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Pisu MC, Andolfatto A, Ferro A, Esposito S, Veronesi MC, Probo M. Effect of a subcutaneous implant of deslorelin acetate on serum testosterone concentrations in male Hermann's (Testudo hermanni sp.) and Greek (Testudo graeca sp.) tortoises. Vet Res Commun 2023; 47:2279-2284. [PMID: 37173553 DOI: 10.1007/s11259-023-10138-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2022] [Accepted: 05/10/2023] [Indexed: 05/15/2023]
Abstract
Deslorelin acetate is a gonadotropin-releasing hormone agonist formulated in a controlled-release subcutaneous implant and designed for reversible suppression of testosterone production in dogs. It has also been demonstrated to be effective in other animal species, but no data on its effectiveness in male land tortoises are available. This study aimed to evaluate the effect of a 4.7-mg deslorelin acetate implant on serum testosterone concentrations in male Hermann's (Testudo hermanni sp.) and Greek (Testudo graeca sp.) tortoises. Twenty adult male tortoises housed under the same environmental conditions were enrolled for the study and randomly assigned to a treatment (D, n = 10) or a control (C, n = 10) group. Starting in May, males from the D group were implanted with a 4.7-mg deslorelin acetate device, whereas males from the C group did not receive any treatment. Blood samples were collected once immediately before implant application (S0-May) and at 15 days (S1-June), 2 (S2-July), and 5 (S3-October) months after application. Serum testosterone at each sampling time was measured through a solid-phase, enzyme-labeled, competitive chemiluminescent immunoassay. Median serum testosterone concentrations were not significantly different between the two groups in all sampling times, and no interaction between treatment and sampling time was observed. The present study, therefore, suggests that a single treatment with a 4.7-mg deslorelin acetate implant has no effect on testosterone circulation in male Hermann's and Greek tortoises during the following 5 months.
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Affiliation(s)
| | | | - Angelica Ferro
- The Royal (Dick) School of Veterinary Studies and the Roslin Institute, University of Edinburgh, Edinburgh, UK
| | | | - Maria Cristina Veronesi
- Department of Veterinary Medicine and Animal Sciences, Università degli Studi di Milano, Lodi, Italy
| | - Monica Probo
- Department of Veterinary Medicine and Animal Sciences, Università degli Studi di Milano, Lodi, Italy.
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Thompson DM, Ligon DB, Edmond BS, Jane Spangler S, Fillmore BM, Graves KG, Lovern M. Reproductive Cycles of Alligator Snapping Turtles (Macrochelys temminckii). Gen Comp Endocrinol 2023:114310. [PMID: 37244410 DOI: 10.1016/j.ygcen.2023.114310] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/11/2021] [Revised: 04/04/2023] [Accepted: 05/21/2023] [Indexed: 05/29/2023]
Abstract
The alligator snapping turtle (Macrochelys temminckii) is a species for which captive propagation and reintroduction programs are well established; however, little is known about its reproductive behavior and physiology. In this study, we measured monthly plasma sex steroid hormone concentrations of androgen (T+DHT) estradiol-17B (E2), and progesterone (P4), and used ultrasonography to monitor annual reproductive cycles of a captive population of alligator snapping turtles that is maintained under semi-natural conditions in southeastern Oklahoma. Concurrently, we used automated radio telemetry to measure the relative activity levels of male and female alligator snapping turtles and examine these activity patterns in the context of their reproductive cycles. We also measured monthly concentrations of the glucocorticoid (GC) corticosterone (CORT). Seasonal variation was only detected for T in males, but was observed for T, E2, and P4 in females. Vitellogenesis began in August and ended in April and coincided with elevated E2. Ovulation took place 10-29 April and the nesting period lasted from 11 May - 3 June. Males exhibited greater relative activity levels than females in the fall, winter, and early spring, which coincided with the period when mature sperm would be available for mating. Females were more active than males during the peri-nesting period in the spring. Seasonal changes in CORT were detected and did not differ between males and females. CORT concentrations were elevated in the late spring and summer, coincident with the foraging season, and depressed in the fall, and winter, and at their nadir in the early spring.
