Juan Fuentes

Juan Fuentes
Centro de Ciências do Mar | CCMAR

Doctor of Philosophy

About

121
Publications
12,960
Reads
How we measure 'reads'
A 'read' is counted each time someone views a publication summary (such as the title, abstract, and list of authors), clicks on a figure, or views or downloads the full-text. Learn more
2,143
Citations
Citations since 2016
38 Research Items
1056 Citations
2016201720182019202020212022050100150200
2016201720182019202020212022050100150200
2016201720182019202020212022050100150200
2016201720182019202020212022050100150200
Introduction
I'm a physiologist with a particular interest in marine and euryhaline fish. My research program uses an integrative multilevel approach through the whole animal in vivo and in vitro studies, epithelial electrophysiology, cellular and molecular techniques
Additional affiliations
January 2002 - September 2020
Centro de Ciências do Mar
Position
  • Senior Researcher
April 1997 - December 2001
Centro de Ciências do Mar
Position
  • PDF
January 1995 - December 1996
University of Dundee
Position
  • PDF

Publications

Publications (121)
Article
Full-text available
In marine fish, high epithelial intestinal HCO₃−secretion generates luminal carbonate precipitates of divalent cations that play a key role in water and ion homeostasis. The present study was designed to expose the putative role for calcium and the calcium-sensing receptor (CaSR) in the regulation of HCO₃−secretion in the intestine of the sea bream...
Article
Full-text available
Background: In the animal production sector, enteritis is responsible for serious economic losses, and intestinal parasitism is a major stress factor leading to malnutrition and lowered performance and animal production efficiency. The effect of enteric parasites on the gut function of teleost fish, which represent the most ancient bony vertebrate...
Article
Full-text available
Lampreys are the most basal vertebrates with an osmoregulatory strategy. Previous research has established that salinity tolerance of sea lamprey increases dramatically during metamorphosis, but underlying changes in the gut have not been examined. In the present work, we examined changes in intestinal function during metamorphosis and seawater exp...
Article
Full-text available
Abstract The aim of this work was to evaluate two functional feeds for the gilthead seabream, Sparus aurata, containing low inclusion of two microalgae-based products (LB-GREENboost, LBGb; and LB-GUThealth, LBGh). Fish (12–13 g) were fed for 13 weeks a control diet or one of the four diets supplemented with both products at 0.5% or 1%. LBGb and LBG...
Article
Post-smolt mortality and stunted growth is a problem in Norwegian salmon farming that can be partly traced back to sub-optimal smolt quality in connection with ongoing changes in smolt production practices. In the present study, we compared smolt development and post-smolt performance in seawater (SW) of Atlantic salmon subjected to 1) traditional...
Preprint
Full-text available
To support the expected increase in aquaculture production during the next years, a wider range of alternative ingredients to fishmeal is needed, towards contributing to an increase in production sustainability. This study aimed to test diets formulated with non-conventional feed ingredients on gilthead seabream (Sparus aurata) growth performance,...
Article
Full-text available
Overexpression of asip1 in transgenic zebrafish disrupts dorsoventral pigment pattern in addition to increasing food intake levels and linear growth. A higher feed intake is unnecessary in transgenic fish to enable larger and heavier growth. A plausible explanation may rely on the enhanced feeding efficiency mediated by improved nutrient absorption...
Article
Full-text available
The agouti-signaling protein (ASIP) acts as both a competitive antagonist and inverse agonist of melanocortin receptors which regulate dorsal-ventral pigmentation patterns in fish. However, the potential role of ASIP in the regulation of additional physiological pathways in the skin is unknown. The skin plays a crucial role in the immune function,...
Article
The aim of this work was to evaluate the effects on growth performance, intermediary metabolism and welfare of the inclusion of two commercial microalgae-based ingredients called LB-ChromaBream (LB-CB) and LB-ChromaBream-plus (LB-CBplus) in the diet of gilthead seabream (Sparus aurata) close to commercial size. For this purpose, fish of ~182 g of i...
