Growth performance of gilthead sea bream Sparus aurata in different osmotic conditions: Implications for osmoregulation and energy metabolism

The influence of three different environmental salinities (seawater, SW: 38 ppt salinity; brackish water, BW: 12 ppt; and low salinity water, LSW: 6 ppt salinity) on the growth, osmoregulation and metabolism of young gilthead sea bream (Sparus aurata L.) was studied over a period of 100 days. 480 inmature fish (20 g mean body weight) were randomly divided into six tanks of 2500 l (80 fish per tank) and maintained under three different salinities (38 ppt, 12 ppt and 6 ppt) in an open system. Every three weeks, 10 fish from each tank were anesthetized, weighed and lenghed. At the end of experiment, 10 fish from each tank were anesthetized, weighed and sampled for plasma, brain, gill and liver. Gill Na⁺, K⁺-ATPase activity, plasma osmolality, ions (sodium and chloride), glucose, lactate, protein and triglyceride, and hepatosomatic index were examined. In addition, levels of glycogen, lactate, ATP and activities of potential regulatory enzymes (hexokinase, pyruvate kinase, glycogen phosphorylase, and glucose 6-phosphate dehydrogenase) were assesed in liver, brain, and gill. BW-acclimated fish showed a better growth with respect to SW- or LSW-acclimated fish (12 > 38 > 6 ppt). The same relationship was observed for weight gain and specific growth rate. Osmoregulatory parameters in plasma (osmolality, Na⁺ and Cl⁻ levels) were similar in SW- and BW-acclimated fish but significantly higher than those of LSW-acclimated fish. Gill Na⁺, K⁺-ATPase activity showed lower values in intermediate salinity (6 > 38 > 12 ppt). No changes were observed in metabolic parameters analyzed in plasma, whereas only minor changes were observed in metabolic parameters of liver, gills and brain that could be correlated with the higher growth rates observed in fish acclimated to BW, which do not allow us to attribute the best growth rate observed at 12 ppt to lower metabolic rates in that salinity.     

Self-feeding activity patterns in gilthead sea bream (Sparus aurata), red porgy (Pagrus pagrus) and their reciprocal hybrids

This study was conducted to monitor feeding activity of gilthead sea bream (Sa) and red porgy (Pp) and to investigate the hereditary effects on feeding in their hybrids (female Sa×male Pp, female Pp×male Sa), obtained after artificial crosses. All fish groups were held in 500-l tanks under ambient temperature (15–25°C) and light conditions (daylength from 9 h 30 min to 14 h 48 min). Fish (initial body weight 100–165 g) were fed by means of self-feeders, which were connected to a computer, recording fish feeding activity for a year. Results showed that there was a 24-h periodicity in all fish types over the experiment. In their daily feeding patterns, both parental species were diurnal: red porgies had a stable daily pattern over the experiment, while gilthead sea bream shifted their activity from a general daylight fluctuation in warm periods to an afternoon peak in cold periods. The Sa×Pp hybrids showed intermediate feeding patterns compared to their parents in warm periods and a pattern that was similar to the red porgy in cold periods, while the Pp×Sa hybrids had rather unchangeable daily feeding patterns, which were not related to the parental ones. The proportion of night feed demands increased in cold periods independent of fish group. The relationship between temperature and feed intake was species-dependent. Finally, this study indicated that feeding expression in hybrids was related to the combination of the parental genome, supporting our hypothesis for a hereditary influence on feeding activity in fish.     

Immunological and pathological status of gilthead sea bream (Sparus aurata L.) under different long-term feeding regimes

The possible influence of the feeding regime (FR) on the immune system and pathological status of gilthead sea bream was studied. Two growth trials were performed starting at different seasons (trial 1=March; trial 2=June) under controlled experimental conditions. In both trials, FR-1 groups received a restricted amount of food, whereas FR-2 groups were fed to visual satiety. The pathology study included parasitological and bacteriological examination, and the immunological traits analysed were respiratory burst activity of head kidney leucocytes, serum lysozyme and alternative pathway complement activity (ACH₅₀). The immunological status of gilthead sea bream not only was not impaired by the restricted feeding regime, but also seemed to be enhanced in some aspects, as the respiratory burst of FR-1 fish of trial 2 was significantly higher. No differences in the bacterial isolates were detected between the two feeding regimes, and Vibrio harveyi was the most prevalent species in both cases, especially in warm months. Also, fish under FR-1 regimes had significantly lower mortality, lower prevalence of infection of all the parasites except Cryptosporidium molnari, and less histopathological alterations in liver and intestine than those under FR-2 regimes.     

