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The Senegalese sole (Solea senegalensis) is an economically important flatfish species. In this study, a genome draft was analyzed to identify microsatellite (SSR) markers for whole-genome genotyping. A subset of 224 contigs containing SSRs were preselected and validated by using a de novo female hybrid assembly. Overall, the SSR density in the genome was 886.7 markers per megabase of genomic sequences and the dinucleotide motif was the most abundant (52.4%). In silico comparison identified a set of 108 SSRs (with di-, tetra- or pentanucleotide motifs) widely distributed in the genome and suitable for primer design. A total of 106 markers were structured in thirteen multiplex PCR assays (with up to 10-plex) and the amplification conditions were optimized with a high-quality score. Main genetic diversity statistics and genotyping reliability were assessed. A subset of 40 high polymorphic markers were selected to optimize four supermultiplex PCRs (with up to 11-plex) for pedigree analysis. Theoretical exclusion probabilities and real parentage allocation tests using parent-offspring information confirmed their robustness and effectiveness for parental assignment. These new SSR markers were combined with previously published SSRs (in total 229 makers) to construct a new and improved integrated genetic map containing 21 linkage groups that matched with the expected number of chromosomes. Synteny analysis with respect to C. semilaevis provided new clues on chromosome evolution in flatfish and the formation of metacentric and submetacentric chromosomes in Senegalese sole. This study was funded by project RTA2017-00054-C03-01, RTA2017-00054-C03-02 and RTA2017-00054-C03-03 funded from MCIU/AEI/FEDER, UE. IGC is funded by a predoctoral fellowship from INIA

The present study investigated the effects of nutritional programming through parental feeding on offspring performance and expression of selected genes related to stress resistance in a marine teleost. Gilthead seabream broodstock were fed diets containing various fish oil (FO)/vegetable oil ratios to determine their effects on offspring performance along embryogenesis, larval development and juvenile on-growing periods. Increased substitution of dietary FO by linseed oil (LO) up to 80 % LO significantly reduced the total number of eggs produced by kg per female per spawn. Moreover, at 30 d after hatching, parental feeding with increasing LO up to 80 % led to up-regulation of the fatty acyl desaturase 2 gene (fads2) that was correlated with the increase in conversion rates of related PUFA. Besides, cyclo-oxygenase 2 (cox2) and TNF-α (tnf-α) gene expression was also up-regulated by the increase in LO in broodstock diets up to 60 or 80 %, respectively. When 4-month-old offspring were challenged with diets having different levels of FO, the lowest growth was found in juveniles from broodstock fed 100 % FO. An increase in LO levels in the broodstock diet up to 60LO raised LC-PUFA levels in the juveniles, regardless of the juvenile’s diet. The results showed that it is possible to nutritionally programme gilthead seabream offspring through the modification of the fatty acid profiles of parental diets to improve the growth performance of juveniles fed low FO diets, inducing long-term changes in PUFA metabolism with up-regulation offads2expression. The present study provided the first pieces of evidence of the up-regulation of immune system-related genes in the offspring of parents fed increased FO replacement by LO.

Hydroxyproline (L-Hyp) is amply present in fishmeal but limited in plant-protein sources. This study was conducted to evaluate the effects of supplementation with dietary L-Hyp on the distribution of collagen types in the muscle, and on the texture, survival rate, growth rate, feed utilization, body composition as well as the expression of the gene that encodes the pro-alpha2 chains of type I collagen (Col Iα2) of large European sea bass (initial body weight 609.21 ± 75.39 g) from high plant-protein diets. Four isoproteic (42 % crude protein) and isolipidic (20 % crude lipid) experimental diets were formulated adding 0.6 (HL diet), 1.2 (HM diet), and 2% (HH diet) L-Hyp, respectively. Three periods of feeding of 45, 99 and 143 days were studied. L-Hyp supplementation at 1.2 % and 2 % significantly improved specific growth rate (SGR) and feed conversion ratio (FCR). In the white muscle, type I, IV collagen and trichromic stain were significantly higher in HH feed than the control diet. In the red muscle, only type I collagen was higher. HH diet, also increases Col Iα2 mRNA levels in muscle significantly. It can be concluded that the addition of crystalline l-Hyp at 1.2 % or 2 % in high plant-protein diets indicates positive effects on growth performance of adult European sea bass and increase in muscle total collagen deposition. info:eu-repo/semantics/publishedVersion

Modern aquaculture feeds tend to contain lower levels of fish based ingredients, while increasing the content of plant ingredients. However, this may alter the vitamin profile of the feeds, leading to unbalanced vitamin supply. Requirements for several vitamins have been established for species such as carps and salmonids, but adequate levels for gilthead sea bream are yet unknown. Vitamin D is mainly involved in Ca homeostasis by regulating Ca uptake and liberation from bone intervening in bone remodeling. Fish are unable to synthesize vitamin D and so require absorbing it directly from the diet, thus, it is considered essential for fish. A practical plant-based diet containing 10% fish meal and 6% fish oil containing five levels of vitamin D3 (0.15, 0.43, 0.50, 0.55 and 0.65 mg kg− 1 or 5.8, 17.0, 20.0, 22.0 and 26.0 IU g− 1 ) were formulated to identify the optimum levels for gilthead seabream juveniles. Feeding juveniles of gilthead seabream with a range of vitamin D3 levels between 5.8 and 26.0 IU g− 1 for 70 days did not markedly alter growth. Increase dietary vitamin D3 significantly raised the liver contents in vitamin D3 in a dose-dependent manner following a potential regression. Increased dietary vitamin D3 levels up to 11.6 IU g− 1 may reduce the incidence of skeletal anomalies, particularly caudal and maxillary anomalies, whereas further elevation of dietary vitamin D3 levels increased the concentration of vitamin D3 in liver as well as skeletal anomalies in association to the up-regulation of alp and bmp2 gene expression. The occurrence of myocarditis signs in fish fed vitamin D3 levels of 20.0 IU g− 1 or more denote the toxic effects of these dietary levels. These results, together with the increased occurrence of skeletal anomalies in seabream fed the highest dietary vitamin D3 levels, suggest initial signs of hypervitaminosis D. Thus, the recommended level for vitamin D3 for gilthead seabream juveniles fed diets containing high levels of plant ingredients was suggested to be 11.6 IU g− 1.

Genetic selection programmes in gilthead seabream mainly focus on traits related to growth, disease resistance, skeletal anomalies, or fillet quality. However, the effect of selection for growth on the reproductive performance of seabream broodstock has not received much attention. The present study aimed to determine the effect of selection for growth traits, high (HG) or low (LG) growth, and broodstock feeding with fish oil (FO diet) or rapeseed oil (RO diet) as main lipid sources, on reproductive performance of gilthead seabream. For the first part of the spawning season (Phase I) HG and LG broodstock were fed a commercial diet and the HG broodstock produced a higher number of larvae and higher viable eggs, hatching and larval survival rates than LG broodstock, affecting egg fatty acid profiles. For the second part of the study (Phase II) broodstock were fed one of the two diets containing FO or RO. Fecundity in terms of viable eggs, hatchlings, and larvae produced, as well as fertilization rates, were improved in HG broodstock. Some fatty acids such as 18:0, 20:2n-6, 20:3n-3 or EPA/ARA were also affected by the growth selection. According to the two-way ANOVA analysis, feeding the RO diet did not significantly affect fecundity parameters, but slightly reduced fertilization and hatching rates in HG broodstock. Nevertheless, HG broodstock showed better spawning quality parameters than LG broodstock, even when they were fed the RO diet. Egg fatty acid profiles reflected diet composition, although DHA contents were not affected. In conclusion, broodstock selected for high growth had a positive effect on broodstock performance, and FO replacement by RO did not markedly affect reproduction providing that fatty acid contents were sufficient to fulfill the essential fatty acid requirements of gilthead seabream broodstock.