Article
Full-text available
Calcium balance is of paramount importance for vertebrates. In fish, the endocrine modulators of calcium homeostasis include the stanniocalcin (STC), and some members of the parathyroid hormone (PTH) family, such as the PTH-related protein (PTHrP), acting as antagonists. STC is ubiquitously expressed in higher vertebrates. In turn, bony fish exhibi...
Article
Full-text available
Aflatoxin B1 (AFB1) is a mycotoxin often present in food. This study aimed to understand the physiological effects of AFB1 on the seabream (Sparus aurata) gastrointestinal system. In a first in vitro approach, we investigated ion transport using the short-circuit current (Isc) technique in Ussing chambers in the anterior intestine (AI). Application...
Article
Full-text available
Two ncc orthologues (termed ncca and nccb ) were found in the sea lamprey genome, whereas nkcc2 was not. In a phylogenetic comparison among other vertebrate amino acids, NCC and NKCC deduced sequences, the sea lamprey NCC’s occupied basal positions within the NCC clade. In freshwater, ncca mRNA was found only in the gill and nccb only in the intest...
Article
Full-text available
Several studies in fish have shown that aflatoxin B1 (AFB1) causes a disparity of species-dependent physiological disorders without compromising survival. We studied the effect of dietary administration of AFB1 (2 mg AFB1 kg−1 diet) in gilthead seabream (Sparus aurata) juveniles in combination with a challenge by stocking density (4 vs. 40 g L−1)....
Article
The effects of ocean acidification mediated by an increase in water pCO2 levels on marine organisms are currently under debate. Elevated CO2 concentrations in the seawater induce several physiological responses in teleost fish, including acid-base imbalances and osmoregulatory changes. However, the consequences of CO2 levels enhancement on energy m...
Article
Mycotoxins are an increasing threat to all the related commodities from agriculture. Its occurrence is expected to increase due to climate change. Here, we examined the impacts of dietary toxicity of aflatoxin B1 (AFB1) in gilthead sea bream (Sparus aurata) at levels of 1 or 2 mg AFB1 kg−1 fish feed. Inclusion of AFB1 in the diet resulted in 80% in...
Article
The intestine of marine fishes contributes to the ocean carbon cycle producing carbonate aggregates as part of the osmoregulatory process. Therefore, this study aimed to evaluate physiological adjustments of European sea bass (Dicentrarchus labrax) intestine to a higher pCO2 environment likely in the near future (~1700 μatm). At the whole-body leve...
Article
Full-text available
Within a scenario of increasing atmospheric CO2 and ocean acidification (OA), it is highly relevant to investigate its impacts not only on fish performance but also on fish intestinal microbiome and how that reflects on host performance and health. The main objective of this study was to establish if the intestinal microbiota of the sea bream (Spar...
Article
To support the expected increase in aquaculture production during the next years, a wider range of alternative ingredients to fishmeal is needed, towards contributing to an increase in production sustainability. This study aimed to test diets formulated with non‐conventional feed ingredients on gilthead seabream (Sparus aurata) growth performance,...
Article
Full-text available
Marine fish contribute to the carbon cycle by producing mineralized intestinal precipitates generated as by-products of their osmoregulation. Here we aimed at characterizing the control of epithelial bicarbonate secretion and intestinal precipitate presence in the gilthead sea bream in response to predicted near future increases of environmental CO...
Article
Full-text available
Polyoxometalates (POMs) are promising inorganic inhibitors for P-type ATPases. The experimental models used to study the effects of POMs on these ATPases are usually in vitro models using vesicles from several membrane sources. Very recently, some polyoxotungstates, such as the Dawson anion [P2W18O62]6−, were shown to be potent P-type ATPase inhibi...
Article
In 2019, Europe will adopt a no-discards policy in fisheries. This entails the landing of captured species unless strong evidence is provided supporting their survival and recovery after fishing. Thus, research on this topic is gaining momentum. Bottom-trawling, as a non-selective fishing method, is characterized by a high proportion of discards in...
