Lasting effects of butyrate and low FM/FO diets on growth performance, blood haematology/biochemistry and molecular growth-related markers in gilthead sea bream (Sparus aurata)

Four isoproteic/isolipidic plant protein-based diets were formulated to assess the lasting effects of feed additives and low fish meal (FM) and fish oil (FO) diet formulations on gilthead sea bream growth performance. FM was included at 23% in the control diet (D1) and at 3% in the other three diets (D2, D3, D4). Added oil was either FO (D1) or a blend of vegetable oils replacing 58% (D2) and 84% (D3, D4 diets) of FO. A commercial sodium butyrate preparation (NOREL, 70-BP) was added to the D4 diet at 0.4%. Each diet was allocated to triplicate groups of juvenile fish fed to satiety over an 8-month feeding trial (May-December). All fish grew efficiently from 15. g of initial body weight to 296-320. g with an overall feed efficiency (FE) of 0.95-1.01, although fish fed D3 and D4 diets showed transient growth impairments over the course of the first four weeks of the trial. Data on biometric indexes, whole body composition, haematology and blood biochemistry revealed a strong effect of sampling time in fish sampled at mid-summer (August) and late autumn (December). In contrast, the diet effect was mostly reduced to a few blood parameters. Low inclusion levels of FM reduced plasma haemoglobin levels (D2, D3), but these effects were reversed by butyrate supplementation (D4). The same phenomena occurred for total cholesterol with the highest circulating concentration of choline and IGF-I in fish fed the D4 diet during their summer growth spurt. At the transcriptional level, gene expression profiling of liver and skeletal muscle with a PCR-array of 87 growth markers provided additional evidence for an overall well-growth condition in all of the experimental groups. Up to 73 genes were found at detectable levels in the liver tissue, but only 13 were differentially expressed. Likewise, 84 genes were actively transcribed in the skeletal muscle, but only nine were differentially expressed in at least one experimental group. Butyrate supplementation reversed the up-regulated expression of inflammatory cytokines (TNFα) and muscle markers of cellular morphogenesis and protein breakdown (CDH15, CAPN3, PSMA5, PSMB1, UBE2N) in the muscle of fish fed the extreme D3 diet. These results support the use of low FM/FO diets alone or supplemented with feed additives, which have the potential to improve or reverse metabolic steady-states. Statement of relevance: Butyrate effect on low fish meal/fish oil diets.This study was funded by the European Union (ARRAINA, FP7-KBBE-2011-5-288925, Advanced research initiatives for nutrition and aquaculture) projects. Additional funding was obtained from the Spanish MINECO (MI2-Fish, AGL2013-48560) and from Generalitat Valenciana (PROMETEO FASE II-2014/085).Peer Reviewe

Targeting the Mild-Hypoxia Driving Force for Metabolic and Muscle Transcriptional Reprogramming of Gilthead Sea Bream (Sparus aurata) Juveniles

Reduced oxygen availability generates a number of adaptive features across all the animal kingdom, and the goal of this study was targeting the mild-hypoxia driving force for metabolic and muscle transcriptional reprogramming of gilthead sea bream juveniles. Attention was focused on blood metabolic and muscle transcriptomic landmarks before and after exhaustive exercise. Our results after mild-hypoxia conditioning highlighted an increased contribution of lipid metabolism to whole energy supply to preserve the aerobic energy production, a better swimming performance regardless of changes in feed intake, as well as reduced protein turnover and improved anaerobic fitness with the restoration of normoxia. On-growing juveniles of gilthead sea bream were acclimated for 45 days to mild-hypoxia (M-HYP, 40-60% O-2 saturation), whereas normoxic fish (85-90% O-2 saturation) constituted two different groups, depending on if they were fed to visual satiety (control fish) or pair-fed to M-HYP fish. Following the hypoxia conditioning period, all fish were maintained in normoxia and continued to be fed until visual satiation for 3 weeks. The time course of hypoxia-induced changes was assessed by changes in blood metabolic landmarks and muscle transcriptomics before and after exhaustive exercise in a swim tunnel respirometer. In M-HYP fish, our results highlighted a higher contribution of aerobic metabolism to whole energy supply, shifting towards a higher anaerobic fitness following normoxia restoration. Despite these changes in substrate preference, M-HYP fish shared a persistent improvement in swimming performance with a higher critical speed at exercise exhaustion. The machinery of muscle contraction and protein synthesis and breakdown was also largely altered by mild-hypoxia conditioning, contributing this metabolic re-adjustment to the positive regulation of locomotion and to the catch-up growth response during the normoxia recovery period. Altogether, these results reinforce the presence of large phenotypic plasticity in gilthead sea bream, and highlights mild-hypoxia as a promising prophylactic measure to prepare these fish for predictable stressful events.This work was financially supported by a grant from the European Commission of the European Union under the Horizon 2020 research infrastructure project AQUAEXCEL2020 (652831) to J.P-S. Additional funding was obtained by a Spanish MICINN project (Bream-AquaINTECH, RTI2018-094128-B-I00). J.A.M.-S. received a Postdoctoral Research Fellowship (Juan de la Cierva-Formacion, Reference FJCI-2014-20,161)