The present work investigated how the combination of poultry oil with microalgae oils, rich in eicosapentaenoic acid and docosahexaenoic acid (ED diets) or n-6 docosapentaenoic acid and n-3 docosahexaenoic acid (DD diets) modulates hepatic lipid metabolism in gilthead sea bream juveniles. Diets were tested using two different fishmeal contents (15% and 7.5%) and compared against a fish oil-based diet (CTRL) and two negative control diets based on poultry oil as lipid source (PO diets). After 74 days of feeding, sea bream fed 15% FM ED or DD diets showed similar daily growth index to those fed CTRL, while those fed PO diets caused reduced growth. Fish livers reflected the highest contents in n-3 long-chain polyunsaturated fatty acids when fed CTRL, ED or DD diets, which down-regulated fas, scd-1a, fads2, lpl and cpt1, reducing hepatic lipid accumulation and hepatocytes size. In contrast, fish fed PO diets showed the lowest deposition of n-3 long-chain polyunsaturated fatty acids and the highest oleic acid in liver, leading with the highest hepatosomatic index due to increased liver lipids. Therefore, these fish revealed a severe hepatic steatosis associated with an increased expression of lipogenesis-related genes, particularly fas, lpl and sbrep1. Furthermore, PO diets seemed to activate desaturation pathways in fish livers, reflected by the highest accumulation of fatty acids that are products from desaturases and the highest fads2 and scd-1a expressions. The reduction of the dietary fishmeal content to 7.5% lowered fish growth, although hepatic lipid metabolism seemed to be more affected by FO replacement than FM replacement. Combining microalgae with poultry oil could be an alternative lipid and essential fatty acid source to fish oil in marine fish diets.

© 2021 The Authors., In this study, a total of 18 novel productive traits, three related to carcass [cNiT] and fifteen related to morphometric [mNiT]), were measured in gilthead seabream (Sparus aurata) using Non-invasive Technologies (NiT) as implemented in IMAFISH_ML (MatLab script). Their potential to be used in industrial breeding programs were evaluated in 2348 offspring reared under different production systems (estuarine ponds, oceanic cage, inland tank) at harvest. All animals were photographed, and digitally measured and main genetic parameters were estimated. Heritability for growth traits was medium (0.25–0.37) whereas for NiT traits medium-high (0.24–0.61). In general, genetic correlations between mNiT, cNiT and growth and traits were high and positive. Image analysis artifacts such as fin unfold or shades, that may interfere in the precision of some digital measurements, were discarded as a major bias factor since heritability of NiT traits after correcting them were no significantly different from original ones. Indirect selection of growth traits through NiT traits produced a better predicted response than directly measuring Body Weight (13–23%), demonstrating that this methodological approach is highly cost-effective in terms of accuracy and data processing time., This study was funded from the European Maritime and Fisheries Fund (EMFF) by Ministerio de Agricultura y Pesca, Alimentación y Medio Ambiente (MAPAMA), framed in PROGENSA-II III project (Mejora de la Competitividad del Sector de la Dorada a Través de la Selección Genética, programa JACUMAR).

Simple Summary The present study was on the gene expression of a rate-limiting enzyme in long chain polyunsaturated fatty acids (LC-PUFAs), fatty acyl desaturase 2 (fads2), throughout the embryonic development of a gilthead sea bream. The results showed a maternal transfer of fads2 mRNA to the developing oocyte. The embryonic fads2 expression might start after the neurula stage. No effect was found in fads2 expression in developing eggs from broodstock fed with a diet rich in rapeseed oil or fish oil. The present study provides information on the change of LC-PUFA biosynthesis during embryogenesis. Abstract Previous studies have shown that it is possible to increase the ability of marine fish to produce long-chain polyunsaturated fatty acid from their 18C precursors by nutritional programming or using broodstock with a higher fatty acyl desaturase 2 (fads2) expression. However, those studies failed to show the effect of these interventions on the expression of the fads2 gene in the developing egg. Moreover, there were no studies on the temporal expression of the fads2 during ontogeny in the gilthead sea bream (Sparus aurata). In order to determine the changes in expression of fads2 during ontogeny, gilthead sea bream broodstock with a high (HRO) or low (LRO) fads2 expression fed a diet previously used for nutritional programming, or a fish oil-based diet (LFO) were allowed to spawn. The samples were taken at the stages of spawning, morula, high blastula, gastrula, neurula, heart beating, hatch and 3 day-old first exogenous feeding larvae to determine fads2 expression throughout embryonic development. The results showed the presence of fads2 mRNA in the just spawned egg, denoting the maternal mRNA transfer to the developing oocyte. Later, fads2 expression increased after the neurula, from heart beating until 3-day-old larvae, denoting the transition from maternal to embryonic gene expression. In addition, the eggs obtained from broodstock with high fads2 expression showed a high docosahexaenoic acid content, which correlated with the downregulation of the fads2 expression found in the developing embryo and larvae. Finally, feeding with the nutritional programming diet with the partial replacement of fish oil by rapeseed oil did not affect the long chain polyunsaturated fatty acid (LC-PUFA) contents nor fads2 expression in the gilthead sea bream developing eggs.

The principle aim of this study is to elucidate the relationship between the fatty acid desaturase 2 gene (fads2) expression pattern in peripheral blood cells (PBCs) and liver of gilthead seabream (GSB), Sparus aurata broodstock in order to determine the possible use of fads2 expression as a potential biomarker for the selection of broodstock. This selection could be utilized for breeding programs aiming to improve reproduction, health, and nutritional status. Passive Integrated Transponder (PIT)-tagged GSB broodstock (Male-1.22 &plusmn, 0.20 kg, 44.8 &plusmn, 2 cm and female-2.36 &plusmn, 0.64 kg, 55.1 cm) were fed a diet containing low levels of fish meal and fish oil (EPA 2.5, DHA 1.7 and n-3 LC-PUFA 4.6% TFA) for one month. After the feeding period, fads2 expression in PBCs and liver of both male and female broodstock were highly significantly correlated (r = 0.89, p &lt, 0.001). Additionally, in male broodstock, liver fads2 expression was significantly correlated (p &lt, 0.05) to liver contents in 16:0 (r = 0.95, p = 0.04) and total saturates (r = 0.97, p = 0.03) as well as to 20:3n&ndash, 6/20:2n&ndash, 6 (r = 0.98, p = 0.02) a Fads2 product/precursor ratio. Overall, we found a positive and significant correlation between fads2 expression levels in the PBCs and liver of GSB broodstock. PBCs fads2 expression levels indicate a strong potential for utilization as a non-invasive method to select animals having increased fatty acid bioconversion capability, better able to deal with diets free of fish meal and fish oil.

