Differential expression of gonadotropin and estrogen receptors and oocyte cytology during follicular maturation associated with egg viability in European eel (Anguilla anguilla)

Filipa F. G. da Silva*, Helge Tveiten, Gersende Maugars, Anne-Gaëlle Lafont, Sylvie Dufour, Josianne Gatt Støttrup, Elin Kjørsvik, Jonna Tomkiewicz

*Corresponding author for this work

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Abstract

In captivity, oogenesis and ovarian follicle maturation in European eel can be induced experimentally using hormonal therapy. The follicle's ability to respond effectively to the induction of maturation and ovulation, resulting in viable eggs, depends on the oocyte stage at the time of induction. We hypothesized that variation in the expression of key hormone receptors in the ovary and size of oocyte lipid droplets are associated with changes in oocyte stage. Thus, we induced ovarian follicle maturation using a priming dose of fish pituitary extract followed by the administration of a 17α, 20β-dihydroxy-4-pregnen-3-one (DHP) injection. Females were then strip-spawned, the eggs were fertilized in vitro, incubated and larval survival was recorded at 3 days post hatch (dph). The expression of gonadotropin receptors (fshr, lhcgr1 and lhcgr2) and estrogen receptors (esr1, esr2a, esr2b, gpera and gperb) was quantified and the size of oocyte lipid droplets measured. Larval survival at 3 dph was used to differentiate high- and low-quality egg batches. Results showed significantly higher abundance of lhcgr1 and esr2a at priming for high-quality egg batches whereas fshr and gperb transcripts were significantly higher at DHP injection for low-quality egg batches. Therefore, high levels of lhcgr1 and esr2a may be important for attaining follicular maturational competence, while high fshr and gperb mRNA levels may indicate inadequate maturational competence. Furthermore, lipid droplet size at DHP and in ovulated eggs was significantly smaller in high-quality egg batches than in low-quality, which indicates that droplet size may be a useful marker of follicular maturational stage.
Original languageEnglish
JournalComparative Biochemistry and Physiology - Part A: Molecular & Integrative Physiology
Volume221
Pages (from-to)44-54
ISSN1095-6433
DOIs
Publication statusPublished - 2018

Keywords

  • Egg quality
  • Estrogen receptors
  • Follicular maturation
  • Gonadotropin receptors
  • Lipid droplet

Cite this

@article{c67d0e2227d3416c97dcfd9d9ca62ffe,
title = "Differential expression of gonadotropin and estrogen receptors and oocyte cytology during follicular maturation associated with egg viability in European eel (Anguilla anguilla)",
abstract = "In captivity, oogenesis and ovarian follicle maturation in European eel can be induced experimentally using hormonal therapy. The follicle's ability to respond effectively to the induction of maturation and ovulation, resulting in viable eggs, depends on the oocyte stage at the time of induction. We hypothesized that variation in the expression of key hormone receptors in the ovary and size of oocyte lipid droplets are associated with changes in oocyte stage. Thus, we induced ovarian follicle maturation using a priming dose of fish pituitary extract followed by the administration of a 17α, 20β-dihydroxy-4-pregnen-3-one (DHP) injection. Females were then strip-spawned, the eggs were fertilized in vitro, incubated and larval survival was recorded at 3 days post hatch (dph). The expression of gonadotropin receptors (fshr, lhcgr1 and lhcgr2) and estrogen receptors (esr1, esr2a, esr2b, gpera and gperb) was quantified and the size of oocyte lipid droplets measured. Larval survival at 3 dph was used to differentiate high- and low-quality egg batches. Results showed significantly higher abundance of lhcgr1 and esr2a at priming for high-quality egg batches whereas fshr and gperb transcripts were significantly higher at DHP injection for low-quality egg batches. Therefore, high levels of lhcgr1 and esr2a may be important for attaining follicular maturational competence, while high fshr and gperb mRNA levels may indicate inadequate maturational competence. Furthermore, lipid droplet size at DHP and in ovulated eggs was significantly smaller in high-quality egg batches than in low-quality, which indicates that droplet size may be a useful marker of follicular maturational stage.",
keywords = "Egg quality, Estrogen receptors, Follicular maturation, Gonadotropin receptors, Lipid droplet",
author = "{da Silva}, {Filipa F. G.} and Helge Tveiten and Gersende Maugars and Anne-Ga{\"e}lle Lafont and Sylvie Dufour and St{\o}ttrup, {Josianne Gatt} and Elin Kj{\o}rsvik and Jonna Tomkiewicz",
year = "2018",
doi = "10.1016/j.cbpa.2018.03.010",
language = "English",
volume = "221",
pages = "44--54",
journal = "Comparative Biochemistry and Physiology - Part A: Molecular & Integrative Physiology",
issn = "1095-6433",
publisher = "Elsevier",

}

Differential expression of gonadotropin and estrogen receptors and oocyte cytology during follicular maturation associated with egg viability in European eel (Anguilla anguilla). / da Silva, Filipa F. G.; Tveiten, Helge; Maugars, Gersende; Lafont, Anne-Gaëlle; Dufour, Sylvie; Støttrup, Josianne Gatt; Kjørsvik, Elin; Tomkiewicz, Jonna.

