Peracetic acid can be used as a disinfectant for gilthead sea bream (Sparus aurata) juveniles without affecting fish welfare

Peracetic acid (PAA) is a European Union Commission-authorized disinfectant for use in animal health care. It has shown a strong inactivation potential for bacteria, viruses, fungi, and bacterial spores. A stress-related adaptive response after exposure to PAA has been described in different species of fish such as carp (Cyprinus carpio), and rainbow trout (Oncorhynchus mykiss). The present study aims to evaluate the response of gilthead seabream systemic (plasma) as mucosal (gill and skin) defenses after PAA a unique exposure (5 min), by measuring cortisol, glucose, and lactate in plasma, as well as the expression of several genes (glutathione peroxidase, glucocorticoid receptor, superoxide dismutase 2 and superoxide dismutase involved in the response to oxidative stress in mucosal tissues). study. We observe how seabream (Sparus aurata) copes with oxidative stress induced by PAA. PAA exposure did not induce an important antioxidant response in fish, whereas induced a mild response to stress, with a fast and effective recovery of basal levels after 24 h. Although PAA triggers a mild stress response, the response described in our study reflects that it can be used for sea bream in the concentration tested with no severe physiological consequencespublishedVersio

Thermophilic anaerobic conversion of raw microalgae: Microbial community diversity in high solids retention systems

[EN] The potential of microbial communities for efficient anaerobic conversion of raw microalgae was evaluated in this work. A long-term operated thermophilic digester was fed with three different Organic Loading Rates (OLR) (0.2, 0.3 and 0.4¿g·L¿1·d¿1) reaching 32¿41% biodegradability values. The microbial community analysis revealed a remarkable presence of microorganisms that exhibit high hydrolytic capabilities such as Thermotogae (~44.5%), Firmicutes (~17.6%) and Dictyoglomi, Aminicenantes, Atribacteria and Planctomycetes (below ~5.5%) phyla. The suggested metabolic role of these phyla highlights the importance of protein hydrolysis and fermentation when only degrading microalgae. The ecological analysis of the reactor suggests the implication of the novel group EM3 in fermentation and beta-oxidation pathways during microalgae conversion into methane. Scenedesmus spp. substrate and free ammonia concentration strongly shaped thermophilic reactor microbial structure. Partial Least Square Discriminant Analysis (PLS-DA) remarked the resilient role of minor groups related to Thermogutta, Armatimonadetes and Ruminococcaceae against a potential inhibitor like free ammonia. Towards low-cost biogas production from microalgae, this study reveals valuable information about thermophilic microorganisms that can strongly disrupt microalgae and remain in high solids retention anaerobic digesters.This research work has been supported by the Spanish Ministry of Economy and Competitiveness (MINECO, Project CTM2011-28595-C02-02) jointly with the European Regional Development Fund (ERDF), which are gratefully acknowledged. The authors are thankful to Fernando Fdz-Polanco research team (University of Valladolid, Spain) for providing the thermophilic sludge from their pilot plant to inoculate the bioreactor and Llúcia Martínez and Giusseppe D'Aria from FISABIO sequencing service (Valencia, Spain) for their technical support during the Illumina sequencing design.Zamorano-López, N.; Greses-Huerta, S.; Aguado García, D.; Seco Torrecillas, A.; Borrás Falomir, L. (2019). Thermophilic anaerobic conversion of raw microalgae: Microbial community diversity in high solids retention systems. Algal Research. 41:1-9. https://doi.org/10.1016/j.algal.2019.101533S194

Supplementation of arachidonic acid rich oil in European sea bass juveniles (Dicentrarchus labrax) diets: Effects on growth performance, tissue fatty acid profile and lipid metabolism

