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Control of the reproductive cycle is essential to achieve a successful aquaculture industry. Seahorse reared in captivity often shows eggs of poor quality and low offspring survival due to unsuitable rearing and nutritional protocols. This study aimed to evaluate the effect of dietary enrichment, added exclusively during the spawning season, on the egg quality of Hippocampus hippocampus. The effect of enriching mysis throughout the spawning season was analysed in terms of female fecundity, egg viability, egg size and fatty acid profile. The results showed that fecundity was not affected by the enrichment of the diet, but egg viability was increased when females were fed the enriched mysis (84.9 ± 4.1% compared to 62.2 ± 9.4%). Moreover, the content of several PUFA (20:4n-6, 18:2n-6, 22:5n-3, 22:5n-6, sum of n-6) decreased throughout the spawning season, especially in the last clutch, in eggs originated from females fed non-enriched mysis. Eggs from females fed the enriched diet maintained the fatty acid profile throughout the spawning season. In conclusion, enrichment of the diet of H. hippocampus improved egg viability and avoided a decrease in the quality of eggs by maintaining PUFA content in the last clutches of the spawning season. [ABSTRACT FROM AUTHOR]

A 14 weeks growth trial was performed to estimate the protein requirement for growth and maintenance of zebra sea bream ( Diplodus cervinus) juveniles. For that purpose, nine isolipidic diets were formulated to contain increasing protein levels (from 50 to 550 g kg−1) at the expense of carbohydrate. Each diet was assigned to duplicate groups of 20 fish, with an average body weight of 7.7 g. Feed efficiency improved with dietary protein up to 400 g kg−1, no further differences being noticed at higher protein levels. Fish fed the 50 g kg−1 protein diet lost weight during the trial. In the other groups, weight gain improved as dietary protein increased up to 350-400 g kg−1. Fish fed diets with 250 g kg−1 protein or lower had lower whole-body protein content than the other groups. A curvilinear-plateau model was used to adjust weight gain and protein gain (g kg ABW−1 day−1) to dietary protein levels. Based on that model, the optimum dietary protein requirement for maximum weight gain was estimated to be 437.6 g kg−1 and for maximum protein gain 461.9 g kg−1, corresponding to a protein intake of 7.63 g kg ABW−1 day−1. Protein requirement for maintenance was estimated to be 1.01 g kg ABW−1 day−1. [ABSTRACT FROM AUTHOR]

To assess the effect of feeding frequency on the utilization of dietary starch by white sea bream juveniles, triplicate groups of fish were fed an experimental diet (400 g kg−1 protein, 140 g kg−1 lipids and 350 g kg−1 pregelatinized maize starch) to apparent visual satiation 2, 3 or 4 times a day for 63 days. Growth performance, feed utilization efficiency, glycaemia, cholesterolaemia, plasma triacylglycerides, liver lipids and glycogen content were unaffected by feeding frequency. α-Amylase activity increased from the pyloric caeca to the posterior intestine and was higher in fish fed twice a day than in fish fed 3 or 4 times a day. Hepatic glucokinase ( GK) activity decreased with the increase in feeding frequencies, whereas fructose-1,6-bisphosphatase ( FBPase) activity increased. Hepatic glucose-6-phosphate dehydrogenase and glutamate dehydrogenase activities were unaffected by feeding frequency. Overall, feeding frequency did not improve white sea bream dietary starch utilization. α-Amylase, GK and FBPase activities responded to dietary starch consumed at each meal, denoting a good metabolic adaptation of the fish to the feeding conditions. [ABSTRACT FROM AUTHOR]

