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Sparus aurata is one of the two most important cultured fish species in the Mediterranean region. The present work investigates the effects of culturing in S. aurata liver tissue at the molecular level using Fourier Transform Infrared (FTIR) spectroscopy. FTIR spectroscopy revealed dramatic differences between the wild and aquacultured fish liver cells, which mainly indicated that the level of glycogen increased in the aquacultured samples and the protein/lipid ratio decreased by 42.29% indicating that triglycerides and cholesterol esters increased and the protein content decreased in the aquacultured samples. The 15.99% increase in the level of unsaturation indicated elevated lipid peroxidation. Structural/organisational changes in the nucleic acids along with increased transcriptional status of the liver tissue cells were observed in the cultured fish tissue. All these results indicated that culturing induces significant changes in fish physiology. In addition FTIR spectroscopy is a promising method to monitor the physiological changes in fish physiology., (Copyright © 2013 Elsevier Ltd. All rights reserved.)

The molecular profiles of perchloric acid solutions extracted from the flesh of Sparus aurata fish specimens, produced according to different aquaculture systems, have been investigated. The (1)H-NMR spectra of aqueous extracts are indicative of differences in the metabolite content of fish reared under different conditions that are already distinguishable at their capture, and substantially maintain the same differences in their molecular profiles after sixteen days of storage under ice. The fish metabolic profiles are studied by top-down chemometric analysis. The results of this exploratory investigation show that the fish metabolome accurately reflects the rearing conditions. The level of many metabolites co-vary with the rearing conditions and a few metabolites are quantified including glycogen (stress indicator), histidine, alanine and glycine which all display significant changes dependent on the aquaculture system and on the storage times.

The economic impact of skeletal anomalies in aquaculture farming is a significant issue for the industry, as deformed fish are frequently discarded because of their low survival rate and a variety of other disadvantages, including increased costs, consumer distrust of aquaculture products, and ethical concerns. The goal of this article is to propose a method for calculating the direct costs of severe skeletal anomalies in typical Mediterranean seabream and seabass aquaculture hatcheries using a deterministic static model programmed in MATLAB that simulates their annual operation. Our findings suggest that larger hatcheries experience higher direct costs associated with severe skeletal anomalies but have better financial stability and significantly higher expected profits. Mean results indicate that the annual economic losses of severe skeletal anomalies for seabream and seabass Mediterranean aquaculture are 22.88 million euros per year for a scenario of low severe skeletal anomalies, 65.34 million euros per year for a scenario of medium severe skeletal anomalies, and 115.98 million euros per year for a scenario of high severe skeletal anomalies. Furthermore, some options for increasing the financial stability of the hatcheries are to increase the sale price of fingerlings, reduce the feed conversion ratio, and reduce the feed unit cost. [ABSTRACT FROM AUTHOR]

Aquaculture is the fastest-growing food production sector and nowadays provides more food than extractive fishing. Studies focused on the understanding of how teleost growth is regulated are essential to improve fish production. Cysteamine (CSH) is a novel feed additive that can improve growth through the modulation of the GH/IGF axis; however, the underlying mechanisms and the interaction between tissues are not well understood. This study aimed to investigate the effects of CSH inclusion in diets at 1.65 g/kg of feed for 9 weeks and 1.65 g/kg or 3.3 g/kg for 9 weeks more, on growth performance and the GH/IGF-1 axis in plasma, liver, stomach, and white muscle in gilthead sea bream (Sparus aurata) fingerlings (1.8 ± 0.03 g) and juveniles (14.46 ± 0.68 g). Additionally, the effects of CSH stimulation in primary cultured muscle cells for 4 days on cell viability and GH/IGF axis relative gene expression were evaluated. Results showed that CSH-1.65 improved growth performance by 16% and 26.7% after 9 and 18 weeks, respectively, while CSH-3.3 improved 32.3% after 18 weeks compared to control diet (0 g/kg). However, no significant differences were found between both experimental doses. CSH reduced the plasma levels of GH after 18 weeks and increased the IGF-1 ones after 9 and 18 weeks. Gene expression analysis revealed a significant upregulation of the ghr-1, different igf-1 splice variants, igf-2 and the downregulation of the igf-1ra and b, depending on the tissue and dose. Myocytes stimulated with 200 µM of CSH showed higher cell viability and mRNA levels of ghr1, igf-1b, igf-2 and igf-1rb compared to control (0 µM) in a similar way to white muscle. Overall, CSH improves growth and modulates the GH/IGF-1 axis in vivo and in vitro toward an anabolic status through different synergic ways, revealing CSH as a feasible candidate to be included in fish feed. [ABSTRACT FROM AUTHOR]

