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Sánchez-Rivera UÁ, Medrano A, Cruz-Cano NB, Alcántar-Rodríguez A, Dávila-Govantes R, Castro-Camacho YJ, Martínez-Torres M. Implementation of a method for sperm cryopreservation in sceloporine lizards. CONSERVATION PHYSIOLOGY 2022; 10:coac068. [PMID: 36382339 PMCID: PMC9644977 DOI: 10.1093/conphys/coac068] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/16/2022] [Revised: 10/06/2022] [Accepted: 10/23/2022] [Indexed: 06/16/2023]
Abstract
Actual loss of lizard biodiversity continues, even with the implementation of conventional conservation programs. An approach including assisted reproductive techniques such as sperm cryopreservation may contribute to the management of endangered species. We developed a method for sperm cryopreservation in sceloporine lizards and compared the response among the studied species. Prior to the mating season, we obtained semen from adult males of Sceloporus aeneus (n = 21), Sceloporus grammicus (n = 20) and Sceloporus torquatus (n = 21) via pressure of the genital papilla. Volume and sperm concentration were measured before semen dilution in a Tris-egg yolk (TEY) medium to evaluate progressive motility, sperm viability, morphology, plasma membrane and acrosome integrity. Then, we cooled the remaining volumes to 5°C at a rate of 0.1°C per minute to incorporate glycerol (8% v/v) in two fractions. Immediately afterwards, we placed 40 μl of the mix on solid CO2 to form pellets and immersed them in liquid nitrogen for storage. We thawed the pellets at 29°C for 3 minutes and diluted them 1:1 (v/v) in TEY medium to assess sperm quality. We found a positive relationship between body weight and seminal volume in S. grammicus and S. torquatus and a negative correlation with sperm concentration in S. grammicus (P < 0.05). Moreover, we observed that the freezing-thawing process decreased sperm quality in the three species, mostly affecting motility and viability. However, S. torquatus and S. aeneus showed a higher sperm tolerance than S. grammicus.
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Affiliation(s)
- Uriel Á Sánchez-Rivera
- Laboratorio de Biología de la Reproducción. Facultad de Estudios Superiores Iztacala, Universidad Nacional Autónoma de México, 54090, México
- Laboratorio de Reproducción Animal. Facultad de Estudios Superiores Cuautitlán, Universidad Nacional Autónoma de México, 54714, México
- Posgrado en Ciencias de la Producción y de la Salud Animal, Universidad Nacional Autónoma de México, 04510, México
| | - Alfredo Medrano
- Laboratorio de Reproducción Animal. Facultad de Estudios Superiores Cuautitlán, Universidad Nacional Autónoma de México, 54714, México
| | - Norma B Cruz-Cano
- Laboratorio de Biología de la Reproducción. Facultad de Estudios Superiores Iztacala, Universidad Nacional Autónoma de México, 54090, México
| | - Alicia Alcántar-Rodríguez
- Laboratorio de Reproducción Animal. Facultad de Estudios Superiores Cuautitlán, Universidad Nacional Autónoma de México, 54714, México
| | - Rodrigo Dávila-Govantes
- Laboratorio de Biología de la Reproducción. Facultad de Estudios Superiores Iztacala, Universidad Nacional Autónoma de México, 54090, México
| | - Yabín J Castro-Camacho
- Laboratorio de Biología de la Reproducción. Facultad de Estudios Superiores Iztacala, Universidad Nacional Autónoma de México, 54090, México
| | - Martín Martínez-Torres
- Laboratorio de Biología de la Reproducción. Facultad de Estudios Superiores Iztacala, Universidad Nacional Autónoma de México, 54090, México
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Cryopreservation of Sperm from an Endangered Snake with Tests of Post-Thaw Incubation in Caffeine. Animals (Basel) 2022; 12:ani12141824. [PMID: 35883371 PMCID: PMC9311608 DOI: 10.3390/ani12141824] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2022] [Revised: 07/14/2022] [Accepted: 07/15/2022] [Indexed: 11/30/2022] Open
Abstract
Simple Summary Cryopreservation of sperm from reptiles to aid the recovery of endangered species continues to be a challenge. In this study, we tested the cryoperformance of a cryoprotective agent (CPA) mixture to cryopreserve sperm from the endangered Louisiana pinesnake (Pituophis ruthveni). The mixture contained Lake’s buffer with 10% N,N-dimethyl formamide (DMF), 2% methanol, 5% clarified egg yolk, (v/v% final concentration) and was tested against 16 experimental mixtures containing variable concentrations and mixtures of diluents, extenders, CPAs, and additives. In addition, we investigated the effects of post-thaw incubation on sperm motility in TL HEPES supplemented with 10% fetal bovine serum (H10) alone or supplemented with caffeine. We found that the majority of our test additives did not significantly improve the post-thaw motility or viability of sperm. The best performing experimental CPA mixture contained Lake’s buffer with 10% DMF, 2% methanol, and 5% clarified egg yolk with the addition of 5 mg/mL bovine serum albumin (BSA), and post-thaw incubation