Gilthead Sea Bream Muscle Research Articles

Gene markers of dietary macronutrient composition and growth in the skeletal muscle of gilthead sea bream (Sparus aurata)

To increase our current knowledge on the nutritional regulation of growth and gene expression pattern in fish skeletal muscle, the effect of dietary macronutrient composition was assessed on digestibility, nutrient retention, growth performance, and the mRNA levels of key genes involved in functionality, growth and development of the skeletal muscle in gilthead sea bream (Sparus aurata). Long-term starvation decreased the expression of myogenic regulatory factors such as Myod2, Myf5, myogenin (Myog) and Myf6 in the skeletal muscle of S. aurata. The supply of high or medium protein, low carbohydrate diets enhanced growth parameters, feed efficiency ratio, feed conversion ratio and significantly upregulated myod2. However, the supply of low protein, high carbohydrate diets restricted growth and stimulated the mRNA levels of myostatin, while downregulated follistatin (fst), igf1, mtor and rps6. Microarray analysis revealed igfals, tnni2, and gadd45a as gene markers upregulated by diets enriched with protein, lipids and carbohydrates, respectively. The results of the present study show that in addition to myod2, fst, igf1, mtor and rps6, the expression levels of igfals, tnni2 and remarkably gadd45a in the skeletal muscle can be used as markers to evaluate the effect of dietary macronutrient changes on fish growth and muscle development in S. aurata.

Ultrasonography and X-ray micro-computed tomography characterization of the effects caused by carrageenin in the muscle of gilthead seabream (Sparus aurata)

The current work aimed to carry out an in vivo study of the λ-carrageenin-induced inflammation in the skin of gilthead seabream (Sparus aurata). The fish were injected intramuscularly with phosphate-buffered saline (PBS, as control) or λ-carrageenin (1% in PBS), and the injection zone was evaluated by real-time ultrasonography (Vevo Lab, VisualSonics) at 1.5, 3, 6, 12, and 24 h post-injection (p.i.). Results demonstrated that the skin thickness was increased in fish injected with λ-carrageenin and sampled at 1.5, 3, and 6 h p.i. However, the skin thickness of the injected area decreased to the normal values in those fish sampled at 12 and 24 h p.i. In addition, fish injected with λ-carrageenin and analysed at 1.5, 3, and 6 h p.i. showed, in the underlying muscle at the injection place, several hyperechoic small foci surrounded by an anechoic area which were not observed in control fish. Furthermore, the fish were analysed by X-ray micro-computed tomography (micro-CT). The analysis of the micro-CT acquisitions revealed also a dark area in the place of the injection with λ-carrageenin at 1.5, 3, and 6 h. These areas were smaller in fish analysed at longer times (12 h p.i.) and were almost disappeared in fish sampled at 24 h p.i. These areas had an average density of −850 to −115 HU, which did not correspond with any tissue density of the rest of the body. Furthermore, similar dark areas at the injection zones were never observed in control fish. Present results support the use of both non-invasive techniques to study the inflammatory process in fish of commercial interest such as gilthead seabream.

Short-term exposure to polymethylmethacrylate nanoplastics alters muscle antioxidant response, development and growth in Sparus aurata

Polymethylmethacrylate (PMMA) plastic fragments have been found abundant in the environment, but the knowledge regarding its effects on the physiology of aquatic animals is still poorly studied. Here the short-term (96 h) effects of waterborne exposure to PMMA nanoplastics (PMMA-NPs) on the muscle of gilthead sea bream (Sparus aurata) fingerlings was evaluated at a concentration range that includes 0.001 up to 10 mg/L. The expression of key transcripts related to cell stress, tissue repair, immune response, antioxidant status and muscle development, together with several biochemical endpoints and metabolic parameters. Results indicate that exposure to PMMA-NPs elicit mildly antioxidant responses, enhanced the acetylcholinesterase (AChE) activity, and inhibited key regulators of muscle development (growth hormone receptors ghr-1/ghr-2 and myostatin, mstn-1 transcripts). However, no effects on pro-inflammatory cytokines (interleukin 1β, il1β and tumor necrosis factor α, tnfα) expression nor on the levels of energetic substrates (glucose, triglycerides and cholesterol) were found.