Gut microbiomes of fish species consist of thousands of bacterial taxa that interact among each other, their environment, and the host. These complex networks of interactions are regulated by a diverse range of factors, yet little is known about the hierarchy of these interactions. Here, we introduce SAMBA (Structure-Learning of Aquaculture Microbiomes using a Bayesian Approach), a computational tool that uses a unified Bayesian network approach to model the network structure of fish gut microbiomes and their interactions with biotic and abiotic variables associated with typical aquaculture systems. SAMBA accepts input data on microbial abundance from 16S rRNA amplicons as well as continuous and categorical information from distinct farming conditions. From this, SAMBA can create and train a network model scenario that can be used to (i) infer information of how specific farming conditions influence the diversity of the gut microbiome or pan-microbiome, and (ii) predict how the diversity and functional profile of that microbiome would change under other variable conditions. SAMBA also allows the user to visualize, manage, edit, and export the acyclic graph of the modelled network. Our study presents examples and test results of Bayesian network scenarios created by SAMBA using data from a microbial synthetic community, and the pan-microbiome of gilthead sea bream (Sparus aurata) in different feeding trials. It is worth noting that the usage of SAMBA is not limited to aquaculture systems as it can be used for modelling microbiome–host network relationships of any vertebrate organism, including humans, in any system and/or ecosystem. [ABSTRACT FROM AUTHOR]

Routine monitoring of monogenean loads is a crucial step for infection management in aquaculture facilities. This analysis is usually performed from partial gill analyses and thus, knowledge of parasite distribution and size can be helpful to optimise diagnosis, estimate infection levels and improve management procedures. Gill location preferences and intraspecific size variations relative to parasite age, host factors and parasite abundance are herein determined for the monogenean Sparicotyle chrysophrii, one of the most challenging pathogens in gilthead sea bream aquaculture. Present findings on parasite location show that the life-history stages of S. chrysophrii have distinct location preferences. Analysis of intraspecific size variations of adult stages of S. chrysophrii revealed that the size of most morphological features of S. chrysophrii increased significantly with parasite age and host size. Positive and significant relationships between the size of the posteriormost clamp and host size pointed out the adaptation of the parasite to the gilthead sea bream size from the initial settlement. Host size also seems to restrict the development of parasites after maturity as the oldest specimens were exclusively found in mid-large fish (>18 cm). By contrast, no clear patterns were observed for the relationship between parasite size and location or abundance. Post-maturity size variations of S. chrysophrii should be considered for parasite identification and the clamp pair number should be fixed for accurate taxonomic diagnosis. Based on the site location of S. chrysophrii, the dorsal sections or the outermost holobranches would be suitable for adult detection while the analysis of the central and dorsal sections of the outermost holobranches may be a better option for finding most of the adult, juvenile or post-larval stages.

Abstract 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 vertebrates, is far from being understood. The intestinal myxozoan parasite Enteromyxum leei dwells between gut epithelial cells and causes severe enteritis in gilthead sea bream (Sparus aurata), anorexia, cachexia, growth impairment, reduced marketability and increased mortality. Methods This study aimed to outline the gut failure in this fish-parasite model using a multifaceted approach and to find and validate non-lethal serum markers of gut barrier dysfunction. Intestinal integrity was studied in parasitized and non-parasitized fish by immunohistochemistry with specific markers for cellular adhesion (E-cadherin) and tight junctions (Tjp1 and Cldn3) and by functional studies of permeability (oral administration of FITC-dextran) and electrophysiology (Ussing chambers). Serum samples from parasitized and non-parasitized fish were analyzed using non-targeted metabolomics and some significantly altered metabolites were selected to be validated using commercial kits. Results The immunodetection of Tjp1 and Cldn3 was significantly lower in the intestine of parasitized fish, while no strong differences were found in E-cadherin. Parasitized fish showed a significant increase in paracellular uptake measured by FITC-dextran detection in serum. Electrophysiology showed a decrease in transepithelial resistance in infected animals, which showed a diarrheic profile. Serum metabolomics revealed 3702 ions, from which the differential expression of 20 identified compounds significantly separated control from infected groups in multivariate analyses. Of these compounds, serum inosine (decreased) and creatine (increased) were identified as relevant and validated with commercial kits. Conclusions The results demonstrate the disruption of tight junctions and the loss of gut barrier function, a metabolomic profile of absorption dysfunction and anorexia, which further outline the pathophysiological effects of E. leei.

The present research tested the effects of dietary nisin-producing Lactococcus lactis on growth performance, feed utilization, intestinal morphology, transcriptional response, and microbiota in gilthead sea bream (Sparus aurata). A feeding trial was conducted with fish weighting 70–90 g. Fish were tagged with passive, integrated transponders and distributed in nine 500 L tanks with 40 fish each. Fish were fed for 12 weeks with either a control (diet A) or experimental diets (diets B and C) in triplicate (3 tanks/diet). Extruded pellets of diets B and C were supplemented with a low (2 × 109 CFU/kg) and a high (5 × 109 CFU/kg) dose of probiotic, respectively. No significant differences were found between groups for the feed conversion ratio or specific growth rates. However, the final body weight of fish fed diet C was significantly higher than the control group with intermediate values for fish fed diet B. Histological analysis conducted using a semi-quantitative scoring system showed that probiotic did not alter the morphology of the intestine and did not trigger inflammation. With regard to the transcriptomic response, a customized PCR array layout was designed to simultaneously profile a panel of 44 selected genes. Significant differences in the expression of key genes involved in innate and acquired immunity were detected between fish fed probiotic and control diets. To analyze the microbiota associated to the feeds and the gut autochthonous microbial communities, we used the Illumina MiSeq platform for sequencing the 16S rRNA gene and a metagenomics pipeline based on VSEARCH and RDP databases. The analysis of gut microbiota revealed a lack of colonization of the probiotic in the host’s intestinal mucosa. However, probiotic did modulate the fish gut microbiota, confirming that colonization is not always necessary to induce host modification. In fact, diets B and C were enriched with Actinomycetales, as compared to diet A, which instead showed a higher percentage of Pseudomonas, Sphyngomonas, and Lactobacillus genera. These results were confirmed by the clear separation of gut bacterial community of fish fed with the probiotic from the bacterial community of control fish group in the beta-diversity and PLS-DA (supervised partial least-squares discriminant analysis) analyses.