The aim of this study was to evaluate the effects of increasing dietary arachidonic acid (ARA) levels (from 1 up to 6 % of total fatty acids) on European sea bass (Dicentrarchus labrax) juveniles growth performance, tissue fatty acid profile, liver morphology as well as long chain polyunsaturated fatty acids (LC-PUFA) biosynthesis, triglyceride and cholesterol synthesis and lipid transport. A diet with total fish oil (FO) replacement and defatted fish meal (FM) containing a 0.1 g ARA g-1 diet was added to the experimental design as a negative control diet. Dietary ARA inclusion levels below 0.2 g ARA g-1 diet significantly worsened growth even only 30 days after the start of the feeding trial, whereas dietary ARA had no effect on fish survival. Liver, muscle and whole body fatty acid profile mainly reflected dietary contents and ARA content increased accordingly with ARA dietary levels. Tissue eicosapentaenoic acid (EPA), docosapentaenoic acid (DPA) and docosahexaenoic acid (DHA) levels were positively correlated among them. Hepatic lipid vacuolization increased with reduced dietary ARA levels. Expressions of fatty acyl desaturase 2 and 3-hydroxy-3-methylglutaryl-coenzyme genes were up-regulated in fish fed the negative control diet compared to the rest of the dietary treatments denoting the influence of ARA on lipid metabolism. Results obtained highlight the need to include adequate n-6 levels and not only n-3 LC-PUFA levels in European sea bass diets. Keywords: Dicentrarchus labrax, arachidonic acid, growth performance, tissue fatty acid profile, lipid metabolis

Effect of long residence time and high temperature over anaerobic biodegradation of Scenedesmus microalgae grown in wastewater

[EN] Anaerobic digestion of indigenous Scenedesmus spp. microalgae was studied in continuous lab-scale anaerobic reactors at different temperatures (35 degrees C and 55 degrees C), and sludge retention time - SRT (50 and 70 days). Mesophilic digestion was performed in a continuous stirred-tank reactor (CSTR) and in an anaerobic membrane bioreactor (AnMBR). Mesophilic CSTR operated at 50 days SRT only achieved 11.9% of anaerobic biodegradability whereas in the AnMBR at 70 days SRT and 50 days HRT reached 39.5%, which is even higher than the biodegradability achieved in the thermophilic CSTR at 50 days SRT (30.4%). Microbial analysis revealed a high abundance of cellulose-degraders in both reactors, AnMBR (mainly composed of 9.4% Bacteroidetes, 10.1% Chloroflexi, 8.0% Firmicutes and 13.2% Thermotogae) and thermophilic CSTR (dominated by 23.8% Chloroflexi and 12.9% Firmicutes). However, higher microbial diversity was found in the AnMBR compared to the thermophilic CSTR which is related to the SRT. since high SRT promoted low growth-rate microorganisms, increasing the hydrolytic potential of the system. These results present the membrane technology as a promising approach to revalue microalgal biomass, suggesting that microalgae biodegradability and consequently the methane production could be improved operating at higher SRT. (C) 2018 Elsevier Ltd. All rights reserved.This research work has been supported by the Spanish Ministry of Economy and Competitiveness (MINECO, Project CTM2011-28595-C02-01/02) jointly with the European Regional Development Fund (ERDF), which are gratefully acknowledged. The authors are thankful to Fernando Fernandez-Polanco for providing the thermophilic sludge to inoculate the reactor.This research work has been financially supported by the Generalitat Valenciana (PROMETEO/2012/029 PROJECT), which is gratefully acknowledged.Greses-Huerta, S.; Zamorano -López, N.; Borrás Falomir, L.; Ferrer, J.; Seco Torrecillas, A.; Aguado García, D. (2018). Effect of long residence time and high temperature over anaerobic biodegradation of Scenedesmus microalgae grown in wastewater. Journal of Environmental Management. 218:425-434. https://doi.org/10.1016/j.jenvman.2018.04.086S42543421

Genetic selection for high growth improves the efficiency of gilthead sea bream (Sparus aurata) in using novel diets with insect meal, single-cell protein and a DHA rich-microalgal oil