The negative effects of oxidative damage on larval development, growth and survival are among the factors markedly affecting marine fish larvae production success. Whereas α-tocopherol (vit E) and l -ascorbic acid (vit C) are strong antioxidants, the potential antioxidant role of taurine (Tau) in fish diets and its relation with other antioxidant nutrients needs further clarification. The present study aimed to determine the potential interactions between the dietary levels of vit E plus vit C and Tau on survival, growth, bone development and oxidative metabolism in gilthead seabream larvae. Six micro-bound diets containing two levels of Tau combined with three levels of vit E plus vit C were manually fed 24 times/day to 16 dph larvae for 15 days. Elevation of dietary vit E and vit C over 3000 mg/kg, led to unbalanced body vit C/vit E ratio and up-regulation of genes coding for antioxidant enzymes, the highest incidence of bone anomalies and the lowest larval survival. Increase in dietary vit C + vit E up to 1800 mg/kg, down-regulated GPX expression, up-regulated OC expression and reduced maxillary bone anomalies. Increase in dietary Tau up to 7.1 g/kg significantly improved larval growth, down-regulated antioxidant enzyme genes and reduced the incidence of bone anomalies. Moreover, the pro-oxidative effects of the high supplementation of vit C and E where mitigated by increase in dietary Tau levels. Finally, increase in dietary vit E, vit C and Tau up to 1783 mg/kg, 1921 mg/kg and 7 g/kg lead to the highest larval survival and growth, the highest OC gene expression and the lowest incidence of bone anomalies, including lordosis, kyphosis, branchiostegal and maxillary bones anomalies.

Nutrition during periconception and early development can modulate metabolic routes to prepare the offspring for adverse conditions through a process known as nutritional programming. In gilthead sea bream, replacement of fish oil (FO) with linseed oil (LO) in broodstock diets improves growth in the 4-month-old offspring challenged with low-FO and low-fishmeal (FM) diets for 1 month. The present study further investigated the effects of broodstock feeding on the same offspring when they were 16 months old and were challenged for a second time with the low-FM and low-FO diet for 2 months. The results showed that replacement of parental moderate-FO feeding with LO, combined with juvenile feeding at 4 months old with low-FM and low-FO diets, significantly (Pα-linolenic acid and linoleic acid in broodstock diets lead to a significant down-regulation of hepatic lipoprotein lipase (PPn-3, 18 : 3n-6, 20 : 5n-3, 22 : 6n-3 and 22 : 5n-6. Thus, this study demonstrated the long-term nutritional programming of gilthead sea bream through broodstock feeding, the effect of feeding a ‘reminder’ diet during juvenile stages to improve utilisation of low-FM/FO diets and fish growth as well as the regulation of gene expression along the fish’s life-cycle.

The main objective of this study was to assess the effects of graded levels of replacement of fishmeal (FM) and fish oil (FO) by terrestrial meals (TM) and vegetable oils (VO) on gut health of European sea bass (Dicentrarchus labrax) based on gut morphology, gut-associated immune system (GALT) and gut microbiota composition. Reducing the dietary FM and FO levels down to 10 and 3%, respectively did not affect the growth of European sea bass. Increase in TM and VO markedly affected anterior and posterior gut morphology and fatty acid composition, which mirrored the dietary fatty acid profile. FO replacement by VO increased lipid deposition in anterior gut lamina propria, denoting an effect in lipid metabolism and lipoprotein synthesis. In posterior gut, FM replacements by TM induced an engrossment of the submucosa, an up-regulation of the proinflammatory cytokines IL-1β and TNFα genes, a relatively high mucus production and changes in mucosal microbiota profiles. Finally, supplementation of 0%FM-0%FO diets with LC-PUFA contributed to maintain gut homeostasis in terms of GALT response and microbiota profiles alterations. Statement of relevance FM and FO appropriate dietary levels for European seabass

Environmental factors such as nutritional interventions during early developmental stages affect and establish long-term metabolic changes in all animals. Diets used during the spawning period causes a nutritional programming effect in offspring of gilthead sea bream and affects long-term metabolism. Studies showed modulation of genes such as fads2 which is considered to be a rate-limiting step in the synthesis of n-3 long chain polyunsaturated fatty acids (n-3 LC-PUFA). However, it is still unknown whether this adaptation is related to the presence of precursors or limitations in the pre-formed products, n-3 LC-PUFA, contained in the diets used during nutritional programming. This study investigates the combined effects of nutritional programming through broodstock diets during the spawning period and broodfish showing higher or lower fads2 expression levels in the blood after 1-month feeding with a diet containing high levels of plant protein sources and vegetable oils (VM/VO). Broodfish showing high fads2 expression had a noticeable improvement in the spawning quality parameters as well as on the growth of 6 months old offspring when challenged with a high VM/VO diet. Further, nutritional conditioning with 18:3n-3 rich diets had an adverse effect in comparison to progeny obtained from fish fed high fish meal and fish oil (FM/FO) diets, with a reduction in growth of juveniles. Improved growth of progeny from the high fads2 broodstock combined with similar muscle fatty acid profiles is an excellent option also for tailoring and increasing the flesh n-3 LC-PUFA levels to meet the recommended dietary allowances for human consumption.

Polyunsaturated fatty acids (PUFA) in parental diets play a key role in regulating n-3 LC-PUFA metabolism of the offspring. However, it is not clear whether this metabolic regulation is driven by the precursors presented in the diet or by the parental ability to synthesize them. To elucidate this, broodstocks of gilthead sea bream with different blood expression levels of fads2, which encodes for the rate-limiting enzyme in the n-3 LC-PUFA synthesis pathway, were fed either a diet supplemented with alpha-linolenic acid (ALA, 18:3n-3) or a control diet. The progenies obtained from these four experimental groups were then challenged with a low LC-PUFA diet at the juvenile stage. Results showed that the offspring from parents with high fads2 expression presented higher growth and improved utilization of low n-3 LC-PUFA diets compared to the offspring from parents with low fads2 expression. Besides, an ALA-rich diet during the gametogenesis caused negative effects on the growth of the offspring. The epigenetic analysis demonstrated that methylation in the promoter of fads2 of the offspring was correlated with the parental fads2 expression levels and type of the broodstock diet., This work has been (partly) funded under the EU Horizon 2020 programme by the PERFORMFISH project no. 727610: Consumer driven production: Integrating innovative approaches for competitive and sustainable performance across the Mediterranean aquaculture value chain.