The aquaculture sector has experienced rapid and important growth with the subsequent increase of feeding and nutritional issues for sustaining this activity, mainly related to the use of high quality, safe and environmentally friendly feed ingredients. The use of additives in aquafeeds has proven to be a suitable option to improve different productive indicators in farmed fish. In the present study, the effect of adding the GHRP-6 peptide, a ghrelin analog, to a commercial diet of gilthead sea bream (Sparus aurata) was studied at two proportions (100 or 500 μg/kg of feed). Both experimental diets show an increase in growth performance, as well as in feed efficiency after 97 days of experiment. The lower inclusion of GHRP-6 (100 μg/kg) results in a better aerobic metabolism, while the higher inclusion significantly increased plasma GH levels in agreement with the GH secretagogue effects of ghrelin. Similar growth outcome and differences between GHRP-6 levels in aerobic metabolism and GH stimulation suggest that improvements in culture performance by this peptide may occur through different mechanisms. Taken together, this compound can be considered as a viable dietary supplement for increasing production efficiency of sea bream aquaculture, although a better understanding of its dose-specific effects is still required.

Gill monogenean Sparicotyle chrysophrii is considered the most detrimental fish parasite to the Mediterranean aquaculture. Treatment of sparicotylosis relies on frequent gill inspections correlated with the seasonal increase in seawater temperature, application of functional feeds, and treatments with formalin baths where permitted. While the latter is bound to be banned in Europe, other synthetic anthelminthics, such as praziquantel and ivermectin, are prone to induce resistance in the parasites. Therefore, we investigated, in vitro, 14 synthetic and natural compounds against adult S. chrysophrii, developing dose–response modelsm and estimated toxicity levels at 20%, 50%, and 80% parasite mortality. Bactericidal activity of target compounds was also tested in two important aquaculture bacteria; Vibrio harveyi and V. anguillarum, while their potential host toxicity was evaluated in gilthead seabream SAF-1 cell line. Synthetic compound bithionate sodium exerted the most potent toxicity against the monogenean, no host cytotoxicity, and a medium and high potency against two bacterial pathogens. In comparison, target natural compounds were approximately 20 (cedrol) or up to 154 times (camphor) less toxic for the monogenean. Rather than completely dismissing natural compounds, we suggest that their application in combination with synthetic drugs, especially if administered in the feed, might be useful in sparicotylosis treatment.

European fish farming drives the development of sustainable marine fish feed where marine ingredients are replaced by alternatives such as plant meals and vegetable oils. A new scenario emerges where noncurrent and/or new contaminants enter into the fish food chain as potential food safety and/or welfare concerns. Novel analytical methodologies must be developed to assess the large variety of contaminants from different families in feed ingredients, feeds based on these ingredients and fish farmed on the novel feeds. Of the novel contaminants identified in feed ingredients and feeds, the pesticides, such as chlorpyrifos‐methyl, pirimiphos‐methyl, boscalid and azoxystrobin, and the mycotoxins, such as deoxynivalenol and fumonisins (B1 + B2 + B3), were detected. Polyaromatic hydrocarbons, especially those with ≤4 ring, were found in all samples. Information of the transfer of contaminants from feed to public foodstuffs is essential for an appropriate human risk assessment of feed contaminants as well as for the harmonization of legislation of contaminants throughout the aquaculture production chain. However, the pesticides and mycotoxins found in feed were not detected in fish fillet, and hence, no transfer factor could be established. As a result, no apparent risk seems to be associated with these contaminants in fish fillets at the current background exposure levels by feeds. Recent achievements in aquafeeds with marine fish oil and fish meal below 10% represented food safety risks considerably reduced. The use of plant‐based diets implies that POPs were not found. Polar pesticides and mycotoxins were not transferred to edible fillets while PAHs were widely found in both feed and fillets. [ABSTRACT FROM AUTHOR]

A metabolomic study has been performed to identify sensitive and robust biomarkers of malnutrition in farmed fish, using gilthead sea bream (Sparus aurata) as a model. The metabolomic fingerprinting of serum from fasted fish was assessed by means of ultra-high performance liquid chromatography coupled to quadrupole time-of-flight mass spectrometry. More than 15,000 different m/z ions were detected and Partial Least Squares–Discriminant analysis allowed a clear differentiation between the two experimental groups (fed and 10-day fasted fish) with more than 90% of total variance explained by the two first components. The most significant metabolites (up to 45) were elucidated on the basis of their tandem mass spectra with a broad representation of amino acids, oligopeptides, urea cycle metabolites, L-carnitine-related metabolites, glutathione-related metabolites, fatty acids, lysophosphatidic acids, phosphatidylcholines as well as biotin- and noradrenaline-related metabolites. This untargeted approach highlighted important adaptive responses in energy and oxidative metabolism, contributing to identify robust and nutritionally-regulated biomarkers of health and metabolic condition that will serve to assess the welfare status of farmed fish.