Multiorgan histopathological changes in the juvenile seabream Sparus aurata as a biomarker for zinc oxide particles toxicity.

Zinc oxide nanoparticles are widely used in some domains (cosmetics, pharmaceuticals optical devices, and agricultural field) due to their physical, optical, and antimicrobial properties. However, the release of ZnO-NPs into the environment may affect organisms like fish with potential consequences for human health. Histological approaches of the acute effects of these materials on fish are scarce; thus, the present study aimed to investigate the potential toxic effects of acute exposure to ZnO particles in marine environments, by assessing histological changes in the gills, liver, spleen, and muscle of gilthead seabream (Sparus aurata) juveniles. Thus, fish were exposed for 96 h, via water, to 1 mg L-1 of ionic zinc and zinc oxide particles (1.1, 1.2, and 1.4 μm of size). Histological examination revealed gills as the most affected organ, followed by liver, muscle, and spleen. In the gills, histopathological changes included hyperplasia of epithelial cells, fusion of the secondary lamellae, and lifting of the lamellar epithelium with edema. In the liver, lipid vacuolation of several degrees, necrosis of hepatic and pancreatic tissues, blood congestion in sinusoids and hepatoportal vessels, presence of cellular infiltrate, and melano-macrophages diffusion was found. Muscle showed degeneration, atrophy, thickening and necrosis of muscle fibers with edema between them, and presence of melano-macrophages in the muscle layer. Spleen was the less damaged organ, displaying congested blood, white pulp increase/rupture, and bigger and darker melano-macrophage aggregates in the splenic stroma. These results underline that the size of particles plays a determinant role in their potential pernicious effects. A short-term exposure caused major histopathological changes in relevant organs of S. aurata juveniles, possibly affecting their function.

Pharmacokinetics of chloramphenicol (CAP) in gilthead sea bream (Sparus aurata) and its in vitro activities against important bacterial fish pathogens

The pharmacokinetics of chloramphenicol (CAP) in gilthead sea bream (Sparus aurata), a warm water farmed fish species and its in vitro efficacy against important bacterial diseases of Mediterranean mariculture were investigated in this study. After an intravascular injection (10 mg/kg/fish), the distribution half-life (tl/2a) and the elimination half-life (tl/2ß) of CAP were calculated to be 1.6 and 69 h, respectively. Tissue penetration of CAP was found to be moderate since both the apparent volume of distribution of the drug at steady-state (V<i(ss)) and the apparent volume of the central compartment (Vc) were calculated to be 1.13 and 0.90 L/kg. The total clearance (CLp) of the drug was slow (0.022 L/kg/h). The minimum inhibitory concentration (MIC) values of CAP in distilled water supplemented with 2% NaCl against Vibrio anguillarum serotype lb, Photobacterium damsela subsp. piscicida, V alginolyticus and V ßuvialis were determined to be 4.78 pg/mL, while it was 0.60 pg/mL for V. damsela. The addition of 10 mM Ca2+ and 55 mM Mg2+ in the medium revealed MIC values of 19.13 pg/mL for V alginolyticus and V ßuvialis, whereas showed no effect for V anguillarum P. damsela subsp. Piscicida and V damsela. The results indicate that CAP displayed a satisfactory kinetic profile and it is eliminated fast from gilthead sea bream muscle; however, its high MIC values stress show a possible inefficacy against important bacterial pathogens of Mediterranean mariculture.