In: Comparative Biochemistry and Physiology - Part A: Molecular & Integrative Physiology, Vol. 221, 2018, p. 44-54.

Research output: Contribution to journalJournal articleResearchpeer-review

TY - JOUR

T1 - Differential expression of gonadotropin and estrogen receptors and oocyte cytology during follicular maturation associated with egg viability in European eel (Anguilla anguilla)

AU - da Silva, Filipa F. G.

AU - Tveiten, Helge

AU - Maugars, Gersende

AU - Lafont, Anne-Gaëlle

AU - Dufour, Sylvie

AU - Støttrup, Josianne Gatt

AU - Kjørsvik, Elin

AU - Tomkiewicz, Jonna

PY - 2018

Y1 - 2018

N2 - In captivity, oogenesis and ovarian follicle maturation in European eel can be induced experimentally using hormonal therapy. The follicle's ability to respond effectively to the induction of maturation and ovulation, resulting in viable eggs, depends on the oocyte stage at the time of induction. We hypothesized that variation in the expression of key hormone receptors in the ovary and size of oocyte lipid droplets are associated with changes in oocyte stage. Thus, we induced ovarian follicle maturation using a priming dose of fish pituitary extract followed by the administration of a 17α, 20β-dihydroxy-4-pregnen-3-one (DHP) injection. Females were then strip-spawned, the eggs were fertilized in vitro, incubated and larval survival was recorded at 3 days post hatch (dph). The expression of gonadotropin receptors (fshr, lhcgr1 and lhcgr2) and estrogen receptors (esr1, esr2a, esr2b, gpera and gperb) was quantified and the size of oocyte lipid droplets measured. Larval survival at 3 dph was used to differentiate high- and low-quality egg batches. Results showed significantly higher abundance of lhcgr1 and esr2a at priming for high-quality egg batches whereas fshr and gperb transcripts were significantly higher at DHP injection for low-quality egg batches. Therefore, high levels of lhcgr1 and esr2a may be important for attaining follicular maturational competence, while high fshr and gperb mRNA levels may indicate inadequate maturational competence. Furthermore, lipid droplet size at DHP and in ovulated eggs was significantly smaller in high-quality egg batches than in low-quality, which indicates that droplet size may be a useful marker of follicular maturational stage.

AB - In captivity, oogenesis and ovarian follicle maturation in European eel can be induced experimentally using hormonal therapy. The follicle's ability to respond effectively to the induction of maturation and ovulation, resulting in viable eggs, depends on the oocyte stage at the time of induction. We hypothesized that variation in the expression of key hormone receptors in the ovary and size of oocyte lipid droplets are associated with changes in oocyte stage. Thus, we induced ovarian follicle maturation using a priming dose of fish pituitary extract followed by the administration of a 17α, 20β-dihydroxy-4-pregnen-3-one (DHP) injection. Females were then strip-spawned, the eggs were fertilized in vitro, incubated and larval survival was recorded at 3 days post hatch (dph). The expression of gonadotropin receptors (fshr, lhcgr1 and lhcgr2) and estrogen receptors (esr1, esr2a, esr2b, gpera and gperb) was quantified and the size of oocyte lipid droplets measured. Larval survival at 3 dph was used to differentiate high- and low-quality egg batches. Results showed significantly higher abundance of lhcgr1 and esr2a at priming for high-quality egg batches whereas fshr and gperb transcripts were significantly higher at DHP injection for low-quality egg batches. Therefore, high levels of lhcgr1 and esr2a may be important for attaining follicular maturational competence, while high fshr and gperb mRNA levels may indicate inadequate maturational competence. Furthermore, lipid droplet size at DHP and in ovulated eggs was significantly smaller in high-quality egg batches than in low-quality, which indicates that droplet size may be a useful marker of follicular maturational stage.

KW - Egg quality

KW - Estrogen receptors

KW - Follicular maturation

KW - Gonadotropin receptors

KW - Lipid droplet

U2 - 10.1016/j.cbpa.2018.03.010

DO - 10.1016/j.cbpa.2018.03.010

M3 - Journal article

VL - 221

SP - 44

EP - 54

JO - Comparative Biochemistry and Physiology - Part A: Molecular & Integrative Physiology

JF - Comparative Biochemistry and Physiology - Part A: Molecular & Integrative Physiology

SN - 1095-6433

ER -