The present study provides updated information on amphipod assemblages of the southern Portuguese coast, the most south-western part of continental Europe. The influence of depth and sediment type on the spatial distribution of shallow soft-bottom amphipods was tested by means of univariate and multivariate methods. Samples were collected down to 40 m depth within areas ranging from very fine sand to gravel. The ratio between density and diversity was found to increase with depth and from coarser to finer sediments. Both physical variables tested were found to play a major role in structuring amphipod assemblages. However, some dominance of depth was evident as samples were mainly separated according to this variable. Moreover, while only 15 taxa were common to all depth levels, 35 were collected from all sediment types. Both depth and sediment type may override the potential effects of geographical location, as samples from different areas along the southern Portuguese coast were biologically related. A peculiar habitat was sampled in this study: a maerl bed, which was confirmed to be a hotspot of density. Nevertheless, this habitat did not harbor a distinct amphipod assemblage but some taxa such as Caprella spp., Lembos websteri, lysianassids and Gammarella fucicola were preferentially collected there. The biogeographical analysis pointed out the occurrence of 8% of Mediterranean endemic species, confirming the influence of the Mediterranean Sea beyond the Strait of Gibraltar, and the Atlantic-Mediterranean feature of the amphipod fauna of this geographically relevant area. The present results support the need to interpret the spatial distribution patterns of marine species in relation to the combined effect of depth and sediment characteristics. [ABSTRACT FROM AUTHOR]

This study aimed to investigate the relationships between levels of organochlorine compounds (PCBs and DDTs), polycyclic aromatic hydrocarbons (PAHs), metals and biomarkers of exposure (EROD and GST) and oxidative stress biomarkers, in wild and cultured European seabass (Dicentrarchus labrax). Additionally, the fatty acid profile was determined in muscle to assess differences between cultivated and wild specimens of marketable size. Although results pointed to relatively low concentration of contaminants, wild specimens presented enhanced accumulation of metals and cultivated specimens higher levels of organic compounds. Biomarkers were correlated with contaminants in tissues, showing that higher levels can cause effects at the biochemical level. Wild specimens have presented higher content on omega-3 fatty acids in muscle. Besides the useful application of biomarkers in wild species, this study has shown that they can also be applied to monitor biological effects in the fish farming process. [Copyright &y& Elsevier]

Fish larvae present high amino acid requirements due to their high growth rate. Maximizing this growth rate depends on providing a balanced amino acid diet which can fulfil larval amino acid nutritional needs. In this study, two experimental microencapsulated casein diets were tested: one presenting a balanced amino acid profile and another presenting an unbalanced amino acid profile. A control diet, live feed based, was also tested. Trials were performed with larvae from 1 to 25 days after hatching (DAH). Microencapsulated diets were introduced at 8 DAH in co-feeding with live feed and at 15 DAH larvae were fed the microencapsulated diets alone. Results showed a higher survival for the control group (8.6 ± 1.3% versus 4.2 ± 0.6% and 3.2 ± 1.8%) although dry weight and growth were similar in all treatments. The proportion of deformed larvae as well as the ammonia excretion was lower in the group fed a balanced diet than in the unbalanced or control groups (38.3% deformed larvae in control, 30% in larvae fed unbalanced diet and 20% on balanced diet group). Furthermore, larvae fed the microencapsulated diets presented higher docosahexaenoic acid and arachidonic acid levels. This study demonstrates that dietary amino acid profile may play an important role in larval quality. It also shows that balanced microencapsulated diets may improve some of the performance criteria, such as skeletal deformities, compared to live feeds. [ABSTRACT FROM AUTHOR]

A trial was undertaken to estimate the protein requirement of white sea bream ( Diplodus sargus). Five fish meal-based diets were formulated to contain graded levels of protein (from 60 to 490 g kg−1). Each diet was assigned to triplicate groups of 25 fish with a mean individual body weight of 22 g. Fish fed the 60 g kg−1 protein diet lost weight during the trial, while growth improved in the other groups as dietary protein level increased up to 270–370 g kg−1. Feed efficiency improved as dietary protein level increased. Maximum protein efficiency ratio (PER) was observed with the 17% protein diet. N retention (NR) (% N intake) was not different among groups fed diets with 17% protein and above. Ammonia excretion (g kg−1ABW day−1) increased as dietary protein level increased, while no differences in urea excretion were noted. An exponential model was used to adjust specific growth rate and NR (g kg−1 day−1) to dietary protein level. Based on that model, dietary protein required for maximum retention was 330 g kg−1, while for maximum growth it was 270 g kg−1. On a wet weight basis, there were no differences in whole body composition of fish-fed diets with 170 g kg−1 protein and above, except for the protein content, which was lower in group fed the 170 g kg−1 protein diet than the 490 g kg−1 protein diet. Specific activities of hepatic amino acid catabolism enzymes (glutamate dehydrogenase, alanine aminotransferase and aspartate aminotransferase) increased as dietary protein levels increased. There were no differences among groups in fatty acid synthetase and malyc enzyme but 6-phosphate dehydrogenase (G6PDH) was significantly lower in fish fed the 60 g kg−1 protein diet than the 170 and 490 g kg−1 protein diets. [ABSTRACT FROM AUTHOR]