Evaluation of antimicrobials residues in farmed gilthead seabream (Sparus aurata) after administration through medicated feed

The use of antimicrobials in aquaculture is a well-known fact and merits the focus of the scientific community. In the present study, five drugs (oxytetracycline, sulfadiazine, trimethoprim, oxolinic acid and flumequine) were selected to assess their retention in muscle tissues from gilthead seabream (Sparus aurata). Fish were placed in 150 L tanks at 18 °C, and fed for 7 days with experimental diets containing two concentrations of each antimicrobial (ranging from 5.51 to 131.16 mg kg−1). Edible tissues were then analyzed through a validated multi-class quantification method (UHPLC-MS/MS). The results indicate that sulfadiazine concentrations were the highest immediately after the feeding period and decreased towards day 3. Flumequine was only detected on the first day with concentrations below the MRL. Both trimethoprim and oxolinic acid concentrations were below the MRLs 3 days after the feeding period was over (oxolinic acid was not detected in muscle samples at day 14 for prophylaxis and day 28 for both treatments). Oxytetracycline residues in muscle tissues were the highest through time, with concentrations above the MRL for 7 days (Cday7 of 111.2 and 157.2 μg kg−1 for both dosages). Results suggest that these antimicrobials can be present in gilthead seabream muscle samples for longer periods than previously reported, when realistic conditions are tested. With the exception of oxytetracycline, concentrations were below the MRLs established 3 days after the feeding trial was over meaning that adverse effects related to human consumption are not likely. Nevertheless, allergic reactions or resistance to antimicrobials can be developed if low concentrations of such compounds are ingested on a frequent basis, as is the case of the Mediterranean diet.

Characterization and in vitro sensitivity of cholinesterases of gilthead seabream (Sparus aurata) to organophosphate pesticides.

The characterization of cholinesteraseactivity in brain and muscle of gilthead seabream was carried out using four specific substrates and three selective inhibitors. In addition, K m and V max were calculated from the Michaelis-Menten equation for ASCh and BSCh substrates. Finally, the in vitro sensitivity of brain and muscle cholinesterases to three organophosphates (OPs) was also investigated by estimating inhibition kinetics. The results indicate that AChE is the enzyme present in the brain, whereas in muscle, a typical AChE form is present alongwith an atypical form of BChE. Very low ChE activity was found in plasma with all substrates used. The inhibitory potency of the studied OPs on brain and muscle AChEs based on bimolecular inhibition constants (k i ) was: omethoate<dichlorvos<azinphosmethyl-oxon. Furthermore, muscle BChE was found to be several orders of magnitude (from 2 to 4) more sensitive than brain and muscle AChE inhibition by dichlorvos and omethoate.

NADPH production, a growth marker, is stimulated by maslinic acid in gilthead sea bream by increased NADP-IDH and ME expression

NADPH plays a central role in reductive biosynthesis of membrane lipids, maintenance of cell integrity, protein synthesis and redox balance maintenance. Hence, NADPH is involved in the growth and proliferation processes. In addition, it has been shown that changes in nutritional conditions produced changes in NADPH levels and growth rate. Maslinic acid (MA), a pentacyclic triterpene of natural origin, is able to stimulate NADPH production, through regulation of the two oxidative phase dehydrogenases of the pentose phosphate pathway. Our main objective was to study the effects of MA on the kinetic behaviour and on the molecular expression of two NADPH-generating systems, NADP-dependent isocitrate dehydrogenase (NADP-IDH) and malic enzyme (ME), in the liver and white muscle of gilthead sea bream (Sparus aurata). Four groups of 12g of a mean body mass were fed for 210days in a fish farm, with diets containing 0 (control), and 0.1g of MA per kg of diet. Two groups were fed ad libitum (C-AL and MA-AL) and another's two, with restricted diet of 1% of fish weight (C-R and MA-R). Results showed that MA significantly increased the main kinetic parameter of the NADPH-forming enzymes (NADP-IDH and ME). In this sense, specific activity, maximum velocity, catalytic efficiency and activity ratio values were higher in MA conditions than control groups. Moreover, these changes were observed in both feeding regimen, AL and R. Meanwhile, the Michaelis constant changed mainly in groups fed with the MA and restricted diet, these changes are related to the best substrate affinity by enzyme. Moreover, in the Western-blot result, we found that MA increased both protein levels studied, this behaviour being consistent with the regulation of the number of enzyme molecules. All results, indicate that MA, independently of the fed regimen, could potentially be a nutritional additive for fish as it improved the metabolic state of fish, as consequence of increased activity and expression of NADP-IDH and ME enzymes.

