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Swimming exercise to control precocious maturation in male seabass (Dicentrarchus labrax)

BACKGROUND: Male European seabass, already predominant (~ 70%) in cultured stocks, show a high incidence (20–30%) of precocious sexual maturation under current aquaculture practices, leading to important economic losses for the industry. In view of the known modulation of reproductive development by...

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Autores principales: Graziano, Marco, Benito, Raul, Planas, Josep V., Palstra, Arjan P.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: BioMed Central 2018
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5897932/
https://www.ncbi.nlm.nih.gov/pubmed/29649968
http://dx.doi.org/10.1186/s12861-018-0170-8
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author Graziano, Marco
Benito, Raul
Planas, Josep V.
Palstra, Arjan P.
author_facet Graziano, Marco
Benito, Raul
Planas, Josep V.
Palstra, Arjan P.
author_sort Graziano, Marco
collection PubMed
description BACKGROUND: Male European seabass, already predominant (~ 70%) in cultured stocks, show a high incidence (20–30%) of precocious sexual maturation under current aquaculture practices, leading to important economic losses for the industry. In view of the known modulation of reproductive development by swimming exercise in other teleost species, we aimed at investigating the effects of sustained swimming on reproductive development in seabass males during the first year of life in order to determine if swimming could potentially reduce precocious sexual maturation. METHODS: Pre-pubertal seabass (3.91 ± 0.22 g of body weight (BW)) were subjected to a 10 week swimming regime at their optimal swimming speed (U(opt)) in an oval-shaped Brett-type flume or kept at rest during this period. Using Blazka-type swim tunnels, U(opt) was determined three times during the course of the experiment: 0.66 m s(− 1) at 19 ± 1 g BW, 10.2 ± 0.2 cm of standard length (SL) (week 1); 0.69 m s(− 1) at 38 ± 3 g BW, 12.7 ± 0.3 cm SL (week 5), and also 0.69 m s(− 1) at 77 ± 7 g BW, 15.7 ± 0.5 cm SL (week 9). Every 2 weeks, size and gonadal weight were monitored in the exercised (N = 15) and non-exercised fish (N = 15). After 10 weeks, exercised and non-exercised males were sampled to determine plasma 11-ketotestosterone levels, testicular mRNA expression levels of genes involved in steroidogenesis and gametogenesis by qPCR, as well as the relative abundance of germ cells representing the different spermatogenic stages by histological examination. RESULTS: Our results indicate that sustained swimming exercise at U(opt) delays testicular development in male European seabass as evidenced by decreased gonado-somatic index, slower progression of testicular development and by reduced mRNA expression levels of follicle stimulating hormone receptor (fshR), 3-beta-hydroxysteroid dehydrogenase (3βhsd), 11-beta hydroxysteroid dehydrogenase (11βhsd), estrogen receptor-beta (erβ2), anti-mullerian hormone (amh), structural maintenance of chromosomes protein 1B (smc1β), inhibin beta A (inhba) and gonado-somal derived factor 1 (gsdf1) in exercised males as compared with the non-exercised males. CONCLUSIONS: Swimming exercise may represent a natural and non-invasive tool to reduce the incidence of sexually precocious males in seabass aquaculture.
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spelling pubmed-58979322018-04-20 Swimming exercise to control precocious maturation in male seabass (Dicentrarchus labrax) Graziano, Marco Benito, Raul Planas, Josep V. Palstra, Arjan P. BMC Dev Biol Research Article BACKGROUND: Male European seabass, already predominant (~ 70%) in cultured stocks, show a high incidence (20–30%) of precocious sexual maturation under current aquaculture practices, leading to important economic losses for the industry. In view of the known modulation of reproductive development by swimming exercise in other teleost species, we aimed at investigating the effects of sustained swimming on reproductive development in seabass males during the first year of life in order to determine if swimming could potentially reduce precocious sexual maturation. METHODS: Pre-pubertal seabass (3.91 ± 0.22 g of body weight (BW)) were subjected to a 10 week swimming regime at their optimal swimming speed (U(opt)) in an oval-shaped Brett-type flume or kept at rest during this period. Using Blazka-type swim tunnels, U(opt) was determined three times during the course of the experiment: 0.66 m s(− 1) at 19 ± 1 g BW, 10.2 ± 0.2 cm of standard length (SL) (week 1); 0.69 m s(− 1) at 38 ± 3 g BW, 12.7 ± 0.3 cm SL (week 5), and also 0.69 m s(− 1) at 77 ± 7 g BW, 15.7 ± 0.5 cm SL (week 9). Every 2 weeks, size and gonadal weight were monitored in the exercised (N = 15) and non-exercised fish (N = 15). After 10 weeks, exercised and non-exercised males were sampled to determine plasma 11-ketotestosterone levels, testicular mRNA expression levels of genes involved in steroidogenesis and gametogenesis by qPCR, as well as the relative abundance of germ cells representing the different spermatogenic stages by histological examination. RESULTS: Our results indicate that sustained swimming exercise at U(opt) delays testicular development in male European seabass as evidenced by decreased gonado-somatic index, slower progression of testicular development and by reduced mRNA expression levels of follicle stimulating hormone receptor (fshR), 3-beta-hydroxysteroid dehydrogenase (3βhsd), 11-beta hydroxysteroid dehydrogenase (11βhsd), estrogen receptor-beta (erβ2), anti-mullerian hormone (amh), structural maintenance of chromosomes protein 1B (smc1β), inhibin beta A (inhba) and gonado-somal derived factor 1 (gsdf1) in exercised males as compared with the non-exercised males. CONCLUSIONS: Swimming exercise may represent a natural and non-invasive tool to reduce the incidence of sexually precocious males in seabass aquaculture. BioMed Central 2018-04-12 /pmc/articles/PMC5897932/ /pubmed/29649968 http://dx.doi.org/10.1186/s12861-018-0170-8 Text en © The Author(s). 2018 Open AccessThis article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.
spellingShingle Research Article
Graziano, Marco
Benito, Raul
Planas, Josep V.
Palstra, Arjan P.
Swimming exercise to control precocious maturation in male seabass (Dicentrarchus labrax)
title Swimming exercise to control precocious maturation in male seabass (Dicentrarchus labrax)
title_full Swimming exercise to control precocious maturation in male seabass (Dicentrarchus labrax)
title_fullStr Swimming exercise to control precocious maturation in male seabass (Dicentrarchus labrax)
title_full_unstemmed Swimming exercise to control precocious maturation in male seabass (Dicentrarchus labrax)
title_short Swimming exercise to control precocious maturation in male seabass (Dicentrarchus labrax)
title_sort swimming exercise to control precocious maturation in male seabass (dicentrarchus labrax)
topic Research Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5897932/
https://www.ncbi.nlm.nih.gov/pubmed/29649968
http://dx.doi.org/10.1186/s12861-018-0170-8
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