Abstract: The relationship between organic enrichment and macrobenthic colonization patterns was investigated during an 8-month period in Diplodus sargus (white seabream) production ponds. A stratified sampling design was applied and each pond was divided into three zones: water entrance (WE); central (C); and automatic feeder zones (AF). Generally, the number of species and Shannon–Wiener diversity increased from the WE to the AF zone. Abundance did not present a clear trend. The recently developed marine biotic index (AMBI) was applied and showed to be sufficiently robust to discriminate, within a relatively small area, differences in macrobenthic communities due to organic enrichment. Nevertheless, caution is advised when applying this index or others based on ecological group’s assignment, as the classification of a certain area may differ when allocating a certain species to an unsuitable group. This is particularly evident when common species are involved. [Copyright &y& Elsevier]

In this study, two growth trials were conducted to evaluate the effect of dietary protein and lipid levels on growth and feed utilization of white sea bream ( Diplodus sargus) juveniles. For the first trial, five diets were formulated to contain 120 g kg−1 lipid and increasing levels of protein, ranging from 400 to 600 g kg−1. Two additional diets were formulated with 400 and 600 g kg−1 protein and 180 g kg−1 lipids. The diets were fed to apparent visual satiety to duplicate groups of fish with a mean weight of 1.5 g for 10 weeks. For the second growth trial, four diets were formulated to contain 120 g kg−1 lipid and 380–520 g kg−1 protein. Two additional diets were formulated with 380 and 520 g kg−1 protein and 180 g kg−1 lipids. The diets were fed to apparent visual satiety to triplicate groups of fish with a mean weight of 41 g for 12 weeks. At the end of both trials, there were no growth differences among groups independent of the dietary protein content. In the first trial, growth was negatively correlated to dietary lipid levels. No significant differences of feed intake were detected among groups in both trials, but a direct correlation between feed efficiency and dietary protein level was observed. Protein efficiency ratio and nitrogen (N) retention (% N intake) significantly decreased with the increase of dietary protein levels. In both trials, energy retention (% energy intake) was highest in groups fed on diets with the highest protein-to-energy (P/E) ratio. At the end of both trials, no significant differences in whole-body composition were observed among groups. Specific activity of enzymes involved in amino acid catabolism [aspartate aminotransferase (AST), alanine aminotransferase (ALT) and glutamate dehydrogenase (GDH)] showed no significant differences with dietary protein level in both trials. Nevertheless, in the first trial, a significantly lower GDH activity was observed in fish fed with higher dietary lipid levels. No differences were found for specific activity of the lipogenic enzymes, fatty aid synthetase and glucose-6-phosphate dehydrogenase, in the second trial. Results of this study indicate that a diet with a protein level of 380–420 g kg−1 and a P/E ratio of 20 g protein MJ−1 satisfies the growth requirements of D. sargus juveniles. Also, within the range tested, no evidence of protein sparing by dietary lipids seems to occur. [ABSTRACT FROM AUTHOR]