Multi-residue and multi-class determination of antibiotics in gilthead sea bream (Sparus aurata) by ultra high-performance liquid chromatography-tandem mass spectrometry

This paper describes a method for the determination of 41 antibiotics from seven different classes in gilthead sea bream (Sparus aurata) by ultra-high-performance liquid chromatography with tandem mass spectrometry (UPLC-MS/MS). Sulfonamides, trimethoprim, tetracyclines, macrolides, quinolones, penicillins and chloramphenicol were simultaneously determined. Fourteen procedures for sample treatment were tested and an extraction with acetonitrile and ethylenediaminetetra acetic acid was found to be the best option. The methodology was validated in accordance with Decision 2002/657/EC. Precision in terms of relative standard deviation (RSD) was under 17% for all compounds, and the recoveries ranged from 92% to 111%. CCα and CCβ were determined according to the maximum residue limit or the minimum required performance limit, when necessary. The validation provided evidence that the method was suitable for application in routine analysis for the detection and confirmation of antibiotics in muscle of gilthead sea bream, an important and intensively produced fish in aquaculture.

Effect of oregano and rosemary essential oils on lipid oxidation of stored frozen minced gilthead sea bream muscle

The study aimed to determine the effect of oregano and rosemary essential oils addition to minced gilthead sea bream muscle on lipid oxidation during frozen storage. Each essential oil was added to minced fish muscle at 500 mg/kg concentration which then was stored at −22 °C for 12 months. Oregano essential oils inhibited the formation of conjugated diene and triene hydroperoxides and thiobarbituric reactive substances when compared with untreated samples after the first month and rosemary essential oils after the first and third month of frozen storage. Oregano and rosemary essential oils could be used as ingredients to prevent oxidation in stored frozen minced gilthead sea bream muscle, when long term preservation is not needed. The rate of lipid oxidation depends on antioxidant source. The rosemary essential oil proved to be more efficient in preventing lipid oxidation of minced gilthead sea bream muscle than oregano essential oil.

Insulin-like growth factors effects on the expression of myogenic regulatory factors in gilthead sea bream muscle cells

Gilthead sea bream (Sparus aurata) is a widely cultured fish; however, muscle development regulation is poorly known. Myogenesis can be activated by the myogenic regulatory factors (MRFs: MyoD, Myf5, myogenin and MRF4) and by endocrine signals from the growth hormone (GH)/insulin-like growth factors (IGFs) axis. We cultured gilthead sea bream myocytes to better understand the role of IGFs in muscle growth and differentiation through the regulation of MRFs expression. First, we studied the expression pattern during culture development of IGFs and IGF-I splice variants. The expression of igf-II was highest at the beginning of the culture and decreased when the cells started to differentiate, similarly to that observed for total igf-I. Igf-Ib showed a paralleled expression pattern as that of total igf-I, whereas igf-Ic was more stable during culture progression. Next, we analyzed the expression of IGFs and MRFs after incubation of cells at day 4 with GH, IGF-I, IGF-II and combinations of them at 3, 6 and 18h. IGF-II increased myod2 and myf5 expression, genes involved in early muscle cell proliferation. Moreover, IGF-I caused an increase on mrf4 and myogenin expression, both involved in the later stages of development corresponding to differentiation. Regarding the regulation of IGFs expression, igf-I was stimulated by GH and IGF-II alone and combined, whereas igf-II expression was increased in response to IGF-I, suggesting a nice model of crossed regulation. Overall, the present model could be very useful to understand the different regulatory roles of these endocrine and transcription factors on fish myogenesis.