A method for studying the efficacy of sulfadiazine as a marker to estimate feed intake is presented. Feeding studies were carried out with two species, rainbow trout as a freshwater fish model and gilthead sea bream as a marine fish model, using two temperatures and two sizes of juveniles. The study showed the different feeding behaviour observed in both species, depending on the temperature and the number of days feeding the particles with sulfadiazine, and confirmed a dominant-subordinate behaviour especially in the case of gilthead sea bream juveniles. [ABSTRACT FROM AUTHOR]

This study evaluated the ambient noise effect of onshore and offshore aquaculture systems on oxidative status and on some immune parameters in gilthead sea bream ( Sparus aurata) juveniles. The experiment was performed for 40 days, projecting two different playlists of acoustic stimuli: offshore aquaculture noise condition that created the typical acoustic field in proximity of an offshore sea cage for fish farming, using a random sequence of quite sea background and boat noises; and onshore aquaculture noise condition that represented the acoustic field inside an open concrete tank for fish farming. A third group without any acoustic projection was used as a control. After 40 days from the beginning of acoustic noise, fish exposed to the offshore aquaculture condition showed significantly higher levels of total oxidant status, lysozyme activity, antiprotease activity and white blood cells together with a lower albumin/globulin ratio in comparison to fish from the control group; whereas fish exposed to the onshore condition showed analytical data placed between the other groups, though never significantly different. These results demonstrate that the offshore aquaculture noise, and in particular the sea soundscape, adversely influences the oxidative status and the immune function of gilthead sea bream determining a mild stress condition that could affect the sea bream welfare. [ABSTRACT FROM AUTHOR]

Low water temperatures during winter are common in farming of gilthead sea bream in the Mediterranean. This causes metabolic disorders that in extreme cases can lead to a syndrome called 'winter disease.' An improved immunostimulatory nutritional status might mitigate the effects of this thermal metabolic stress. A trial was set up to assess the effects of two different diets on gilthead sea bream physiology and nutritional state through plasma proteome and metabolites. Four groups of 25 adult gilthead sea bream were reared during winter months, being fed either with a control diet (CTRL) or with a diet called 'winter feed' (WF). Proteome results show a slightly higher number of proteins upregulated in plasma of fish fed the WF. These proteins are mostly involved in the immune system and cell protection mechanisms. Lipid metabolism was also affected, as shown both by plasma proteome and by the cholesterol plasma levels. Overall, the winter feed diet tested seems to have positive effects in terms of fish condition and nutritional status, reducing the metabolic effects of thermal stress. [ABSTRACT FROM AUTHOR]

The gilthead sea bream ( Sparus aurata L.) is one of the most important marine fish species produced in southern European countries. Over the last two decades, microsatellites have become a powerful tool for DNA studies of fish populations, making it possible to establish existing genealogical relationships between individuals and to perform reliable estimates of genetic parameters. In the present study, a total of 7959 fish (494 breeders and 7465 fry) were genotyped using two rounds of multiplex reactions with four microsatellite markers each. Offspring were assigned based on the Mendelian exclusion principles, using FAP program. Genealogical information was successfully obtained for more than 83 % of the progeny. Heritability estimates were close to 0.40 in all cases and for all considered traits. The lowest value was for the length at first age (350 ± 6 dph) and the highest for the length at the second age (500 ± 7 dph). The heritabilities for the first and the second weight were similar although somewhat higher for the second age, but not significant. The highest genetic correlations were found between weight and length at the same age and the lowest between weight and length at different ages. Based on the results of this study, it seems reasonable to expect that the implementation of a breeding program for improved growth in this population of gilthead sea bream will offer comparable performances to those achieved in other populations and species of great success in aquaculture around the world. [ABSTRACT FROM AUTHOR]

Biometric and metabolic responses of gilthead sea bream to cold challenge are described following a growth trial divided into three water temperature steps, namely cooling, cold maintenance and recovery. Experimental data provide a useful description of fish response to thermal stress at both zootechnical and molecular level. Although no mortality has been observed, Nuclear Magnetic Resonance-based metabolomics confirms the marked sensitivity of this fish species to low water temperature, and explains some key molecular events associated to fish response to cold. Increase in hepatosomatic index is associated to liver fat accumulation, as a consequence of lipid mobilization from muscle and other extrahepatic tissues, and metabolic rearrangements linked to homeoviscous adaptation of cellular membranes are observed. Following primary responses to descending temperature from 18 °C to 11 °C, the energetic metabolism (insulin signaling, glycolysis) is first clearly affected; then, at constant low water temperature (11 °C), the most perturbed metabolic pathways are related to methionine cycle in liver, while osmoregulatory function is exerted by TMAO in muscle. Water temperature recovery from 11 °C to 18 °C stimulates gluconeogenesis and glycogen synthesis activities at hepatic level, although the rate of a thermo-compensatory response seems to be slower than that of the cooling phase. The obtained results are intended to guide novel high-performance feed formulations for gilthead sea bream reared during winter. [ABSTRACT FROM AUTHOR]

