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The immunomodulatory effect of different dietary arachidonic acid (ARA), eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA) ratios was evaluated in gilthead sea bream juveniles after intraperitoneal injection (i.p.) with formalin‐killed Photobacterium damselae subsp. piscicida (Phdp). Fish were fed with four isoproteic (47% crude protein) and isolipidic (18% crude lipids) diets with the following long‐chain polyunsaturated fatty acids (LC‐PUFA) ratios: Diet A (2.0% ARA: 0.2% EPA: 0.1% DHA); Diet B (1.0% ARA: 0.4% EPA: 0.4% DHA); Diet C (0% ARA: 0.6% EPA: 0.6% DHA); Diet D (0% ARA: 0.3% EPA: 1.5% DHA). After being fed for 56 days with the experimental diets, fish from each dietary treatment were randomly selected and i.p. injected with 0.2 ml of killed Phdp (1 × 108 CFU ml−1) or phosphate‐buffered saline (control group). Four and twenty‐four hours (i.e., twice) after the i.p., the haematological profile, plasma humoral innate immune parameters, and the intestine expression of immune‐related genes were assessed. Results showed that fish fed diet D (high DHA content) had increased complement activity and higher intestinal expression of cyclooxygenase 2 (cox2) and interleukin 1β (il‐1β) at 4 and 24 hours after i.p., as well as increased intestinal tumour necrosis factor α (tnfα) expression at 4 hours. On the other hand, fish fed with diet A (high ARA content) showed higher plasma bactericidal activity against Phdp than fish fed with diet D. Overall, the results of this study suggest a positive modulatory effect of DHA in response to the pathogenic agent. [ABSTRACT FROM AUTHOR]

However, fish species of major importance in the Mediterranean mariculture, namely gilthead sea bream ( I Sparus aurata i ) and red sea bream ( I Pagrus major i ), also suffer from gaping, and consequently, economic losses burden their industry. Keywords: assessors; gapping; Gilthead sea bream; image analysis; red sea bream; scale EN assessors gapping Gilthead sea bream image analysis red sea bream scale 689 693 5 01/07/22 20220201 NES 220201 A number of commercially important farmed fish species are marketed as fillets, primarily to satisfy consumer demands. These indicate that the proposed method for evaluating gaping in Sparidae species is easy to apply in practice, allowing the scoring procedure to be accessible to all commercial gilthead sea bream and/or red sea bream farms. [Extracted from the article]

Abstract: Microbial communities play different functions in the digestive tract of fish and represent a source of bioactive compounds. This study was aimed to detect the presence of biosurfactant (BS)‐producing bacteria in the intestine of gilthead sea bream (Sparus aurata L.) to select strains candidate for biotechnological applications in aquaculture. A total of 100 bacterial strains were isolated from the guts of three groups of fish and analysed by different qualitative screening tests and the tensiometric analysis. BSs were extracted, characterized by thin‐layer chromatography (TLC) and their antibacterial activity against bacterial pathogens of interest in aquaculture was determined. A total of 17 out of 100 strains, affiliated to the genera Pseudomonas (11 isolates), Acinetobacter (1 isolate), Sphingomonas (4 isolates) and Aeromonas (1 isolate), displayed a stable emulsion production with the E24 index from 0% to 44%, a surface tension reduction from 8.3 to 30 mN/m and 11 of them exhibited antibacterial activity against fish pathogens. The TLC analysis indicated that the intestinal BSs consisted of compounds ascribed to the class of glycolipids–rhamnolipids. This is the first study reporting on the isolation and selection of BS‐producing bacteria from fish gut, a natural novel source of surface active compounds with potential biotechnological applications in aquaculture. [ABSTRACT FROM AUTHOR]