Article
The regulatory role of taurocholic acid (TC) and taurolithocholic acid (TLC) in ion transport was investigated with the short-circuit current (Isc) technique in the intestine of Senegalese sole (Solea senegalensis). Under voltage clamp conditions, Isc was stable for over 3 h and averaged −15.42 ± 2.75 μA/cm² and −65.28 + 7.69 μA/cm² in the anterior...
Article
Full-text available
Polyoxometalates are transition metal complexes that exhibit a broad diversity of structures and properties rendering them promising for biological purposes. They are able to inhibit a series of biologically important enzymes including various phosphatases, thus affecting many biochemical processes. In the present study, we analyzed and compared th...
Article
Full-text available
There is a constant need to find feed additives that improve health and nutrition of farmed fish and lessen the intestinal inflammation induced by plant-based ingredients. The objective of this study was to evaluate the effects of adding an organic acid salt to alleviate some of the detrimental effects of extreme plant-ingredient substitution of fi...
Data
Ingredients and chemical composition of experimental diets fed to gilthead sea bream in trial 1 (T1). (DOCX)
Data
Ingredients and chemical composition of experimental diets fed to gilthead sea bream in trial 2 (T2). (DOCX)
Data
Gene expression profile of the posterior intestine of gilthead sea bream in trial 2 (T2). Functional gene categories: 1 = cell differentiation and proliferation; 2 = intestinal architecture and permeability; 3 = enterocyte mass and epithelial damage; 4 = interleukins and cytokines; 5 = pattern recognition receptors; 6 = mitochondria function and bi...
Data
Representative intestinal sections of gilthead sea bream fed the control diet in trial 1 (T1-D1), comparing anterior (A, C, E) and posterior segments (B, D, F). Stainings: Fatty acid binding protein 2 (A, B); proliferating cell nuclear antigen (C, D); intestinal alkaline phosphatase activity (F, G). Scale bars = 20 μm. (TIF)
Data
Progression of trans-epithelial electrical resistance (Rt, Ω cm2) in the anterior intestine of gilthead sea bream in trial 3 (T3). Fish from T3-A (~1,420 g) and T3-B (~250 g) trials were fed with three different diets (D1: Control; D3: Extreme plant diet; D4; Extreme plant diet plus 0.4% BP-70). Rt was manually recorded at 30 min intervals for 150...
Data
Forward and reverse primers for real-time PCR of gilthead sea bream genes used in T1 and T2 trials. (DOCX)
Data
Gene expression profile of the anterior intestine of gilthead sea bream in trial 2 (T2). Functional gene categories: 1 = cell differentiation and proliferation; 2 = intestinal architecture and permeability; 3 = enterocyte mass and epithelial damage; 4 = interleukins and cytokines; 5 = pattern recognition receptors; 6 = mitochondria function and bio...
Article
Full-text available
Background Marine species have colonized extreme environments during evolution such as freshwater habitats. The amphidromous teleost fish, Galaxias maculatus is found mainly migrating between estuaries and rivers, but some landlocked populations have been described in lakes formed during the last deglaciation process in the Andes. In the present st...
Conference Paper
Full-text available
Senegalese sole (Solea senegalensis, Kaup 1858) is a commercially important teleost fish. The osmoregulatory system of this species has been previously characterized, especially at branchial and renal levels; however, the osmoregulatory role of the digestive tract has not been studied so far. In this study we assessed the modifications induced in t...
Article
Full-text available
Aquaporins (AQPs) are specific trans-membrane water channels with an important function in water homeostasis. In terrestrial vertebrates, AQP2 function is regulated by vasopressin (AVP) to accomplish key functions in osmoregulation. The endocrine control of aquaporin function in teleosts remains little studied. Therefore, in this study we investiga...