The molecular profiles of perchloric acid solutions extracted from the flesh of Sparus aurata fish specimens, produced according to different aquaculture systems, have been investigated. The 1H-NMR spectra of aqueous extracts are indicative of differences in the metabolite content of fish reared under different conditions that are already distinguishable at their capture, and substantially maintain the same differences in their molecular profiles after sixteen days of storage under ice. The fish metabolic profiles are studied by top-down chemometric analysis. The results of this exploratory investigation show that the fish metabolome accurately reflects the rearing conditions. The level of many metabolites co-vary with the rearing conditions and a few metabolites are quantified including glycogen (stress indicator), histidine, alanine and glycine which all display significant changes dependent on the aquaculture system and on the storage times.

Aquaculture is one of the worldwide strategic development fields, and its importance is evident in its significant worldwide growth in the last decades. This growth is associated with the implementation of intensive and semi-intensive production methods, with the use of antibiotics in order to prevent the emergence and spread of infectious diseases in fish. This practice constitutes a real public health problem, not only due to the presence of antimicrobial residues in edible tissues, which can cause allergic reactions in hypersensitive individuals, but also due to the emergence of bacterial resistance. Consequently, the Regulatory Agencies have established maximum residue limits (MRL). In the present study, a validated multiclass multi-residue ultra-high-performance liquid chromatography coupled with mass spectrometry in tandem methodology was used for the determination of 41 antibiotics from seven different classes-sulfonamides, trimethoprim, tetracyclines, macrolides, quinolones, penicillins and chloramphenicol-in 29 samples of gilthead sea bream of aquaculture origin, purchased in Portugal. The analysed samples showed that, in eight of them, antibiotic residues were present, three being of doxycycline-antibiotic for which no MRL is established-that was detected in concentrations ranging from 0.35 to 0.61 μg kg Other antibiotics were also detected and quantified and their concentrations were below the MRL established by the European legislation. [ABSTRACT FROM AUTHOR]

This work is aimed at obtaining farmed fish designed to contain targeted PUFAs. To this end, an experiment was conducted with farmed specimens of gilthead sea bream ( Sparus aurata L.), which were fed meal containing different percentages of common green bottle fly ( Lucilia sericata Meigen) larvae, cultured on appropriate substrates, and then the fatty acid profiles in fish muscles were determined. Results indicate that arachidonic acid content in fish muscle is significantly increased when replacing different proportions of fishmeal by larvae from L. sericata, which contains arachidonic acid up to 10.6% of total fatty acids. Thus, larvae seem to be a suitable vector for introducing target PUFA in fish muscle and it could also contribute to reduce the use of wild fish stocks for fishmeal production. [ABSTRACT FROM AUTHOR]

The aim of the study was to validate a dummy regression approach for predictive modelling the fillet fatty acid ( FA) composition of cultured European sea bass with dietary FA composition and lipid fillet content as independent variables. The model used our own data on gilthead sea bream as reference subgroup dataset and data from turbot, sole and European sea bass as dummy variables. Most of the observed variance within and among species was explained by the regression model without statistical significant interactions on blocks between diet composition and fish species subgroups. For the validation of European sea bass FA descriptors, predictive values derived from data on fish reared at laboratory scale were plotted against those obtained in farmed fish harvested at commercial size. A close linear association near to equality was found for 12 representative FAs, including saturated FAs, monoenenes and polyunsaturated FAs. This finding reinforces the possibility to produce tailored and healthy seafood products according to the guidelines of essential FA requirements in humans. FA algorithms for all the species in the model are hosted at as a multispecies tool to interrogate the nutritionally regulated FA composition of four cultured marine fish species of a high added value. [ABSTRACT FROM AUTHOR]

Marine aquaculture in Greece is a relatively new industry based on the culture of aquatic species such as the Mediterranean sea bass (Dicentrarchus labrax), gilthead sea bream (Sparus aurata), and Mediterranean mussel (Mytilus galloprovincialis). In the early 1980s, the results of research and development were applied to develop pilot semiacademic commercial farms. Such farms were gradually moved to the industrial scale of today, producing some 80,00–120,000 tons of finfish and up to 25,000–35,000 tons of mussels annually. The problems encountered during the adaptation of innovation to the production and management of this blue revolution is critically discussed from the early developmental phases up to the present. [ABSTRACT FROM AUTHOR]