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Affiliation(s)
- Denise M Thompson
- Department of Biology, Missouri State University, 901 S. National Ave., Springfield, MO 65897, USA; Department of Integrative Biology, Oklahoma State University, 501 Life Sciences West, Stillwater, OK 74078, USA.
| | - Day B Ligon
- Department of Biology, Missouri State University, 901 S. National Ave., Springfield, MO 65897, USA
| | - Brian S Edmond
- Computer Services, Missouri State University, 901 S. National Ave., Springfield, MO 65897, USA
| | - S Jane Spangler
- U.S. Fish and Wildlife Service, Klamath Falls Fish and Wildlife Office, 1936 California Ave., Klamath Falls, OR 97601, USA; Tishomingo National Fish Hatchery, 5501 W. Hwy 7, Tishomingo, OK 73460, USA
| | - Brian M Fillmore
- U.S. Fish and Wildlife Service, Oklahoma Fish and Wildlife Conservation Office, 5700 W. Hwy 7, Tishomingo, OK, 73460, USA; Tishomingo National Fish Hatchery, 5501 W. Hwy 7, Tishomingo, OK 73460, USA
| | - Kerry G Graves
- Tishomingo National Fish Hatchery, 5501 W. Hwy 7, Tishomingo, OK 73460, USA
| | - Matthew Lovern
- Department of Integrative Biology, Oklahoma State University, 501 Life Sciences West, Stillwater, OK 74078, USA
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Currylow AFT, Rafeliarisoa TH, Louis EE, Stanford CB, Randrianjafizanaka ST, Chinn SM, Crocker DE. Characterization of seasonal reproductive and stress steroid hormones in wild Radiated Tortoises, Astrochelys radiata. Gen Comp Endocrinol 2017; 253:70-78. [PMID: 28888695 DOI: 10.1016/j.ygcen.2017.09.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/31/2016] [Revised: 08/29/2017] [Accepted: 09/03/2017] [Indexed: 10/18/2022]
Abstract
The critically endangered Radiated Tortoise (Astrochelys radiata) is endemic to the southern coastlines of Madagascar. Once common, wild populations of this tortoise have undergone dramatic declines in recent years. Although there have been studies documenting reproductive activities, reproductive physiological parameters are unknown yet may be crucial in the recovery of the species. Over four research seasons in remote field locations native to A. radiata, we surveyed for, radio-tracked, and sampled wild, free ranging tortoises. We sampled and measured stress and reproductive parameters (corticosterone [CORT], testosterone [T], estradiol-17β [E2], and progesterone [P]) in 311 plasma samples from 203 wild A. radiata, capturing their active period. Generally, hormone concentrations were associated with body condition, temperature, and humidity. There was wide variation in CORT that varied monthly and by group. Juvenile tortoises maintained more than twice the mean basal CORT concentrations than either adult sex, with the most dramatic distinctions in the middle of the wet season. For adult sex hormones, the last months of the dry season and into the wet season when ground humidities are low and just begin to rise prior to temperature declines, male T concentrations gradually increased to a peak before returning to near undetectable values into the dry season. We had limited data for T concentrations in females, but found average T concentrations were much lower than in males and positively correlated with larger female home range sizes. For female hormone cycles, E2 also peaked in the early 1/3 of the wet season along with male T, and was followed by an uptick in P which correlates to the putative ovulatory cycle. Females tracked over four years showed variation in patterns of P, indicating that number and frequency of clutches vary. Our results suggest that 1) there is high species plasticity in response to stress; 2) A. radiata reproductive cycling is somewhat dissociated with courtship timing and is instead triggered by environmental cues; and 3) individual female reproductive output is irregular. This study is oone of the first to document and describe multi-year seasonal stress and reproductive hormones in a free-ranging Malagasy chelonian. These data may be used to identify key high-production habitats for conservation, and aide in captive management and reproduction in assurance colonies for species health and survival.
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Affiliation(s)
- Andrea F T Currylow
- Integrative and Evolutionary Biology, University of Southern California, Los Angeles, CA, USA.