Stock enhancement of gilthead sea bream (Sparus aurata, L.): assessment of season, fish size and place of release in SW Spanish coast

Gilthead sea bream, Sparus aurata L., is a highly level protein species in Mediterranean countries and can easily be produced in hatcheries. Despite the commercial interest in the species, alternatives to aquaculture such as ranching and stock enhancement, which have proven to be profitable for other species, have not been attempted for the gilthead sea bream. The aim of this paper is to evaluate the feasibility of these alternatives for the Atlantic coast of the southern Iberian Peninsula, where this species is highly valuable for professional and amateur fishermen. A total of 30 323 individuals marked with average weights of 15, 100, 316 and 854 g were released between 1993 and 1997 at six different locations. For each of these locations, the displacements, growths, the oldest recapture and the percentage of recapture were determined. The Bay of Cádiz turned out to be the most suitable location since the highest recapture (2.41%, S.E. 0.53) and specific growth rates (0.86, S.E. 0.09), as well as small displacements (8.16 km, S.E. 0.95), were found in this location. One hundred grams was the best size for enhancement as fish of 15 g showed very low recapture rates (0.12%, S.E. 0.08), while fish larger than 316 g made significant displacements (42.87 km, S.E. 4.73). Growth and displacement also point to summer versus spring, winter or fall as the best releasing period for stock enhancement of this species in the analysed area. These elements point to the feasibility of implementing a stocking program for gilthead sea bream. This must have the bay of Cádiz as the core place of interest, releasing 100-g fish in late summer.     

Effects of dietary amino acid profile on growth performance, key metabolic enzymes and somatotropic axis responsiveness of gilthead sea bream (Sparus aurata)

Juvenile gilthead sea bream were fed to visual satiety with isonitrogenous diets based on fish meal and different plant ingredients (33–35% replacement) supplemented with free amino acids to meet the desired indispensable amino acid (IAA) profile and dispensable amino acid (DAA) content. In diets M and WB, IAA profile and DAA content resemble that of the muscle or whole body, respectively. In diets MGlu and WBGlu, DAA content was increased by adding -glutamic acid (Glu) and thus the IAA/DAA ratio varied from 1.13 (diet M) to 0.80 (diet WBGlu). Growth rates were not significantly different among experimental groups, but feed conversion ratio and nitrogen retention were impaired by the decrease of dietary IAA/DAA ratio. Postprandial ammonia excretion increased with the increase of dietary DAA content irrespective of IAA profile. Conversely, hepatic activity of glutamate dehydrogenase (GDH) was lower in fish fed diet WBGlu than in fish fed diet M. Hepatic growth hormone (GH) binding was not significantly affected by the dietary treatment, but circulating levels of insulin-like growth factor-I (IGF-I) and GH were, respectively, down- and up-regulated in fish fed diet WBGlu, which suggests some defect in the transmission of GH receptor signal. Fat retention and hepatic activities of lipogenic enzymes (glucose-6-phosphate dehydrogenase, G6PD; malic enzyme, ME) were decreased in fish fed diet MGlu. Key metabolic enzymes of hepatic glycolysis (glucokinase, GK) and gluconeogenesis (phosphoenolpyruvate carboxykinase, PEPCK) were also altered in this group of fish. Since soybean meal concentration was highest in diet MGlu, results on lipid and carbohydrate metabolism can be primarily attributed to this component of the diet. In contrast, data on growth performance, ammonia excretion and GH axis mainly reflect changes in the dietary amino acid profile, which reveals that a muscle IAA profile and a high IAA/DAA ratio are important in feeds for gilthead sea bream.     