Skin mucus of gilthead sea bream (sparus aurata l.). protein mapping and regulation in chronically stressed fish

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Under control: how a dietary additive can restore the gut microbiome and proteomic profile, and improve disease resilience in a marine teleostean fish fed vegetable diets

[Background]: The constant increase of aquaculture production and wealthy seafood consumption has forced the industry to explore alternative and more sustainable raw aquafeed materials, and plant ingredients have been used to replace marine feedstuffs in many farmed fish. The objective of the present study was to assess whether plant-based diets can induce changes in the intestinal mucus proteome, gut autochthonous microbiota and disease susceptibility of fish, and whether these changes could be reversed by the addition of sodium butyrate to the diets. Three different trials were performed using the teleostean gilthead sea bream (Sparus aurata) as model. In a first preliminary short-term trial, fish were fed with the additive (0.8%) supplementing a basal diet with low vegetable inclusion (D1) and then challenged with a bacteria to detect possible effects on survival. In a second trial, fish were fed with diets with greater vegetable inclusion levels (D2, D3) and the long-term effect of sodium butyrate at a lower dose (0.4%) added to D3 (D4 diet) was tested on the intestinal proteome and microbiome. In a third trial, the long-term effectiveness of sodium butyrate (D4) to prevent disease outcome after an intestinal parasite (Enteromyxum leei) challenge was tested. [Results]: The results showed that opposed forces were driven by dietary plant ingredients and sodium butyrate supplementation in fish diet. On the one hand, vegetable diets induced high parasite infection levels that provoked drops in growth performance, decreased intestinal microbiota diversity, induced the dominance of the Photobacterium genus, as well as altered the gut mucosal proteome suggesting detrimental effects on intestinal function. On the other hand, butyrate addition slightly decreased cumulative mortality after bacterial challenge, avoided growth retardation in parasitized fish, increased intestinal microbiota diversity with a higher representation of butyrate-producing bacteria and reversed most vegetable diet-induced changes in the gut proteome. [Conclusions]: This integrative work gives insights on the pleiotropic effects of a dietary additive on the restoration of intestinal homeostasis and disease resilience, using a multifaceted approach.This work has been carried out with financial support from the European Union under grant projects ARRAINA (FP7-KBBE-2011-288,925) to JPS, MP and VK and ParaFishControl (H2020-634429) to ASB. Additional funding has been received from Spanish Ministry of Economy and Competitiveness (MINECO) project no. AGL2013- 48560-R to JPS and ASB, and Generalitat Valenciana (PROMETEOII/2014/085) to ASB. MCP was contracted under CSIC PIE project no. 201740E013 and MINECO FPDI-2013-15741, and IE under APOSTD/2016/037 grant by the “Generalitat Valenciana”.We acknowledge support by the CSIC Open Access Publication Initiative through its Unit of Information Resources for Research (URICI)

Tissue-Specific Orchestration of Gilthead Sea Bream Resilience to Hypoxia and High Stocking Density

