English   español  
Please use this identifier to cite or link to this item: http://hdl.handle.net/10261/95711
logo share SHARE   Add this article to your Mendeley library MendeleyBASE
Visualizar otros formatos: MARC | Dublin Core | RDF | ORE | MODS | METS | DIDL
Exportar a otros formatos:


Continuous light administration during the photolabile period alters the natural endocrine profiles both at early and late gametogenesisi of sea bass

AuthorsRodríguez, Rafael ; Felip, Alicia ; Hala, Edmond; Zanuy, Silvia ; Carrillo, Manuel
Issue DateSep-2011
PublisherAsociación Ibérica de Endocrinología Comparada
Citation8º Congreso de la Asociación Ibérica de Endocrinología Comparada (2011)
AbstractThe objective of this study is to report the effect of the continuous light (LL) on endocrine profiles of male juvenile sea bass both at early and late gametogenesis during their first year of age. According to the photo-sensible period (August-September) recently identified in this species, six different LL regimes were applied as follows: 1) LL from August 1 to September 30 (W1-AS); 2) LL from September 1 to September 30 (W2-SS); 3) LL from August 15 to September 15 (W3-15AS); 4) LL from August 1 to August 30 (W4-AA); 5) positive control group or constant simulated natural photoperiod, and 6) negative control group or constant LL all year round (W6-LL). Steroid plasma levels (17-ß estradiol, E2 and 11-ketotestosterone, 11-KT) and brain content of gonadotropin-releasing hormone type 2 (GnRH2) have been analyzed both at early and late gametogenesis. Gonadosomatic index (GSI), and the rates of spermiating males have been also assessed. Our results show that E2 plasma levels of fish exposed to LL decreased earlier than those of control group during early gametogenesis. Similarly, plasma levels of 11-KT and GnRH2 brain content of fish exposed to LL, peaked 15 days before than those of control group, both at early gametogenesis and at late gametogenesis. Finally, the amplitude of the hormonal rhythms of fish exposed to LL was lower than those of control group, being more noticeable in those groups with lower GSI and rates of spermiation (i.e. W2-SS and W6-LL). These results suggest that the exposure to LL within the photo-sensible period is able to modify the hormonal profiles of juvenile males, thus reducing the number of early pubertal fish and their gonadal development. Likely, the alteration in the production of E2, 11-KT and GnRH2 caused by the photoperiod might be a limiting factor of the spermatogonial proliferation towards meiosis as well as of the onset of meiosis in the male sea bass. At late gametogenesis the dramatic decrease of 11-KT is highly correlated with the strong reduction of the gonadal development and the absence of spermiating fish. Presently, mRNA expression profiles of some target genes such as the anti-Müllerian hormone (amh) and the estrogen receptors (erß1 and erß2) are evaluated at the gonadal level to elucidate the molecular mechanisms involved in the reduction of sexual maturation.
DescriptionPonencia presentada en el 8º Congreso de la Asociación Ibérica de Endocrinología Comparada celebrado en Madrid del 5 al 7 septiembre 2011
Appears in Collections:(IATS) Comunicaciones congresos
Files in This Item:
File Description SizeFormat 
Continuous_light_administration.pdf50,76 kBUnknownView/Open
Show full item record
Review this work

WARNING: Items in Digital.CSIC are protected by copyright, with all rights reserved, unless otherwise indicated.