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Prévot D'Alvise N, Ascensio E, Richard S. Influence of EE2 exposure, age and sex on telomere length in European long-snouted seahorse (Hippocampus guttulatus). Gen Comp Endocrinol 2024; 346:114419. [PMID: 38040384 DOI: 10.1016/j.ygcen.2023.114419] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/15/2023] [Revised: 11/17/2023] [Accepted: 11/26/2023] [Indexed: 12/03/2023]
Abstract
After a Telomere Lengthening in juvenile stage, a progressive telomere shortening occurs with age despite higher telomerase level. Telomere Length (TL) may also reflect past physiological state such as a chronic chemical stress. Several studies have revealed a correlation between TL, ageing and/or sex in vertebrates, including teleosts; however, the patterns of telomere dynamics with telomerase mRNA expression, sex, lifespan or chemical stress in teleosts are unclear. The first aim of this study is to verify if telomere length is age and sex-dependent. The second aim is to consider if TL is a useful indicator of stress response in European long-snouted seahorse, Hippocampus guttulatus, an ectothermic and non-model system. We showed that after telomere lengthening during the juvenile stage, a telomeric attrition became significant in sexually mature individuals (p = 0.042). TL decreased in older seahorses despite the presence of somatic telomerase mRNA expression at all life stages studied. There was no difference in TL between males and females, but telomerase mRNA expression was consistently higher in females than males. Exposure to EE2 had no effect on TL in young seahorses, but was correlated with a significant increase in telomerase mRNA expression and various physiological disruptions. Here, a growth retardation of -10 % for body length (p = 0.016) and approximately -45 % for mass (p = 0.001) compared to healthy juvenile seahorses was observed. Our data suggest that telomere dynamics alone should not be used as a marker of EE2 exposure in juvenile seahorses.
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Affiliation(s)
- Nathalie Prévot D'Alvise
- Mediterranean Institute of Oceanography (MIO), UMR 7294, Équipe EMBIO, Université de Toulon, CS 60584 - 83 041 Toulon Cedex 9, France.
| | - Eliette Ascensio
- Mediterranean Institute of Oceanography (MIO), UMR 7294, Équipe EMBIO, Université de Toulon, CS 60584 - 83 041 Toulon Cedex 9, France
| | - Simone Richard
- Mediterranean Institute of Oceanography (MIO), UMR 7294, Équipe EMBIO, Université de Toulon, CS 60584 - 83 041 Toulon Cedex 9, France
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Holt WV, Fazeli A, Otero-Ferrer F. Sperm transport and male pregnancy in seahorses: An unusual model for reproductive science. Anim Reprod Sci 2022; 246:106854. [PMID: 34579988 DOI: 10.1016/j.anireprosci.2021.106854] [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: 05/21/2021] [Revised: 09/14/2021] [Accepted: 09/15/2021] [Indexed: 12/14/2022]
Abstract
The Syngnathidae (seahorses and pipefishes) are a group of teleost fishes in which, uniquely, developing embryos are hosted throughout pregnancy by males, using a specialized brood pouch situated on the abdomen or tail. Seahorses have evolved the most advanced form of brood pouch, whereby zygotes and embryos are intimately connected to the host's circulatory system and also bathed in pouch fluid. The pouch is closed to the external environment and has to perform functions such as gaseous exchange, removal of waste and maintenance of appropriate osmotic conditions, much like the mammalian placenta. Fertilization of the oocytes occurs within the brood pouch, but unlike the mammalian situation the sperm transport mechanism from the ejaculatory duct towards the pouch is unclear, and the sperm: egg ratio (about 5:1) is possibly the least of any vertebrate. In this review, there is highlighting of the difficulty of elucidating the sperm transport mechanism, based on studies of Hippocampus kuda. The similarities between seahorse pouch function and the mammalian placenta have led to suggestions that the pouch provides important nutritional support for the developing embryos, supplementing the nutritional functions of the yolk sac provided by the oocytes. In this review, there is a description of the recent evidence in support of this hypothesis, and also emphasis, as in mammals, that embryonic development depends on nutritional support from the placenta-like pouch at important stages of the gestational period ("critical windows").