in both H10 and H10 with caffeine showed improved forward motility. Cryopreservation of sperm from the Louisiana pinesnake improved with the addition of BSA to our base CPA mixture, and post-thaw incubation in H10 improved with caffeine. Abstract Cryopreservation of sperm to preserve the genetic diversity of declining populations is a promising technique to aid in the recovery of endangered species such as the Louisiana pinesnake (Pituophis ruthveni). However, this technique has been performed on only a handful of snake species and with limited success. Here, we tested a cryoprotective agent (CPA) mixture containing Lake’s buffer with 10% N,N-dimethyl formamide (DMF), 2% methanol, 5% clarified egg yolk, (v/v% final concentration) against 16 other CPA-treatment mixtures. These contained either Lake’s buffer or TEST egg yolk buffer as the base diluent with a penetrating or non-penetrating CPA on the post-thaw recovery of sperm motility and viability. We also investigated the effect of post-thaw incubation treatment in TL HEPES supplemented with 10% fetal bovine serum (H10) alone or with caffeine on post-thaw motility parameters. Sperm from 16 Louisiana pinesnakes was cryopreserved, and the effectiveness of the CPA treatment mixtures and post-thaw treatments was determined based on measurements of sperm motility and viability. Sperm cryopreservation significantly reduced initial post-thaw sperm quality for all of the extender treatments. Viability of sperm was best maintained when cryopreserved in an CPA treatment mixture containing Lake’s buffer with 10% DMF, 2% methanol, and 5% clarified egg yolk with the addition of 5 mg/mL bovine serum albumin (BSA). For several extender mixtures a similar percent of post-thaw motility was observed, but no forward motility returned in any post-thaw samples prior to incubation in dilution treatments. Following incubation in both post-thaw treatments, the percent of forward motility and the index of forward progressive movement improved significantly. Post-thaw dilution with H10 containing caffeine improved motility parameters over H10 alone, suggesting further investigation of post-thaw treatment in caffeine could be beneficial. Although, cryopreservation of sperm from the Louisiana pinesnake continues to present a challenge, post-thaw dilution and the addition of BSA to CPA mixtures provides areas for improving cryopreservation methods for this endangered species.
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Blank M, Novaes G, Losano J, Sant’Anna S, Vieira S, Grego K, Pereira R. Insights on sperm assays and cryopreservation in six Neotropical pit vipers. Cryobiology 2022; 106:55-65. [DOI: 10.1016/j.cryobiol.2022.04.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2022] [Revised: 04/12/2022] [Accepted: 04/13/2022] [Indexed: 11/03/2022]
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Clulow S, Clulow J, Marcec-Greaves R, Della Togna G, Calatayud NE. Common goals, different stages: the state of the ARTs for reptile and amphibian conservation. Reprod Fertil Dev 2022; 34:i-ix. [PMID: 35275052 DOI: 10.1071/rdv34n5_fo] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Amphibians and reptiles are highly threatened vertebrate taxa with large numbers of species threatened with extinction. With so many species at risk, conservation requires the efficient and cost-effective application of all the tools available so that as many species as possible are assisted. Biobanking of genetic material in genetic resource banks (GRBs) in combination with assisted reproductive technologies (ARTs) to retrieve live animals from stored materials are two powerful, complementary tools in the conservation toolbox for arresting and reversing biodiversity decline for both amphibians and reptiles. However, the degree of development of the ARTs and cryopreservation technologies differ markedly between these two groups. These differences are explained in part by different perceptions of the taxa, but also to differing reproductive anatomy and biology between the amphibians and reptiles. Artificial fertilisation with cryopreserved sperm is becoming a more widely developed and utilised technology for amphibians. However, in contrast, artificial insemination with production of live progeny has been reported in few reptiles, and while sperm have been successfully cryopreserved, there are still no reports of the production of live offspring generated from cryopreserved sperm. In both amphibians and reptiles, a focus on sperm cryopreservation and artificial fertilisation or artificial insemination has been at the expense of the development and application of more advanced technologies such as cryopreservation of the female germline and embryonic genome, or the use of sophisticated stem cell/primordial germ cell cryopreservation and transplantation approaches. This review accompanies the publication of ten papers on amphibians and twelve papers on reptiles reporting advances in ARTs and biobanking for the herpetological taxa.
