Swimming stimulates oocyte development in European eel

Palstra, Arjan P.; Curiel, Danilo; Fekkes, Minne; Bakker, Merijn A. G. de; Székely, Csaba; Ginneken, Vincent van; Thillart, G. van den

doi:10.1016/j.aquaculture.2007.04.015

Cited by 55 publications

(45 citation statements)

References 20 publications

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“…No statistical differences (P [ 0.05) were found in these study groups by the end of the experiment in terms of the percentage of oocytes in various size classes ( Table 2). The oocyte diameters observed in this study after 5 weeks of stimulating the female fish were larger (0.176 ± 0.018 mm) than those observed by other authors after 6 weeks of the experiment (0.109 ± 0.041 mm) in a study examining the effect of swimming on the size of oocytes (Palstra et al 2007). It may be concluded that hormonal treatment considerably accelerates the process of gamete maturation, which was also confirmed by a study conducted by Nowosad et al (2014).…”

Section: Discussioncontrasting

confidence: 64%

Changes in European eel ovary development and body and ovary chemistry during stimulated maturation under controlled conditions: preliminary data

et al. 2014

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This study compared changes in the biochemical composition of muscles and ovaries of maturing female European eels during hormonal stimulation with carp pituitary homogenate under controlled conditions and in the development of oocytes. It has been found that differentiation of oocyte size in eel is visible from the beginning of the gamete maturation process. This differentiation increases as gonads grow. Furthermore, oocytes are at different development stages and are still highly differentiated in terms of size during ovulation. Moreover, the biochemical composition of the body and gonads was found to change. During the process of maturation, the relative fat content in the eel body decreases both in the muscles (from 21.99 ± 4.3 to 18.48 ± 3.3 %) and in gonads (from 25.76 ± 2.71 to 15.21 ± 4.7 %), with the changes in ovaries being more rapid. Protein content in muscles also decreased (from 15.98 ± 3.13 to 12.35 ± 1.6 %) during the process of female maturation. Different trends were observed for polyunsaturated fatty acids (EPA and DHA). The total amount of these acids decreased in muscles (P \ 0.05) but increased in ovaries (P [ 0.05).

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Section: Discussioncontrasting

confidence: 64%

Changes in European eel ovary development and body and ovary chemistry during stimulated maturation under controlled conditions: preliminary data

et al. 2014

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“…Perhaps migrating eels use regular exposure to cooler water to regulate the rate of maturation? As indicated previously, swimming itself promotes maturation (Palstra et al 2007, and achieving maturity well in advance of arrival at spawning grounds would be disadvantageous. The later stage of oogenesis, egg hydration, occurs within a few weeks and results in a substantial increase in the girth of the female abdomen.…”

Section: Discussionmentioning

confidence: 85%

“…The rate of maturation is affected by temperature (Boëtius & Boëtius 1980, Sato et al 2006, pressure (Dufour & Fontaine 1985, Sebert et al 2009) and even swimming itself (Palstra et al 2007. Final maturation and hydration of oocytes probably occur at, or close to, the spawning grounds (Palstra et al 2005).…”

Section: Discussionmentioning

confidence: 99%

Vertical migrations may control maturation in migrating female Anguilla dieffenbachii

Jellyman¹,

Tsukamoto²

2010

Mar. Ecol. Prog. Ser.

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The marine spawning area of the New Zealand longfin eel Anguilla dieffenbachii is unknown. The present study used 3 popup tags to obtain information on the offshore swimming behaviour and possible swimming directions and destination of migrating eels. All 3 eels showed very consistent behaviour and underwent daytime dives to depths of 600 to 900 m, where they experienced temperatures of 6 to 7°C. These dives were followed by nighttime ascents to depths of 200 to 300 m. From the consistency of these dives, we propose that eels are using regular exposure to cool temperatures to regulate the rate of maturity. While swimming at depth could also reduce predation, the increased pressure would stimulate development of the ovaries, something mediated by ascent to shallower water. Comparisons of ascent locations and swimming speeds are consistent with spawning in the tropics, possibly in the South Fiji basin. KEY WORDS: Anguilla dieffenbachii · Freshwater eel · Diving · ThermoregulationResale or republication not permitted without written consent of the publisher