Poster
Full-text available
Animal welfare concerns have led to including cephalopods in Directive 2010/63/EU. This group of animals is widely used as marine and biomedical model at international level and there is the need for transportation of cuttlefish (Sepia officinalis) individuals between research centers and public aquaria. Transportations have been previously perform...
Article
Full-text available
In marine fish, high epithelial bicarbonate secretion by the intestine generates luminal carbonate precipitates of divalent cations that play a key role in water and ion homeostasis. In vitro studies highlight the involvement of the calciotropic hormones PTHrP (Parathyroid hormone related protein) and stanniocalcin (STC) in the regulation of epithe...
Chapter
Full-text available
A role in osmotic stress has been proposed for the vasotocinergic and isotocinergic systems in different fish species. We assessed, in a time course response study (day 0, 12 hours, and days 1, 3, 7 and 14 post transfer), the changes in branchial, renal, hypothalamic and hepatic vasotocin and isotocin receptors (AVTRs and ITR, respectively) mRNA ex...
Article
The dynamic changes in mRNA expression levels for vasotocin (AVT) and isotocin (IT) receptor gene levels were assessed in a time-course response study in immature male specimens of the gilthead sea bream (Sparus aurata) submitted to hyper- (55 ‰ salinity) and hypo-osmotic (5 ‰ salinity) challenges. Two different cDNAs for the AVT receptor and one f...
Article
DAX1 is an orphan nuclear receptor with actions in mammalian sex determination, regulation of steroidogenesis, embryonic development and neural differentiation. Conserved patterns of DAX1 gene expression from mammals to fish have been taken to suggest conserved function. In the present study, the European sea bass, Dicentrarchus labrax, DAX1 promot...
Article
Full-text available
In the present study, the protective effect of nucleotides over damages induced by the consumption of a diet containing a high amount of vegetable ingredients (560 g kg(-1)) in the intestinal epithelia of the meagre (Argyrosomus regius) was assessed by assays performed with an Ussing-type chamber. Two experimental feeds were prepared including or n...
Article
Full-text available
In addition to high drinking rates, processing of intestinal fluid is essential for osmoregulation in marine fish. This study analyzed the long-term response of the sea bream (Sparus aurata L.) to relevant changes of external salinity 12, 35 and 55ppt focusing on the anterior intestine and in the less often studied rectum. Intestinal water absorpti...
Article
Full-text available
The pituitary hormone prolactin is a pleiotropic endocrine factor that plays a major role in the regulation of ion balance in fish, with demonstrated actions mainly in the gills and kidney. The role of prolactin in intestinal ion transport remains little studied. In marine fish, which have high drinking rates, epithelial bicarbonate secretion in th...
Article
Full-text available
In the marine fish intestine luminal, HCO3− can remove divalent ions (calcium and magnesium) by precipitation in the form of carbonate aggregates. The process of epithelial HCO3− secretion is under endocrine control, therefore, in this study we aimed to characterize the involvement of transmembrane (tmACs) and soluble (sACs) adenylyl cyclases on th...
Article
The skin is the largest organ in the body and is a barrier between the internal and external environment. The present study evaluates how PTU, a goitrogen, that is used to treat hyperthyroidism affects the structure and electrical properties of the frog (Xenopus laevis) skin. The results are considered in the context of the two-membrane model estab...
Article
Full-text available
Parathyroid hormone (PTH) and PTH-related peptide (PTHrP) belong to a family of endocrine factors that share a highly conserved N-terminal region (amino acids 1-34) and play key roles in calcium homeostasis, bone formation and skeletal development. Recently, PTH-like peptide (PTH-L) was identified in teleost fish raising questions about the evoluti...
Data
Full-text available
Chicken PTHrP alternative transcripts. The five PTHrP transcripts that result from alternative exon skipping events are mapped against the structure of the chicken PTHrP gene and their respective EST accession number and size (bp) indicated. The novel chicken transcripts were named according to the size of the deduced mature peptide (139 or 141) pr...