European 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, expression of genes not
previously studied in this species (cyp19a1, ara, arb, gnrhr1a,
gnrhr1b, gnrhr2, zpb and zpc) was analyzed in eels reared under a
constant thermal regime, accordingly to the usual rearing
conditions. Also, the effect of rearing temperature on gene
expression and steroid profile (T, 11-KT and E2) was studied. In
fact, eels migrate to Sargasso Sea to reproduce and during the
travel experiment temperature changes, while traditionally they are
reared at a constant high temperature which could affect
vitellogenesis progression and final oocyte quality.
For the study it was necessary cloning and characterizing some
genes which have not still been sequenced in European eel. Gene
expression was studied by qPCR after designing primer and
optimizing the qPCR race. Steroid profiles were analyzed by
immunoassays and the gonadal development stages were
established by histology.
The first result obtained at the end of the study were six new genes
characterized in European eel.
The analysis of gene expression allowed to understand the
involvement of specific genes during vitellogenesis (arb, gnrhr1b
and gnrhr2) in different brain regions.
The temperature was conformed as a crucial environmental factor
affecting vitellogenesis. On one hand, eels matured at lower starting
temperatures showed better reproductive parameters which could
have an influence in the final oocyte quality. On the other hand
higher temperatures are necessary to achieve further vitellogenetic
stages / Mazzeo, I. (2014). Effect of thermal regime on the expression of key reproductive genes during hormonally-induced vitellogenesis in female European eels [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/48490 / TESIS
| Identifer | oai:union.ndltd.org:upv.es/oai:riunet.upv.es:10251/48490 |
| Date | 19 December 2015 |
| Creators | Mazzeo, Ilaria |
| Contributors | Asturiano Nemesio, Juan Francisco, Sánchez Peñaranda, David, Universitat Politècnica de València. Departamento de Ciencia Animal - Departament de Ciència Animal |
| Publisher | Universitat Politècnica de València |
| Source Sets | Universitat Politècnica de València |
| Language | English |
| Detected Language | English |
| Type | info:eu-repo/semantics/doctoralThesis, info:eu-repo/semantics/acceptedVersion |
| Rights | http://rightsstatements.org/vocab/InC/1.0/, info:eu-repo/semantics/openAccess |
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