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Affiliation(s)
- William V Holt
- Academic Unit of Reproductive and Developmental Medicine, Department of Oncology and Metabolism, University of Sheffield, Level 4, Jessop Wing, Tree Root Walk, Sheffield S10 2SF, UK.
| | - Alireza Fazeli
- Institute of Veterinary Medicine and Animal Sciences, Estonian University of Life Sciences, Tartu, Estonia; Department of Pathophysiology, Institute of Biomedicine and Translational Medicine, Faculty of Medicine, Tartu University, Tartu, Estonia; Academic Unit of Reproductive and Developmental Medicine, Department of Oncology and Metabolism, Medical School, University of Sheffield, Sheffield, UK
| | - Francisco Otero-Ferrer
- University Institute of Sustainable Aquaculture and Marine Ecosystems (IU ECOAQUA) Scientific and Technological Marine Park, University of Las Palmas de Gran Canaria, 35200, Spain
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Home range use in the West Australian seahorse Hippocampus subelongatus is influenced by sex and partner’s home range but not by body size or paired status. J ETHOL 2021. [DOI: 10.1007/s10164-021-00698-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
AbstractGenetic monogamy is the rule for many species of seahorse, including the West Australian seahorse Hippocampus subelongatus. In this paper, we revisit mark-recapture and genetic data of H. subelongatus, allowing a detailed characterization of movement distances, home range sizes and home range overlaps for each individual of known sex, paired status (paired or unpaired) and body size. As predicted, we find that females have larger home ranges and move greater distances compared to males. We also confirm our prediction that the home ranges of pair-bonded individuals (members of a pair known to reproduce together) overlap more on average than home ranges of randomly chosen individuals of the opposite or same sex. Both sexes, regardless of paired status, had home ranges that overlapped with, on average, 6–10 opposite-sex individuals. The average overlap area among female home ranges was significantly larger than the overlap among male home ranges, probably reflecting females having larger home ranges combined with a female biased adult sex ratio. Despite a prediction that unpaired individuals would need to move around to find a mate, we find no evidence that unpaired members of either sex moved more than paired individuals of the same sex. We also find no effect of body size on home range size, distance moved or number of other individuals with which a home range overlapped. These patterns of movement and overlap in home ranges among individuals of both sexes suggest that low mate availability is not a likely explanation for the maintenance of monogamy in the West Australian seahorse.
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Whittington CM, Friesen CR. The evolution and physiology of male pregnancy in syngnathid fishes. Biol Rev Camb Philos Soc 2020; 95:1252-1272. [PMID: 32372478 DOI: 10.1111/brv.12607] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2019] [Revised: 04/09/2020] [Accepted: 04/09/2020] [Indexed: 12/24/2022]
Abstract
The seahorses, pipefishes and seadragons (Syngnathidae) are among the few vertebrates in which pregnant males incubate developing embryos. Syngnathids are popular in studies of sexual selection, sex-role reversal, and reproductive trade-offs, and are now emerging as valuable comparative models for the study of the biology and evolution of reproductive complexity. These fish offer the opportunity to examine the physiology, behavioural implications, and evolutionary origins of embryo incubation, independent of the female reproductive tract and female hormonal milieu. Such studies allow us to examine flexibility in regulatory systems, by determining whether the pathways underpinning female pregnancy are also co-opted in incubating males, or whether novel pathways have evolved in response to the common challenges imposed by incubating developing embryos and releasing live young. The Syngnathidae are also ideal for studies of the evolution of reproductive complexity, because they exhibit multiple parallel origins of complex reproductive phenotypes. Here we assay the taxonomic distribution of syngnathid parity mode, examine the selective pressures that may have led to the emergence of male pregnancy, describe the biology of syngnathid reproduction, and highlight pressing areas for future research. Experimental tests of a range of hypotheses, including many generated with genomic tools, are required to inform overarching theories about the fitness implications of pregnancy and the evolution of male pregnancy. Such information will be widely applicable to our understanding of fundamental reproductive and evolutionary processes in animals.