Fish quality traits are important criteria for consumers in the commercial market as well as growth. In this study, flesh composition and morphology traits, in comparison with growth traits, were selected to study their additive genetic variation at harvest size, and their genetic and phenotypic correlations between different environments (cage and estuary). Flesh composition was measured by NIR and FFM technologies, while morphology was carried out by using image analysis with the IMAFISH_ML software. Heritability estimates ranged from low to medium (0.08–0.40) for growth, flesh composition and morphological traits. The genetic correlations were positive and high between growth traits (weight and SGR), negative and high between moisture versus lipids, negative and low for proteins vs. moisture and lipids, and high for morphological traits. At harvest size, GxE interactions were calculated from the same families cultured in cages and estuaries. The estimations were mainly high for all traits, suggesting a priori scarce GxE interaction. In conclusion, new technological traits showed additive variation components and genetic correlations between them and with growth traits.

Manganese (Mn) is an essential metal for fish and requirements have been established for several finfish but not for gilthead sea bream. Thus, the present study aims to establish the optimal dietary supplementation level of Mn in gilthead sea bream fingerlings fed vegetable based diets. Gilthead sea bream fingerlings (weight 12.6 ± 1.5 g, mean ± S.D.) were fed five practical diets high in vegetable ingredients (fish meal: 10%, fish oil: 6%). The diets were supplemented to contain 19, 27, 30, 41 and 66 mg Mn kg−1 as MnSO4. Four hundred and fifty sea bream fingerlings were randomly distributed in 15 tanks and fed one of the five diets until apparent satiation three times per day for 42 days. Growth parameters including feed intake, thermal growth coefficient and feed conversion ratio were calculated. At the end of the trial, samples were taken for biochemical, mineral, histological and gene expression analyses. After the feeding trial, fish almost tripled their weight, but dietary Mn levels did not affect growth parameters or survival. The high fish meal substitution levels led to high Mn contents in the basal diet (19 mg Mn kg−1 diet), that seemed to be sufficient to promote sea bream growth. Body lipid composition, protein and ash were not affected by the dietary Mn. Similarly, whole body, liver and vertebrae mineral contents were not affected by Mn supplementation. Morphological characteristics of liver had no significant differences among dietary Mn levels. However, increase of Mn contents beyond 30 mg Mn kg−1 down-regulated mnsod expression. Expression of cat gene was not affected. Overall, results suggest that the Mn content present in the basal diet (19 mg Mn kg−1) was sufficient to cover the requirements in juvenile gilthead sea bream fed practical plant-based diets, although results from oxidative status markers might point out the need to increase supplementation levels beyond this point when fish are under conditions that may affect their oxidative status.

Nutritional intervention with vegetable oils (VO) supplemented to fish broodstock diets enhances progeny ability to utilize low fish meal (FM) and fish oil (FO) diets. However, the intervention with vegetable meals (VM) in broodstock diets has been scarcely tested in marine fish. This study aims to determine the effect of FM replacement by VM alone or in combination with FO replacement by VO as a programming tool. Different broodstocks of gilthead sea bream were fed one of three diets: one contained 35% FM and 10% FO, another contained VM in replacement of FM (FM: 15%) or a third one had both VM and VO in replacement of FM and FO (15% FM and 2.7% FO). At the weight of 3 g, their offspring were challenged with a low FM (5%) and FO (3%) diet for 45 days. FM replacement by VM in broodstock diets did not affect fish reproductive performance but in offspring juveniles reduced growth and feed efficiency and in liver, altered fatty acids profiles and down-regulated fatty acyl desaturase 2 (fads2) expression. Combined supplementation of VM and VO in broodstock diets led to a poor reproductive performance, reducing female fecundity and the egg content in eicosapentaenoic acid (EPA) and docosahexanoic acid (DHA). At molecular level, the expression of fads2 and target of rapamycine (tor) genes in the eggs were upregulated. Similarly, in liver of juvenile progenies fads2 and elongase of very long chain fatty acids 6 (elovl6) expression were up-regulated, whereas fads2 expression was correlated to sterol regulatory element-binding protein transcription factor 1 (srebp1). However, methylation rates of CpG rich regions in fads2 promoter were not significantly different among juvenile groups. Thus, the replacement of FM by VM, alone or in combination with FO in diets for gilthead sea bream broodstock negatively affected growth performance of juvenile offspring, whereas the replacement of FO by VO enhanced the fatty acid desaturase and elongase activities in the offspring, especially when juveniles were fed a diet with a high replacement of FM and FO by VM and VO.

The complete removal of fishmeal (FM) and fish oil (FO) is required to promote the sustainable development of aquaculture and for that, fast growing high quality fish that are fed without FM and FO are necessary. Early nutritional programming may allow the production of fish better adapted to utilize diets with vegetable meals (VM) and oils (VO). The main objective of this study was to research in the potential value of fatty acids as modulators of early nutritional programming in marine fish for a better utilization of VO/VM. For that purpose gilthead sea bream (Sparus aurata) broodstock were fed four different replacement levels of FO by linseed oil (LO) and their effect on fecundity and spawn quality, egg composition, Δ-6-desaturase (Δ6D) gene expression, progeny growth performance and their growth response to a challenge with diets low in FO and FM, but high in VO and VM. The results showed that feeding gilthead sea bream broodstock with high LO diets had very long-term effects on the progeny. Thus, FO replacement by LO up to 80–100% in broodstock diets for gilthead sea bream not only reduced fecundity and spawn quality, but also growth of 45 dah and 4-month-old juveniles, as well as Δ6D gene expression. However, when the 4 month-old juveniles were fed with a low FM and FO diet, even those from broodstock fed only 60% replacement of FO by LO showed a higher growth and feed utilization than juveniles from parents fed FO. These results demonstrate the interesting potential of early nutritional programming of marine fish by broodstock feeding to improve long-term performance of the progeny. Further studies are being conducted to determine optimum nutrient levels in the broodstock diets and the molecular mechanisms implied to develop effective nutritional intervention strategies for this species. Statement of relevance This study demonstrates for the first time in fish the potential of broodstock nutrition to conduct early nutritional programming of culture fish for a better utilization of low fish meal and fish oil diets by the progeny, showing its effect not only during reproduction and larval development but also during on-growing.

The presence of skeletal deformities in farmed fish is a major problem affecting aquaculture industry. In this study, the first QTL analysis for three of the most frequent deformities in gilthead seabream ( Sparus aurata L.) is reported. A F1 full-sibling family consisting of 152 fish was genotyped by using a set of 13 multiplex PCRs (ReMsa1–ReMsa13). This PCR includes 106 microsatellite markers from the genetic map of this species. For vertebral fusion, one significant QTL (located in linkage group LG 21) and two suggestive QTL (located in LG4 and LG13, respectively) were detected. For lordosis, one significant QTL (located in LG9) at chromosome and genome-wide level and one suggestive QTL (located in LG22) were detected. For jaw deformity, one significant QTL (located in LG13) and one suggestive QTL (located in LG16) were detected. The percentages of variance explained by the QTL effect ranged from 1.6 to 11.4%. Hd-46-T was the closest-to-vertebral-fusion-significant-QTL microsatellite marker and showed a statistical association between male allelic segregation and phenotype. CId-26-H and CId-03-F were the two closest-to-jaw-deformity-significant-QTL microsatellite markers and showed a statistical association with female allelic segregation. Considering these results can help to decrease the prevalence of these deformities in future by Marker Assisted Selection breeding and to solve one of the most important aquaculture industry problems. However, additional analyses in other gilthead seabream families are needed in order to confirm these QTL. Statement of relevance The results of the present study show the first QTL identified for skeletal deformities in gilthead seabream, which could help to decrease these deformity prevalence. These results, although in preliminary way, could help to solve one of the most important aquaculture industry problems.

