http://hdl.handle.net/10498/10859 Thu, 05 Nov 2026 19:26:48 GMT 2026-11-05T19:26:48Z http://hdl.handle.net/10498/34899 Transport and recovery of gilthead sea bream (Sparus aurata L.) sedated with clove oil and MS222: Effects on oxidative stress status Teles, Mariana; Oliveira, Miguel; Jerez Cepa, Ismael; Franco-Martínez, Lorena; Tvarijonaviciute, Asta; Tort, Lluis; Mancera Romero, Juan Miguel The use of anesthesia is a common practice in aquaculture to sedate fish and mitigate handling stress. Although the employ of anesthesia is considered beneficial for fish, as it reduces stress and improves welfare, at the same time it may induce hazardous side-effects. The aim of the present study was to investigate the effects of clove oil (CO) and tricaine methanesulfonate (MS222), two of the most used anesthetics, on several oxidative stress related parameters in gilthead sea bream (Sparus aurata), as these types of effects of anesthetics have been seldom investigated. To assess these effects, S. aurata juveniles were placed in a setup of mobile water tanks and were transported during 6 h with either 2.5 mg/L CO or 5 mg/L MS222. After transport, half of the fish were sampled, whereas the remaining fish were transferred to tanks without anesthetics where they were allowed to recover for 18 h before sampling. Changes in the expression levels of several target genes related with the antioxidant response and cell-tissue repair were evaluated in the gills, liver and brain. Those transcripts included glutathione peroxidase 1 (gpx1), catalase (cat), glutathione S-transferase 3 (gst3), glutathione reductase (gr), superoxide dismutase [Zn] (sod2), heat shock protein-70 (hsp70), and metallothionein (mt). Antioxidant enzymatic activities glutathione S-transferase, GST; catalase, CAT; and glutathione reductase, GR, levels of non-enzymatic antioxidants (non-protein thiols – NPT), and pro-oxidative damage, assessed as lipid peroxidation (LPO), were determined in gills, liver and brain. Acetylcholinesterase activity (AChE) was determined in plasma, gills, brain, muscle and heart as an indicator of neuro-muscular alterations. In plasma, the total antioxidant capacity (TAC) and total oxidative status (TOS) were also measured. Results showed that the use of both anesthetic agents, CO and MS222, interferes with fish antioxidant status. All tested biological matrices displayed alterations in antioxidant endpoints, confirming that these substances, although minimizing the effects of transport stress, may have long term effects on fish defenses. This result is of high relevance to aquaculture considering that the oxidative stress, may increase the susceptibility to different environmental or biotic stress and different types of pathologies. Wed, 01 May 2019 00:00:00 GMT http://hdl.handle.net/10498/34899 2019-05-01T00:00:00Z http://hdl.handle.net/10498/34419 The gonadotropin-releasing hormones: lessons from fish. Muñoz Cueto, José Antonio; Zmora, Nilli; Paullada Salmerón, José Antonio; Marvel, Miranda; Mañanos, E.L.; Zohar, Yonathan Fish have been of paramount importance to our understanding of vertebrate comparative neuroendocrinology and the mechanisms underlying the physiology and evolution of gonadotropin-releasing hormones (GnRH) and their genes. This review integrates past and recent knowledge on the Gnrh system in the fish model. Multiple Gnrh isoforms (two or three forms) are present in all teleosts, as well as multiple Gnrh receptors (up to five types), which differ in neuroanatomical localization, pattern of projections, ontogeny and functions. The role of the different Gnrh forms in reproduction seems to also differ in teleost models possessing two versus three Gnrh forms, Gnrh3 being the main hypophysiotropic hormone in the former and Gnrh1 in the latter. Functions of the non-hypothalamic Gnrh isoforms are still unclear, although under suboptimal physiological conditions (e.g. fasting), Gnrh2 may increase in the pituitary to ensure the integrity of reproduction under these conditions. Recent developments in transgenesis and mutagenesis in fish models have permitted the generation of fish lines expressing fluorophores in Gnrh neurons and to elucidate the dynamics of the elaborate innervations of the different neuronal populations, thus enabling a more accurate delineation of their reproductive roles and regulations. Moreover, in combination with neuronal electrophysiology, these lines have clarified the Gnrh mode of actions in modulating Lh and Fsh