| | - Tsilavo H Rafeliarisoa
- Animal Biology Department, University of Antananarivo, Antananarivo, Madagascar; Madagascar Biodiversity Partnership; Conservation Genetics Department, Omaha's Henry Doorly Zoo and Aquarium, Omaha, NE, USA
| | - Edward E Louis
- Madagascar Biodiversity Partnership; Conservation Genetics Department, Omaha's Henry Doorly Zoo and Aquarium, Omaha, NE, USA
| | - Craig B Stanford
- Integrative and Evolutionary Biology, University of Southern California, Los Angeles, CA, USA; Herpetology Section, Los Angeles County Natural History Museum, Los Angeles, CA, USA
| | | | - Sarah M Chinn
- Department of Biology, Sonoma State University, Rohnert Park, CA, USA
| | - Daniel E Crocker
- Department of Biology, Sonoma State University, Rohnert Park, CA, USA
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Sacchi R, Scali S, Mangiacotti M, Sannolo M, Zuffi MAL, Pupin F, Gentilli A, Bonnet X. Seasonal variations of plasma testosterone among colour-morph common wall lizards (Podarcis muralis). Gen Comp Endocrinol 2017; 240:114-120. [PMID: 27667154 DOI: 10.1016/j.ygcen.2016.09.012] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/26/2016] [Revised: 09/13/2016] [Accepted: 09/21/2016] [Indexed: 10/21/2022]
Abstract
Sexual steroids influence reproductive behaviours and promote secondary sexual traits. In male lizards, increasing levels of testosterone (T) bolster conspicuous colouration, stimulate territoriality, and trigger antagonistic interactions among rivals. Moreover, in colour polymorphic species, reproductive strategy, aggressiveness and T levels can differ between morphs. Therefore, T level is considered as an important mechanism that regulates the expression of colour polymorphism and sexual behaviours of males. But in the polymorphic territorial wall lizard (Podarcis muralis), a lack of relationship between morphs and aggressiveness challenges the notion that T plays such a role. To examine this issue, we compared adult T levels among three colour morphs (white, yellow and red) through repeated sampling during the mating season. High T levels were observed at the onset of the mating season followed by a significant decrease, a pattern documented in other lizard species. Mean T levels did not differ among morphs. However, yellow males maintained significantly higher T levels over time and displayed a stronger subsequent decline. Overall, in this species, seasonal T patterns differ among morphs, not mean values. Previous studies revealed that T suppresses the immune response; suggesting that a strong initial investment promoted by high T levels may trade-off against immunity (maintenance). Further experimental investigations are required to clarify the relationship between T and reproductive effort in polymorphic species that exhibit complex temporal pattern of T levels.
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Affiliation(s)
- Roberto Sacchi
- Dipartimento di Scienze della Terra e dell'Ambiente, Università degli Studi di Pavia, I-27100 Pavia, Italy.
| | - Stefano Scali
- Museo Civico di Storia Naturale di Milano, Corso Venezia 55, I-20121 Milano, Italy
| | - Marco Mangiacotti
- Museo Civico di Storia Naturale di Milano, Corso Venezia 55, I-20121 Milano, Italy
| | - Marco Sannolo
- CIBIO-InBIO, Universidade do Porto, Campus Agrário de Vairão, 4485-661 Vairão, Portugal
| | - Marco A L Zuffi
- Museo di Storia Naturale dell'Università di Pisa, Via Roma 79, I-56011, Calci (PI), Italy
| | - Fabio Pupin
- MUSE, Museo delle Scienze di Trento, Corso del Lavoro e della Scienza 3, I-38100 Trento, Italy
| | - Augusto Gentilli
- Dipartimento di Scienze della Terra e dell'Ambiente, Università degli Studi di Pavia, I-27100 Pavia, Italy
| | - Xavier Bonnet
- CNRS, Centre d'Etudes Biologiques de Chizé, F-79360 Villiers en Bois, France.
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Sibeaux A, Michel CL, Bonnet X, Caron S, Fournière K, Gagno S, Ballouard JM. Sex-specific ecophysiological responses to environmental fluctuations of free-ranging Hermann's tortoises: implication for conservation. CONSERVATION PHYSIOLOGY 2016; 4:cow054. [PMID: 27933166 PMCID: PMC5142051 DOI: 10.1093/conphys/cow054] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/19/2016] [Revised: 10/10/2016] [Accepted: 10/17/2016] [Indexed: 06/01/2023]
Abstract
Physiological parameters provide indicators to evaluate how organisms respond to conservation actions. For example, individuals translocated during reinforcement programmes may not adapt to their novel host environment and may exhibit elevated chronic levels of stress hormones and/or decreasing body condition. Conversely, successful conservation actions should be associated with a lack of detrimental physiological perturbation. However, physiological references fluctuate over time and are influenced by various factors (e.g. sex, age, reproductive status). It is therefore necessary to determine the range of natural variations of the selected physiological metrics to establish useful baselines. This study focuses on endangered free-ranging Hermann's tortoises (Testudo hermanni hermanni), where conservation actions have been preconized to prevent extinction of French mainland populations. The influence of sex and of environmental factors (site, year and season) on eight physiological parameters (e.g. body condition, corticosterone concentrations) was assessed in 82 individuals from two populations living in different habitats. Daily displacements were monitored by radio-tracking. Most parameters varied between years and seasons and exhibited contrasting sex patterns but with no or limited effect of site. By combining behavioural and physiological traits, this study provides sex-specific seasonal baselines that can be used to monitor the health status of Hermann's tortoises facing environmental threats (e.g. habitat changes) or during conservation actions (e.g. translocation). These results might also assist in selection of the appropriate season for translocation.