The concept of nutritional programming raises the interesting possibility of directing specific metabolic pathways or functions in juvenile fish, for example, to improve the use of substitutes to fishmeal and oil, and hence to promote sustainability in aquaculture. The aim of the study was to determine effects of early nutritional stimuli of gilthead seabream larvae and check if nutritional programming of gilthead sea bream is possible between 16 days post hatching (dph) and 26 dph. A trial was conducted to determine the effects of early nutritional stimuli of gilthead seabream larvae. Five experimental microdiets (pellet size

The decreased availability of fish oil, traditionally used as oil source in marine aquafeeds, has lead to the search for alternatives oils. Vegetable oils (VO) are being extensively used as lipid sources in marine fish diets, inducing an imbalance on certain dietary fatty acids. Alteration on the dietary ratio of w-6/w-3 has been described to have detrimental effects on fish immunity. Senegalese sole has high susceptibility to stress and diseases, and little is known on the effects of dietary VO on its immunity. In this study, Senegalese sole juveniles were fed diets (56% crude protein, 12% crude lipid) containing linseed (100LO), soybean (100SO) or fish (100FO) oils as unique oil source. Growth, cortisol and intestinal fatty acid composition were determined after 90 days. Moreover, at the final of the experiment a stress test (5 min of net chasing) was carried out. To evaluate the effect of diets and stress on intestine immunology, expression profiles of a set of 53 immune-related genes using RT-qPCR was also performed. The use of VO did not induced changes in fish growth, but affected fatty acid profile of intestine and expression of immune-related genes. The use of SO (rich in n-6 fatty acids) induced an over-expression of those genes related to complement pathway, recognizing pathogen associated to molecular patterns, defensive response against bacteria, defensive response against viruses, antigen differentiation, cytokines and their receptors. This general over-expression could indicate an activation of inflammatory processes in fish gut. When a stress was applied, a decrease of mRNA levels of different immune-related genes with respect to the unstressed control could be observed in fish fed 100FO. However, fish fed 100LO, with a higher ALA/LA ratio, seemed to ameliorate the effects of combined effects of FO substitution plus stressful situation whereas fish fed 100SO did not show this type of response.

Summary One of the most important problems of fish aquaculture is the high incidence of fish deformities, which are mainly skeletal. In this study, genetic parameters on gilthead seabream (Sparus aurata L.) for skeleton deformities at different ages (179, 269, 389, 539 and 689 days) and their correlations with growth traits were estimated, as were as their genotype × environment interactions (G × E) at harvesting age. A total of 4093 offspring from the mass spawning of three industrial broodstocks belonging to the PROGENSA® breeding programme were mixed and on-grown by different production systems in four Spanish regions: Canary Islands (tanks and cage), Andalusia (estuary), Catalonia (cage) and Murcia (cage). Parental assignment was inferred using the standardized SMsa1 microsatellite multiplex PCR. From three broodstocks, 139 breeders contributed to the spawn and a total of 297 full-sibling families (52 paternal and 53 maternal half-sibling families) were represented. Heritabilities at different ages were medium for growth traits (0.16–0.48) and vertebral deformities (0.16–0.41), and low for any type of deformity (0.07–0.26), head deformities (0.00–0.05) and lack of operculum (0.06–0.11). The genetic correlations between growth and deformity traits were medium and positive, suggesting that to avoid increasing deformities they should be taken into account in breeding programmes when growth is selected. The G × E interactions among the different facilities were weak for length and deformity and strong for growth rate during this period. These results highlight the potential for the gilthead seabream industry to reduce the prevalence of deformities by genetic improvement tools.

Substituting fishmeal (FM) with vegetable meal (VM) can markedly affect the mineral composition of feeds, and may require additional mineral supplementation. Their bioavailability and optimal supplementation levels depend also on the form of delivery of minerals. The aim of the study was to determine the effect of different delivery forms of three major trace elements (Zn, Mn and Se) in a marine teleost. Gilthead sea bream juveniles of 22.5 g were fed a VM-based diet for 12 weeks that was either not supplemented with these minerals or supplemented with inorganic, organic, or encapsulated inorganic forms of minerals in triplicate and compared to a FM-based diet. Our results showed that mineral delivery form significantly affected the biochemical composition and morphology of posterior vertebrae. Supplementation of VM-based diets with inorganic forms of the target minerals significantly promoted growth, increased the vertebral weight and content of ash and Zn, enhanced bone mineralization and affected the vertebral shape. Conversely, encapsulation of inorganic minerals reduced fish growth and vertebral mineral content, whereas supplementation of organic minerals, enhanced bone osteogenesis by upregulating bone morphogenetic protein 2 (bmp2)gene and produced vertebrae with a larger length in relation to height. Furthermore, organic mineral forms of delivery downregulated the expression of oxidative stress related genes, such as Cu/Zn superoxide dismutase (Cu/Znsod) and glutathione peroxidase 1 (gpx-1),suggesting thus that dietary minerals supplemented in the organic form could be reasonably considered more effective than the inorganic and encapsulated forms of supply.

The aim of this study was to assess the effects of low levels of dietary fish meal (FM) and fish oil (FO) on disease resistance and gut associated lymphoid tissue (GALT) response after an experimental intestinal infection with V. anguillarum in European sea bass (Dicentrarchus labrax) For that purpose, sea bass juveniles were fed one of four diets containing combined levels of FO and FM as follows: 20%FM/6%FO, 20%FM/3%FO, 5%FM/6%FO and 5%FM/3%FO during 153 days. At the end of the feeding trial, fish were subjected to either an in vivo exposure to a sub-lethal dose of V. anguillarum via anal inoculation or to an ex vivo exposure to V. anguillarum. Additionally, inducible nitric oxide synthase (iNOS) and tumor necrosis factor α (TNFα) gut patterns of immunopositivity were studied. Growth performance was affected by dietary FM level, however ex vivo gut bacterial translocation rates and survival after the in vivo challenge test were affected by dietary FO level. After 5 months of feeding, low dietary FM levels led to a posterior gut up-regulation of interleukin-1β (IL-1β) and TNFα, major histocompatibility complex-II (MHCII) and cyclooxygenase-2 (COX2), which in turn reduced the gut associated lymphoid tissue (GALT) capacity of response after 24 h post infection and conditioned European sea bass capacity to recover gut homeostasis 7 days post infection. Immunoreactivity to anti-iNOS and anti-TNFα presented a gradient of increased immunopositivity towards the anus, regardless of the dietary FM/FO fed. Strong positive anti-TNFα isolated enterocytes were observed in the anterior gut in relation to low levels of dietary FM/FO. Submucosa and lamina propria immunoreactivity grade was related to the amount of leucocyte populations infiltrated and goblet cells presented immunopositivity to anti-iNOS but not to anti-TNFα. Thus, reducing FO content from 6% to a 3% by VO in European sea bass diets increases ex vivo and in vivo gut bacterial translocation rates, whereas reducing FM content from 20% down to 5% up-regulates the expression of several posterior gut inflammation-related genes conditioning fish growth and GALT capacity of response after bacterial infection.