activities. While loss of function and genome editing studies had the premise to elucidate the exact roles of the multiple Gnrhs in reproduction and other processes, they have instead evoked an ongoing debate about these roles and opened new avenues of research that will no doubt lead to new discoveries regarding the not-yet-fully-understood Gnrh system. Fri, 15 May 2020 00:00:00 GMT http://hdl.handle.net/10498/34419 2020-05-15T00:00:00Z http://hdl.handle.net/10498/34418 Does the activation of sea bass GnIH receptor modulate GnRH receptor signaling? Wang, Bin; Paullada Salmerón, José Antonio; Verges Castillo, Alba; Muñoz Cueto, José Antonio Previous studies have revealed the stimulatory and inhibitory actions of gonadotropin-releasing hormone (GnRH) and gonadotropin-inhibitory hormone (GnIH) on the control of reproduction in European sea bass (Dicentrarchus labrax) and other vertebrates, respectively. However, information on the possible interactions between GnRH and GnIH on cell signaling is sparse in vertebrates. In the current study, we investigated if activation of sea bass GnIH receptor (GnIHR) can interfere with GnRH receptor II-1a (GnRHR-II-1a) involving the PKA pathway. Our results showed that GnIH and GnRH functioned via their cognate receptors, respectively. However, it appears that neither GnIH1 nor GnIH2 can block GnRH/GnRHR-II-1a-induced PKA signaling in sea bass. This is the first study to examine the potential interactions of GnIH with GnRH receptor signaling in teleosts. Further research seems necessary to shed light on unknown interactions in other signaling pathways and other GnIH/GnRH receptors involved in the physiological functions of these two relevant neuropeptides, not only in sea bass but also in other species. Tue, 01 Oct 2024 00:00:00 GMT http://hdl.handle.net/10498/34418 2024-10-01T00:00:00Z http://hdl.handle.net/10498/33587 A functional light-entrainable molecular clock is revealed in gilthead seabream (Sparus aurata) from early developmental stages using an embryonic stem cell line Martín-Robles, Á. J.; Verges Castillo, Alba; Muñoz Cueto, José Antonio; Durán-Sáez, J.; Pendón Meléndez, Carlos; Martín Robles, Águeda Jimena Like other vertebrates, fish exhibit physiological and behavioural rhythms that are synchronized by the cyclic variations in the external environment, being photoperiod, i.e., the alternation of light and dark during the 24-h cycle, the most predictable and powerful environmental cue. Many of these rhythms are endogenous and controlled by a molecular clock present in cells from early developmental stages. In a previous study, we have developed and characterised a new monoclonal embryonic stem cell line, SAEC-H7, derived from the morula stage embryos of a marine teleost, the gilthead seabream (Sparus aurata), a species with high commercial value for European aquaculture. In the present study, we aimed to identify the main components from the positive (clock and bmal1) and negative (cry1a, per1, per2 and per3) feedback loops of the molecular clock in this embryonic cell line and characterise putative daily variations and circadian rhythms in their expression under different photoperiod regimes, as well as the effects of nocturnal light pulses on their transcriptional activation. Our results revealed that SAEC-H7 cells contain a molecular clock that is entrained by the daily light-dark (LD) cycle. All clock genes analysed showed daily rhythms under LD conditions and were able to re-entrain to a 12-h phase shift (DL) in the photocycle, some of them (clock, bmal1, per1, per3) exhibiting circadian rhythms that persisted over a certain period under constant conditions, although with affected amplitudes and acrophases. Both cry1a and per2 genes showed a statistically significant increase in expression after a nocturnal light pulse, confirming the light-inducible character of these clock genes. The results obtained reveal that seabream embryonic cells are highly sensitive to light and already contain the phototransduction pathways that entrain the molecular clock and overt rhythms from the morula stage, making this embryonic cell line a useful tool for developmental and chronobiological studies in fish. Our results also reinforce the importance of maintaining natural cyclic light conditions in in vitro studies performed with fish cell lines as well as in embryonic and larval rearing protocols in aquaculture practices. Tue, 14 May 2024 00:00:00 GMT http://hdl.handle.net/10498/33587 2024-05-14T00:00:00Z