Synergistic effects of estradiol and 11-ketotestosterone on vitellogenin physiology in the shortfinned eel (Anguilla australis)

Thomson‐Laing, Georgia; Damsteegt, Erin L.; Nagata, Jun; Ijiri, Shigeho; Adachi, Souichi; Todo, Takashi; Hiramatsu, Naoshi; Lokman, P. Mark

doi:10.1093/biolre/ioz007

Cited by 15 publications

(16 citation statements)

References 52 publications

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“…Whilst androgens look to be the main driver reducing the time and amount of SPH required for induced maturation, estrogens could be instrumental for improving egg quality. Indeed, co-treatment of androgen and estrogen was previously seen to affect yolk accumulation in oocytes of shortfinned eels on the one hand, and to modulate plasma sex steroid levels to values deemed comparable to those in wild eels on the other [26].…”

Section: Discussionmentioning

confidence: 99%

“…Fish handling was approved by the University of Otago Animal Ethics Committee and conducted in accordance with the guidelines of the Australian & New Zealand Council for the Care of Animals in Research and Teaching. All details of fish collection, husbandry and steroid pre-treatment are described in Thomson-Laing et al [26]. Briefly, 36 early pubertal ('silver'), wild-caught, female shortfinned eels (body weight: 748.7 ± 11.6 g; total length: 74.1 ± 0.6 cm; condition factor: 2.73 ± 0.05) were housed in 200L recirculating tanks at 10-15 ppt and 14-17 o C on a 12:12 light regime.…”

Section: Kt and E 2 Pre-treatmentmentioning

confidence: 99%

“…Six eels were assigned to each treatment and treatment groups housed in separate tanks. At 12 weeks, all eels were ovary-biopsied (see: [26]), transferred to seawater and recruited into the induced spawning experiment described below.…”

Section: Kt and E 2 Pre-treatmentmentioning

confidence: 99%

“…Three fish died during steroid pre-treatment (see: [26]). Only 2 of the remaining 33 eels did not reach the pre-spawning condition; one fish treated with 11KT + 0.2 mg E 2 died following hCG injection, possibly due to a blocked gonopore, and another one (2 mg E 2 ) did not respond to SPH injection and was euthanised after all other fish had spawned.…”

Section: Fish Healthmentioning

confidence: 99%

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Effects of estradiol and 11-ketotestosterone pre-treatment on artificial induction of maturation in silver female shortfinned eels (Anguilla australis)

et al. 2020

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Our previous work documented significant advancements in steroid-induced progression of oogenesis, demonstrating that co-treatment of female eels with 11-ketotestosterone (11KT) and estradiol-17β (E 2) successfully induced uptake of vitellogenin by oocytes. Here we evaluate the effects of this steroid co-treatment on subsequent time to ovulation and egg quality in shortfinned eels artificially matured by hypophysation. Co-treatment with 11KT (1 mg) and E 2 (0.2 or 2 mg) significantly reduced time to ovulation and therefore, the amount of pituitary homogenate required, without any detrimental effects on gonadosomatic index, oocyte diameter or the total weight of stripped eggs. E 2 treatment resulted in promising increases in fertilization rates. These indicators suggest that co-treatment with 11KT and E 2 holds promise for future artificial maturation practices in terms of minimising fish handling and stress, and of reducing the need for expensive pituitary preparations.

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Section: Discussionmentioning

confidence: 99%

Section: Kt and E 2 Pre-treatmentmentioning

confidence: 99%

Section: Kt and E 2 Pre-treatmentmentioning

confidence: 99%

Section: Fish Healthmentioning

confidence: 99%

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Effects of estradiol and 11-ketotestosterone pre-treatment on artificial induction of maturation in silver female shortfinned eels (Anguilla australis)

et al. 2020

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“…These substances could be hormones, released as pheromones, and may be steroids or their sulfo-or glucuro-conjugated metabolites 20 . Steroids such as 11-ketotestosterone have a relatively long half-life and can initiate vitellogenesis in eels 21,22 .…”

mentioning

confidence: 99%

First Observation of a Spontaneously Matured Female European Eel (Anguilla anguilla)

Palstra

Jéhannet

Swinkels³

et al. 2020

Sci Rep

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This study reports on the first observation of a spontaneously matured female European eel. The 43-year-old eel, together with eleven other females, resided at an aquarium house since their capture in 2002 and stocking as glass eels in 1978. In June 2019, the girth of the belly of the female increased as a sign of oocyte maturation. The specimen had an estimated gonadosomatic index (GSI) of 47, only half of the oocytes were hydrated and matured, indicating that European eels are polycyclic batch spawners. The live eels of the cohort were still in the previtellogenic phase but their eye sizes were close to that of the matured eel. We hypothesize that substances released by other maturing and spawning fishes may have triggered puberty of the eel. This first observation, and the possibility of more eels maturing in the near future, provides a natural reference for the sexual maturation of the European eel. Scientific RepoRtS |

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The biology of making an egg: a fish’s perspective

et al. 2022

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Synergistic effects of estradiol and 11-ketotestosterone on vitellogenin physiology in the shortfinned eel (Anguilla australis)

Cited by 15 publications

References 52 publications

Effects of estradiol and 11-ketotestosterone pre-treatment on artificial induction of maturation in silver female shortfinned eels (Anguilla australis)

Effects of estradiol and 11-ketotestosterone pre-treatment on artificial induction of maturation in silver female shortfinned eels (Anguilla australis)

First Observation of a Spontaneously Matured Female European Eel (Anguilla anguilla)

The biology of making an egg: a fish’s perspective

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