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Aldeadávila de la Ribera, Spain

Guzman J.M.,Institute of Aquaculture of Torre la Sal | Cal R.,Spanish Institute of Oceanography | Garcia-Lopez A.,CSIC - Institute of Marine Sciences | Chereguini O.,Spanish Institute of Oceanography | And 7 more authors.
Comparative Biochemistry and Physiology - A Molecular and Integrative Physiology | Year: 2011

The Senegalese sole (Solea senegalensis) is a flatfish that exhibits severe reproductive dysfunctions in captivity. This study aimed at investigating the existence of a dopamine (DA) inhibitory tone on the reproductive axis of this species. Four groups of Senegalese sole breeders were treated with, saline (controls, CNT), the DA antagonist pimozide (PIM, 5mg kg-1), gonadotropin-releasing hormone agonist (GnRHa, 40μg kg-1) or a combination of PIM + GnRHa (COMB). Effects were evaluated on pituitary GnRH levels (ELISA), pituitary gonadotropin subunit transcript levels (qPCR), plasma levels of sex steroids and vitellogenin (ELISA), gonad development (histology), spermiation and egg production. The GnRHa treatment induced egg release and stimulated testis maturation. In males, PIM did not affect pituitary GnRH content, but enhanced GnRHa-induced pituitary GPα transcripts and modified plasma androgen levels; moreover, PIM stimulated spermatogenesis and milt production, both alone and combined with GnRHa. In females, PIM did not affect pituitary and plasma endocrine parameters and did not affect egg production and fertilization success of the broodstock, either alone or in the combined treatment. In conclusion, data indicated the existence of a DA inhibition in mature males, which would be absent or weakly expressed in females. © 2010 Elsevier Inc.

Guzman J.M.,Institute of Aquaculture of Torre la Sal | Ramos J.,Institute of Aquaculture of Torre la Sal | Mylonas C.C.,Hellenic Center for Marine Research | Mananos E.L.,Institute of Aquaculture of Torre la Sal
Aquaculture | Year: 2011

The aquaculture of Senegalese sole (Solea senegalensis) is limited by the failure of cultured breeders (F1 generation) to produce fertilized spawning. Critical reproductive dysfunctions have been observed in both female and male Senegalese sole cultured breeders, including reduced fecundity and diminished sperm production. The present work aimed to study the effectiveness of different hormonal treatments on the stimulation of male reproduction. Male Senegalese sole cultured breeders were treated with 1) saline injections (controls), 2) gonadotropin-releasing hormone agonist (GnRHa) injections (25μgkg-1), 3) GnRHa slow release implants (40μgkg-1) or 4) human chorionic gonadotropin (hCG) injections (1000IUkg-1). Each group of males was placed in separated spawning tanks together with females treated with GnRHa implants.All three hormonal treatments increased plasma testosterone (T) and 11-ketotestosterone (11-KT) levels and the gonadosomatic index (GSI), with highest effects exerted by the hCG treatment. Histological examination of the testes showed no effect of the GnRHa injection, but a clear stimulation of germ cell proliferation and testicular maturation by GnRHa implants and hCG injections. As expected, GnRHa implantation of females induced egg release in all experimental tanks and interestingly, female fecundity increased in tanks containing GnRHa- or hCG-treated males. A fertilized spawning was obtained only from the group containing hCG-treated males. In conclusion, hormonal treatments stimulated steroidogenesis and spermatogenesis in male Senegalese sole, with highest efficiency of the hCG multiple injection treatment. Female fecundity was affected by the hormonal treatment applied over the accompanying males, suggesting a pheromone communication between fish. However, none of the treatments seemed to be adequate in solving the problem of lack of fertilized spawning in cultured Senegalese sole broodstocks. © 2011 Elsevier B.V.

Norambuena F.,IRTA Sant Carles de la Rapita | Norambuena F.,Deakin University | Estevez A.,IRTA Sant Carles de la Rapita | Mananos E.,Institute of Aquaculture of Torre la Sal | And 3 more authors.
General and Comparative Endocrinology | Year: 2013

Previous studies on Senegalese sole (Solea senegalensis) indicated that cultured broodstock (first generation, G1) have lower tissue levels of arachidonic acid (20:4n-6, ARA) than wild counterparts. ARA is metabolized to form prostaglandins (PGs) that are involved in steroid production and follicle maturation in fish. In the present study the effects of different dietary levels of ARA on blood lipid and fatty acid composition, prostaglandin (PGF2α, PGF3α, PGE2 and PGE3) levels and plasmatic steroid levels (11-ketotestosterone, 11-KT, testosterone, T and estradiol, E2) in G1 Senegalese sole were studied. For this purpose, 12 groups of ten fish (1:1 male and female), were fed six diets (each diets was fed to two groups) with different dietary ARA levels over nine months (diets A.=0.7, B.=1.6, C.=2.3, D.=3.2, E.=5.0, F.=6.0% ARA). ARA and CHOL levels in blood showed a significant increase in an ARA dose related manner (P<. 0.05) whereas EPA and EPA/ARA ratio were reduced. In males, steroid (11-KT and T) levels increased significantly with increasing dietary ARA in a dose dependent manner, whereas in females E2 did not show any change related to dietary ARA content. Plasma concentration of 3-series PGs (i.e., PGE3 and PGF3α) were reduced in parallel to increased ARA levels in blood (P<. 0.05) and levels of PGs 3-series were always higher than 2-series PGs (PGE2 and PGF2α). In conclusion there is an effect of dietary ARA on steroid production of Senegalese sole males, which might have important consequences in the reproduction of cultured fish. © 2013 Elsevier Inc.