Previous laboratory feeding experiments, representing the state-of-the-art methodology to investigate microplastic (MP) ingestion and its impact for fish, tend to disregard both the significance of applying realistic MP densities and the potential relevance of biofilm-coating for ingestion probability. This experiment assessed the uptake of either pristine or biofilm-coated MP particles and the physiological impacts for juvenile white seabream for MP concentrations consistent with those found in the field along with natural prey over a course of 3.5 weeks. Results indicate the ability of juvenile D. sargus to discriminate between edible and non-edible prey. A distinct preference for biofilm-coated over pristine particles could not be verified. No significant impact on growth and condition was found except for high levels of MP ingestion. The outcomes highlight the importance of performing MP feeding experiments mimicking natural conditions to reliably assess the impact of MP on early life stages of fish. Overview of the experimental design of the 3.5-week-long microplastic (MP) feeding trials with juvenile Diplodus sargus. All treatments are tested by three replicate tanks, each holding approx. 50 juveniles. Fish of the control group were fed with live prey exclusively, whereas fish of the two MP treatments were additionally offered polystyrene particles (either pristine or biofilm-coated). © Figure White Seabream Diplodus sargus : Arias García AM, Drake Moyano P (1990). Estados juveniles de la ictiofauna en los caños de las salinas de la bahía de Cádiz. Cádiz: Instituto de Ciencias Marinas de Andalucía. Unlabelled Image • Feeding experiment with juvenile fish using realistic microplastic densities. • Ingestion rate of pristine particles higher than of biofilm-coated ones. • Juvenile fish were able to distinguish between natural and artificial prey items. • No significant effect on growth and condition due to MP exposure or uptake found. [ABSTRACT FROM AUTHOR]

The gilthead seabream Sparus aurata L. is a sequential spawner whose reproductive cycle can be manipulated to obtain year-round egg and fry production. Hence, there is an overproduction of eggs in commercial hatcheries that is normally wasted. Two feeding experiments were conducted with the purpose of investigating the potential use of fresh and freeze-dried gilthead seabream eggs for the enrichment of live preys. The first experiment was also designed to study the possibility of using freeze-drying as a conservation process for eggs in excess. Larvae were reared for 20 days after hatching (DAH),on a diet of Brachionus sp. As experimental controls, the commercial enrichment emulsion SUPER HUFA was used in the first experiment, and the microalgae Nannochloropsis sp. in the second. This study demonstrated the potential of gilthead seabream eggs as an enrichment product to be used in the feeding of the first larval stages of Sparus aurata L. The data obtained emphasize the need to have an overall perspective of the nutritional requirements of the organisms in culture. [ABSTRACT FROM AUTHOR]

The objective of the present work was to determine the effect of theenrichment of rotifers (Brachionus plicatilis) and brine shrimp (Artemia sp.) with different commercial emulsions and microalgae on polyunsaturated fatty acid (PUFA) composition of gilthead sea bream larvae, Sparus aurata. Rotifers were fed four enrichment diets (marine Chlorelia sp., and three commercial emulsions: Algal Rotifero(TM), Frippak(TM) booster and Selco(TM). The enrichment of Artemia sp. (Artemia Systems(TM) AF type) was carried out with instar I nauplii at a density of 250--300 nauplii/ml in 20-l conical tanks, using two commercial emulsions (Troffic(TM) and Selco(TM) sp.) and a microalgae (Chloreliasp.). The results showed that enriched preys were deficient in PUFA n-3 and may not provide the nutritional requirements of sea bream larvae, although the enrichment methodology seems to be efficient in order to incorporate in the larvae the fatty acid treatment. [ABSTRACT FROM AUTHOR]

Abstract:Several commercial oils of plant and animal origin were tested in order to improve the HUFA content and the DHA:EPA ratio of Artemia sp. metanauplii. The relationship between the n-3 and n-6 fatty acid series, and more recently, the DHA:EPA ratio seem to be indicators for better survival and growth of marine fish larvae. The tested plant oils were derived from linseed, peanut and sunflower, and the animal oils came from squid, sardine, cod liver and Selco emulsion. For each oil emulsion tested, four different enrichment periods (9, 24, 33 and 48 h) were evaluated in the same Artemia sp. strain (Artemia EG from Artemia Systems Inc., Baasrode, Belgium). The results show that oil emulsions of plant origin give very poor results in relation to either HUFA content or DHA:EPA ratio. All the oil emulsions from animal origin resulted in HUFA incorporation. Sardine oil was the poorest and squid oil the best. The HUFA content and the DHA:EPA ratio increased with enrichment periods up to 33 h, followed by a negligible variation up to the final 48 h. [ABSTRACT FROM AUTHOR]