Early weaning of marine fish larvae with dry diets delays gut maturation and reduces growth rates. In juvenile and adult forms of several marine fish species, inclusion of dietary mannan oligosaccharides (MOS) improves gut integrity and functionality, but the effects of MOS inclusion in gilthead sea bream ( Sparus aurata, L.) larval diets have not been addressed yet. Thus, this study assesses the effects of dietary MOS inclusion on survival, growth performance, gut morphology, feed acceptance and quality of gilthead sea bream larvae. For that purpose, 16 days post-hatched gilthead sea bream larvae were fed four graded levels of MOS (Biomos®, Alltech, Nicholasville, KY, USA) in weaning diets as follows: 0 g kg−1 MOS, 0.5 g kg−1 MOS, 1.5 g kg−1 MOS and 2 g kg−1MOS. Dietary MOS did not affect feed acceptance in gilthead sea bream larvae ( P > 0.05). MOS supplementation was correlated in a dose-dependent way with higher larval survival ( P = 0.026). After 15 days of feeding, dietary MOS increased whole larvae ( P < 0.01) arachidonic acid, eicosapentaenoic acid and docosahexaenoic acid. Gilthead sea bream larvae fed 2 g kg−1 MOS presented higher gut occupation with goblet cells after feeding compared with larvae fed the other dietary treatments. Overall, the results suggest that inclusion of MOS in early weaning diets for gilthead sea bream improves essential fatty acid utilization and may promote growth and final survival. [ABSTRACT FROM AUTHOR]

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]

The article discusses a study which evaluate the potential effect of Saccharomy cescerevisiae boulardii in gilthhead seabream. The results of the study show that the Saccharomyces cerevisiae var. boulardii preserves the integrity of intestinal mucosa in gilthead seabream, Sparus aurata subjected to a bacterial challenge with Vibrio anguillarum.

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]

Juvenile sea bream were fed on diets containing 0.0, 2.0 or 4.0 g kg−1 of a soybean trypsin inhibitor (SBTI) for 30 days. The growth performance, total protease activity and intestinal histology were studied after 0, 15 and 30 days of dietary treatment. No significant differences were found in the weight gain, specific growth rate (SGR) and feed conversion rate in fish fed on inhibitor-supplemented diets when compared with those fed on an inhibitor-free diet. Only the SGR at day 15 decreased significantly with protease inhibitor inclusion, although this effect was not observed at day 30. In relation to proteolytic activity at day 15, the total protease activity in the distal intestine decreased in fish fed on inhibitor-supplemented diets. Zymograms of these extracts showed that the SBTI reduced the intensity of some proteolytic fractions in the distal intestine. A noticeable reduction in the protease activity of the intestinal content in fish fed on the highest level of soybean inhibitor (4.0 g kg−1) was also observed. However, at day 30, the inhibition effect on these active bands was not detected, and the total protease activity was similar to that in fish fed on an inhibitor-free diet. Histological examination revealed no perceptible differences in the intestinal structure between any of the diet groups. In addition, all fish were maintained under experimentation for 10 more days and fed on an inhibitor-free diet to determine whether the possible effects caused by the protease inhibitor could be reverted. The administration of SBTI-supplemented diets did not affect sea bream growth performance or intestine histology after 30 days, and only a decrease in the total alkaline protease activity was found at day 15. [ABSTRACT FROM AUTHOR]

Three trials, with classical experimental designs for in vivo digestibility studies, were conducted to determine the apparent digestibility coefficient (ADC) of protein (ADCp), lipid (ADCl), energy (ADCe) and amino acids (AA) in selected animal by-products fed to European sea bass, Dicentrarchus labrax (Trial 1), gilthead sea bream, Sparus aurata (Trial 2), and turbot, Psetta maxima (Trial 3). In each trial, five experimental diets [including a reference diet (RD)] where fish meal (FM) was used as the sole protein source were fed ad libitum to the fish for a period of 4 weeks. Test diets were based on the FM RD and obtained by replacing 30% of the RD with a category III designated European animal by-products (fit for human consumption), namely: steam hydrolysed feather meal (HFM), enzyme-treated feather meal (EFM), poultry meat meal (PMM) and spray-dried haemoglobin meal (SDHM). Faecal material was collected using the ‘Guelph system’, and nutrient and energy digestibility coefficients were related to the measurement of chromic oxide (Cr2O3) incorporated into the diet at a rate of 0.5%. Without any exception, FM diets yielded the best digestibility values for all macro-nutrients and by all fish. Among the test ingredients, ADCp was consistently higher for PMM and SDHM in the three species (85.5%, 91.1% in sea bass; 79.2%, 82.8% in sea bream; and 78.4%, 74.8% in turbot). Conversely, ADCp of HFM and EFM were less efficiently digested (67.2%, 68.2% in sea bass; 21.5%, 21.7% in sea bream; and 46.6%, 36.0% in turbot). However, the novel processing method applied to feather meal did not considerably influence the digestibility of most of the nutrients in this feedstuff. The current investigation yielded valuable numerical ADC for EAA considered to be of prime importance in generating balanced diet formulations. [ABSTRACT FROM AUTHOR]