Two different O-2 levels (normoxia: 75-85% O-2 saturation; moderate hypoxia: 42-43% O-2 saturation) and stocking densities (LD: 9.5, and HD: 19 kg/m(3)) were assessed on gilthead sea bream (Sparus aurata) in a 3-week feeding trial. Reduced O-2 availability had a negative impact on feed intake and growth rates, which was exacerbated by HD despite of the improvement in feed efficiency. Blood physiological hallmarks disclosed the enhancement in O-2-carrying capacity in fish maintained under moderate hypoxia. This feature was related to a hypo-metabolic state to cope with a chronic and widespread environmental O-2 reduction, which was accompanied by a differential regulation of circulating cortisol and growth hormone levels. Customized PCR-arrays were used for the simultaneous gene expression profiling of 34-44 selected stress and metabolic markers in liver, white skeletal muscle, heart, and blood cells. The number of differentially expressed genes ranged between 22 and 19 in liver, heart, and white skeletal muscle to 5 in total blood cells. Partial Least-Squares Discriminant Analysis (PLS-DA) explained [R2Y(cum)] and predicted [Q2Y(cum)] up to 95 and 65% of total variance, respectively. The first component (R2Y = 0.2889) gathered fish on the basis of O-2 availability, and liver and cardiac genes on the category of energy sensing and oxidative metabolism (cs, hif-1 alpha, pgc1 alpha, pgc1 beta, sirts 1-2-4-5-6-7), antioxidant defense and tissue repair (prdx5, sod2, mortalin, gpx4, gr, grp-170, and prdx3) and oxidative phosphorylation (nd2, nd5, and coxi) highly contributed to this separation. The second component (R2Y = 0.2927) differentiated normoxic fish at different stocking densities, and the white muscle clearly promoted this separation by a high over-representation of genes related to GH/IGF system (ghr-i, igfbp6b, igfbp5b, insr, igfbp3, and igf-i). The third component (R2Y = 0.2542) discriminated the effect of stocking density in fish exposed to moderate hypoxia by means of hepatic fatty acid desaturases (fads2, scd1a, and scd1b) and muscle markers of fatty acid oxidation (cpt1a). All these findings disclose the different contribution of analyzed tissues (liver >= heart > muscle > blood) and specific genes to the hypoxic- and crowding stress-mediated responses. This study will contribute to better explain and understand the different stress resilience of farmed fish across individuals and species

Somatotropic Axis Regulation Unravels the Differential Effects of Nutritional and Environmental Factors in Growth Performance of Marine Farmed Fishes

The Gh/Prl/Sl family has evolved differentially through evolution, resulting in varying relationships between the somatotropic axis and growth rates within and across fish species. This is due to a wide range of endogenous and exogenous factors that make this association variable throughout season and life cycle, and the present minireview aims to better define the nutritional and environmental regulation of the endocrine growth cascade over precisely defined groups of fishes, focusing on Mediterranean farmed fishes. As a result, circulating Gh and Igf-i are revitalized as reliable growth markers, with a close association with growth rates of gilthead sea bream juveniles with deficiency signs in both macro- or micro-nutrients. This, together with other regulated responses, promotes the use of Gh and Igf-i as key performance indicators of growth, aerobic scope, and nutritional condition in gilthead sea bream. Moreover, the sirtuin-energy sensors might modulate the growth-promoting action of somatotropic axis. In this scenario, transcripts of igf-i and gh receptors mirror changes in plasma Gh and Igf-i levels, with the ghr-i/ghr-ii expression ratio mostly unaltered over season. However, this ratio is nutritionally regulated, and enriched plant-based diets or diets with specific nutrient deficiencies downregulate hepatic ghr-i, decreasing the ghr-i/ghr-ii ratio. The same trend, due to a ghr-ii increase, is found in skeletal muscle, whereas impaired growth during overwintering is related to increase in the ghr-i/ghr-ii and igf-ii/igf-i ratios in liver and skeletal muscle, respectively. Overall, expression of insulin receptors and igf receptors is less regulated, though the expression quotient is especially high in the liver and muscle of sea bream. Nutritional and environmental regulation of the full Igf binding protein 1–6 repertoire remains to be understood. However, tissue-specific expression profiling highlights an enhanced and nutritionally regulated expression of the igfbp-1/-2/-4 clade in liver, whereas the igfbp-3/-5/-6 clade is overexpressed and regulated in skeletal muscle. The somatotropic axis is, therefore, highly informative of a wide-range of growth-disturbing and stressful stimuli, and multivariate analysis supports its use as a reliable toolset for the assessment of growth potentiality and nutrient deficiencies and requirements, especially in combination with selected panels of other nutritionally regulated metabolic biomarkers

Selection for growth is associated in gilthead sea bream (Sparus aurata) with diet flexibility, changes in growth patterns and higher intestine plasticity