Background The zootechnical performance of three different commercial feeds and their impact on liver and serum proteins of gilthead sea bream (Sparus aurata, L.) were assessed in a 12 week feeding trial. The three feeds, named A, B, and C, were subjected to lipid and protein characterization by gas chromatography (GC) and liquid chromatography-tandem mass spectrometry (LC-MS/MS), respectively. Results Feed B was higher in fish-derived lipids and proteins, while feeds C and A were higher in vegetable components, although the largest proportion of feed C proteins was represented by pig hemoglobin. According to biometric measurements, the feeds had significantly different impacts on fish growth, producing a higher average weight gain and a lower liver somatic index in feed B over feeds A and C, respectively. 2D DIGE/MS analysis of liver tissue and Ingenuity pathways analysis (IPA) highlighted differential changes in proteins involved in key metabolic pathways of liver, spanning carbohydrate, lipid, protein, and oxidative metabolism. In addition, serum proteomics revealed interesting changes in apolipoproteins, transferrin, warm temperature acclimation-related 65 kDa protein (Wap65), fibrinogen, Ftype lectin, and alpha-1-antitrypsin. Conclusions This study highlights the contribution of proteomics for understanding and improving the metabolic compatibility of feeds for marine aquaculture, and opens new perspectives for its monitoring with serological tests. [ABSTRACT FROM AUTHOR]

The authors in a previous work had reported on the determination of seven quinolone antibiotics in gilthead sea bream using liquid chromatography–tandem mass spectrometry, which is a rather expensive and not always available analytical technique. In this work, photodiode array detection is used, so that no sophisticated instrumentation is necessary, following the same sample preparation procedure. A high performance liquid chromatography method for the determination of seven quinolone antibiotics in fish feed and gilthead sea bream (Sparus aurataL.) tissue was developed and validated in terms of selectivity, linearity, accuracy, precision, sensitivity, robustness, and stability, according to European Decision 2002/657/EC. Ciprofloxacin, danofloxacin, enrofloxacin, sarafloxacin, oxolinic acid, nalidixic acid, and flumequine were separated on a Perfectsil ODS-3 (250 mm × 4 mm, 5 µm) column by gradient elution, using a mobile phase consisting of 0.1% trifluoroacetic acid (pH = 1), acetonitrile, and methanol at 25°C. Analytes were monitored by diode array detector at 255 nm for acidic quinolones (oxolinic acid, nalidix acid, and flumequine) and 275 nm for ciprofloxacin, danofloxacin, enrofloxacin, and sarafloxacin. The method was successfully applied to gilthead sea bream from aquaculture after dietary administration of flumequine and oxolinic acid. [ABSTRACT FROM AUTHOR]

The aquaculture sector has experienced rapid and important growth with the subsequent increase of feeding and nutritional issues for sustaining this activity, mainly related to the use of high quality, safe and environmentally friendly feed ingredients. The use of additives in aquafeeds has proven to be a suitable option to improve different productive indicators in farmed fish. In the present study, the effect of adding the GHRP-6 peptide, a ghrelin analog, to a commercial diet of gilthead sea bream (Sparus aurata) was studied at two proportions (100 or 500 μg/kg of feed). Both experimental diets show an increase in growth performance, as well as in feed efficiency after 97 days of experiment. The lower inclusion of GHRP-6 (100 μg/kg) results in a better aerobic metabolism, while the higher inclusion significantly increased plasma GH levels in agreement with the GH secretagogue effects of ghrelin. Similar growth outcome and differences between GHRP-6 levels in aerobic metabolism and GH stimulation suggest that improvements in culture performance by this peptide may occur through different mechanisms. Taken together, this compound can be considered as a viable dietary supplement for increasing production efficiency of sea bream aquaculture, although a better understanding of its dose-specific effects is still required. [ABSTRACT FROM AUTHOR]

Interactions between fisheries and aquaculture have become a major issue that is still insufficiently studied. Therefore, the objective of this article is to test whether the cultured and wild gilthead sea bream in the Spanish seafood markets are integrated. By using the Johansen methodology, cointegration of the price series of farmed and wild gilthead sea bream was tested. In contrast to previous studies, our econometric results show that wild and the farmed gilthead sea bream form two heterogeneous products in the Spanish market. These new results question the generalization currently accepted by the scientific literature that farmed and wild fish are substitutes when they belong to the same species. The binomial product-market, along with some specific features of the Spanish market, such as the negative perceptions of aquaculture by some significant groups of consumers, appeared to have a great explanatory power for justifying these different results. [ABSTRACT FROM AUTHOR]

Abstract: Gilthead sea bream (Sparus aurata) is considered the most important finfish aquaculture product in the Mediterranean Sea, but inadequate number of domestic hatcheries has reflected in fact that 70% of fingerlings are imported, mainly from Italy and France. In order to assess potential genetic differentiation between wild and cultured sea breams, we screened eight microsatellite loci. Analyses evidenced heterogeneous genotypic distributions for each population, with extensive polymorphism and overall expected heterozygosity levels >71%. Such a high admixture and weak population structuring has previously been reported in the rest of the Mediterranean Sea. Results imply that farmed escapees are involved in genetic pollution of adjacent wild populations showing lower differentiation among themselves. Inference of such a situation strongly encourages strengthening of routine aquaculture practice in the Adriatic through development of genetic-based management for broodstock, fingerlings and farmed fish, as well as better zootechnological protocol related to maintenance of nets and cages. [Copyright &y& Elsevier]