Influence of supplemental maslinic acid (olive-derived triterpene) on the post-mortem muscle properties and quality traits of gilthead seabream

Maslinic acid, a natural triterpene, was evaluated as a dietary supplement to modulate glycogen post-mortem mobilization in gilthead seabream muscle. For this purpose, a multidisciplinary trial was undertaken, where flesh quality criteria, as well as biochemical and histological parameters, enzymatic activities and protein expression in the muscle were assessed. Supplementing gilthead seabream diets with maslinic acid mainly resulted in hypertrophy of muscle fibres and inhibition of cathepsin B activity, with no observed differences in terms of glycogen and ATP content of the muscle, as well as glycogen phosphorylase activity. Proteomic analysis showed a low impact of maslinic acid supplementation on muscle metabolism, with most changes reflecting increased stress coping capacity and muscle hypertrophy in maslinic acid-fed fish. As a finishing strategy to improve the muscle's energetic status, the usefulness of maslinic acid seems limited. However, it shows potential for promoting muscle growth in this species.

Dietary Tools To Modulate Glycogen Storage in Gilthead Seabream Muscle: Glycerol Supplementation

The quality and shelf life of fish meat products depend on the skeletal muscle's energetic state at slaughter, as meat decomposition processes can be exacerbated by energy depletion. In this study, we tested dietary glycerol as a way of replenishing muscle glycogen reserves of farmed gilthead seabream. Two diets were tested in duplicate (n = 42/tank). Results show 5% inclusion of crude glycerol in gilthead seabream diets induces increased muscle glycogen, ATP levels and firmness, with no deleterious effects in terms of growth, proximate composition, fatty acid profile, oxidative state, and organoleptic properties (aroma and color). Proteomic analysis showed a low impact of glycerol-supplementation on muscle metabolism, with most changes probably reflecting increased stress coping capacity in glycerol-fed fish. This suggests inclusion of crude glycerol in gilthead seabream diets (particularly in the finishing phase) seems like a viable strategy to increase glycogen deposition in muscle without negatively impacting fish welfare and quality.

Effect of Storage Conditions on Total Volatile Base Nitrogen Determinations in Fish Muscle Extracts

Total volatile base nitrogen (TVBN) is a widely used fish spoilage indicator. Because TVBN is typically measured from muscle extracts, analytical laboratories would benefit from understanding how different conditions for storing extracts affect TVBN results. To examine this question, extracts from the muscle of gilthead sea bream (Sparus aurata) were prepared and stored. Different storage temperatures (4, −20, and −80°C) and storage periods (7 days to 2 months) were tested. To compare how well the different storage conditions worked for different TVBN levels, the study took advantage of the fact that TVBN values change depending on how long the gilthead sea bream is stored before extracts are prepared. Extracts were prepared from fish maintained in ice for 0, 4, and 10 days postmortem. Comparing the storage conditions tested, all offered statistically identical results independent of the storage period and temperature. Nevertheless, only the extract maintained at 4°C for 7 days achieved statistically equal values to not stored extracts.

Effects of Preslaughter Stress Levels on the Post-mortem Sarcoplasmic Proteomic Profile of Gilthead Seabream Muscle

Fish welfare is an important concern in aquaculture, not only due to the ethical implications but also for productivity and quality-related reasons. The purpose of this study was to track soluble proteome expression in post-mortem gilthead seabream muscle and to observe how preslaughter stress affects these post-mortem processes. For the experiment, two groups of gilthead seabream (n = 5) were subjected to distinct levels of preslaughter stress, with three muscle samples being taken from each fish. Proteins were extracted from the muscle samples, fractionated, and separated by 2DE. Protein identification was performed by MALDI-TOF-TOF MS. Analysis of the results indicates changes on several cellular pathways, with some of these changes being attributable to oxidative and proteolytic activity on sarcoplasmic proteins, together with leaking of myofibrillar proteins. These processes appear to have been hastened by preslaughter stress, confirming that it induces clear post-mortem changes in the muscle proteome of gilthead seabream.