Genetic selection and novel raw materials for aquafeeds are current key tools in the ongoing effort to increase the productivity, efficiency, and sustainability of the aquaculture sector. Selective breeding could also improve the utilization of novel dietary formulations with emergent ingredients. Gilthead sea bream juveniles, either coming from a selective breeding program based on growth traits, or a non-selected population, were nutritionally challenged with two novel dietary formulations that were compared with a Control diet based on 15% FM and 6% FO dietary commercial levels for this species. The novel formulations included an insect meal diet (INS) at 5% of the diet to replace 33.3% of the dietary FM, or a single-cell protein diet (SCP) at 10% of the diet and to replace 66.7% of the dietary FM. Fish oil was also totally replaced in these diets by a blend of poultry oil and Veramaris algal oil. Better growth and feed utilization of the selected genotype compared to non-selected fish was observed, at any of the diets assayed. INS and SCP novel diets reduced general performance of fish by reducing feed intake. However, selected fish fed novel diets showed very similar growth and lower feed conversion ratio compared with non-selected fish fed a control diet. The novel formulations increased n-3 LC-PUFA in fish tissues, particularly DHA, irrespective of the genotype, as a result of the dietary inclusion of the DHA-rich microalgal oil. Neither genetic selection nor the use of novel raw materials affected fillet proximate composition and consequently, sea bream fillet quality in terms of texture and sensorial perception of consumers. Overall, the results reaffirm the positive effects of selective breeding programs in improving sea bream key productive indicators, as well as support the use of novel dietary formulations, using insect meal from H. illucens, single-cell protein from M. capsulatus as partial replacers of FM in diets for gilthead sea bream (33 and 66% of replacement, respectively), and a blend of DHA-rich microalgal and poultry oils as total replacer of FO.This work was supported by the European Union‘s Horizon 2020 research and innovation program under grant agreement no. 818367; AquaIMPACT—Genomic and nutritional innovations for genetically superior farmed fish to improve efficiency in European aquaculture.info:eu-repo/semantics/publishedVersio

Effects of thermal stress on the expression of glucocorticoid receptor complex linked genes in Senegalese sole (Solea senegalensis): Acute and adaptive stress responses

The present study examined the short and mid-term effects of a rise in temperature from 18 ºC to 24 ºC 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 1 month of acclimation at 18 ºC. After this process, samples of different tissues were collected from a total of 96 fish at four sampling points: 1 hour, 24 hours, 3 days and 1 week. 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 1 h 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 24 h 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

Genetically superior European sea bass (Dicentrarchus labrax) and nutritional innovations: Effects of functional feeds on fish immune response, disease resistance, and gut microbiota

The objective of this study was to determine if selected fish genotypes could benefit from the use of functional additives in novel aqua feed formulations to improve growth performance, gut microbiota, immune response, and disease resistance in fish. Two batches of juvenile European sea bass selected for high growth (HG; selected sires x selected dams), and wild types (WT; wild sires x selected females) were fed a “future diet” coated with three different functional additives for 12 weeks as follows: (i) 2 weeks with a high dose, followed by (ii) 10 weeks with a low dose. The functional additives tested were a mixture of probiotics (PROB), organic acids (ORG), and phytogens (PHYTO). A pathogen challenge test (Vibrio anguillarum) and a stress condition (overcrowding) were performed after each dose. At the end of the feeding experiment, fish from the HG group performed better than fish from the WT group in terms of body weight, relative growth, SGR, and DGI. The results of the two challenge tests performed after two weeks of high dose and ten weeks of low dose showed a significant effect of diet on fish survival. GALT-associated gene expression analysis revealed an interaction between the genotype and diet for il-1β in the distal gut. Finally, regarding the gut microbiota, discriminant analysis showed no clear separation between fish fed the future diet and those fed the same diet with experimental additives. Nevertheless, the relative abundance of certain taxa varied between experimental groups. For example, fish fed the ORG diet had higher relative abundance of Streptococcus in both genotypes, whereas fish fed the PHYTO diet had higher abundance of Lactobacillales. In contrast, fish fed PROB had lower abundance of Pseudomonas and Acinetobacter.The current study was supported by the EU Horizon 2020 AquaIMPACT (Genomic and nutritional innovations for genetically superior farmed fish to improve efficiency in European aquaculture), number: 818367.info:eu-repo/semantics/publishedVersio

Inorganic, organic, and encapsulated minerals in vegetable meal based diets for Sparus aurata (Linnaeus, 1758)

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/Zn sod) 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

An insight into piscidins : The discovery, modulation and bioactivity of greater amberjack, Seriola dumerili, piscidin

This project has received funding from the European Union’s Seventh Framework Programme for research, technological development and demonstration (KBBE-2013-07 single stage, GA 603121, DIVERSIFY).Peer reviewedPostprin