Abstract: This work describes a metabolic profiling study of gilthead sea bream, from three different aquaculture systems, using 1H NMR and chemometrics. A total of 54 samples under two different storage regimens were analysed. The assignment of all major NMR signals of the perchloric extracts was performed. A comprehensive multivariate data analysis proved able to distinguish the fish metabolism amongst the different aquaculture systems and to determine whether a fish was stored or not. The state of energy metabolism of inosine proved a robust biomarker for evaluating storage time. A new multivariate classification tool, iECVA, revealed several metabolites which are important biomarkers for characterising the three different aquaculture systems: glycogen (stress indicator), histidine, alanine and especially glycine for long storage times and mainly betaine for fresh samples. The findings represent a step forward in understanding how in vivo and postmortem processes affect the total quality of the final product. [Copyright &y& Elsevier]

The effects of steam pelleting or extrusion of a commercial feed on performance of 2 g (small) and 40 g (large) gilthead sea bream was studied. In addition the apparent digestibility of diets, gastric evacuation time (GET) and trypsin and amylase activities were measured in large fish. Fish size significantly increased protein and energy productive value, body protein and lipid, liver glycogen and liver lipid, however decreased daily growth index, feed intake and feed utilization, body moisture and hepatosomatic index. Extrusion processing decreased feed intake, more strongly for small fish, and increased daily growth index, feed utilization, protein and energy productive value, body protein and lipid. Digestibility of starch and energy increased with extrusion and GET of extruded feed was double that of steam-pelleted conditioned feed (i.e. 544 min versus 284 min). Digestive enzyme activities approached maximum values after 240 min for the pelleted diet, while those of the extruded continued to increase, at higher rates for amylase than trypsin. Pelleted diet indicated higher moisture for stomach digesta, while the moisture of the intestinal precipitate indicated a higher water-binding capacity for the extruded diet. The overall results indicate a better assimilation of the extruded diet, which could result from its prolonged gastric evacuation. [ABSTRACT FROM AUTHOR]

Abstract: The gilthead sea bream (Sparus aurata) is the most important marine cultured species in the Mediterranean. Dichlorvos is one of the main chemical agents used in bath treatments against ectoparasites of marine farmed fish. The main objective of this study was to investigate the effects of 24 h dichlorvos baths on selected biomarkers that are involved in important physiological functions or indicative of gilthead sea bream fingerlings growth. To attain this objective, the in vivo effects of dichlorvos on cholinesterases'' activity (ChE), lipid peroxidation (TBARS), RNA/DNA ratio, glutathione S-transferases activity (GST) and heat shock proteins HSP70 were studied. The characterization of ChE in brain and muscle was previously determined to select the most sensitive tissue in this species. The exposure of gilthead sea bream fingerlings to dichlorvos caused an inhibition of ChE activity, an increase in lipid peroxidation (TBARS) and a decrease in the RNA/DNA ratio. In contrast, no significant changes in GST and HSP70 were found. The results indicate that ChE, TBARS and RNA/DNA ratio seem to be sensitive biomarkers to detect sub−lethal effects of dichlorvos aquaculture treatments in gilthead sea bream fingerlings. [Copyright &y& Elsevier]

Farmed gilthead sea bream, Sparus aurata, frequently escape from the sea cages and interact with wild populations. The impact of these interactions on the wild populations will depend, in part, on differences in performance of the bream. This study compared the swimming performance of the wild and farmed fish in a current channel. The absolute critical swimming speed ( Ucrit) increased with increasing size while the relative Ucrit decreased. Even at the same length there were noticeable performance differences between the individuals. The wild sea bream have significantly higher ( P<0.05) absolute Ucrit performance (0.86±0.01 m s−1) than the farmed fish (0.79±0.01 m s−1) and significantly higher ( P<0.05) relative Ucrit performance (4.52±0.05 BL s−1) than the farmed fish (4.21±0.05 BL s−1). The present study suggests that cultured sea bream may not have the ability to compete with wild sea bream in native seawaters. [ABSTRACT FROM AUTHOR]

More than 25% of Greek fish farms and 20% of Greek hatcheries of gilthead sea bream ( Sparus aurata) and sea bass ( Dicentrarchus labrax) are located along the Western Hellenic coast. The part of sea bream production is about 60% of the total production of these species. During the last decade, a spectacular increase in both the number of farms and their production, accompanied by a substantial price decrease and modification of their structure and functioning, has been recorded. These changes resulted in the maintenance in cages of large individuals (more than 500 g) of gilthead sea bream which are potential spawners. The study, based on both the maturity stage and the decrease in individual mean weights during the reproductive period of the species, confirmed reproduction in cages. In parallel, during the last 5 years a remarkable increase (about 80%) in sea bream landings from the fish trap fisheries of the Messolonghi-Etoliko lagoon, which is a typical nursery for the species, was recorded. The increase was accompanied by a decrease both in price and mean size of the 0-group individuals. The possible influence of the rearing activities in the area, the density-dependent mechanisms and the negative impacts of this unintentional enhancement of the traditional lagoon fisheries of the area are discussed. [ABSTRACT FROM AUTHOR]