Norambuena F.,IRTA Sant Carles de la Rapita | Norambuena F.,Deakin University | Morais S.,IRTA Sant Carles de la Rapita | Estevez A.,IRTA Sant Carles de la Rapita | And 5 more authors.
Aquaculture | Year: 2013

Previous studies have shown higher levels of arachidonic acid (20:4n-6, ARA) in testis, liver, and muscle of wild Senegalese sole (Solea senegalensis) compared to fish reared in captivity (first generation, G1). The present study was conducted to establish the optimal level of dietary ARA for G1 Senegalese sole broodstock, using as a reference the fatty acid profile of wild broodstock (gonads, liver and muscle). A total of 120 Senegalese sole broodstock were randomly distributed into 12 tanks (1:1 male and female) and fed in duplicate with six experimental diets containing increasing amounts of ARA (0.7%, 1.6%, 2.3%, 3.2%, 5.0%, and 6.0 % of total fatty acids) for 9. months. The relative ARA levels in liver, muscle and male and female gonads at the end of the feeding period increased in a dose dependent manner. Dietary ARA was mainly incorporated and stored in testis or ovary, followed by liver and muscle. Fish fed 2.3% and 3.2% ARA showed no differences in the ARA content of testis, ovary and liver when compared to wild fish. In male fish, a significant increase in the levels of 22:4n-6 and 22:5n-6 fatty acids was also observed, which was consistent with the up-regulation of fatty acyl elongase ( elovl5) and desaturase ( d4fad) transcript levels in the liver of fish fed 0.7%, 2.3% and 6% ARA. These results suggest that dietary inclusion of 3.2% ARA during periods shorter than 9. months, or of 2.3% ARA for prolonged periods, can maintain optimal levels of tissue ARA in captive Senegalese sole broodstock. In addition, the data indicate that male Senegalese sole is able to elongate and desaturate ARA to 22:4n-6 and 22:5n-6, suggesting that these fatty acids may be important for male reproduction. © 2012 Elsevier B.V.

Crespo D.,University of Barcelona | Mananos E.L.,Institute of Aquaculture of Torre la Sal | Roher N.,Autonomous University of Barcelona | MacKenzie S.A.,Autonomous University of Barcelona | And 2 more authors.
Biology of Reproduction | Year: 2012

In fish, like in other vertebrates, luteinizing hormone (Lh) is an essential hormone for the completion of oocyte maturation. In salmonid fish (i.e., salmon and trout), oocyte maturation is induced by Lh through its stimulation of the production of the maturation-inducing steroid, 17alpha,20beta-dihydroxy-4-pregnen-3-one (17,20beta-P). In mammals, several factors, including ovarian cytokines and growth factors, have been reported to contribute to the regulation of oocyte maturation. In fish, growing evidence suggests that tumor necrosis factor alpha (hereafter referred to as Tnf) could play multiple physiological roles in the control of ovarian function. In the present study, we have investigated the possible involvement of Tnf in the regulation of oocyte maturation in brown trout (Salmo trutta). Our results show that in vitro treatment of brown trout preovulatory follicles with coho salmon (Oncorhynchus kisutch) Lh (sLh) significantly increased oocyte maturation, as assessed by germinal vesicle breakdown (GVBD), and that this effect was blocked by TAPI-1 (an inhibitor of Tnf-converting enzyme or Tace/Adam17). Furthermore, treatment of preovulatory follicles with sLh increased the expression of tnf and tace/adam17 as well as the secretion of the Tnf protein. Importantly, recombinant trout Tnf (rtTnf) significantly increased GVBD in vitro. Our results also show that the stimulatory effects of rtTnf on oocyte maturation may be the result of the direct involvement of rtTnf in stimulating the production of the maturation-inducing steroid as evidenced, first, by the stimulatory effects of rtTnf on 17,20beta-P production in vitro and on the expression of cholesterol side-chain cleavage P450 cytochrome (p450scc) and 20beta-hydroxysteroid dehydrogenase/carbonyl reductase 1 (cbr1), the enzyme responsible for the production of 17,20beta-P, and, second, by the ability of TAPI-1 to block the stimulatory effects of sLh on 17,20beta-P production and cbr1 expression. Furthermore, sLh and rtTnf increased the expression of the Lh receptor (lhr) and decreased the expression of aromatase (cyp19a1), and TAPI-1 completely blocked the effects of sLh. These results strongly suggest that Tnf may contribute to the regulation of oocyte maturation by Lh in trout. © 2012 by the Society for the Study of Reproduction, Inc.

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