Maslinic acid, a natural triterpene, and ration size increased growth and protein turnover of white muscle in gilthead sea bream (Sparus aurata)

Maslinic acid (MA) is a pentacyclic triterpene used, at experimental level, as an additive to stimulate growth, protein-turnover rates and hyperplasia in fish. In this experiment we have studied the effects of feeding with MA at daily fixed ration of 10 g kg−1 of body mass, on growth, protein-turnover rates and nucleic acid concentration in white muscle of gilthead sea bream grown in a local fish farm. The experimental groups contained 0 (control), 50 (MA50) and 100 (MA100) mg MA per kg of diet. Two groups were provided feed ad libitum (control AL and MA100AL), while three were given a fixed ration (control R, MA50R, and MA100R). We have determined the following: growth rate; nucleic acid and protein levels; relative and absolute protein-accumulation (KG, AG), synthesis (KS, AS) and degradation (KD, AD) rate, protein-synthesis capacity (CS), protein-synthesis efficiency (KRNA), protein-synthesis rate per DNA (KDNA) and protein-retention efficiency. At the end of the experiment, higher body weights and muscle growth rates were found in both groups of fish fed with 100 mg MA per kg of diet. Feed-efficiency rate, protein-efficiency ratio and protein productive value, were higher in the MA100AL group than in control AL. Fractional and absolute protein-synthesis and degradation rates in white muscle of MA100AL and MA100R fish were higher than in the control, resulting in a higher protein-accumulation rate and tissue growth. Total DNA content, indicated cell hyperplasia, was higher in MA100AL and MA100R than its respective controls. Studies of optical and electronic microscopy corroborated these results. These findings indicate that MA added to the diet can stimulate the growth, white-muscle protein-turnover rates and tissue hyperplasia in gilthead sea bream.

Metabolic Effects of Insulin and IGFs on Gilthead Sea Bream (Sparus aurata) Muscle Cells

Primary cultures of gilthead sea bream myocytes were performed in order to examine the relative metabolic function of insulin compared with IGF-I and IGF-II (insulin-like growth factors, IGFs) at different stages in the cell culture. In these cells, the in vitro effects of insulin and IGFs on 2-deoxyglucose (2-DG) and l-alanine uptake were studied in both myocytes (day 4) and small myotubes (day 9). 2-DG uptake in gilthead sea bream muscle cells was increased in the presence of insulin and IGFs in a time dependent manner and along with muscle cell differentiation. On the contrary, l-alanine uptake was also stimulated by insulin and IGFs but showed an inverse pattern, being the uptake higher in small myocytes than in large myotubes. The results of preincubation with inhibitors (PD-98059, wortmannin, and cytochalasin B) on 2-DG uptake indicated that insulin and IGFs stimulate glucose uptake through the same mechanisms, and evidenced that mitogenesis activator protein kinase (MAPK) and PI3K–Akt transduction pathways mediate the metabolic function of these peptides. In the same way, we observed that GLUT4 protein synthesis was stimulated in the presence of insulin and IGFs in gilthead sea bream muscle cells in a different manner at days 4 or 9 of the culture. In summary we describe here, for the first time, the effects of insulin and IGFs on 2-DG and l-alanine uptake in primary culture of gilthead sea bream muscle cells. We show that both MAPK and PI3K–Akt transduction pathways are needed in order to control insulin and IGFs actions in these cells. Moreover, changes in glucose uptake can be explained by the action of the GLUT4 transporter, which is stimulated in the presence of insulin and IGFs throughout the cell culture.