The objective of the present study was to compare the effectiveness of dietary marine phospholipids (MPL) obtained from krill and soybean lecithin (SBL) on the rearing performance and development of seabream (Sparus aurata) larvae. Larvae were fed from 16 to 44 day posthatching (dph) five formulated microdiets with three different levels (50, 70 and 90 g kg–1) of phospholipids (PL) obtained either from an MPL or from a SBL source. Larvae-fed MPL show a higher survival, stress resistance and growth than those-fed SBL, regardless the dietary PL level. Overall, the increase in MPL up to 70 g kg–1 total PL in diet was enough to improve larval gilthead seabream performance, whereas even the highest SBL inclusion level (90 g kg–1 PL) was not able to provide a similar success in larval growth or survival. Inclusion of SBL markedly increased the peroxidation risk as denoted by the higher TBARs in larvae, as well as a higher expression of CAT, GPX and SOD genes. Moreover, SBL tends to produce larvae with a lower number of mineralized vertebrae and a lower expression of osteocalcin, osteopontin and BMP4 genes. Finally, increasing dietary MPL or SBL lead to a better assimilation of polyunsaturated fatty acids in the larvae, n-3HUFA (especially 20:5n-3) or n-6 fatty acids (especially 18:2n-6), respectively. In conclusion, MPL had a higher effectiveness in promoting survival, growth and skeletal mineralization of gilthead seabream larvae in comparison with SBL.

Although dietary marine phospholipids are able to improve culture performance of marine fish larvae in a further extend than soybean lecithin, both types of phospholipids (PL) markedly increase oxidative risk. The inclusion of a fat-soluble antioxidant such as the vitamin E α-tocopherol could allow a better control of oxidative stress. The objective of this study was to determine the combined effect of graded levels of α-tocopherol with different levels and sources of krill phospholipids (KPL) and soybean lecithin (SBL) on growth, survival, resistance to stress, oxidative status, bone metabolism-related genes expression and biochemical composition of sea bream larvae. Sea bream larvae were completely weaned at 16 dph and fed for 30 days seven microdiets with three different levels of PL (0, 40 and 80 g kg−1 diet) and two of α-tocopherol 1500 and 3000 mg kg−1 diet. Sea bream larvae fed diets without PL supplementation showed the lowest survival, growth and stress resistance, whereas increase in PL, particularly KPL, markedly promoted larval survival and growth. However, feeding SBL markedly increased TBARs and GPX gene expression increasing the peroxidation risk in the larvae. Besides, KPL inclusion improved incorporation of n-3 HUFA and, particularly, EPA into larval tissues, these fatty acids being positively correlated with the expression of BMP-4, RUNX 2, ALP, OC and OP genes and to bone mineralization for a given larval size class. The increase in dietary α-tocopherol tends to improve growth in relation to the n-3 HUFA levels in the diet, denoting the protective role of this vitamin against oxidation. Indeed, dietary α-tocopherol decreased the oxidative stress in the larvae as denoted by the reduction in larval TBARs contents and gene expression of SOD and CAT, but not GPX. Thus, increase in dietary α-tocopherol effectively prevented the formation of free radicals from HUFA, particularly EPA, but did not affect the incidence of bone anomalies or the expression of genes related to osteogenetic processes.

The inclusion of complementary antioxidative factors, such as selenium (Se), could counteract the high oxidation risk in early weaning diets high in polyunsaturated fatty acids (PUFA). The present study investigated the effects of graded levels of Se derived yeast with krill phospholipids (KPL) on skeletal development, survival, stress resistance, oxidative status and biochemical composition of seabream larvae. Seabream larvae were completely weaned at 16 dph and fed five microdiets for 30 days with different levels of Se: 2SE, 4SE, 6SE, 8SE and 12SE (1.73, 3.91, 6.41, 8.47, 11.65 mg kg− 1 dietary dry weight, respectively). Increases in Se up to 11.65 mg kg− 1 dietary dry weight significantly improved survival rate (54%) and stress resistance, but did not affect larval growth. Seabream larvae fed diets supplemented with 12SE (11.65 mg kg− 1) showed a gradual increase in this mineral according to dietary Se levels, denoting the progressive absorption of this nutrient. The degree of larval lipid oxidation, as indicated by malondialdehyde (MDA) content and antioxidant enzyme (AOE) gene expression, was significantly lower in larvae fed 8SE and 12SE diets compared to those fed 2SE and 4SE diets. Furthermore, a reactive response as a result of Se inclusion was observed by the increase in osteocalcin, osteonectin, osteopontin, alkaline phosphatase and matrix gla protein gene expression in larval tissues, suggesting a well skeletal development. These results denoted the high efficiency of Se as an antioxidant factor and the importance of the inclusion of adequate levels (11.65 mg Se kg− 1 diet) in early weaning diets.

The lymphocystis disease (LCD) is a viral infection with a high economic impact in gilthead sea bream aquaculture. In this study, genetic estimates associated with lymphocystis disease virus (LCDV) disease susceptibility and growth were determined in sea bream juveniles. Two fish batches (named batch 1 and batch 2) were built from mass spawning and reared under industrial conditions until disease outbreak. At the moment of the sampling (n = 500 specimens for each batch), all animals had the typical LCDV lesions in the skin. For phenotyping, animals were weighted and photographed for image analysis (surface covered and lesion intensity). LCDV DNA copies were quantified in the liver by qPCR. Batch 1 had a higher surface covered and lesion intensity than batch 2, and the body caudal region was the lowest affected region in both batches. The average LCDV DNA copies in liver were higher in the batch 1 than batch 2, and they were positively correlated with severity index (SI) categories (r2 = 0.90&ndash, 0.94). The total number of families evaluated were 150 and 128 for batch 1 and batch 2, respectively, with a high bias in offspring contribution by family and broodstock. Heritabilities for weight and length were 0.18 and 0.14 in batch 1 and 0.06 and 0.05 in batch 2, respectively. Heritability for the number of viral DNA copies was low (&lt, 0.08) in both batches. Heritabilities for SI in binary scale were 0.32/0.33 and 0.21/0.24 (underlying liability/Bayesian approach) for batch 1 and batch 2, respectively. Genetic correlations were very high and positive when growth traits (weight and length) or disease traits (LCDV DNA copies and SI) were compared. In contrast, the genetic correlations between growth and disease traits were moderate&ndash, high and positive in the batch 1 but negative in batch 2. These results indicate the genetic selection for LCDV susceptibility and growth is feasible in sea bream juveniles, although estimates are highly dependent on the age. The information provided is relevant to designing selective breeding programs in sea bream.