Farmed gilthead sea bream (Sparus aurata) is able to grow efficiently with new feed formulations based on plant ingredients. Here, two experimental diets with standard and high inclusion levels of plant ingredients were formulated to assess the suited use of plant-based diets in fish with different growth genetic backgrounds. To pursue this issue, a long-term feeding trial (12-months) was conducted with fish (17 g initial body weight) of 16 families coming from the broodstock of PROGENSA project, that were grown communally in the IATS-CSIC experimental facilities. All fish in the study (2545) were PIT-tagged, and their pedigree was re-constructed with 96% success by using a SMsa1 multiplex of 11 microsatellites, which revealed the main parents contributions of 5 females and 6 males. Each diet was randomly assigned to replicate 3000 L tanks, gathering each replicate a similar family composition through all the feeding trial. Data on growth performance highlighted a strong ge- netic effect on growth trajectories, associated with enhanced growth during winter in fish selected for faster growth. No main dietary effects were found on growth rates or condition factor, and regression-correlation analyses of growth rates across families on both diets suggest that genome by diet interaction was weak, while genetic variation accounted for most of the growth phenotypic variation. Hepatosomatic index (HSI) and me- senteric fat index (MSI) of five families, covering the growth variability of the population, were regulated nu- tritionally and genetically, but without statistically significant genome by diet interactions. Fish from faster growing families showed shorter intestines after being fed the control diet, but this phenotype was masked by the enriched plant-based diet. Collectively, the results demonstrate that selection for faster growth is associated in gilthead sea bream with different growth trajectories and a high diet flexibility and intestine plasticity.Versión del editor2,04

Physiological trade-offs associated with fasting weight loss, resistance to exercise and behavioral traits in farmed gilthead sea bream (Sparus aurata) selected by growth

Three gilthead sea bream families representative of slow, intermediate and fast heritable growth in the Spanish PROGENSA (R) selection program were used to uncover the effects of such selection on energy partitioning through measurements of fasting weight loss, swimming performance and behavioral traits in one- and two-year-old fish. Firstly, selection for fast growth significantly increased fasting weight loss and decreased the hormonal ratio of circulating Igf-i/Gh in short-term fasting fish (17 days). This is indicative of a stronger negative energy balance that explains the reduced compensatory growth of fast-growing fish during the subsequent short-term refeeding period (7 days). Selection for fast growth also decreased the critical speed (Ucrit, 6-7 BL sxfffd; 1) at which fish become exhausted in a swim tunnel respirometer. The maximum metabolic rate (MMR), defined as the maximum rate of oxygen consumption during forced exercise, was almost equal in all fish families though the peak was achieved at a lowest speed in the fast-growing family. Since circulating levels of lactate were also slightly decreased in freeswimming fish of this family group, it appears likely that the relative energy contribution of anaerobic metabolism to physical activity was lowered in genetically fast-growing fish. Selection for heritable growth also altered activity behavior because slow-growing families displayed an anticipatory food response associated with more pronounced daily rhythms of physical activity. Also, respiratory frequency and body weight showed and opposite correlation in slow- and fast-growing free-swimming fish as part of the complex trade-offs of growth, behavior and energy metabolism. Altogether, these results indicate that selective breeding for fast growth might limit the anaerobic fitness that would help to cope with limited oxygen availability in a scenario of climate change.We acknowledge the support of Veronica de las Heras and the Animalarium Service of IATS (Felix Alvarez and Jose Ramon Mateo) for their support in fish rearing

Análisis molecular y funcional de las sirtuínas como marcadores metabólicos en dorada (Sparus aurata)