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Affiliation(s)
- Camilla M Whittington
- The University of Sydney, School of Life and Environmental Sciences, Sydney, New South Wales, 2006, Australia.,The University of Sydney, Sydney School of Veterinary Science, Sydney, New South Wales, 2006, Australia
| | - Christopher R Friesen
- The University of Wollongong, School of Earth, Atmospheric and Life Sciences, Faculty of Science, Medicine and Health, Wollongong, New South Wales, 2522, Australia.,Illawarra Health and Medical Research Institute (IHMRI), University of Wollongong, Wollongong, New South Wales, 2522, Australia
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D'Alvise NP, Richard S, Aublanc P, Bunet R, Bonnefont JL. When male seahorses take the female contraceptive pill .. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2020; 27:16528-16538. [PMID: 32128727 DOI: 10.1007/s11356-020-08152-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/11/2019] [Accepted: 02/19/2020] [Indexed: 06/10/2023]
Abstract
17α-ethinylestradiol (EE2), the female contraceptive pill, has been detected in mediterranean coasts where seahorse populations, Hippocampus guttulatus, live. Low environmental concentrations have the potential to disrupt growth but also endocrine metabolism, and this imbalance is all the more critical in early life stage. To investigate the impact of EE2 in reared seahorses, we exposed aged 2 months and sexually undifferentiated seahorses to an environmental concentration of 21 ng/L of EE2 for a period of 30 days. EE2 exposure led to a 19% reduction in weight, but also a mortality rate of 27%. This exposure predicted demasculinization of male individuals with a late onset of secondary sexual characteristics. EE2 exposure led to an increase of the free androgen index, but significant reductions of estradiol and testosterone in males were observed. This low estrogen concentration seemed to impact the positive feedback on luteinizing hormone (LH) with a decrease in LH production. Added to this, synthetic estrogen had a negative impact on the production and the release of follicle-stimulating hormone. Contrary to all expectations, females demonstrated a significant decrease in vitellogenin, following exposure to EE2 at 21 ng/L, while no changes were detected in males. This first study on the European long-snouted seahorses confirmed the deleterious impact of the female contraceptive pill with a real impact on growth, sexual differentiation, and maturation in young immature seahorses.
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Affiliation(s)
- Nathalie Prévot D'Alvise
- Mediterranean Institute of Oceanography (MIO) - UMR 7294, Équipe EMBIO, Université de Toulon, CS 60584, 83 041, Toulon Cedex 9, France.
| | - Simone Richard
- Mediterranean Institute of Oceanography (MIO) - UMR 7294, Équipe EMBIO, Université de Toulon, CS 60584, 83 041, Toulon Cedex 9, France
| | - Philippe Aublanc
- Institut Océanographique Paul Ricard (IOPR), Ile des Embiez, 83140, Six Fours Les Plages, France
| | - Robert Bunet
- Institut Océanographique Paul Ricard (IOPR), Ile des Embiez, 83140, Six Fours Les Plages, France
| | - Jean-Luc Bonnefont
- Institut Océanographique Paul Ricard (IOPR), Ile des Embiez, 83140, Six Fours Les Plages, France
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Shao P, Yong P, Wang X, Xie S, Fan Y, Zang L, Cui L, Sun J. Isolation, identification, and histopathological analysis of Vibrio tubiashii from lined seahorse Hippocampus erectus. DISEASES OF AQUATIC ORGANISMS 2019; 133:195-205. [PMID: 31187734 DOI: 10.3354/dao03350] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
The lined seahorse Hippocampus erectus is an economically important aquaculture species; however, the low survival rate of juvenile seahorses severely restricts their large-scale cultivation. According to previous research, dead juvenile seahorses (4-6 cm) showed symptoms of suspected enteritis, including abdominal depression, raised cloaca, partial hepatic congestion, and yellow sticky liquid filling the intestine. Here, we isolated a Gram-negative bacterium from diseased juvenile seahorses and tentatively named the strain HEL-5. Healthy juvenile seahorses were then challenged with the strain through intraperitoneal injection, with results confirming that HEL-5 was pathogenic for seahorses at a median lethal dose of 5.81 × 105 CFU g-1 fish weight. Based on morphological observations, biochemical characteristics, and sequence analysis of 16S rRNA and housekeeping genes (gyrB, ftsZ, and gapA), we identified HEL-5 as Vibrio tubiashii. Histopathological observations revealed that V. tubiashii was capable of causing lytic necrosis of hepatocytes and forming obvious necrotic foci, and renal pathology was characterized by tubular collapse and tubular epithelial-cell shedding into the lumen accompanied by a large number of inflammatory cells infiltrating the tissues of the intestines and kidneys. Antimicrobial-susceptibility testing showed that the strain was highly sensitive to macrolides, chloramphenicol, sulfonamides, aminoglycosides, and cephalosporins. These findings represent the first report of isolation of V. tubiashii from diseased juvenile seahorses and provide a foundation for the prevention and treatment of vibrio disease in seahorse aquaculture.
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Affiliation(s)
- Peng Shao
- Tianjin Key Lab of Aqua-Ecology and Aquaculture, College of Fisheries, Tianjin Agricultural University, Tianjin 300384, PR China
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