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“…Swimming stimulates fat deposition in oocyte, as it was evidenced by histology and GSI and EI increase (Palstra et al, 2007b;van Ginneken et al, 2007). However, yolk globules have not been observed in these experiments, suggesting that swimming only triggers lipid mobilization which is depressed in yellow eels at prepubertal stage (Palstra et al, 2009).…”

Section: Indexmentioning

confidence: 97%

Section: Indexmentioning

confidence: 99%

Effect of thermal regime on the expression of key reproductive genes during hormonally-induced vitellogenesis in female European eels

Mazzeo¹

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RESUMENLa población de anguilla europea (Anguilla anguilla L., 1758) está sufriendo una drástica reducción. A su vez se trata de una especie muy apreciada por el mercado y su ciclo reproductivo no se ha podido cerrar puesto que esta especie no madura en cautividad. Por estas razones, hasta el momento, la producción global de anguila recae sobre las poblaciones naturales. Todos estos factores hacen urgente el cierre del ciclo productivo y para ello es necesario comprender la fisiología reproductiva y las razones de su imposibilidad de madurar en cautividad.Con la presente tesis, se pretende aportar mayores conocimientos sobre la fisiología reproductiva en hembras de anguila europea maduradas hormonalmente Para alcanzar este objetivo, se analizó la expresión de los genes: cyp19a1, ara, arb, gnrhr1a, gnrhr1b, gnrhr2, zpb and zpc, en animales bajo el regimen térmico comunemente utilizado. Por último se quiso evaluar el efecto de la temperatura sobre la vitelogenesis tanto sobre la expresión génica como en el perfil de esteroides (T,. De hecho, la anguila europea cuando migra al mar de los Sargazos para reproducirse experimenta un regimen térmico desde temperaturas más bajas a más altas.Tradicionalmente en acuicultura las anguilas se han madurado a temperatura constante y relativamente alta lo que podría afectar a la vitelogenesis y la calidad final de los oocitos.Para este estudio fue necesario la clonación y caracterización de nuevos genes. Su expresion genica fue estudiada por qPCR tras el diseño de los primers. El perfil esteroidogénico fue analizado por immunoensayos y los estados de desarrollo gonadal se calsificaron histológicamente.Como primer resultado se obtuvieron la secuencia para 6 genes en anguila europea. El análisis de la expresión génica permitió comprender la función de algunos de los genes estudiados a lo largo de la vitelogénesis (arb, gnrhr1b and gnrhr2) en diferentes regiones del cerebro.La temperatura se confirmó como un factor crucial durante la vitelogénesis. Por un lado, las anguilas sometidas a bajas temperaturas al inicio de la vitelogenésis mostraron mejores parámetros reproductivos, los cuales podrían tener un efecto en la calidad final de los oocitos. Por otra parte, temperaturas más altas son indispensables para alcanzar los estadios más avanzados de la vitelogenesis. ABSTRACTEuropean eel (Anguilla anguilla, L., 1758) is suffering a strong population decrease and at the same time it is a very appreciated species and by now it has not been possible closing its cycle life. In fact, this species does not mature in captivity unless hormonally induced. So all the production is up to the natural population. All these factors together make urgent achieving the closing of the productive cycle and for this aim it is important to understand the reproductive physiology and the reasons of this development blockage.The present thesis wants to be a new contribution to the knowledge of reproductive physiology in female European eel submitted at hormonal treatment. To achieve this goal, expressio...

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Swimming stimulates oocyte development in European eel

Cited by 55 publications

References 20 publications

Changes in European eel ovary development and body and ovary chemistry during stimulated maturation under controlled conditions: preliminary data

Changes in European eel ovary development and body and ovary chemistry during stimulated maturation under controlled conditions: preliminary data

Vertical migrations may control maturation in migrating female Anguilla dieffenbachii

Effect of thermal regime on the expression of key reproductive genes during hormonally-induced vitellogenesis in female European eels

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