and Life Sciences, University of Newcastle, Callaghan, New South Wales, Australia
- FAUNA Research Alliance, Kahibah, New South Wales, Australia
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Howell LG, Witt RR. Emerging arguments for reproductive technologies in wildlife and their implications for assisted reproduction and conservation of threatened marsupials. Theriogenology 2023; 198:19-29. [PMID: 36529108 DOI: 10.1016/j.theriogenology.2022.12.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2022] [Accepted: 12/06/2022] [Indexed: 12/12/2022]
Abstract
Assisted reproductive technologies (ARTs) have significant potential to make a meaningful contribution to the conservation of threatened wildlife. This is true of Australia's iconic, and endangered koala (Phascolarctos cinereus). If developed, ARTs could offer a solution to manage genetic diversity and costs in breeding programs and may provide frozen repositories for either insurance or the practical production of genetically resilient koalas for release and on-ground recovery. Holding back the wider use of ARTs for koalas and other wildlife is a lack of funding to close the remaining knowledge gaps in the marsupial reproductive sciences and develop the reproductive tools needed. This lack of funding is arguably driven by a poor understanding of the potential contribution ARTs could make to threatened species management. We present a review of our cross-disciplinary and accessible strategy to draw much needed public attention and funding for the development of ARTs in wildlife, using emerging cost and genetic modelling arguments and the koala as a case study.
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Affiliation(s)
- Lachlan G Howell
- School of Environmental and Life Sciences, University of Newcastle, Callaghan, NSW, 2308, Australia; Centre for Integrative Ecology, School of Life and Environmental Sciences, Deakin University Geelong, Melbourne Burwood Campus, 221 Burwood Highway, Burwood, VIC, 3125, Australia; FAUNA Research Alliance, Kahibah, NSW, 2290, Australia.
| | - Ryan R Witt
- School of Environmental and Life Sciences, University of Newcastle, Callaghan, NSW, 2308, Australia; FAUNA Research Alliance, Kahibah, NSW, 2290, Australia.
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Witt RR, Hinds LA, Rodger JC. Human chorionic gonadotrophin does not induce ovulation in the tammar wallaby. AUSTRALIAN MAMMALOGY 2021. [DOI: 10.1071/am20050] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
We investigated whether human chorionic gonadotrophin (hCG), rather than porcine luteinising hormone (pLH), could induce ovulation in the tammar wallaby (Notamacropus eugenii) after priming with pregnant mare serum gonadotrophin (PMSG). pLH is effective, but is more expensive and supply is problematic. On Day 0 pouch young were removed (RPY) and 5mgkg−1 of bromocriptine mesylate was administered to all non-pregnant wallabies (n=12) to reactivate an oestrous cycle. On Day 20 RPY each female received 20IU PMSG i.m. and three days later (Day 23 RPY), the Single-Dose group (n=6) received 500IU of hCG suspended in oil at 0900 hours, and the Multi-Dose group (n=6) received 500IU of hCG at 0900, 1230 and 1630 hours. From Day 25 to Day 28 RPY copulatory plugs were observed in the Single-Dose (n=4 of 6; Day 25.3 to 28.3 RPY) and Multi-Dose (n=5 of 6; Day 25 to 28 RPY) groups. Autopsy on Day 31 RPY revealed that all females had reactivated, and despite all having large preovulatory follicles (4–6mm) in both ovaries, no ovulations or embryos were observed. We conclude that hCG is not an effective source of exogenous LH for the induction of ovulation in the tammar wallaby.
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Rodger JC. Marsupials the alternative therians - From gametes to birth. Theriogenology 2020; 150:405-411. [PMID: 32093964 DOI: 10.1016/j.theriogenology.2020.02.027] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2020] [Accepted: 02/16/2020] [Indexed: 11/15/2022]
Abstract
Marsupial reproduction shares many common features with the more familiar eutherian mammals but things are often done differently, in alternative ways. Like the eutherians marsupials are placental but the period and degree of development supported in the uterus is much shorter and the long growth phase of development is supported by lactation. But these different ways of achieving often similar outcomes are also seen in gamete formation and function, fertilization and early development. This review presents an overview of marsupial reproductive biology with an emphasis on gamete biology.
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Affiliation(s)
- John C Rodger
- FAUNA Research Alliance & School of Environmental & Life Sciences, University of Newcastle, NSW, Australia.
