1
|
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").
Collapse
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
| |
Collapse
|
2
|
Diversity of Seahorse Species (Hippocampus spp.) in the International Aquarium Trade. DIVERSITY 2021. [DOI: 10.3390/d13050187] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Seahorses (Hippocampus spp.) are threatened as a result of habitat degradation and overfishing. They have commercial value as traditional medicine, curio objects, and pets in the aquarium industry. There are 48 valid species, 27 of which are represented in the international aquarium trade. Most species in the aquarium industry are relatively large and were described early in the history of seahorse taxonomy. In 2002, seahorses became the first marine fishes for which the international trade became regulated by CITES (Convention for the International Trade in Endangered Species of Wild Fauna and Flora), with implementation in 2004. Since then, aquaculture has been developed to improve the sustainability of the seahorse trade. This review provides analyses of the roles of wild-caught and cultured individuals in the international aquarium trade of various Hippocampus species for the period 1997–2018. For all species, trade numbers declined after 2011. The proportion of cultured seahorses in the aquarium trade increased rapidly after their listing in CITES, although the industry is still struggling to produce large numbers of young in a cost-effective way, and its economic viability is technically challenging in terms of diet and disease. Whether seahorse aquaculture can benefit wild populations will largely depend on its capacity to provide an alternative livelihood for subsistence fishers in the source countries. For most species, CITES trade records of live animals in the aquarium industry started a few years earlier than those of dead bodies in the traditional medicine trade, despite the latter being 15 times higher in number. The use of DNA analysis in the species identification of seahorses has predominantly been applied to animals in the traditional medicine market, but not to the aquarium trade. Genetic tools have already been used in the description of new species and will also help to discover new species and in various other kinds of applications.
Collapse
|
3
|
Otero-Ferrer F, Lättekivi F, Ord J, Reimann E, Kõks S, Izquierdo M, Holt WV, Fazeli A. Time-critical influences of gestational diet in a seahorse model of male pregnancy. ACTA ACUST UNITED AC 2020; 223:jeb.210302. [PMID: 31862853 PMCID: PMC7033721 DOI: 10.1242/jeb.210302] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2019] [Accepted: 12/18/2019] [Indexed: 12/15/2022]
Abstract
Sex role reversal is not uncommon in the animal kingdom but is taken to the extreme by the Syngnathidae, in which male pregnancy is one of the most astonishing idiosyncrasies. However, critical and time-dependent environmental effects on developing embryos, such as those extensively studied in mammalian pregnancy, have not been investigated in the male pregnancy context. Here, we tested the hypothesis that seahorse pregnancy is subject to ‘critical windows’ of environmental sensitivity by feeding male long-snouted seahorses (Hippocampus reidi) a diet deficient in polyunsaturated fatty acids during specific periods before and during pregnancy. Despite embryos being nourished principally by maternally supplied yolk, we found that offspring morphology, fatty acid composition and gene expression profiles were influenced by paternal diet in a manner that depended critically on the timing of manipulation. Specifically, reception of a diet deficient in polyunsaturated fatty acids in the days preceding pregnancy resulted in smaller newborn offspring, while the same diet administered towards the end of pregnancy resulted in substantial alterations to newborn gene expression and elongation of the snout at 10 days old. Although paternal diet did not affect 10 day survival, the observed morphological alterations in some cases could have important fitness consequences in the face of natural selective pressures such as predation and food availability. Our results demonstrate that, under male pregnancy, fine-scale temporal variation in parental diet quality and subsequent critical window effects should not be overlooked as determinants of developing offspring fitness. Summary: Food quality has a time-dependent impact on the offspring of male seahorses, revealing new insights into male pregnancy and its potential adaptive importance for syngnathid offspring.