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Affiliation(s)
- Adélaïde Sibeaux
- CRCC Centre for Research and Conservation of Chelonians, SOPTOM, Var, 83590 Gonfaron, France
- CIE Centre for Integrative Ecology, School of Life and Environmental Sciences, Deakin University, 3125 Victoria, Australia
| | - Catherine Louise Michel
- Centre d'Etudes Biologiques de Chizé, CEBC UMR-7372, CNRS-Université de La Rochelle, 79360 Villiers en bois, France
| | - Xavier Bonnet
- Centre d'Etudes Biologiques de Chizé, CEBC UMR-7372, CNRS-Université de La Rochelle, 79360 Villiers en bois, France
| | - Sébastien Caron
- CRCC Centre for Research and Conservation of Chelonians, SOPTOM, Var, 83590 Gonfaron, France
| | - Kévin Fournière
- CRCC Centre for Research and Conservation of Chelonians, SOPTOM, Var, 83590 Gonfaron, France
| | - Stephane Gagno
- CRCC Centre for Research and Conservation of Chelonians, SOPTOM, Var, 83590 Gonfaron, France
| | - Jean-Marie Ballouard
- CRCC Centre for Research and Conservation of Chelonians, SOPTOM, Var, 83590 Gonfaron, France
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Lepeigneul O, Ballouard JM, Bonnet X, Beck E, Barbier M, Ekori A, Buisson E, Caron S. Immediate response to translocation without acclimation from captivity to the wild in Hermann’s tortoise. EUR J WILDLIFE RES 2014. [DOI: 10.1007/s10344-014-0857-5] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Moulherat S, Delmas V, Slimani T, El Mouden EH, Louzizi T, Lagarde F, Bonnet X. How far can a tortoise walk in open habitat before overheating? Implications for conservation. J Nat Conserv 2014. [DOI: 10.1016/j.jnc.2013.11.004] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Currylow AF, Tift MS, Meyer JL, Crocker DE, Williams RN. Seasonal variations in plasma vitellogenin and sex steroids in male and female Eastern Box Turtles, Terrapene carolina carolina. Gen Comp Endocrinol 2013; 180:48-55. [PMID: 23174697 DOI: 10.1016/j.ygcen.2012.11.005] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/10/2012] [Revised: 11/08/2012] [Accepted: 11/09/2012] [Indexed: 11/29/2022]
Abstract
The Eastern Box Turtle (Terrapene carolina carolina) is a widespread species that has recently experienced precipitous declines throughout its range. Although many studies have documented aspects of reproduction in box turtles, reproductive physiology of free-ranging animals is unknown and can be crucial in this species' recovery. Over a two-year period, we measured reproductive parameters, (vitellogenin [Vtg], estradiol-17β [E2], and total testosterone [TT]), in plasma of 116 free-ranging Eastern Box Turtles across their active season. We found similar seasonal variations of Vtg and E2 within females. Mid-season, females showed a sharp peak in E2 that correlates with the putative beginning of the ovarian cycle. Individual females lacking these expected peaks of both Vtg and E2 suggest that some female T. c. carolina may not reproduce annually. Females typically expressed undetectable levels of TT, yet there was a small peak in TT early in the active season. Male Eastern Box Turtles exhibited a dual peak in TT. Elevated TT in males was significantly associated with observed sexual behaviors and smaller home ranges. Body condition had no effect on the concentration of TT or E2 in either sex. This is the first study to (1) document Vtg and sex steroid hormones in free-ranging animals of this genus, and (2) relate those metrics to individuals, the population, the purported annual cycle, and to other chelonian species.
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Affiliation(s)
- Andrea F Currylow
- Department of Forestry and Natural Resources, Purdue University, West Lafayette, IN 47907, USA.
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