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Affiliation(s)
- Simon Clulow
- Centre for Conservation Ecology & Genomics, Institute for Applied Ecology, University of Canberra, Bruce, ACT 2617, Australia
| | - John Clulow
- University of Newcastle, Conservation Biology Research Group, University Drive, Callaghan, NSW 2308, Australia
| | | | - Gina Della Togna
- Universidad Interamericana de Panama, Direccion de Investigacion, Campus Central, Avenida Ricardo J. Alfaro, Panama City, Panama; and Smithsonian Tropical Research Institute, Panama Amphibian Rescue and Conservation Project, Panama
| | - Natalie E Calatayud
- San Diego Zoo Wildlife Alliance, Beckman Center for Conservation Research, 15600 San Pasqual valley Road, Escondido, CA 92025, USA; and Conservation Science Network, 24 Thomas Street, Mayfield, NSW 2304, Australia
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Perry SM, Mitchell MA. Reptile assisted reproductive technologies: can ART help conserve 300million years of evolution by preserving extant reptile biodiversity? Reprod Fertil Dev 2021; 34:385-400. [PMID: 34914885 DOI: 10.1071/rd21034] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2021] [Accepted: 11/04/2021] [Indexed: 11/23/2022] Open
Abstract
Biodiversity loss is the greatest environmental problem threatening ecosystem, animal, and human health. Anthropogenic induced changes to climate, habitat, disease, species distributions, poaching, and unsustainable trade have accelerated extinction rates in all vertebrates, including reptiles. Preventing reptile extinctions will require humans to acknowledge these losses and develop ex situ and in situ plans to preserve them. Assisted reproductive technologies (ART) are management tools used to protect numerous vertebrate taxa; however, progress in developing ART for reptiles has lagged. Creating functional and sustainable reptile ART will strengthen our conservation capacity by capturing genetic material from select individuals to overcome natural or manmade boundaries. Utilising short-term gamete storage and genome resource banking, in conjunction with timed artificial insemination (AI) or ex ovo incubation, could lead to profound advances in reptile conservation, mitigating the loss of reptile biodiversity. In this article, we review ART reptile research completed since the 1970s. Topics include AI, hormonal control of reproduction, gamete collection, gamete storage, and genome resource banking. Additionally, we review the potential application of advanced reproductive methodologies, including in vitro/ex ovo fertilisation, intracytoplasmic sperm injection, cloning (somatic cell nuclear transfer), and genetic editing.
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Affiliation(s)
- Sean M Perry
- Department of Veterinary Clinical Sciences, Louisiana State University School of Veterinary Medicine, Skip Bertman Drive, Baton Rouge, LA, USA; and Mississippi Aquarium, 2100 E Beach Boulevard, Gulfport, MS, USA
| | - Mark A Mitchell
- Department of Veterinary Clinical Sciences, Louisiana State University School of Veterinary Medicine, Skip Bertman Drive, Baton Rouge, LA, USA
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Campbell L, Clulow J, Doody JS, Clulow S. Optimal cooling rates for sperm cryopreservation in a threatened lizard conform to two-factor hypothesis of cryo-injury. Cryobiology 2021; 103:101-106. [PMID: 34499890 DOI: 10.1016/j.cryobiol.2021.09.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2021] [Revised: 09/01/2021] [Accepted: 09/03/2021] [Indexed: 10/20/2022]
Abstract
Assisted reproductive technologies provide important tools for wildlife conservation but have rarely been developed for reptiles. A critical step in developing cryopreservation protocols is establishing optimal cooling rates for cell survival. The two-factor hypothesis explaining cryoinjury to cells originates from an inverted 'U' shape of recovery curves generated in many cell types thawed after cryopreservation, due to cell recovery declining at cooling rates either side of a single optimum. We generated such a curve for the yellow-spotted monitor lizard Varanus panoptes, the first for any reptile. We cryopreserved sperm using two cooling devices (LN2 dry shipper; LN2 bath vapour) and two sperm-holding vessels (Cassou sperm straws; Nunc CryoTubes) to generate four different cooling-rate curves during freezing. Sperm motility and viability (47.3% and 76.5% respectively) were highest when frozen in straws suspended in a LN2 bath at an intermediate cooling rate of 73 °C/min between 0 and -50 °C, whereas sperm frozen in straws suspended in a dry shipper at the fastest cooling rate (231 °C/min between 0 and -50 °C) produced the lowest recovery (10.4% and 36.4% motility and viability, respectively). Sperm frozen in cryotubes at the lowest cooling rates in either LN2 bath vapour or dry shipper produced intermediate recovery. The shape of the optimal cooling curve conformed to the two-factor hypothesis of cryoinjury, the first such evidence in reptile sperm. This in turn led to the identification of simple cryopreservation setups (LN2 vapour with straws and cryotubes; dry shipper with cryotubes but not straws) suitable for cryopreserving lizard sperm in the field.
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Affiliation(s)
- Lachlan Campbell
- School of Environmental and Life Sciences, University of Newcastle, Callaghan, New South Wales, 2308, Australia
| | - John Clulow
- School of Environmental and Life Sciences, University of Newcastle, Callaghan, New South Wales, 2308, Australia
| | - J Sean Doody
- Department of Integrative Biology Sciences, University of South Florida, St. Petersburg Campus, St. Petersburg, Florida, 33701, USA
| | - Simon Clulow
- Centre for Conservation Ecology and Genomics, Institute for Applied Ecology, University of Canberra, Bruce, Australian Capital Territory, 2617, Australia; Department of Biological Sciences, Macquarie University, Sydney, New South Wales, 2109, Australia.