The growth and consolidation of the gilthead seabream (Sparus aurata) industry require improvement based on permanent and cumulative aspects, such as those derived from genetic breeding programmes. Marker Assisted Selection (MAS) by Quantitative Trait Loci (QTL) can be usefully implemented with the appropriate tools. In this study, 138 microsatellite markers from the genetic map of gilthead seabream were redesigned to be amplified under the same PCR conditions. A final set of 13 multiplex PCRs (named ReMsa) with 106 of these markers was developed to cover 100% of the linkage groups. These effective multiplex PCRs enable to optimize QTL searching with a critical reduction in costs and errors. Results showed that the mean value of the number of alleles for 106 markers was 6.9. The mean observed heterozygosity ranged from 0.53 to 0.86, and 74.5% of markers were highly informative according to their polymorphic information content. The correct inheritance and segregation of alleles of each locus was confirmed after genotyping 62 individuals of a full-sib family by these multiplex PCRs. In addition, genetic features of the 20 microsatellite markers that worked correctly but were not included in any multiplex PCR are also reported to provide geneticists with the possibility of including them in more comprehensive screening studies.

The present study examined the short and mid-term effects of a rise in temperature from 18°C to 24°C on the expression of genes related to the stress response regulation in juveniles of Senegalese sole, Solea senegalensis. The animals were exposed to a temperature increase of 6°C, after 1month of acclimation at 18°C. After this process, samples of different tissues were collected from a total of 96 fish at four sampling points: 1h, 24h, 3days and 1week. The transcript levels of a set of genes involved in the stress response such as glucocorticoid receptors 1 and 2, corticotrophin-releasing factor, corticotrophin-releasing factor binding proteins, proopiomelanocortin A and B, and cellular stress defense (heat shock protein 70, 90AA and 90AB) were quantified at these sampling points. Additionally, blood samples were also taken to measure the circulating plasma cortisol concentration. Thermal stress induced by increasing temperature prompted an elevation of plasma cortisol levels in juvenile Senegalese sole after 1h as a short-term response, and a consecutive increase after one week, as a mid-term response. Senegalese sole seemed to respond positively in terms of adaptive mechanisms, with a rapid over-expression of grs and hsps in liver and brain, significantly higher after one hour post stress, denoting the fast and acute response of those tissues to a rapid change on temperature. The ratio hsp90/gr also increased 24h after thermal shock, ratio proposed to be an adaptive mechanism to prevent proteosomal degradation of GR. As a mid-term response, the elevation of brain crfbp gene expression one week after thermal shock could be an adaptive mechanism of negative feedback on HPI axis. Taken together, these data suggested an initial up-regulation of the glucocorticoid receptor complex linked genes in response to a temperature increase in Senegalese sole, with heat shock protein 90 potentially being a regulatory factor for the glucocorticoid receptor in the presence of cortisol.

The effect of two physical tagging systems, Visible Implant Elastomer (VIE) and Passive Integrated Transponder (PIT), was evaluated in red porgy (Pagrus pagrus) fingerlings, at different sizes. For VIE tagging, the weight classes were

In this study, heritabilities for body composition traits, their genetic correlations with growth traits and the genotype–environment interaction (G × E) were estimated at 509 days (harvest size) for the first time in gilthead seabream ( Sparus auratus L . ), from the offspring in two different production systems (cages and tanks) in the Canary Islands. A total of 867 offspring from an industrial mass-spawning of 66 broodstocks were analysed. Parental assignment showed a total of 89 full-sib families (between 1 and 53 descendents per family) and was inferred using the RimA multiplex PCR designed by Navarro et al. (2008) [Navarro, A., Badilla, R., Zamorano, M.J., Pasamontes, V., Hildebrandt, S., Sanchez, J.J., Afonso, J.M., 2008. Development of two new microsatellite multiplex PCRs for three sparid species: gilthead seabream ( Sparus auratus L.), red porgy ( Pagrus pagrus L.) and redbanded seabream ( P. auriga , Valenciennes, 1843) and their application to paternity studies. Aquaculture 285, 30–37.] with 100% success. The G × E interaction was analysed in 61 families present in the two environments and was null for visceral fat and it cannot be excluded for flesh composition traits. The heritability for visceral fat, expressed as a percentage of body weight, was 0.50 ± 0.07. The heritabilities for flesh composition traits, expressed as a percentage of fresh muscle weight, were 0.05 ± 0.03 for fat, 0.09 ± 0.03 for moisture, 0.08 ± 0.03 for ash and 0.02 ± 0.01 for collagen. Genetic and phenotypic correlations among body composition traits were mainly low–medium, except for moisture vs. muscular fat (− 0.98 and −0.61, respectively), moisture vs. collagen (0.85 and 0.45, respectively), collagen vs. muscular fat (− 0.80 and −0.35, respectively), and dressing percentage vs. visceral fat (− 0.92 and −0.51 respectively). Genetic correlations between body composition traits and growth traits were low for weight and length except with collagen for which they were high, and, in general, they were medium–high for condition factor. All these phenotypic correlations were low. These data suggest that selection through growth would improve flesh texture, but could decrease muscular fat in the long term. The latter trait could be improved by selection through moisture which is the flesh composition trait with the highest heritability and is the easiest to measure. The data also suggest that the inclusion of visceral fat percentage in a selection programme would thwart the negative effect of fat concentrated in the visceral cavity and increase the dressing percentage.

In this study, for the first time on gilthead seabream (Sparus auratus L.), genetic parameters for growth and carcass traits were estimated at 509 days (harvest size), and for growth only at another three ages (130, 165 and 330 days). A total of 867 offspring from an industrial mass spawning of 66 broodstocks were analysed. Parental assignment was inferred using the RimA multiplex PCR designed by Navarro et al. [Navarro, A., Badilla, R., Zamorano, M.J., Pasamontes, V., Hildebrandt, S., Sanchez, J.J., Afonso, J.M., 2008. Development of two new microsatellite multiplex PCRs for three sparid species: Gilthead seabream (Sparus auratus L.), red porgy (Pagrus pagrus L.) and redbanded seabream (P. auriga, Valenciennes, 1843) and their application to paternity studies. Aquaculture 285, 30–37.] and 100% success was obtained. Seventeen dams and 11 sires contributed to the spawn and a total of 89 full-sib families (eight paternal half-sib families and 16 maternal half-sib families) were represented. The heritability estimates at harvest were 0.34 ± 0.06 for body weight, 0.33 ± 0.07 for fork length, 0.13 ± 0.04 for condition factor, 0.26 ± 0.06 for gutted body weight, 0.15 ± 0.04 for fillet weight, 0.31 ± 0.07 for dressing percentage, and 0.12 ± 0.03 for fillet percentage. For growth traits at different ages, heritabilities ranged from 0.28 to 0.34 for weight, from 0.27 to 0.35 for length, and from 0.05 to 0.13 for condition factor. At any age, the correlation between weight and length was close to one. Correlations for lengths or weights at two consecutive ages were also high but they decreased with increasing difference in age. Negative and medium genetic correlations between fillet percentage and growth traits (weight and length) were obtained, however these correlations were positive and high for fillet weight. These data suggest that direct selection of length, which is an easily measurable trait, also improves carcass traits. However, the inclusion of fillet percentage in breeding programmes is recommended due to the negative genetic correlation with length. These results highlight the potential for the gilthead seabream industry to improve its production not only through handling but also through the exploitation of additive genetic variation.