Abstract: Proximate composition, fatty acid and amino acid profiles and sensory attributes of semi-intensive cultured gilthead sea bream were determined without feeding interruption and with feeding interruption from 1 to 13 days. Average proximate composition was protein: 19.4–19.9%, fat 14.1–15.4%, moisture: 64.1–65.3%, and ash: 1.3%. The monounsaturated fatty acids (MUFA) were dominant: 43%, followed by polyunsaturated fatty acids (PUFA): 32% and saturated fatty acids (SFA) 25%. For each fatty acid class the major compounds were palmitic acid (SFA), vaccenic and oleic acid (MUFA) and docosahexaenoic acid (PUFA). Regarding the feeding interruption, it appears that the perivisceral fat can supply the required energy for up to 13 days of starvation. [Copyright &y& Elsevier]

We have studied how the diet energy level affects gilthead sea bream ( Sparus aurata) daily pattern of demand-feeding activity and nutritional use of the diet under summer- and winter-like conditions. To that end, animals were kept in a closed circuit under controlled temperature and photoperiod, and fed one of two commercial diets with either high (H: 238 g kg−1 fat) or low (L: 172 g kg−1 fat) energy content. In summer conditions (26 °C; 12 : 12 L : D), both diets yielded similar growth rate (0.7 ± 0.0 and 0.7 ± 0.1) and thermal unit growth coefficient values (0.6 ± 0.0 and 0.6 ± 0.0), and although the daily rate of delivered feed was somewhat higher for fish under the high-energy diet (16 ± 2 g kg−1 of fish) the difference was not significant. In winter conditions (17 °C; 9 : 15 L : D), on the other hand, no differences were found for any of the parameters evaluated. Thus, the higher lipid content of the diet does not appear to have any protein sparing effect. The ‘summer’ demand-feeding pattern displayed three daily peaks, which were quite apparent for fish under the low-energy diet, but rather smoothed for those that ate the energy-rich diet. This profile was replaced in winter conditions by a single peak around noon, and the animals also displayed a lower overall number of demands. [ABSTRACT FROM AUTHOR]

This study was carried out to investigate the genetic variability and the population genetics ofSparus auratus.In fact, despite its importance in Mediterranean fisheries and aquaculture, very little it is known concerning its population structure. Samples of wild gilthead sea bream were collected in seven different localities along the Mediterranean and Atlantic coasts and were genetically characterized by means of microsatellite markers. Genotyping at four microsatellite loci revealed high polymorphism (7–38 alleles/locus) and expected heterozygosities, which ranged from 0.80 to 0.85. A slight but significant population structure was found (FST = 0.010). In fact, at least three populations of gilthead sea bream within the Western Mediterranean Sea were identified (Sardinian Sea, Sardinian Channel and Central Tyrrhenian Sea), which are also genetically differentiated from those of the Atlantic Ocean and the Adriatic Sea. [ABSTRACT FROM AUTHOR]

Many fish species have evolved feeding mechanisms and behaviours enabling them to feed on specific prey. However, such mechanisms may not be optimal for feeding on commercial-pelleted diets in aquaculture. Gilthead sea bream chew and occasionally eject pellets or parts of pellets from the mouth when feeding on commercial diets. This may result in an increase in nutritional waste from the intensive culture of this species. In this study we examined the prevalence of this food processing behaviour in two sizes of sea bream, feeding on three types of natural prey items in comparison to a commercial pellet, to give an insight into the circum- stances in which excess chewing and ejection of food items from the mouth occurred. These included two hard-textured food items (commercial pellet and hard-shelled prey) and two soft-textured food items (larvae and small crustacean). Both sizes of sea bream frequently consumed the soft-textured food types, however large sea bream also frequently consumed hard-textured pellets. Hard-textured food required longer handling times and elicited more chewing and the ejection of food items from the mouth. These results suggest that future investigations on the food processing behaviour and consequent waste when fed commercial diets differing in texture could give an insight into improving diets and feeding efficiency for intensively cultivated gilthead sea bream. [ABSTRACT FROM AUTHOR]

Gill monogenean Sparicotyle chrysophrii is considered the most detrimental fish parasite to the Mediterranean aquaculture. Treatment of sparicotylosis relies on frequent gill inspections correlated with the seasonal increase in seawater temperature, application of functional feeds, and treatments with formalin baths where permitted. While the latter is bound to be banned in Europe, other synthetic anthelminthics, such as praziquantel and ivermectin, are prone to induce resistance in the parasites. Therefore, we investigated, in vitro, 14 synthetic and natural compounds against adult S. chrysophrii, developing dose–response modelsm and estimated toxicity levels at 20%, 50%, and 80% parasite mortality. Bactericidal activity of target compounds was also tested in two important aquaculture bacteria; Vibrio harveyi and V. anguillarum, while their potential host toxicity was evaluated in gilthead seabream SAF-1 cell line. Synthetic compound bithionate sodium exerted the most potent toxicity against the monogenean, no host cytotoxicity, and a medium and high potency against two bacterial pathogens. In comparison, target natural compounds were approximately 20 (cedrol) or up to 154 times (camphor) less toxic for the monogenean. Rather than completely dismissing natural compounds, we suggest that their application in combination with synthetic drugs, especially if administered in the feed, might be useful in sparicotylosis treatment. [ABSTRACT FROM AUTHOR]