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Hobbs RJ, Upton R, Keogh L, James K, Baxter-Gilbert J, Whiting MJ. Sperm cryopreservation in an Australian skink (Eulamprus quoyii). Reprod Fertil Dev 2021; 34:428-437. [PMID: 34420549 DOI: 10.1071/rd21031] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2021] [Accepted: 07/19/2021] [Indexed: 11/23/2022] Open
Abstract
Assisted reproductive technologies for population and genetic management for threatened herpetofauna have grown substantially in the past decade. Here we describe experiments to optimise sperm cryopreservation in a model squamate, the eastern water skink Eulamprus quoyii. Small, concentrated volumes of highly motile spermatozoa were reliably collected from adult male E. quoyii by non-lethal ventral massage. Samples were used to: (1) test whether protein-rich diluents, namely Beltsville poultry semen extender (BPSE) and TES and Tris (TEST) yolk buffer (TYB), improve post-thaw quality metrics compared with Dulbecco's phosphate-buffered saline (DPBS); and (2) compare the efficacy of these diluents in combination with either 1.35M glycerol or 1.35M dimethyl sulfoxide (DMSO) at two freezing rates, fast (approximately -20°C min-1) versus slow (-6°C min-1). Glycerol and DMSO performed equally well in preserving spermatozoa under slow freezing rates. Under these conditions, the use of the complex diluents BPSE and TYB significantly improved post-thaw total motility compared with DPBS. Complex interactions occurred between cryodiluent type, cryoprotectant and freezing rate when testing fast versus slow freezing rates among treatment groups. Under slow freezing rates, DMSO was better at preserving membrane integrity and motility, regardless of diluent type, but successful fast freezing required complex diluents to support motility and membrane integrity, which has implications for implementation in a field setting.
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Affiliation(s)
- Rebecca J Hobbs
- Taronga Institute of Science and Learning, Taronga Conservation Society Australia, Mosman, NSW 2088, Australia; and Corresponding author
| | - Rose Upton
- Conservation Biology Research Group, School of Environmental and Life Sciences, The University of Newcastle, Callaghan, NSW 2308 Australia
| | - Leesa Keogh
- Office of the NSW Chief Scientist and Engineer, MLC Centre, Sydney, NSW 2000, Australia
| | - Karen James
- Taronga Conservation Society Australia, Taronga Western Plains Zoo, Dubbo, NSW 2830, Australia
| | - James Baxter-Gilbert
- Centre for Invasion Biology, Stellenbosch University, Stellenbosch 7600, South Africa
| | - Martin J Whiting
- Department of Biological Sciences, Macquarie University, Sydney, NSW 2109, Australia
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Young C, Ravida N, Rochford M, Mazzotti F, Curtis M, Durrant B. Sperm cryopreservation in the Burmese python Python bivittatus as a model for endangered snakes. Reprod Fertil Dev 2021; 34:401-409. [PMID: 34412771 DOI: 10.1071/rd21023] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2021] [Accepted: 07/02/2021] [Indexed: 11/23/2022] Open
Abstract
Burmese pythons Python bivittatus captured in the Florida Everglades as part of an invasive species monitoring program served as a model for the development of sperm cryopreservation protocols for endangered snakes. Spermatozoa were collected from the vas deferens and initial motility, plasma membrane integrity and acrosome integrity were recorded before cryopreservation. Spermatozoa were extended in TES and Tris (TEST) yolk buffer with glycerol (GLY) or dimethyl sulfoxide (DMSO) concentrations of 8%, 12% or 16%, or combinations of GLY and DMSO with final concentrations of 4%:4%, 6%:6% or 8%:8%, and frozen at a rate of 0.3°C min-1. Sperm frozen in combinations of GLY and DMSO exhibited greater post-thaw motility and plasma membrane integrity than those frozen in GLY or DMSO alone. All DMSO and GLY:DMSO treatments preserved a greater proportion of intact acrosomes than GLY alone. To determine the best overall cryopreservation protocol for this species, a sperm quality index was calculated, giving equal weight to each of the three measured indicators of cryosurvival. This analysis revealed that Burmese python spermatozoa frozen in 6% GLY:6% DMSO or 4% GLY:4% DMSO exhibited the highest post-thaw viability. This study represents the first comparative, comprehensive attempt to develop a sperm cryopreservation protocol for any snake species.