Meagre (Argyrosomus regius) belongs to the family Sciaenidae and is a promising candidate for Mediterranean aquaculture diversification. As a relatively recent species in aquaculture, the physiological consequences of the immune system activation in meagre are understudied. Spleen, as a primary lymphoid organ has an essential role in meagre immune and inflammatory responses. In this study, we have evaluated the in vivo effects of lipopolysaccharide (LPS) on the spleen transcriptome of meagre by RNA-seq analysis at 4 and 24 h after injection. [ABSTRACT FROM AUTHOR]

Focuses on the development of the swim bladder of cultured sparus aurata, better known as the red porgy. Materials and methods employed in the experiment of the fish; Presentation of the abnormalities of the fish; Chronology of the swim bladder development of the fish.

Mytilus galloprovincialis is one of recent bivalve species produced in Portugal offshore. The growth, condition index, and the fatty acid composition of the mussel produced at 2 and 13 m depth was compared in longline on the south coast of Portugal. For each depth, a monitoring of several water quality parameters such as temperature, turbidity, nutrients, and chlorophyll-a was carried out. There were no significant differences between mussel growths at different depths. On the first sampling, shell length mean was 24 mm, reaching 50 mm 9 months after. High dispersion of mussel length was observed due to slow growers. The condition index shows a typical seasonal variation, with high values in autumn and late spring and minimum values in January. Analysis of fatty acids did not reveal differences at both depths and DHA levels (8.71 mg/g) were generally higher than EPA (5.90 mg/g). The water quality revealed few differences in the environmental conditions in the water column, which may explain the similarities between the quality of mussels produced at different depths. Based on these data, the mussel offshore production in that area can be done at this range of profundities 2 and 13 m, without affecting growth and fatty acid composition. [ABSTRACT FROM AUTHOR]

Recently isolated microalgae Tetraselmis sp. IMP3, Tetraselmis sp. CTP4, and Skeletonema sp. were studied. The three novel strains contained relatively high levels of polyunsaturated fatty acids (PUFA) and n3 PUFA. However, highly unsaturated n3 FA contents were relatively low (5.7–13.0% of the total FA). In general, eicosapentaenoic acid (EPA, 20:5 n3) contents were low (< 6.4% of the total FA). However, in Skeletonema biomass, EPA levels were higher than 10% of the total FA. α-Linolenic acid (ALA, 18:3 n3) and 16:3 n4 were the main PUFA in Tetraselmis strains and Skeletonema, respectively. High contents of myristic (14:0) and palmitoleic (16:1 n7) acids were found in Skeletonema (exceeding 20% of the total FA in both cases), whereas the Tetraselmis strains were rich in palmitic (16:0), 15–27% of the total FA, and oleic (18:1 n9) acids, 12–19% of the total FA. Linoleic acid (18:2 n6) content was low in Skeletonema (< 1% of the total FA). This microalga had the highest total polyphenol content, reaching 300–400 mg/100 g dw. Gentisic acid was the main phenolic compound in the aqueous and ethanolic extracts of this microalga. The highest antioxidant activity was displayed by Skeletonema. The ferric ion reducing antioxidant power (FRAP) and 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) methods showed higher antioxidant power for Skeletonema sp. extracts, reaching an ABTS reduction of more than 80%. Concerning anti-inflammatory activity, ethanolic extracts of Skeletonema sp. exhibited the highest inhibitory capacity of cyclooxygenase-2 (COX-2), 82 ± 2%, which compares to 36 ± 9% in Tetraselmis sp. CTP4 and 45 ± 5% in Tetraselmis sp. IMP3. Aqueous extracts had always a lower anti-inflammatory capacity, 6–30%. Therefore, these microalgae have potential for multiple applications, ranging from bioactive feedstocks to aquaculture and nutraceutical uses. [ABSTRACT FROM AUTHOR]