Effects of extrusion and inclusion level of soybean meal on diet digestibility, performance and nutrient utilization of gilthead sea bream (Sparus aurata)

The objective of this study was to evaluate the effects of soybean meal inclusion and treatment on the performance of two sizes of gilthead sea bream (small, 9 g and large 50 g mean initial weight). Seven diets were fed containing soybean meal, before (SBM) and after (SBMex) its extrusion, at increasing levels (0% as control and about 20, 30, and 40% for both soy forms used). For large fish effects on digestibility, as well as on trypsin activity levels and moisture at upper (UI), mid (MI) and lower (LI) intestine were also evaluated, following the growth trial. All experiments were conducted at 22 ± 2 °C. Specific growth rate and whole body composition were not affected by soy inclusion, however an adverse effect of inclusion level on feed conversion ratio and protein productive value was apparent for both soy products and fish sizes. Extrusion of soy affected differently large and small fish improving both protein productive value and feed conversion ratio of large fish, but only protein productive value of small fish. Plasma cholesterol decreased with inclusion level of both types of soy, the effect being significant only at the higher level. Liver lipid and glycogen deposition in large fish appeared to be mostly affected by digestible starch intake, increasing with increased intakes, the same being apparent for hepatosomatic index. Soy inclusion did not appear to have any effect on nutrient digestibilities. Trypsin activity (TA) was decreased from UI to LI for all diets and was significantly higher in C diet compared to all other diets at all segments. Extrusion of SBM increased significantly TA levels. Hydration of digesta in LI increased for low soy levels and decreased for high soy levels compared to the control diet.     

Heritability of skeleton abnormalities (lordosis, lack of operculum) in gilthead seabream (Sparus aurata) supported by microsatellite family data

Body abnormalities constitute an important problem to fish aquaculture. Pigmentation, scale and skeleton abnormalities have been reported in different cultured fish species. Environmental and genetic factors or their interaction have been suggested to explain their origin. Gilthead seabream (Sparus aurata) is one of the most important European cultured species. Lordosis and lack of operculum are common abnormalities in this species, and can reach frequency of 80% or more of commercial batches. In spite of an important body of data suggesting environmental factors related with their origin, scarce and not conclusive genetic data have been reported to date. In our study, a large number of families originating from the usual production process of a commercial farm were used to estimate the heritabilities of both characters. Two independent experiments were carried out for each abnormality. Nine hundred and ninety four (5.6% lordotics; 157 full-sib families; 6.3 offspring/family) and 808 (7.9% lacking operculum; 83 families; 9.7 offspring/family) individuals were used for lordosis and lacking operculum heritability estimations, respectively. The results obtained adjusting an animal model indicated non significant heritabilities for both characters (0.021 (s.e. 0.019) and 0.032 (s.e. 0.023) for lordosis and lack of operculum, respectively). The corresponding values when a threshold model was used, though higher (0.152 and 0.203, respectively), evidenced large standard errors (0.119 and 0.146, respectively) suggesting h² = 0 as the most confident hypothesis (P = 0.838 and 0.766, respectively). A non-parametric permutation test was also applied to evaluate if more related individuals had a higher phenotypic resemblance. The results obtained suggested only a slight familiar association (P < 0.05) when comparing individuals lacking operculum, but neither between lordotics nor between normal ones. These results suggest that most phenotypic variation observed for lordosis and lack of operculum in gilthead seabream is due to environmental factors.     

Genetic comparison of wild and cultivated European populations of the gilthead sea bream (Sparus aurata)

This study represents the first large-scale population genetic analysis of the marine fish gilthead sea bream (Sparus aurata), one of the most significant species in the South European aquaculture. Six wild and five cultivated sample sets covering the South Atlantic and Mediterranean European area have been screened for allozyme, microsatellite and mitochondrial DNA (mtDNA) variation. Microsatellites showed higher levels of polymorphism than allozymes. The low variability of mtDNA offered no basis for population differentiation.

The results reveal levels of variability for S. aurata above those from other sparids. Cultivated populations show a slight decrease of variability related to the wild ones, but not sufficient to document inbreeding depression effects, thus suggesting a fairly proper management. Wild populations reveal a slight degree of differentiation more pronounced with microsatellites than with allozymes, but not apparently associated with geographic or oceanographic factors. The cultivated populations seem to be highly divergent as a result of genetic drift caused by different factors pertaining to their respective histories. With both markers, the two cultivated Spanish sample sets are the most divergent. The high differentiation between cultivated and wild populations from the same area might indicate no evidence for significant genetic flow between them.

This study provides an insight into the population structure of S. aurata, although more questions have arisen that need to be solved. This can be achieved by further screening of small-scaled targeted sample sets in the studied area.     