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Affiliation(s)
- Carly Young
- San Diego Zoo Wildlife Alliance, Beckman Center for Conservation Research, 15600 San Pasqual Valley Road, Escondido, CA 92027, USA; and Corresponding author
| | - Nicole Ravida
- San Diego Zoo Wildlife Alliance, Beckman Center for Conservation Research, 15600 San Pasqual Valley Road, Escondido, CA 92027, USA
| | - Michael Rochford
- Transcon Environmental, Inc., 2455 Bennett Valley Road, Santa Rosa, CA 95404, USA
| | - Frank Mazzotti
- University of Florida, 3205 College Avenue, Davie, FL 33314, USA
| | - Michelle Curtis
- San Diego Zoo Wildlife Alliance, Beckman Center for Conservation Research, 15600 San Pasqual Valley Road, Escondido, CA 92027, USA
| | - Barbara Durrant
- San Diego Zoo Wildlife Alliance, Beckman Center for Conservation Research, 15600 San Pasqual Valley Road, Escondido, CA 92027, USA
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Lamar SK, Nelson NJ, Moore JA, Taylor HR, Keall SN, Ormsby DK. Initial collection, characterization, and storage of tuatara (Sphenodon punctatus) sperm offers insight into their unique reproductive system. PLoS One 2021; 16:e0253628. [PMID: 34237077 PMCID: PMC8266091 DOI: 10.1371/journal.pone.0253628] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2021] [Accepted: 06/09/2021] [Indexed: 12/04/2022] Open
Abstract
Successful reproduction is critical to the persistence of at-risk species; however, reproductive characteristics are understudied in many wild species. New Zealand’s endemic tuatara (Sphenodon punctatus), the sole surviving member of the reptile order Rhynchocephalia, is restricted to 10% of its historic range. To complement ongoing conservation efforts, we collected and characterized mature sperm from male tuatara for the first time. Semen collected both during mating and from urine after courting contained motile sperm and had the potential for a very high percentage of viable sperm cells (98%). Scanning electron microscopy revealed a filiform sperm cell with distinct divisions: head, midpiece, tail, and reduced end piece. Finally, our initial curvilinear velocity estimates for tuatara sperm are 2–4 times faster than any previously studied reptile. Further work is needed to examine these trends at a larger scale; however, this research provides valuable information regarding reproduction in this basal reptile.
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Affiliation(s)
- Sarah K. Lamar
- Centre for Biodiversity and Restoration Ecology, School of Biological Sciences, Victoria University of Wellington, Wellington, New Zealand
- * E-mail:
| | - Nicola J. Nelson
- Centre for Biodiversity and Restoration Ecology, School of Biological Sciences, Victoria University of Wellington, Wellington, New Zealand
| | - Jennifer A. Moore
- Biology Department, Grand Valley State University, Allendale, Michigan, United States of America
| | - Helen R. Taylor
- Royal Zoological Society of Scotland, Edinburgh, United Kingdom
- Department of Anatomy, University of Otago, Dunedin, New Zealand
| | - Susan N. Keall
- Centre for Biodiversity and Restoration Ecology, School of Biological Sciences, Victoria University of Wellington, Wellington, New Zealand
| | - Diane K. Ormsby
- School of Biological Sciences, Victoria University of Wellington, Wellington, New Zealand
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Sandfoss MR, Whittington OM, Reichling S, Roberts BM. Toxicity of cryoprotective agents to semen from two closely related snake species: The endangered Louisiana pinesnake (Pituophis ruthveni) and bullsnake (Pituophis cantenifer). Cryobiology 2021; 101:20-27. [PMID: 34224691 DOI: 10.1016/j.cryobiol.2021.06.008] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2021] [Accepted: 06/28/2021] [Indexed: 11/18/2022]
Abstract
Cryopreservation of sperm is an important tool for the conservation of threatened species. Many species of reptile are under considerable threat of extinction and there has been limited investigation of sperm cryopreservation in this taxonomic group. We performed a comparative test of toxicity to sperm of six commonly used cryoprotective agents (CPAs) at three concentrations (5%, 10%, 20%) from the Louisiana pinesnake, Pituophis ruthveni (n = 11), and the closely related bullsnake, Pituophis cantenifer (n = 8). Our objective was to determine the general toxicity of CPAs for cryopreservation in snakes and the cryoprotective ability of CPAs for sperm from the endangered Louisiana pinesnake. We conducted three experiments to: 1) evaluate the short-term in vitro toxicity of common CPAs in two closely related snake species, 2) determine the effectiveness of cryoprotectants for freezing and thawing semen in the Louisiana pinesnake, and 3) test the possible reduction in toxic effects of individual CPAs on semen of the Louisiana pinesnake by combining two of them. We used measures of motility including total motility, forward motility, and forward progressive motility index to characterize toxic effects and cryoprotective ability of each CPA. The results of our three experiments provide several important findings: 1) sperm of the bullsnake and Louisiana pinesnake responded differently to CPAs, 2) few CPAs provided any cryoprotection, as measured by percent recovered motility, in Louisiana pinesnakes, and 3) using mixtures of CPAs did not reduce toxicity relative to the best performing CPA on its own. Motility was best maintained at a concentration of 5% for CPAs tested; however, cryoprotection was best achieved with glycerol at 20% followed by DMA and DMF at 10%. These results provide further insight into the challenges faced by researchers attempting to cryopreserve sperm from snakes. Further comparative studies are required to determine the generality of cryopreservation methods in reptiles and suggest caution should be taken when developing cryopreservation protocols across species, particularly in snakes. All CPAs tested in this study were permeating CPAs and showed a significant acute toxic effect on motility at concentrations that provided cryoprotection. Future work in snakes might consider additional avenues of cryoprotection and combinations of multiple approaches.