L’aqüicultura és el sector de producció animal amb major creixement a nivell mundial, però per aconseguir cobrir la creixent demanda d’aliments de l’agenda 2030 és necessari duplicar la producció en els propers anys, la qual cosa ha de basar-se en la generació de nou coneixement. Per aquest motiu, és necessari disposar d’unes infraestructures de referència on avaluar diferents condicions de cultiu de forma fiable i fàcilment reproduïble establint estàndards de qualitat basats en bones pràctiques sanitàries, d’alimentació i cultiu. Els últims avenços en el cultiu de l’orada (Sparus aurata) han demostrat que les dietes basades en ingredients vegetals no comprometen el potencial de creixement al llarg del cicle de producció. A més, els efectes negatius relacionats amb processos inflamatoris i canvis en la proporció de sexes, poden revertir-se, en part, mitjançant la suplementació amb àcids grassos de cadena curta (butirat). En canvi, els beneficis de la suplementació amb àcids grassos de 7-12 àtoms de carboni estan més associats amb el creixement i la resposta a l’exercici. Tot això posa en relleu la importància de conèixer en tot moment l’estat metabòlic dels animals en cultiu, per la qual cosa es requereixen marcadors que siguin capaços de relacionar la demanda d’energia amb l’activació de determinats processos o vies metabòliques. Les sirtuïnes són uns bons candidats, ja que aquests enzims son una família de proteïnes dependents de NAD+ que deacilen histones, factors de transcripció i un gran nombre d’enzims del metabolisme intermediari. Les sirtuïnes estan altament conservades tant a nivell gènic com proteic al llarg de l’evolució dels vertebrats. L’orada, a més de les 7 sirtuïnes de vertebrats, presenta còpies addicionals de les sirtuïnes 3 i 5, que també s’han identificat en altres espècies de peixos. Les sirtuïnes d’orada s’expressen de forma ubiqua amb patrons d’expressió específics de teixit que acostumen a coincidir amb nivells alts d’expressió de les sirtuïnes 1, 2 i 5 i baixos o moderats de les sirtuïnes 3, 4, 6 i 7. Les sirtuïnes estan regulades a nivell nutricional, responent tant a la inclusió de diferents additius a la dieta com a la manca de nutrients. En el cas del dejú, les sirtuïnes 1, 5, 6 i 7 estan sobreexpressades i, en general, mostren nivells alts d’expressió en teixits amb una alta demanda energètica. Tanmateix, el patró d’expressió de les diferents sirtuïnes varia quan es compara un estat de demanda energètica degut a la falta de nutrients o a l’acceleració del creixement. En aquest sentit, animals de creixement accelerat i fenotip prim van mostrar una major expressió de les sirtuïnes amb funcions antiinflamatòries en el teixit adipós (sirtuïnes 5 i 6) i l’intestí (sirtuïnes 2, 3, 5 i 7) a més d’una disminució de l’expressió de la sirtuïna 1 a nivell hepàtic i un augment de la sirtuïna 2 al múscul. L’edat i l’estació son altres factors que afecten de forma diferencial l’expressió de les sirtuïnes a nivell hepàtic i muscular. Per tant, les sirtuïnes responen als canvis de l’estat energètic de forma diferent en funció de la intensitat i naturalesa de l’estímul que modifiqui l’estat de demanda o disponibilitat d’energia. Aquesta heterogeneïtat de la resposta també va associada a la presència (sirtuïnes 1 i 3) o absència (sirtuïnes 2, 4-7) de promotors amb illes CG, havent-se observat a nivell muscular, que l’augment de l’expressió de la sirtuïna 1 està associat a una menor metilació del promotor amb l’edat i a l’hivern.La acuicultura es el sector de producción animal con mayor crecimiento a nivel mundial, pero para cubrir la demanda creciente de alimentos de la agenda 2030 es necesario duplicar la producción en los próximos años, lo que debe basarse en la generación de nuevo conocimiento. Para ello es condición indispensable disponer de unas infraestructuras de referencia donde evaluar diferentes condiciones de cultivo de forma fiable y fácilmente reproducible estableciendo unos estándares de calidad, basados en buenas prácticas sanitarias, de alimentación y cultivo. Los últimos avances en el cultivo de la dorada (Sparus aurata) han demostrado que las dietas basadas en ingredientes vegetales no comprometen el potencial de crecimiento a lo largo del ciclo de producción. Es más, los efectos negativos relacionados con procesos inflamatorios y cambios en la proporción de sexos, pueden revertirse, al menos en parte, mediante la suplementación con ácidos grasos de cadena corta (butirato). En cambio, los beneficios de la suplementación con ácidos grasos de 7-12 átomos de carbono están más asociados con el crecimiento y la respuesta al ejercicio. Ello pone de relieve la importancia de conocer en todo momento el estado metabólico de los animales en cultivo, por lo que se requieren marcadores que sean capaces de relacionar la demanda de energía con la activación de determinados procesos o vías metabólicas. Las sirtuínas son unos buenos candidatos al ser estas enzimas una familia de proteínas dependientes de NAD+ que deacilan histonas, factores de transcripción y un gran número de enzimas del metabolismo intermediario. Las sirtuínas están altamente conservadas tanto a nivel génico como proteico a lo largo de la evolución