Insect meals (IM) are being pointed out as a promising sustainable protein source. However, chitin in IM may negatively interfere with fish performance and nutrient availability. Given that carnivorous fish have a low or inexistent ability to digest chitin, novel strategies are needed to overcome chitin-imposed bottlenecks. Carbohydrolytic sporeforming probiotics offer a competitive industrial approach, being able to resist the harsh feed manufacturing process, transport, storage, and animal's gastrointestinal tract, while being able to increase the digestibility of otherwise indigestible components. Aiming to increase IM chitin digestibility, two chitinolytic sporeforming fish isolates (Fish isolates 645 (FI645) and 658 (FI658)), closely related to Bacillus licheniformis , were isolated from European sea bass (ESB) gastrointestinal tract, and incorporated (individually or as a mixture) in ESB diets with high defatted Hermetia illucens larvae meal (HM) levels (30% inclusion). FI were evaluated regarding their effects on ESB growth performance and digestibility. The spores were able to maintain their viability throughout the 180 days of diet storage at room temperature. Dietary inclusion of FI645 led to higher chitin digestibility. Concomitantly, the digestibility of dry matter, protein, and energy increased, overall leading to higher feed efficiency and protein efficiency ratio. Dietary inclusion of FI645 led to increased plasma N -acetylglucosamine (GlcNAc) levels. This is the first evidence for diet-mediated modulation of plasma GlcNAc concentrations. Dietary inclusion of FI645 also increased the expressions of the genes coding for N -acetylglucosamine kinase (nagk) and GlcNAc phosphomutase (pgm3) , key enzymes from the GlcNAc salvage pathway and the hexosamine biosynthetic pathway (HBP). On the other hand, no differences were found for the expression of N -acetyl-D-glucosamine-6-phosphate deacetylase (amdhd2) , a precursor enzyme for GlcNAc redirection to glycolysis. These results hint that free GlcNAc resulting from increased chitin digestibility might be preferentially redirected to protein O-GlcNAcylation processes through HBP in fish cells. Additionally, when challenged with Vibrio anguillarum , and after being feed for one month with the same diets, D645 also increased ESB survival from 52.5% to 77.5%, when compared to the control. Together, these results establish the potential of using FI645 as a probiotic for enhancing chitin digestion and acting as a prophylactic agent for ESB protection against V. anguillarum infection. This strategy opens novel possibilities for using commodities, including high chitin levels in aquafeeds, and reducing the use of antibiotics in aquaculture. • Fish isolate 645 increases chitin, protein, and energy digestibility and feed efficiency. • Increase in chitin digestibility increased N -acetylglucosamine in plasma. • The hexosamine biosynthetic pathway is potentially modulated by N -acetylglucosamine. • Fish isolate 645 increases European sea bass survivability to Vibrio anguillarum. [ABSTRACT FROM AUTHOR]

Abstract This study assessed the effect of supplementation of low-fishmeal (FM) diets with taurine in white seabream (Diplodus sargus) juveniles. Four isoproteic (36% CP) and isolipidic (18% CL) diets were formulated to include 15%FM or 5%FM, supplemented or not with 1% of Taurine (TAU). Twelve groups of 15 fish (IBW = 58 g) were fed each diet to near satiation for 10 weeks. Growth performance, feed intake, and feed efficiency were not affected by dietary FM level. Nevertheless, dietary TAU supplementation increased growth performance and feed efficiency. Nitrogen and energy retention were improved by both dietary FM level and TAU supplementation. Plasma cholesterol, lactate, and bilirubin did not differ among dietary treatments, but dietary TAU supplementation decreased plasma glucose and triglycerides levels. Decrease of FM level reduced total bile salts while TAU supplementation had the opposite effect. No differences were noticed in innate immune parameters assessed. Overall, results indicate that white seabream can be fed with diets almost devoid of FM, and that dietary TAU supplementation increases growth performance and feed efficiency. Moreover, results suggest that dietary TAU was limiting both in 15% and 5% FM diets. [ABSTRACT FROM AUTHOR]