Growth performance and metabolic utilization of diets with native and waxy maize starch by gilthead sea bream (Sparus aurata) juveniles

The effect of dietary starch source and level on growth performance, feed utilization, apparent digestibility coefficients and liver enzyme activities involved in intermediary metabolism of gilthead sea bream juveniles was studied. Five isonitrogenous (47% crude protein) and isolipidic (15% crude lipids) diets were formulated to contain 10% native (diet NS10) or waxy (diet WS10) maize starch; 20% native (diet NS20) or waxy (diet WS20) maize starch or no starch (control). Diets were adjusted with α-cellulose. Another diet was formulated without carbohydrates, and contained 70% crude protein and 15% crude lipids (diet HP). Each diet was fed to triplicate groups of 30 fish (initial weight: 20 g) for 12 weeks. The HP group was fed to near satiation and the other 5 groups were fed on a pair-feeding scheme according to the group that ingested less feed (control diet group). The reduction of dietary protein level from 70% to 47% by the incorporation of 20% starch did not significantly affect gilthead sea bream growth performance or feed efficiency. Compared to the control diet, neither the level nor the nature of starch had any measurable effect on growth performance and feed efficiency. Digestibility of starch was unaffected by source or dietary inclusion level. Diet had no effect on plasma glucose levels, but liver glycogen was higher in diet groups NS20, WS20 and HP. Dietary carbohydrates increased GK and G6PD enzyme activities and decreased ALAT and GDH enzyme activities while had only a minor effect on FBPase activity. The nature of dietary starch tested (native or waxy) had little influence on performance criteria.     

Feeding requirements of sea bream (Sparus aurata) larvae under intensive rearing conditions: Development of a fuzzy logic controller for feeding

Applied methods for larval rearing suffer from the difficulty of accurately predicting larvae quantitative feeding requirements for optimum growth. Even when known, requirements change according to the behavior of each population reared. Computer based feeding systems require tools for adapting the delivered amounts of food to the needs of the reared population. In this work the daily feeding requirements of sea bream (Sparus aurata) larvae were estimated, and based on these estimations a fuzzy logic controller (FLC) for feeding was designed and developed. Sea bream larvae were reared, in triplicate, under intensive conditions in a pilot scale rearing system for 20 days with the pseudo-green water method. Larvae reached 6.7±0.6 mm (mean value and S.D.) at the end of the experimental period while the mean survival of the populations was 48.0±12.6%. Consumption was 0.017±0.009 mg of carbon per individual at first feeding and increased to 0.198±0.032 mg at day 20 post-hatching. The findings were used for the development of a FLC for feeding that adapts the amount of food delivered to the larvae according to changes in the reared population. The FLC utilizes five linguistic variables describing the state of the population and a rule base composed of 316 rules. The developed FLC allows the use of computer based feeding systems during rearing of early larval stages.     

Vaccination trials on gilthead seabream (Sparus aurata) against Pasteurella piscicida

A comparative study of the efficacy of two vaccine formulations, a whole-cell bacterin (WCB) and a toxoid-enriched whole-cell vaccine (WCEB), against Pasteurella piscicida was conducted by bath immersion in gilthead seabream in order to evaluate the role of the extracellular products (ECP) as protective antigens against this pathogen. With this aim, two strains showing differences in their ECP composition were used to prepare both vaccines. Only the toxoid-enriched vaccine conferred protection against P. piscicida within a 4-week period. The relative percent survival (RPS) acheived with this type of vaccine ranged between 37 and 41 depending on the bacterial strain and dose used in the challenge. Although this protection level is not very high, we consider that it is valuable considering the economic importance of the fish susceptible to pasteurellosis throughout the world. The booster immunization with the WCEB P. piscicida formulation did not increase the protection levels of gilthead seabream. The antibody response in the sera of both immunized fish groups was very low with no correlation between the level of agglutinating antibodies and the protection. In addition, this vaccine did not confer cross-protection against serotypes 01 and 02 of Vibrio anguillarum.     

