scholarly journals Pituitary Hormones mRNA Abundance in the Mediterranean Sea Bass Dicentrarchus labrax: Seasonal Rhythms, Effects of Melatonin and Water Salinity

2021 ◽  
Vol 12 ◽  
Author(s):  
Jack Falcón ◽  
Maria Jesus Herrero ◽  
Laura Gabriela Nisembaum ◽  
Esther Isorna ◽  
Elodie Peyric ◽  
...  
Keyword(s):  
Seasonal Variations ◽  
Sea Water ◽  
Dicentrarchus Labrax ◽  
Sea Bass ◽  
Pituitary Hormones ◽  
Reproductive Hormones ◽  
Melatonin Receptors ◽  
Mrna Abundance ◽  
High Plasticity

In fish, most hormonal productions of the pituitary gland display daily and/or seasonal rhythmic patterns under control by upstream regulators, including internal biological clocks. The pineal hormone melatonin, one main output of the clocks, acts at different levels of the neuroendocrine axis. Melatonin rhythmic production is synchronized mainly by photoperiod and temperature. Here we aimed at better understanding the role melatonin plays in regulating the pituitary hormonal productions in a species of scientific and economical interest, the euryhaline European sea bass Dicentrarchus labrax. We investigated the seasonal variations in mRNA abundance of pituitary hormones in two groups of fish raised one in sea water (SW fish), and one in brackish water (BW fish). The mRNA abundance of three melatonin receptors was also studied in the SW fish. Finally, we investigated the in vitro effects of melatonin or analogs on the mRNA abundance of pituitary hormones at two times of the year and after adaptation to different salinities. We found that (1) the reproductive hormones displayed similar mRNA seasonal profiles regardless of the fish origin, while (2) the other hormones exhibited different patterns in the SW vs. the BW fish. (3) The melatonin receptors mRNA abundance displayed seasonal variations in the SW fish. (4) Melatonin affected mRNA abundance of most of the pituitary hormones in vitro; (5) the responses to melatonin depended on its concentration, the month investigated and the salinity at which the fish were previously adapted. Our results suggest that the productions of the pituitary are a response to multiple factors from internal and external origin including melatonin. The variety of the responses described might reflect a high plasticity of the pituitary in a fish that faces multiple external conditions along its life characterized by marked daily and seasonal changes in photoperiod, temperature and salinity.

scholarly journals Prolactin and Male Fertility: The Long and Short Feedback Regulation

2009 ◽  
Vol 2009 ◽  
pp. 1-13 ◽  
Author(s):  
M. K. Gill-Sharma
Keyword(s):  
Chromatin Condensation ◽  
Feedback Regulation ◽  
Pituitary Hormones ◽  
Feedback Mechanism ◽  
Reproductive Hormones ◽  
Male Rats ◽  
Normal Men

In the last 20 years, a pituitary-hypothalamus tissue culture system with intact neural and portal connections has been developed in our lab and used to understand the feedback mechanisms that regulate the secretions of adenohypophyseal hormones and fertility of male rats. In the last decade, several in vivo rat models have also been developed in our lab with a view to substantiate the in vitro findings, in order to delineate the role of pituitary hormones in the regulation of fertility of male rats. These studies have relied on both surgical and pharmacological interventions to modulate the secretions of gonadotropins and testosterone. The interrelationship between the circadian release of reproductive hormones has also been ascertained in normal men. Our studies suggest that testosterone regulates the secretion of prolactin through a long feedback mechanism, which appears to have been conserved from rats to humans. These studies have filled in a major lacuna pertaining to the role of prolactin in male reproductive physiology by demonstrating the interdependence between testosterone and prolactin. Systemic levels of prolactin play a deterministic role in the mechanism of chromatin condensation during spermiogenesis.

Changes in plasma levels of reproductive hormones during first sexual maturation in European male sea bass (Dicentrarchus labrax L.) under artificial day lengths

Aquaculture ◽  
2001 ◽  
Vol 202 (3-4) ◽  
pp. 235-248 ◽  
Author(s):  
Lucinda Rodrı́guez ◽  
Ideal Begtashi ◽  
Silvia Zanuy ◽  
Mónica Shaw ◽  
Manuel Carrillo
Keyword(s):  
Sexual Maturation ◽  
Plasma Levels ◽  
Dicentrarchus Labrax ◽  
Sea Bass ◽  
Reproductive Hormones

Assimilation of dissolved glucose from sea water by the sea bass Dicentrarchus labrax and the sea bream Sparus aurata

1994 ◽  
Vol 120 (2) ◽  
pp. 181-186 ◽  
Author(s):  
J. P. Diaz ◽  
L. mani-Ponset ◽  
E. Guyot ◽  
R. Connes
Keyword(s):  
Sea Water ◽  
Sparus Aurata ◽  
Dicentrarchus Labrax ◽  
Sea Bass ◽  
Sea Bream

Co-culture of Ulva sp. and Dicentrarchus labrax in Recirculating Aquaculture System: effects on growth, retention of nutrients and fatty acid profile

2020 ◽  
Vol 33 ◽  
pp. 19
Author(s):  
Evanthia Chatzoglou ◽  
Panorea Kechagia ◽  
Aristeidis Tsopelakos ◽  
Helen Miliou
Keyword(s):  
Fish Oil ◽  
Sea Water ◽  
Dicentrarchus Labrax ◽  
Sea Bass ◽  
Recirculating Aquaculture System ◽  
Fish Oil Replacement ◽  
European Sea Bass ◽  
Integrated Aquaculture ◽  
Recirculating Aquaculture ◽  
Aquaculture System

European sea bass and Ulva sp. were co-cultured in different tanks of an indoor Recirculating Aquaculture System (Ulva-RAS) with bacterial biofilter, in an effort to optimize the efficiency of the system and to further decrease the waste effluent. A system with similar culture conditions, without Ulva, was used as a control-RAS to elucidate integration effects on growth performance and chemical composition of sea bass. The role of Ulva on N and P concentrations, gas (O2, CO2) and pH in water was also investigated. Fish were fed a diet of fish oil replacement (55%) with a mixture of rapeseed oil and palm oil (1:1). Our data showed that Ulva could uptake N and P nutrients, but could also enrich sea water with phosphates. Sea bass reared in Ulva-RAS exhibited isometric growth, while fish in control-RAS showed a positive allometric growth and an increased variance of body weight and length. In addition, sea bass in Ulva-RAS demonstrated significantly higher levels of condition factor (K), feed intake, protein, lipid, P, EPA and DHA content (% wet weight of total body) and lipid productive value, compared to fish in control-RAS. Ulva, after bi-weekly culture, showed increased protein content (60%) compared to wild seaweed collected nearshore. Cultivated Ulva obtained dark green color, doubled chlorophyll concentrations, and exhibited lower levels of saturated and higher levels of certain monounsaturated and n-3 polyunsaturated fatty acids, indicating increased photosynthetic activity. Present results revealed the beneficial effects of Ulva on sea bass growth and quality, which led to an improved response to the nutritional stress imposed by the fish oil replacement with vegetable oils, thus contributing to a sustainable aquaculture. Moreover, it was concluded that Ulva could improve water quality by increasing pH and O2, reducing CO2 and contribute to bioremediation of ammonia and nitrates from water in integrated aquaculture.

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