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Affiliation(s)
- Mark R Sandfoss
- Memphis Zoo, Conservation and Research Department, 2000 Prentiss Place, Memphis, TN, 38112, USA.
| | - Oliver M Whittington
- Memphis Zoo, Conservation and Research Department, 2000 Prentiss Place, Memphis, TN, 38112, USA
| | - Steve Reichling
- Memphis Zoo, Conservation and Research Department, 2000 Prentiss Place, Memphis, TN, 38112, USA
| | - Beth M Roberts
- Memphis Zoo, Conservation and Research Department, 2000 Prentiss Place, Memphis, TN, 38112, USA
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Young C, Ravida N, Durrant B. Challenges in the development of sperm cryopreservation protocols for snakes. Reprod Fertil Dev 2021; 33:605-609. [PMID: 34059184 DOI: 10.1071/rd21038] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2021] [Accepted: 05/06/2021] [Indexed: 11/23/2022] Open
Abstract
Snake populations are declining worldwide, but research devoted to the development of sperm cryopreservation techniques for this taxon is very limited. Spermatozoa were collected postmortem from snakes of four squamate families (Elapidae, Colubridae, Viperidae and Pythonidae). Viability assessment was performed before and after cryopreservation. Spermatozoa were extended in TES and Tris (TEST) yolk buffer with 12% dimethylsulfoxide (DMSO) or 12% glycerol and frozen at a rate of 0.3°Cmin-1 . The sperm quality index (SQI), representing three viability parameters (motility, plasma membrane and acrosome integrity), was determined. Despite some species differences, glycerol was a more effective cryoprotectant for Colubridae, whereas DMSO provided greater cryoprotection for spermatozoa of members of the other three families.
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Affiliation(s)
- Carly Young
- San Diego Zoo Wildlife Alliance, Beckman Center for Conservation Research, 15600 San Pasqual Valley Road, Escondido, CA 92027, USA; and Corresponding author
| | - Nicole Ravida
- San Diego Zoo Wildlife Alliance, Beckman Center for Conservation Research, 15600 San Pasqual Valley Road, Escondido, CA 92027, USA
| | - Barbara Durrant
- San Diego Zoo Wildlife Alliance, Beckman Center for Conservation Research, 15600 San Pasqual Valley Road, Escondido, CA 92027, USA
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Campbell L, Clulow J, Howe B, Upton R, Doody S, Clulow S. Efficacy of short-term cold storage prior to cryopreservation of spermatozoa in a threatened lizard. Reprod Fertil Dev 2021; 33:555-561. [PMID: 33646936 DOI: 10.1071/rd20231] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2020] [Accepted: 01/21/2021] [Indexed: 11/23/2022] Open
Abstract
Assisted reproductive technologies (ARTs) have a significant role to play in reptile conservation, yet are severely lacking. Previous attempts to cryopreserve spermatozoa in the threatened lizard Varanus panoptes achieved approximately 48% motile sperm post-thaw for samples frozen immediately after collection. However, the feasibility of extended cold storage before cryopreservation has not been tested. We held V. panoptes spermatozoa at either 25°C or 4°C for 8 days, assessing sperm motility at days 1, 2, 4 and 8. Subsamples were cryopreserved on days 1 and 4 following the previously reported protocol for this species. Percentage motility decreased rapidly at 25°C, but did not decrease significantly until 4 days after collection at 4°C, with >30% motility maintained after 8 days. There was no significant difference in post-thaw motility or viability of samples cryopreserved after 1 or 4 days storage at 4°C, yielding substantial results for both parameters (mean motility 23.8% and 28.1% and mean viability 50.1% and 57.5% after 1 and 4 days respectively). We demonstrate the capacity to extend sperm viability for up to 8 days in unfrozen samples and to produce acceptable post-thaw motility in samples frozen after 4 days of storage, contributing to the development of valuable ARTs for lizards and other reptiles.
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Affiliation(s)
- Lachlan Campbell
- School of Environmental and Life Sciences, University of Newcastle, Callaghan, NSW 2308, Australia
| | - John Clulow
- School of Environmental and Life Sciences, University of Newcastle, Callaghan, NSW 2308, Australia
| | - Belinda Howe
- School of Environmental and Life Sciences, University of Newcastle, Callaghan, NSW 2308, Australia
| | - Rose Upton
- School of Environmental and Life Sciences, University of Newcastle, Callaghan, NSW 2308, Australia
| | - Sean Doody
- School of Environmental and Life Sciences, University of Newcastle, Callaghan, NSW 2308, Australia; and Department of Biological Sciences, University of South Florida, St. Petersburg, FL 33701, USA
| | - Simon Clulow
- Institute for Applied Ecology, University of Canberra, Bruce, ACT 2617, Australia; and Department of Biological Sciences, Macquarie University, Sydney, NSW 2109, Australia; and Corresponding author
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13
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Biobanking in amphibian and reptilian conservation and management: opportunities and challenges. CONSERV GENET RESOUR 2020. [DOI: 10.1007/s12686-020-01142-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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14
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Martínez-Torres M, Sánchez-Rivera UÁ, Cruz-Cano NB, Castro-Camacho YJ, Luis J, Medrano A. A non-invasive method for semen collection and evaluation in small and median size lizards. Reprod Domest Anim 2020; 54 Suppl 4:54-58. [PMID: 31625233 DOI: 10.1111/rda.13536] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2019] [Revised: 07/19/2019] [Accepted: 07/21/2019] [Indexed: 11/29/2022]
Abstract
The aim of this study was to develop a non-invasive procedure to stimulate ejaculation in median and small lizards for semen collection. After semen collection, we applied a battery of tests to assess the motility (wave and progressive), viability (eosin-nigrosin stain), morphology (normal/abnormal), sperm concentration and ejaculate number, seminal volume and colour. We obtained this fluid from all males of the four species of sceloporine lizards (n = 30) and one species of Mexican horned lizards (n = 7). We found that semen from all males had a liquid-like consistency and a milky-white appearance. Ejaculate volume and sperm concentration varied among the males and the species studied. We also observed that although the mobility, viability and normal sperm morphology showed a wide variability, their average value in each species was high. We conclude that "genital papilla pressure" was an efficient and non-invasive semen obtaining method for small- and medium-sized lizards that does not imply damage to donors and could be used in other lizard species.