Feed restriction up-regulates uncoupling protein 3 (UCP3) gene expression in heart and red muscle tissues of gilthead sea bream ( Sparus aurata L.) : New insights in substrate oxidation and energy expenditure

The physiological regulation of the mitochondrial uncoupling protein 3 (UCP3) remains practically unexplored in fish and the aim of this study was to examine the effects of ration size on the regulation of UCP3 in heart, red skeletal muscle and white skeletal muscle of gilthead sea bream ( Sparus aurata L.). Juvenile fish were fed at three different levels for 11 weeks: i) full ration until visual satiety (R 100 group), ii) 70% of satiation (R 70 group) and iii) 70% of satiation with two finishing weeks at the maintenance ration (20% of the satiation level) (R 70–20 group). The thirty percent feed restriction improved fish performance, increasing feed conversion efficiency and circulating levels of insulin-like growth factor-I (IGF-I). Fish of the R 70–20 group showed reduced growth and low circulating levels of IGF-I in combination with increased circulating concentrations of growth hormone and free fatty acids. Feed restriction did not alter UCP3 transcript levels in white skeletal muscle, but improved this tissue's oxidative capacity as assessed by changes in glycolytic and oxidative mitochondrial enzyme activities. In contrast, in cardiac and red skeletal muscle tissues, this dietary treatment primarily increased UCP3 mRNA expression. The respiratory control ratio of freshly isolated heart mitochondria was slightly lower in R 70–20 fish than in R 100 fish, which suggests that there was an increase in mitochondrial uncoupling concomitant with the enhanced UCP3 mRNA expression. Altogether, these findings highlight the different adaptive mechanism of glycolytic and highly oxidative muscle tissues for their rapid adjustment to varying feed intake.

Proteomic analysis of muscle tissue from gilthead sea bream ( Sparus aurata, L.) farmed in offshore floating cages

Characterization of the muscle tissue proteome is key to many aspects of fish aquaculture, encompassing physiology, growth, food safety, seafood authentication and quality, traceability and shelf-life. In this study, a 2D-PAGE-MS study was performed on gilthead sea bream ( Sparus aurata, L.) muscle tissue along the production cycle in four offshore floating cage plants and two repopulation lagoons located in different areas of Sardinia, Italy. The aim of this study was to accomplish systematic characterization of the gilthead sea bream muscle proteome, and to gather data about its variability in physiological conditions occurring in both farmed and wild fish. In general, a relatively stable protein expression pattern was observed in farmed sea bream muscle compared to other more dynamic tissue proteomes, such as liver. However, several statistically significant variations in abundance of some proteins and their isoforms were detected, related to growth and environmental factors. Among these, parvalbumins, troponins, and Wap65 showed variations according to fish length and water temperature. Interestingly, the ratio of structural proteins versus glycolytic enzymes was also observed to change during the production cycle, showing an increase with fish length. In order to assess whether the farming conditions were able to induce alterations in the muscle proteome, farmed and wild fish were subjected to a differential proteomics analysis. The data gathered in this study indicate that the protein expression profile of muscle tissue is comparable in wild and maricultured gilthead sea breams of commercial size, supporting the view that farming in offshore floating cages might favor proper muscle tissue development, and therefore enable the production of higher quality fish. In conclusion, this work describes the detailed characterization of the sea bream muscle proteome, and provides a number of insights on its size and environment-related variability.

Simultaneous determination of selected veterinary antibiotics in gilthead seabream ( Sparus Aurata) by liquid chromatography–mass spectrometry

A method was optimised and validated for simultaneous monitoring of several drugs of different classes of antibiotics such as quinolones (oxilinic acid and flumequine), tetracyclines (oxytetracycline), sulfonamides (sulfadiazine) and trimethoprim in fish muscle and skin. The method is based on solid–liquid extraction without further sample clean up followed by liquid chromatography–mass spectrometry (LC–MS) determination with electrospray ion source (ESI) in positive mode. The limits of quantification (LOQs) were lower than 20 μg/kg for all compounds and repeatability, expressed as relative standard deviations (RSD), were lower than 15%. Therefore, the LC–MS method was successfully applied for the quantitative determination of antibiotics in gilthead sea bream muscle and skin and oxytetracycline in medicated fishes.