Preliminary evaluation of pea seed meal in diets for gilthead sea bream (Sparus aurata) juveniles

Juvenile gilthead sea bream with a mean initial body weight of 5 g were fed for 12 weeks with experimental diets containing 10% and 20% fishmeal protein (sole protein source in the control diet) replaced by processed pea seed meals. The processed pea seed meals were dehulled, defibred, extruded and microground pea seed meal (PSM1) or whole pea treated by infrared radiation and ground (PSM2). Apparent digestibility coefficients of the experimental diets were determined in a separate trial. At the end of the growth trial there were no significant differences in growth performance, feed utilization or whole-body composition among experimental groups. There were no differences in apparent protein digestibility among experimental groups (except for fish fed PSM1 at the lowest inclusion level). Both dry matter and energy digestibility of the diets, including PSM2 and with the highest inclusion level of PSM1, were significantly lower than those of the control diet. The results of this study suggest that pea seed meal may replace up to 20% fishmeal protein in diets for gilthead sea bream juveniles without affecting fish performance. Further studies should focus on technological treatments to increase utilization of pea seed meal carbohydrate, as both apparent dry matter and energy digestibility were affected by dietary inclusion level and by pea seed meal processing method.     

Lactobacillus spp. bacteria as probiotics in gilthead sea bream (Sparus aurata, L.) larvae: Effects on growth performance and digestive enzyme activities

In this study, the influence of commercial probiotic, Lactobacillus spp., supplementation was investigated on growth parameters and digestive enzyme activities in gilthead sea bream, Sparus aurata, during larval development. All experiments were triplicated and designed in three different administrations of probiotic from 3 days after hatching (DAH) concurrently with starting of exogenous feeding. In the first group, probiotic was added to live food (rotifer and Artemia). In the second group, probiotic was supplemented directly to both live food and water. In the third group, probiotic was added directly to water. Also, no probiotic treatment was maintained in control group. Total bacterial counts among probiotic probiotic-supplemented groups were significantly different from total bacterial counts in controls in water and digestive tract of larvae (p < 0.05). The mean of total bacterial counts in control was approximately 4 × 10⁴-fold increased from the experimental groups in the sea water (p < 0.05). Besides, mean digestive enzyme activities of all probiotics treatment groups were significantly different (p < 0.05) with that of the control. Except probiotic water supplementation group, in all treatments, the specific activities of pancreatic and intestinal enzymes were significantly higher (p < 0.05) in larvae to which probiotic had been supplemented by live food and live food with water. Also, S. aurata larvae that had probiotic administered by live food with water demonstrated significant (p < 0.05) increases in both survival (13–105% higher) and specific growth rate (2–9% higher) as compared to controls. As a result, supplementation of probiotic to directly tank water could not significantly increase growth parameters and digestive enzyme activities and therefore, administration of probiotics by this method would not be effective in terms of husbandry parameters and nutritional condition.     

Long photoperiod delayed spawning and increased somatic growth in gilthead seabream (Sparus aurata)

The effects of extended photoperiods, mimicking the longest day of the year, were studied in 1- and 2-year seabream. The photoperiod regimes started in late July, 36 and 39 days after the summer solstice and continued for 11 months, well beyond the natural reproductive season of December–March. Regime 1 (long day, 15.5L:8.5D), which used natural and fluorescent light, reduced the incidence of maturity in both year classes and females did not spawn although some gonadal development was observed. Among all 1-year sampled fish of regime 1, a maximum of 5% became spermiating males (March) and 5% reached the yolk granule stage of vitellogenesis (VO3; 250–400 μm diameter) by May. Among 2-year sampled fish of regime 1, 45% became spermiating males and 25% were females, which reached the advanced vitellogenesis stage (VO4; 400–600 μm) by April. Regime 2 (skeleton photoperiod), consisting of natural light and a 1.5-h pulse of fluorescent light during the period 14–15.5 h after sunrise, postponed gonadal development and spawning for up to 3 months. In this regime, a maximum of 80% of 1-year sampled fish were spermiating males in February and a maximum of 10% were VO3 stage females in March. In the sampled 2-year fish, the maximum levels were 50% spermiating males in February and 25% VO3 stage females in March. Control fish, which were exposed to the natural photoperiod (29°34′N), spawned during their natural season. The maximum levels for 1-year sampled control fish were 95% spermiating males and no females in December, while among 2-year sampled fish, maxima of 75% males in February and 45% VO4 stage females in November. Final average weights of photoperiod treated fish (1-year=430 g—regime 1, 400 g—regime 2; 2-year=582 g—regime 1, 518 g—regime 2) were significantly greater (p<0.05) than control fish (1-year=341 g; 2-year=476 g). Daily feed consumption (g/100 g fish) dropped from an average of 1.83 to 0.93 g for 1-year fish during August–December and from 0.88 to 0.54 g for 2-year fish during the same period. This was correlated with reduced autumn and winter water temperatures (26–20°C summer to winter change) and increased fish weight in all treatments. Daily feed consumption was also affected by the onset of spawning in the control and regime 2 (skeleton photoperiod) treatments of both 1- and 2-year fish. The efficiency of feed utilization (FCR) and protein and energy retention were all affected by the photoperiod regimes and followed the same pattern of decrease as weight gain, regime 1 (long day)>regime 2 (skeleton photoperiod)>control.     

