Showing papers by "University of Almería published in 2013"
TL;DR: A number of toxicological interactions of pesticide mixtures at a molecular level are addressed, such as those of pesticides acting as endocrine disruptors, the cumulative toxicity of organophosphates and organochlorines resulting in estrogenic effects and the promotion ofOrganophosphate-induced delayed polyneuropathy.
442 citations
TL;DR: In this article, the authors reviewed the scientific production of renewable energies, namely, solar, wind, biomass, hydropower and geothermal, from 1979 to 2009, and analyzed the production of all the countries in the world, paying particular attention to renewable energies and research institutions.
Abstract: This paper reviews the scientific production of renewable energies, namely, solar, wind, biomass, hydropower and geothermal, from 1979 to 2009. The production of all the countries in the world is analysed, paying particular attention to renewable energies and research institutions. The production of scientific research for each type of energy is represented on world maps to show the degree of relationship between this research and the resources of these energies. It is observed that biomass is the most studied, both by number of publications, with 56% of the publications on renewable energy, and by geographical distribution. The next in importance by number of publications is solar energy (26%). The countries investigating solar energy, however, are not necessarily those with the greatest availability of this resource. Wind is the third positioned in publication (11%). Wind is being investigated by countries that most have implemented this type of energy production. Hydro and geothermal energies are also investigated by countries with great abundance of this resource. It is observed that research on renewable energy is highly concentrated in a few countries (12 or 14, depending on the energy type), accounting for between 70 and 80% of scientific production. The role of the USA as a leader in research in all renewable energies studies is emphasised. NASA is the leading institution for solar and wind energy, the Chinese Academy of Sciences leads in hydropower and biomass, and the U.S. Geological Survey leads in geothermal energy.
302 citations
TL;DR: Different advanced technologies: solar heterogeneous photocatalysis with TiO(2), solar photo-Fenton and ozonation, are studied as tertiary treatments for the remediation of micropollutants present in real municipal wastewater treatment plants effluents at pilot plant scale.
258 citations
TL;DR: The bottlenecks for the scale-up of the different technologies and thus of microalgae production are summarized and the obligation of adequate control strategies is discussed.
Abstract: Microalgae are produced today for human and animal markets, as food-feed and source of active compounds. Microalgae can be also used in wastewater treatment and they has been proposed as biofuels source to reduce global warming problem. Whatever the final application of microalgae its production is based on the same principles as light availability, enough mass and heat transfer and adequate control of culture parameters. In this paper these principals are revised. Moreover, the production must be carried out at adequate scale using photobioreactors. Design of photobioreactor is determined by the final use of biomass and quality required. Different designs today used are revised, including last designs proposed, identifying his characteristics parameters and applications. In addition, the obligation of adequate control strategies is discussed. Finally, the bottlenecks for the scale-up of the different technologies and thus of microalgae production are summarized.
257 citations
TL;DR: The most promising process was photo-Fenton modified with Ethylenediamine-N,N'-disuccinic acid (EDDS), as the pH remained in the neutral range, but has the disadvantage that the water must be previously acidified.
245 citations
TL;DR: Experimental results indicate that the proposed optimizations can significantly improve the performance of the considered algorithms without reducing their anomaly detection accuracy.
Abstract: Anomaly detection is an important task for hyperspectral data exploitation. A standard approach for anomaly detection in the literature is the method developed by Reed and Xiaoli, also called RX algorithm. A variation of this algorithm consists of applying the same concept to a local sliding window centered around each image pixel. The computational cost is very high for RX algorithm and it strongly increases for its local versions. However, current advances in high performance computing help to reduce the run-time of these algorithms. So, for the standard RX, it is possible to achieve a processing time similar to the data acquisition time and to increase the practical interest for its local versions. In this paper, we discuss several optimizations which exploit different forms of acceleration for these algorithms. First, we explain how the calculation of the correlation matrix and its inverse can be accelerated through optimization techniques based on the properties of these particular matrices and the efficient use of linear algebra libraries. Second, we describe parallel implementations of the RX algorithm, optimized for multicore platforms. These are well-known, inexpensive and widely available high performance computing platforms. The ability to detect anomalies of the global and local versions of RX is explored using a wide set of experiments, using both synthetic and real data, which are used for comparing the optimized versions of the global and local RX algorithms in terms of anomaly detection accuracy and computational efficiency. The synthetic images have been generated under different noise conditions and anomalous features. The two real scenes used in the experiments are a hyperspectral data set collected by NASA's Airborne Visible Infra-Red Imaging Spectrometer (AVIRIS) system over the World Trade Center (WTC) in New York, five days after the terrorist attacks, and another data set collected by the HYperspectral Digital Image Collection Experiment (HYDICE). Experimental results indicate that the proposed optimizations can significantly improve the performance of the considered algorithms without reducing their anomaly detection accuracy.