This study reports two new and highly informative multiplex PCRs of microsatellite markers, with redesigned interspecific primer sets for three sparid species: gilthead seabream (Sparus auratus L.), red porgy (Pagrus pagrus L.) and redbanded seabream (P. auriga, Valenciennes, 1843). The evaluation and validation of the two multiplex PCRs, named RimA and RimB (Redesigned Interspecific Multiplex), were carried out upon: 148 individual gilthead seabream (66 breeders of unknown gender, and 82 of their descendents obtained by mass-spawning), 37 red porgy and 125 redbanded seabream. From 15 and 12 redesigned microsatellite markers for RimA and RimB, respectively, the number of markers included in the final multiplex PCRs were 10 in RimA and 7 in RimB for gilthead seabream, 6 in each multiplex PCR for red porgy and 8 in RimA and 5 in RimB for redbanded seabream. The a priori combined parental exclusion probability for each multiplex in the three species was 0.999. For gilthead seabream, it was possible to assign each offspring to a single parent pair (100% success) using the exclusion method with at least seven microsatellite markers for each multiplex PCR. Null alleles were found only for marker PbMS2, through familial segregation, with a frequency similar to the expected one (0.09 vs 0.14). Results revealed that the multiplex reaction no more than one-sixth the cost of single reactions even when these reactions were performed in a unique run, and that genotyping errors were minimized due to automation. These robust multiplex PCRs will be a fundamental tool for the industry to introduce selection programs and to manage their broodstocks under industrial conditions.

Lack of operculum, a neurocranial deformity, is the most common external abnormality to be found among industrially produced gilthead seabream (Sparus aurata L.), and this entails significant financial losses. This study conducts, for the first time in this species, a quantitative trait loci (QTL) analysis of the lack of operculum. A total of 142 individuals from a paternal half-sibling family (six full-sibling families) were selected for QTL mapping. They had previously shown a highly significant association with the prevalence of lack of operculum in a segregation analysis. All the fish were genotyped for 106 microsatellite markers using a set of multiplex PCRs (ReMsa1-ReMsa13). A linear regression methodology was used for the QTL analysis. Four QTL were detected for this deformity, two of which (QTLOP1 and QTLOP2) were significant. They were located at LG (linkage group) nine and LG10 respectively. Both QTL showed a large effect (about 27%), and furthermore, the association between lack of operculum and sire allelic segregation observed was statistically significant in the QTLOP1 analysis. These results represent a significant step towards including marker-assisted selection for this deformity in genetic breeding programmes to reduce the incidence of the deformity in the species.

This study reports for the first time on European sea bass, Dicentrarchus labrax (L.), larvae, the effect of different levels of dietary arachidonic acid (ARA; 20:4n-6) on the expression of genes related to the fish stress response. Copies of mRNA from genes related to steroidogenesis [StAR (steroidogenic acute regulatory protein), c-Fos, and CYP11β (11β-hydroxylase gene)], glucocorticoid receptor complex [GR (glucocorticoid receptor) and HSP (heat shock proteins) 70 and 90) and antioxidative stress (catalase (CAT), superoxide dismutase (SOD), and glutathione peroxidase] were quantified. Eighteen day-old larvae were fed for 14 days with three experimental diets with increasing levels of ARA (0.3, 0.6 and 1.2 % d.w.) and similar levels of docosahexaenoic (22:6n-3) and eicosapentaenoic (20:5n-3) acids (5 and 3 %, respectively). The quantification of stress-related genes transcripts was conducted by One-Step TaqMan real time RT-PCR with the standard curve method (absolute quantification). Increase dietary levels of ARA induced a significantly (p

This study examines the utility of Passive Integrated Transponder (PIT) tagging system in fingerlings of gilthead seabream, Sparus auratus L. Two different body positions (abdominal, dorsal) and four weight classes (2–3 g, 3–4 g, 4–5 g, 5–8 g) were tested in three experiments. Tag loss rate, as well as its effect on growth and mortality rates, was determined. Times of handling and healing were also assessed. Fish tagged in the abdominal cavity showed a significantly lower tag loss rate (14%) than those given dorsal muscle implants (40%). No differences were found in growth within experiment between tagged and untagged fish, their final mean weight ranging between 6–39 g and 6–38 g, respectively. There was no difference in mortality between tagged and untagged fish at any position (0–3.4% and 0–2.1%, respectively). Fish smaller than 3 g suffered significantly higher mortality (14.3%), indicating that the PIT tags are not suitable for very small individuals. PIT retention rate was 100% above 4 g, irrespective of the personal expertise in tagging. Mean tag application time was 19 s per fish. Mean wound healing time was close to 20 days. Hence, these results showed that PIT tagging of gilthead seabream above 3 g is feasible because it does not affect growth or mortality.

The use of the fluorescent visible implant elastomer (VIE) tagging system in juvenile gilthead seabream, Sparus auratus L., between 7 and 18 g was examined. Four different colours (red, green, orange and yellow), three body positions (dorsal, lateral and caudal) and two orientations (horizontal and vertical) were tested. The mean tag application time for each fish was 15.7 +/- 0.32 s. There was no mortality associated with the method of tagging. The most visible tag colour was red. Injection orientation had a significant effect on length, width, fragmentation and fluorescent intensity of the tag. Horizontal tagging is recommended because of high fluorescent intensity, low fragmentation and for double tagging. There were no differences in growth between untagged controls and the VIE-tagged fish.

Immature gilthead sea bream (Sparus aurata L.) with a mean initial weight of 25.6 g were reared over 11 months to market size under different photoperiods: 16L:8D; 24L:0D and a control. Differences in final mean weight were significant between the three treatments (P

The aim of the present work was to evaluate the effectiveness of the use of refrigerated and frozen goat colostrum and commercial sheep colostrum in kids. Forty-five Canary Caprine Group kids were distributed in three groups ( n =15) according to the type of colostrum fed. The refrigerated and frozen colostrum were administered twice daily for 2 days, each kid receiving 5% of the body weight per feed. Both the refrigerated and frozen colostrum had the same IgG concentration before refrigerating or freezing. The commercial colostrum was administered according to the recommendations of the manufacturer. Blood samples were obtained from the kids (by jugular extraction) every 12 h from birth to the third day post-partum and two additional samples were taken at 15 and 30 days of life. The IgG concentration in the blood was measured by radial immunodifusion on agarose gel. At birth the kids were agammaglobulinemic. The peak IgG was at 24 h with frozen goat colostrum fed kids (25.47±19.89 mg/ml), 36 h for kids fed with refrigerated goat colostrum (15.84±5.91 mg/ml) while those fed commercial sheep colostrum peaked at 30 days (0.84±0.65 mg/ml). The birth weight is of great significance with regard to these results. In conclusion, kids fed only with commercial colostrum do not acquire the necessary immunity to protect them during the first month of life.