Seasonal variation in osmoregulatory and metabolic parameters in earthen pond-cultured gilthead sea bream Sparus auratus

Seasonal variations in osmoregulatory and metabolic parameters were assessed in juvenile gilthead sea bream ( Sparus auratus ) cultured in earthen ponds under a natural photoperiod and temperature. Specimens were sampled, and the plasma, gill, kidney and liver were collected during winter 2005 and 2006 (January), spring 2005 (April), summer 2005 (July) and autumn 2005 (October). Plasma osmoregulatory parameters showed higher values in summer, while metabolic parameters presented different patterns of variations. Gill Na⁺,K⁺-ATPase activity decreased significantly in winter, while gill metabolite levels showed different patterns of variations among seasons. The enzymatic activities tested did not present a clear pattern of variation [(glutamate dehydrogenase (EC 1.4.1.2) (GDH) and hexokinase (EC 2.7.1.11) (HK)] or significant differences along seasons [glucose 6-phosphate dehydrogenase (EC 1.1.1.49)]. Kidney Na⁺,K⁺-ATPase activity decreased during summer and autumn. Different patterns of variation were observed in kidney metabolite levels while all the enzymatic activities assessed [lactate dehydrogenase-oxidase (EC 1.1.1.27) (LDH-O), HK and GDH] presented the highest values during summer. In the liver, metabolite levels and enzymatic activities did not show significant variations or present clear patterns of variation along different seasons. These results indicated seasonal variations in the osmoregulatory and metabolic parameters of different organs (blood, gill, kidney and liver) in earthen pond-cultured gilthead sea bream ( S. auratus ), which could be mainly attributed to seasonal changes in temperature.     

Flumequine depletion from muscle plus skin tissue of gilthead seabream (Sparus aurata L.) fed flumequine medicated feed in seawater at 18 and 24 °C

We examined flumequine depletion from muscle plus skin of gilthead seabream held in seawater at 18 and 24 °C. Seven groups of 10 fish each were sampled at intervals ranging from 24 to 168 h after in-feed administration of flumequine at 35 mg/kg/day for 5 days. Muscle plus skin tissue samples were analyzed for flumequine by high-performance liquid chromatography and fluorescence detection (HPLC-SFD). Parent flumequine concentrations declined rapidly from muscle plus skin after dosing with elimination half-lives of t_1/2=22.14 and 21.43 h at 18 and 24 °C, respectively. Withdrawal periods for the maximum residue limit (MRL) of 600 μg/kg flumequine in muscle plus skin at 95% tolerance limit were 106.08 and 75.84 h at 18 and 24 °C, respectively, after treatment.     

Oxytetracycline (OTC) uptake following bath treatment in gilthead sea bream (Sparus aurata)

The uptake and elimination profile of oxytetracycline (OTC) following a prolong bath treatment in gilthhead sea bream (Sparus aurata) were investigated in this study. The bath experiment was carried out using a OTC concentration of 50 μg/ml for 24 h at 17-18 °C water temperature. Plasma and muscle fish samples were analysed at 1, 3, 6 and 24 h during and at 1, 2, 3, 4 and 6 d following the bath. Detectable OTC levels were revealed only at the end of bath treatment (24 h) in examined tissues of gilthead sea bream, where drug concentration was measured to be as low as 0.096 and 0.047 μg/g or ml in muscle plus skin and plasma, respectively. The findings of the present study indicate that OTC bath treatment under this dosage schedule is unlikely to confront systemic bacterial infections.     

Insect larvae as feed ingredient selectively increase arachidonic acid content in farmed gilthead sea bream (Sparus aurata L.)

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.