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Affiliation(s)
- Martín Martínez-Torres
- Laboratorio de Biología de la Reproducción, Facultad de Estudios Superiores Iztacala, Universidad Nacional Autónoma de México, Tlalnepantla, México
| | - Uriel Ángel Sánchez-Rivera
- Laboratorio de Biología de la Reproducción, Facultad de Estudios Superiores Iztacala, Universidad Nacional Autónoma de México, Tlalnepantla, México
| | - Norma Berenice Cruz-Cano
- Laboratorio de Biología de la Reproducción, Facultad de Estudios Superiores Iztacala, Universidad Nacional Autónoma de México, Tlalnepantla, México
| | - Yabín Josué Castro-Camacho
- Laboratorio de Biología de la Reproducción, Facultad de Estudios Superiores Iztacala, Universidad Nacional Autónoma de México, Tlalnepantla, México
| | - Juana Luis
- Laboratorio de Biología de la Reproducción, Facultad de Estudios Superiores Iztacala, Universidad Nacional Autónoma de México, Tlalnepantla, México
| | - Alfredo Medrano
- Laboratorio de Reproducción Animal, Facultad de Estudios Superiores Cuautitlán, Universidad Nacional Autónoma de México, Cuautitlán Izcalli, México
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Campbell L, Cafe SL, Upton R, Doody JS, Nixon B, Clulow J, Clulow S. A model protocol for the cryopreservation and recovery of motile lizard sperm using the phosphodiesterase inhibitor caffeine. CONSERVATION PHYSIOLOGY 2020; 8:coaa044. [PMID: 32607239 PMCID: PMC7307436 DOI: 10.1093/conphys/coaa044] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/04/2019] [Revised: 08/29/2019] [Accepted: 05/12/2020] [Indexed: 05/08/2023]
Abstract
Reproductive technologies such as genome storage and assisted reproduction have a significant role to play in ending or reversing species extinctions. However, such technologies for non-model organisms (i.e. non-mammalian species) are poorly developed. This is particularly true for the reptiles, in which there is a dearth of successful protocols for cryopreserving reptile spermatozoa, despite limited attempts. We investigated sperm cryopreservation in the Australian lizard Varanus panoptes with the objective of addressing the unmet need for an optimized cryopreservation protocol for the spermatozoa of squamate reptiles. We tested the efficacy of two cryoprotectants [dimethyl sulfoxide (DMSO) and glycerol] as well supplementation with a phosphodiesterase inhibitor (caffeine) to promote post-thaw motility. For cryopreservation, sperm were cooled in straws suspended in liquid nitrogen vapour for 5 minutes (approximately -135°C), before being plunged into liquid nitrogen (approximately -196°C), and later thawed in a water bath at 35°C. Samples were incubated post-thaw for 10 minutes in the presence or absence of 10 mM of caffeine. Both cryoprotectant type and concentration significantly affected percent sperm motility pre-freezing, with DMSO being less cytotoxic than glycerol and motility decreasing at higher concentrations of both cryoprotectant types. While cold shock did not significantly affect sperm motility, both cryoprotectant type and concentration did significantly impact the motility of post-thawed spermatozoa. Thus, mid-range concentrations (10% v/v) of DMSO and glycerol yielded a greater post-thaw motility compared with 5 and 20% v/v, while DMSO proved superior to glycerol. The addition of caffeine resulted in a significant recovery of post-thaw motility for both cryoprotectants, with higher rates of motility being associated with higher cryoprotectant concentrations. These protocols provide a significant step forward for in situ and ex situ management of threatened reptiles and add to recent evidence that reptilian sperm may have the full range of phosphorylation-mediated cellular mechanisms associated with capacitation, motility and metabolic regulation found in mammalian sperm.