The present study was performed to determine the effect of soybean meal (SBM) on the performance and gut histology of gilthead sea bream and European sea bass. Three isonitrogenous and isolipidic extruded diets (crude protein, 470 g kg−1 diet; crude fat, 200 g kg−1 diet) were formulated containing 0 (0 SBM), 180 (180 SBM) and 300 (300 SBM) g kg−1 diet SBM and tested on both species in two separate experiments. Fish at an initial average weight of around 18 g were randomly allocated to 800 L square tanks connected to a closed recirculating system. The trials lasted 80 days for sea bream and 89 days for sea bass. Fish were hand-fed to apparent satiation. Increasing the level of SBM had no significant effects on the specific growth rate, feed intake and feed conversion rate in both the species. In the sea bream distal intestine, lamina propria was moderately and diffusely expanded in some fish due to an increase in cell infiltration represented by mononuclear cells, this finding being more frequent in animals fed diet 300 SBM. No other morphological alterations in intestinal folds, enterocytes or other inflammation signs were noticed in the sea bream distal intestine of any group. No histological differences were found in sea bass in any experimental group. [ABSTRACT FROM AUTHOR]

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]

A 12-week growth trial was conducted to evaluate corn gluten meal as an alternative protein source to fish meal in diets for gilthead sea bream juveniles. The experimental diets were formulated to be isonitrogenous and isoenergetic and to have 20%, 40%, 60% and 80% of fish meal protein, the only protein source in the control diet, replaced by corn gluten meal. At the end of the growth trial only the group fed the diet with 80% corn gluten protein exhibited significantly reduced growth and feed efficiency compared with the fish meal-based diet. This was most likely due to a dietary amino acid deficiency in that diet. A trend was noticed for feed efficiency to improve with the replacement of fish meal protein in the diets up to 60%. There were no significant differences among groups in protein and energy retention (as percentage of intake). At the end of the trial whole body water content of the experimental groups was significantly lower and the lipid content of groups including 60% and 80% corn gluten protein was significantly higher than that in the control. No other differences were observed in whole body composition among groups. Apparent digestibility coefficients (ADC) of the diets were evaluated in a separate trial. The ADC of dry matter of the experimental diets was significantly higher than in the control diet; there were no significant differences among diets in the ADC of energy and protein, except for the ADC of protein of diet with 80% corn gluten protein, which was significantly lower than the control. The results of this study indicate that corn gluten meal can replace up to 60% fish meal protein in diets for gilthead sea bream juveniles with no negative effects on fish performance. [ABSTRACT FROM AUTHOR]

A trial was conducted to evaluate the phosphorus requirements of gilthead sea bream juveniles. Seven semipurified diets were formulated to contain 54% crude protein and 15% lipids and phosphorus (di-calcium phosphate) levels ranging from 0.37% to 1.5% (DM basis). Each diet was fed to duplicate groups of 25 fish with an initial average weight of 5 g over 42 days. The fish were fed by hand to visual apparent satiety twice daily, six days a week. At the end of the trial growth rate was not significantly different in groups fed diets containing 0.75% phosphorus or higher, while growth rate of fish fed the 0.37% phosphorus diet was significantly lower than all the other diets. Feed efficiency ratio, protein efficiency ratio and N retention were significantly lower in fish fed the 0.37% phosphorus diet than in those fed diets with 0.75% and higher phosphorus levels. Phosphorus content of the fish averaged 2% (on a dry weight basis) and was not significantly affected by dietary phosphorus content. Phosphorus retention averaged 6.6 g kg[sup -1] weight gain and was not statistically different among groups. Phosphorus retention (% phosphorus intake) decreased with the increase of dietary phosphorus content, being even higher than 100% in groups fed diets with 0.37% and 0.57% phosphorus, indicating phosphorus absorption from the water. The results of this study indicate that phosphorus requirements of gilthead sea bream juveniles were satisfied with a diet including 0.75% phosphorus. [ABSTRACT FROM AUTHOR]

The article cites a research on the impact of starvation and re-alimentation periods on growth performance and hyperphagic response of Sparus aurata. This research was supported by the Research Fund of the University of Ḉukurova in Turkey. The objectives of this research were to understand the phenomenon of compensatory growth response in gilthead seabream to different lengths of re-alimentation, to assess hyperphagic response and find optimum feeding management using cycling deprivation in order to maximize growth.