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Witt RR, Hinds LA, Rodger JC. Induction of synchronous oestrus but not ovulation after pre-treatment with the GnRH agonist, Lucrin® Depot, in the tammar wallaby. Theriogenology 2020; 145:24-30. [PMID: 31982691 DOI: 10.1016/j.theriogenology.2020.01.031] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2019] [Revised: 01/14/2020] [Accepted: 01/14/2020] [Indexed: 10/25/2022]
Abstract
We investigated the capacity for pregnant mare serum gonadotrophin (PMSG) and human chorionic gonadotrophin (hCG) to induce synchronous oestrus and ovulation in the tammar wallaby (Notamacropus eugenii) after follicular suppression with Lucrin® Depot, a one-month GnRH agonist. On Day 0 pouch young were removed (RPY) to reactivate a normal oestrous cycle and then two groups were treated with vehicle (Control; n = 5 and Superovulation (SOvn); n = 5) and two groups were treated with 7.5 mg of Lucrin Depot (Lucrin; n = 6; Lucrin+SOvn, n = 6). On Day 20 RPY the SOvn and Lucrin+SOvn Group received 20 IU of PMSG, which was followed on Day 23 RPY with 500 IU of hCG. The Lucrin+SOvn females underwent a more synchronous oestrus with 5 of 6 mating on Day 26 RPY while the SOvn (n = 5/5) and Control (n = 5/5) Groups copulated over two days, between Day 25-27 RPY and Day 27-29 RPY respectively. Mating plugs were not detected in any of the females in the Lucrin Group by Day 31 RPY. Autopsy on Day 31 RPY confirmed all females in each treatment group had undergone a reactivated cycle as evidenced by the presence of a large corpus luteum (CL) in one ovary. At autopsy the females in the Lucrin+SOvn Group had highly stimulated reproductive tracts, and their ovaries contained many follicles >3 mm; 14 ± 2.1 and 15.3 ± 2.1 follicles >3 mm in the CL-bearing ovary and contralateral ovary respectively. Similarly, females in the SOvn Group had 11.4 ± 2.4 and 17.4 ± 1.9 follicles >3 mm in each respective ovary. Uterine flushing and ovarian histology confirmed that females in Lucrin+SOvn and SOvn Groups had not ovulated, but normal oocytes were present in the follicles. By comparison, the Control Group had ovulated with a single embryo being recovered from the uterus of 4 of 5 females. In contrast to all groups, females in the Lucrin Group showed follicular suppression (all follicles <1.5 mm) and an unstimulated reproductive tract. We conclude that a suppression plus stimulation regimen using Lucrin Depot followed by PMSG and hCG has the capacity to synchronise oestrus, and that 20 IU of PMSG stimulates the development of antral follicles >3 mm in both ovaries. However, a single 500 IU treatment of hCG on Day 23 RPY was not able to induce ovulation in the tammar wallaby.
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Affiliation(s)
- Ryan R Witt
- FAUNA Research Alliance and Conservation Biology Research Group, School of Environmental and Life Sciences, Biology Building, University of Newcastle, University Drive, Callaghan, NSW, 2308, Australia.
| | - Lyn A Hinds
- CSIRO Health and Biosecurity, Canberra, ACT, Australia
| | - John C Rodger
- FAUNA Research Alliance and Conservation Biology Research Group, School of Environmental and Life Sciences, Biology Building, University of Newcastle, University Drive, Callaghan, NSW, 2308, Australia
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Rodger JC. Marsupials: Progress and Prospects. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2019; 1200:309-325. [PMID: 31471802 DOI: 10.1007/978-3-030-23633-5_11] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/30/2023]
Abstract
The chapter provides a review of the application of reproductive science to technologies for marsupial conservation and population management and discusses prospects for the future. This includes the status of technologies such as sperm freezing, artificial insemination, and exogenous hormone treatments to stimulate ovarian activity and cycling in the female. Fertility-based population management for introduced pest species and over-abundant native marsupials remain an elusive goal. Immune-contraceptive approaches, despite demonstration of basic effectiveness, have not progressed to field deliverable agents. Emerging genetic technologies such as gene drives offer great promise, but gene modifications face major challenges to be broadly accepted both socially and politically. A main theme is the potential advantages, both genetic and economic, of integrating frozen stored genomic material, such as sperm, into the captive breeding component of threatened species strategies. However, the sperm of many marsupial species display no or very poor recovery of motility on thawing. For this reason, it is proposed that the traditional assisted breeding paradigm for conservation-cervical artificial insemination with thawed frozen sperm, based on cattle breeding-is not a viable default strategy. Rather, techniques such as sperm injection and emerging stem cell technologies that utilize stored frozen cells, and in the case of sperm, immotile cells, are better candidates for the development of a more generic approach. In addition, this change in focus encourages wide scale proactive genome storage when genetic diversity is greatest, without the need to demonstrate success in traditional sperm cryopreservation and thawing. However, the promise of the potential of reproductive science to conservation and non-lethal population management is problematic without far greater recognition of, and investment in, the needs of wildlife by society.
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Affiliation(s)
- John C Rodger
- FAUNA Research Alliance, School of Environmental and Life Sciences, The University of Newcastle, Callaghan, NSW, Australia.
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