Collapse
Affiliation(s)
- Francisco Otero-Ferrer
- Grupo en Biodiversidad y Conservación, Instituto Universitario en Acuicultura Sostenible y Ecosistemas Marinos (IU-ECOAQUA), Universidad de Las Palmas de Gran Canaria, Marine Scientific and Technological Park, Carretera de Taliarte s/n, E-35214 Telde, Spain
| | - Freddy Lättekivi
- Institute of Biomedicine and Translational Medicine, Department of Pathophysiology, University of Tartu, Ravila 14b, 50411 Tartu, Estonia
| | - James Ord
- Institute of Biomedicine and Translational Medicine, Department of Pathophysiology, University of Tartu, Ravila 14b, 50411 Tartu, Estonia
| | - Ene Reimann
- Institute of Biomedicine and Translational Medicine, Department of Pathophysiology, University of Tartu, Ravila 14b, 50411 Tartu, Estonia
| | - Sulev Kõks
- Perron Institute for Neurological and Translational Science, RR Block, QE II Medical Centre, 8 Verdun Street, Nedlands, WA 6009, Australia
| | - Marisol Izquierdo
- Grupo de Investigación en Acuicultura, Instituto Universitario en Acuicultura Sostenible y Ecosistemas Marinos (IU-ECOAQUA), Universidad de Las Palmas de Gran Canaria, Marine Scientific and Technological Park, Carretera de Taliarte s/n, E-35214 Telde, Spain
| | - William Vincent 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 Biomedicine and Translational Medicine, Department of Pathophysiology, University of Tartu, Ravila 14b, 50411 Tartu, Estonia .,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
| |
Collapse
|
4
|
Novelli B, Otero Ferrer F, Socorro JA, Molina Domínguez L. Early development of the longsnout seahorse Hippocampus reidi (Syngnathidae) within the male brood pouch. JOURNAL OF FISH BIOLOGY 2018; 92:1975-1984. [PMID: 29660108 DOI: 10.1111/jfb.13631] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/21/2017] [Accepted: 04/02/2018] [Indexed: 06/08/2023]
Abstract
Fertilized and unfertilized eggs and embryos of the longsnout seahorse Hippocampus reidi were collected at different stages of development and provided the basis for a description of morphological development from fertilization until release from the paternal pouch. Images of fertilized eggs, as well as their rupture after a few minutes in seawater are reported for the first time. The yolk sac transitioned from ovoid to spherical shape and was reabsorbed progressively until release. The tail began rising from the surface of the deuteroplasm while embryos were in the egg envelope. Embryos lacked a primordial fin fold and developed some species characteristics, such as rays in the dorsal fin, before resorption of the yolk sac. At release, juvenile seahorses were in an advanced stage of development even if they lacked important adult characteristics, such as ring plates and coronet. The tail was not prehensile in juveniles at release; a small caudal fin was present, although this fin is lost in adults.
Collapse
Affiliation(s)
- B Novelli
- Grupo de Investigación en Acuicultura (GIA), IU-ECOAQUA, Universidad de las Palmas de Gran Canaria (ULPGC), Ctra. Taliarte s/n, Telde, 35214, Las Palmas, Canary Islands, Spain
| | - F Otero Ferrer
- Grupo en Biodiversidad y Conservación (BIOCON), IU-ECOAQUA, Universidad de las Palmas de Gran Canaria (ULPGC), Ctra. Taliarte s/n, Telde, 35214, Las Palmas, Canary Islands, Spain
| | - J A Socorro
- Grupo de Investigación en Acuicultura (GIA), IU-ECOAQUA, Universidad de las Palmas de Gran Canaria (ULPGC), Ctra. Taliarte s/n, Telde, 35214, Las Palmas, Canary Islands, Spain
| | - L Molina Domínguez
- Grupo de Investigación en Acuicultura (GIA), IU-ECOAQUA, Universidad de las Palmas de Gran Canaria (ULPGC), Ctra. Taliarte s/n, Telde, 35214, Las Palmas, Canary Islands, Spain
| |
Collapse
|
5
|
Otero-Ferrer F, Izquierdo M, Fazeli A, Holt WV. Embryonic developmental plasticity in the long-snouted seahorse (Hippocampus reidi, Ginsburg 1933) in relation to parental preconception diet. Reprod Fertil Dev 2016; 28:1020-1028. [DOI: 10.1071/rd14169] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2014] [Accepted: 11/17/2014] [Indexed: 11/23/2022] Open
Abstract
The aim of the present study was to investigate the hypothesis that parental periconception nutrition in adult seahorses affects the development and growth of their offspring. We tested the hypothesis that because seahorse embryos develop inside the male’s brood pouch, manipulation of the male’s diet would affect offspring growth and development independently of the female’s diet. Adult males and females were fed separately with either wild-caught crustaceans or commercial aquarium diet for 1 month before conception to influence the periconception environment. Approximately 10 000 offspring were obtained from four different treatment groups (Male/Wild or Male/Commercial × Female/Wild or Female/Commercial). Weights, physical dimensions and fatty acid profiles of the newborns were determined. Offspring produced when the males receiving commercial diet were mated with wild-fed females were larger (P < 0.05) than those produced by wild-fed males. When both males and females were fed with commercial diet, their offspring were significantly smaller than those from the other treatment groups. When commercial diet-fed females were mated with wild-fed males, the offspring showed distortion of the snout : head length ratio. These results support the view that the preconception diet received by males and females differentially affects embryonic development.