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Affiliation(s)
- Lachlan Campbell
- School of Environmental and Life Sciences, University of Newcastle, Callaghan, New South Wales 2308, Australia
| | - Shenae L Cafe
- School of Environmental and Life Sciences, University of Newcastle, Callaghan, New South Wales 2308, Australia
| | - Rose Upton
- School of Environmental and Life Sciences, University of Newcastle, Callaghan, New South Wales 2308, Australia
| | - J Sean Doody
- School of Environmental and Life Sciences, University of Newcastle, Callaghan, New South Wales 2308, Australia
- Department of Biological Sciences, Southeastern Louisiana University, Hammond, LA 70402, USA
- Department of Biological Sciences, University of South Florida, St. Petersburg, FL 33701, USA
| | - Brett Nixon
- School of Environmental and Life Sciences, University of Newcastle, Callaghan, New South Wales 2308, Australia
| | - John Clulow
- School of Environmental and Life Sciences, University of Newcastle, Callaghan, New South Wales 2308, Australia
| | - Simon Clulow
- School of Environmental and Life Sciences, University of Newcastle, Callaghan, New South Wales 2308, Australia
- Department of Biological Sciences, Macquarie University, Sydney, New South Wales 2109 Australia
- Corresponding author: Tel: +61 459 551 370, E-mail:
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Valverde A, Madrigal-Valverde M, Castro-Morales O, Gadea-Rivas A, Johnston S, Soler C. Kinematic and head morphometric characterisation of spermatozoa from the Brown Caiman (Caiman crocodilus fuscus). Anim Reprod Sci 2019; 207:9-20. [PMID: 31266600 DOI: 10.1016/j.anireprosci.2019.06.011] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2019] [Revised: 05/23/2019] [Accepted: 06/11/2019] [Indexed: 01/18/2023]
Abstract
The development of analytical methods for the evaluation of crocodilian semen is an important component for the assessment of male breeding soundness and the development of assisted breeding technology in this taxon. Computer-Assisted Semen Analysis (CASA) technology is becoming an increasingly common technique in seminal evaluations for animals but there has been no application of this technique for reptilian spermatozoa. The aim of this study was to analyse sperm kinematic and morphometric variables in Caiman crocodilus fuscus semen samples and to determine whether there were sperm subpopulations. Four ejaculates from four sexually mature captive caimans were used for this study. A CASA-Mot and CASA-Morph system was used with an image acquisition rate of 50 Hz for 2 s of capture. The ISAS®D4C20 counting chambers were used and spermatozoa incubated at 25 °C. Total and progressive motilities did not differ among animals (P > 0.05). There was a significant animal effect in the model with respect to sperm morphometry, and kinematic indices including linearity (LIN) and straightness (STR) (P < 0.05). Results for principal component (PC) analysis indicated variables were grouped into four components: PC1 related to velocity, PC2 to progressivity, PC3 to oscillation and PC4 to sperm path cross-linking. Subpopulation (SP) structure analysis indicated there were four groups, namely, rapid non-progressive (SP1), slow non-progressive (SP2), rapid progressive (SP3) and medium progressive (SP4), representing 14.5%, 45.4%, 18.7%, and 21.4% respectively. Findings in the present study indicate the importance of continuing development of reliable protocols regarding the standardisation of computer-based semen analyses in reptilian species.
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Affiliation(s)
- Anthony Valverde
- Costa Rica Institute of Technology, School of Agronomy, San Carlos Campus, 223-21001, Alajuela, Costa Rica; University of Valencia, Department of Cellular Biology, Functional Biology and Physical Anthropology, Campus Burjassot, C/ Dr Moliner, 50, 46100, Burjassot, Spain.
| | - Mónica Madrigal-Valverde
- Costa Rica Institute of Technology, School of Agronomy, San Carlos Campus, 223-21001, Alajuela, Costa Rica; Federal University of Bahia, School of Veterinary Medicine and Animal Science, 40170-110, Salvador, Bahia, Brazil
| | - Olivier Castro-Morales
- Costa Rica Institute of Technology, School of Agronomy, San Carlos Campus, 223-21001, Alajuela, Costa Rica
| | - Arnoldo Gadea-Rivas
- Costa Rica Institute of Technology, School of Agronomy, San Carlos Campus, 223-21001, Alajuela, Costa Rica
| | - Stephen Johnston
- School of Agriculture and Food Science, The University of Queensland, Gatton, Qld, 4343, Australia
| | - Carles Soler
- University of Valencia, Department of Cellular Biology, Functional Biology and Physical Anthropology, Campus Burjassot, C/ Dr Moliner, 50, 46100, Burjassot, Spain; Proiser R+D, Scientific Park, University of Valencia, C/ Catedràtic Agustín Escardino, 9, Building 3 (CUE), Floor 1, 46980, Paterna, Valencia, Spain
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17
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López Juri G, Chiaraviglio M, Cardozo G. Electrostimulation is an effective and safe method for semen collection in medium-sized lizards. Theriogenology 2018; 118:40-45. [DOI: 10.1016/j.theriogenology.2018.05.035] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2018] [Revised: 05/26/2018] [Accepted: 05/28/2018] [Indexed: 11/25/2022]
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