de los vertebrados. La dorada, además de las 7 sirtuínas de vertebrados, presenta copias adicionales de las sirtuínas 3 y 5, que también se han identificado en otras especies de peces. Las sirtuínas de dorada se expresan de forma ubicua con patrones de expresión específicos de tejido que suelen coincidir con niveles altos de expresión de las sirtuínas 1, 2 y 5 y bajos o moderados de las sirtuínas 3, 4, 6 y 7. Las sirtuínas están reguladas a nivel nutricional, respondiendo tanto a la inclusión de distintos aditivos en la dieta como a la falta de nutrientes. En el caso del ayuno, las sirtuínas 1, 5, 6 y 7 están sobreexpresadas y en general muestran niveles altos de expresión en tejidos con una alta demanda energética. Sin embargo, el patrón de expresión de los distintos isotipos de sirtuínas es diferente cuando se compara un estado de demanda energética desencadenado por la falta de nutrientes o la aceleración del crecimiento. En este sentido, animales de crecimiento acelerado y fenotipo delgado mostraron una mayor expresión de las sirtuínas con roles antiinflamatorios en el tejido adiposo (sirtuínas 5 y 6) e intestino (sirtuínas 2, 3, 5 y 7) y una disminución de la expresión de la sirtuína 1 a nivel hepático y un aumento de la sirtuína 2 a nivel muscular. La edad y la estación son otros de los factores que afectan de forma diferencial la expresión de las sirtuínas a nivel hepático y muscular. Por tanto, las sirtuínas responden a los cambios del estado energético de forma diferente en función de la intensidad y naturaleza del estímulo que modifique el estado de demanda o disponibilidad de energía. Esta heterogeneidad de la respuesta también va asociada a la presencia (sirtuínas 1 y 3) o ausencia (sirtuínas 2, 4-7) de promotores con islas CG, habiéndose observado a nivel muscular que el aumento de la expresión de la sirtuína 1 está asociado a una menor metilación del promotor con la edad y en época invernal.Aquaculture is the fastest growing food-producing sector worldwide, but the capacity of aquaculture to meet the future demand for seafood to deliver the goals by 2030 will largely depend on doubling production in the coming years, which should be based on the generation of new knowledge. For that purpose, it is crucial to have quality facilities to assess different farming conditions in a reliable and easily reproducible way, establishing quality standards based on good aquaculture practices (i.e. feeding, sanitation, management). The latest achievements in gilthead sea bream (Sparus aurata) have demonstrated that plant-based diets do not compromise fish growth potential over the production cycle. Moreover, the negative effects related to inflammatory processes and sex proportion can be reverted, at least in part, by the supplementation with short chain fatty acids (butyrate). In contrast, the benefits of adding 7-12 carbon fatty acids are more associated with growth and swimming performance. This highlights the importance of knowing the metabolic state of farmed fish and the interest of developing new biomarkers that link the energy demand with the activation of specific metabolic pathways. Sirtuins are good candidates because these enzymes belong to a NAD+-dependent protein family that deacylates histones, transcription factors and a wide range of metabolic enzymes. Sirtuins are highly conserved both at the gene and protein levels throughout the evolution of vertebrates. In addition to the 7 vertebrate sirtuins, gilthead sea bream also has additional copies of sirtuins 3 and 5, which have also been identified in other fish species. Gilthead sea bream sirtuins revealed a ubiquitous gene expression pattern that was tissue-specific for each sirtuin with relatively high levels of sirtuins 1, 2 and 5 and moderate or low in the case of sirtuins 3, 4, 6 and 7. In addition, sirtuins are nutritionally regulated, responding both to the inclusion of different additives in the diet and nutrient availability. In the case of fasting, sirtuins 1, 5, 6 and 7 are up-regulated showing, in general, high gene expression levels in tissues with a high energy demand. However, the expression pattern of sirtuins is different when comparing an energy demand state caused by fasting or fast growth. In this sense, fast-growing fish with a lean phenotype showed a higher expression of sirtuins with anti-inflammatory roles in adipose tissue (sirtuins 5 and 6) and intestine (sirtuins 2, 3, 5 and 7), as well as a reduced hepatic sirtuin 1 expression and an increased sirtuin 2 expression in white skeletal muscle. Age and season are other factors that affect the expression pattern of sirtuins at hepatic and muscular level. Therefore, the differential regulation of sirtuins according to changes in energy status depends on the intensity and nature of the stimulus that modifies the state of demand or energy availability. This heterogeneity of the response is also associated with the presence (sirtuins 1 and 3) or lack (sirtuins 2, 4-7) of promoters with CG islands, being associated at muscular level the increased expression of sirtuin 1 with a lower promoter methylation with age and in winter season.Universitat Autònoma de Barcelona. Programa de Doctorat en Aqüicultur