Collapse
|
6
|
López A, Vera M, Planas M, Bouza C. Conservation genetics of threatened Hippocampus guttulatus in vulnerable habitats in NW Spain: temporal and spatial stability of wild populations with flexible polygamous mating system in captivity. PLoS One 2015; 10:e0117538. [PMID: 25646777 PMCID: PMC4315495 DOI: 10.1371/journal.pone.0117538] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2014] [Accepted: 12/26/2014] [Indexed: 11/19/2022] Open
Abstract
This study was focused on conservation genetics of threatened Hippocampus guttulatus on the Atlantic coast of NW Iberian Peninsula. Information about spatial structure and temporal stability of wild populations was obtained based on microsatellite markers, and used for monitoring a captive breeding program firstly initiated in this zone at the facilities of the Institute of Marine Research (Vigo, Spain). No significant major genetic structure was observed regarding the biogeographical barrier of Cape Finisterre. However, two management units under continuous gene flow are proposed based on the allelic differentiation between South-Atlantic and Cantabrian subpopulations, with small to moderate contemporary effective size based on single-sample methods. Temporal stability was observed in South-Atlantic population samples of H. guttulatus for the six-year period studied, suggesting large enough effective population size to buffer the effects of genetic drift within the time frame of three generations. Genetic analysis of wild breeders and offspring in captivity since 2009 allowed us to monitor the breeding program founded in 2006 in NW Spain for this species. Similar genetic diversity in the renewed and founder broodstock, regarding the wild population of origin, supports suitable renewal and rearing processes to maintain genetic variation in captivity. Genetic parentage proved single-brood monogamy in the wild and in captivity, but flexible short- and long-term mating system under captive conditions, from strict monogamy to polygamy within and/or among breeding seasons. Family analysis showed high reproductive success in captivity under genetic management assisted by molecular relatedness estimates to avoid inbreeding. This study provides genetic information about H. guttulatus in the wild and captivity within an uncovered geographical range for this data deficient species, to be taken into account for management and conservation purposes.
Collapse
Affiliation(s)
- Almudena López
- Department of Genetics, Faculty of Veterinary Science, Universidade de Santiago de Compostela, Campus de Lugo, Lugo, Spain
| | - Manuel Vera
- Laboratori d’Ictiologia Genètica, Departament of Biology, Faculty of Sciences, Universidad de Girona, Campus de Montilivi, Girona, Spain
| | - Miquel Planas
- Department of Ecology and Marine Resources, Instituto de Investigaciones Marinas (CSIC), Vigo, Spain
| | - Carmen Bouza
- Department of Genetics, Faculty of Veterinary Science, Universidade de Santiago de Compostela, Campus de Lugo, Lugo, Spain
| |
Collapse
|
7
|
Saavedra M, Masdeu M, Hale P, Sibbons C, Holt W. Dietary fatty acid enrichment increases egg size and quality of yellow seahorse Hippocampus kuda. Anim Reprod Sci 2014; 145:54-61. [DOI: 10.1016/j.anireprosci.2013.08.004] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2013] [Revised: 07/26/2013] [Accepted: 08/08/2013] [Indexed: 11/25/2022]
|