202 citations
12 Apr 2013
TL;DR: This chapter summarizes the current state of the art on photobioreactor design and operation, discussing the major challenges to be solved to achieve a massive expansion of microalgae-based technologies.
Abstract: Microalgae are produced today for human and animal markets, as food-feed and source of active compounds. Microalgae can be also used in wastewater treatment and they has been proposed as biofuels source to reduce global warming problem. Whatever the final application of microalgae its production is based on the same principles as light availability, enough mass and heat transfer and adequate control of culture parameters. In this paper these principals are revised. Moreover, the production must be carried out at adequate scale using photobioreactors. Design of photobioreactor is determined by the final use of biomass and quality required. Different designs today used are revised, including last designs proposed, identifying his characteristics parameters and applications. In addition, the obligation of adequate control strategies is discussed. Finally, the bottlenecks for the scale-up of the different technologies and thus of microalgae production are summarized.
181 citations
TL;DR: In this article, the authors compared arable soils (AS) from western areas of the Andalusian Autonomous Community (SE Spain) with greenhouse soils (GS) from the province of Almeria, one of the most productive agricultural systems in Europe.
160 citations
TL;DR: In this paper, the authors present a survey of the new collectors with potential application in feeding double effect absorption chillers, and evaluate their use as an occasional alternative to other solar thermal collectors in air conditioning applications by dynamical simulation.
Abstract: The increasing energy demand for air-conditioning in most industrialized countries, as well as refrigeration requirements in the food processing field and the conservation of pharmaceutical products, is leading to a growing interest in solar cooling systems. So far, the more commonly systems used are single-effect water/lithium bromide absorption chillers powered by flat-plate or evacuated tube collectors operating with COP of about 0.5–0.8 and driving temperatures of 75–95 °C. In general terms, performance of thermally driven cooling systems increases to about 1.1–1.4 using double-effect cycles fed by higher temperature sources (140–180 °C). If solar energy is to be used, concentrating technologies must be considered. Although some experiences on the integration of parabolic trough collectors (PTC) and Fresnel lenses in cooling installations can be found in the literature, the quantity is far to be comparable to that of low temperature collectors. Some manufacturers have undertaken the development of modular, small, lightweight and low cost parabolic collectors, compatible for installation on the roofs of the buildings aiming to overcome some of the current technology drawbacks as costs and modularity. After a comprehensive literature review, this work summarises the existing experiences and realizations on applications of PTC in solar cooling systems as well as present a survey of the new collectors with potential application in feeding double effect absorption chillers. In addition to this, it is evaluated its use as an occasional alternative to other solar thermal collectors in air conditioning applications by dynamical simulation. Results for the case studies developed in this work show that PTC present similar levelized costs of energy for cooling than flat plate collector (FPC) and lower than evacuated tube collectors (ETC) and compound parabolic collectors (CPC).
157 citations
TL;DR: Several extraction methods were evaluated in terms of recoveries and extraction precision for 113 pesticides in avocado: QuEChERS with various d-SPE clean-ups (Z-Sep, Z-Sep+, PSA+C18 and silica), miniLuke and ethyl acetate, and validated in two matrices - avocado and almonds.
151 citations
TL;DR: This Spanish translation of the AAQ-II emerges as a reliable and valid measure of experiential avoidance and psychological inflexibility.
Abstract: Background: Experiential avoidance and psychological inflexibility have been recently found to be important constructs related to a wide range of psychological disorders and quality of life. The current study presents psychometric and factor structure data concerning the Spanish translation of a general measure of both constructs: the Acceptance and Action Questionnaire - II (AAQ-II). Method: Six samples, with a total of 712 participants, from several independent studies were analyzed. Results: Data were very similar to the ones obtained in the original AAQ-II version. The internal consistency across the different samples was good (between a= .75 and a= .93). The differences between clinical and nonclinical samples were statistically significant and the overall factor analysis yielded to a one-factor solution. The AAQ-II scores were significantly related to general psychopathology and quality of life measures. Conclusions: This Spanish translation of the AAQ-II emerges as a reliable and valid measure of experiential avoidance and psychological inflexibility.
TL;DR: This work reviews the current state-of-the-art of liquid chromatography coupled to high-resolution mass spectrometry (LC-HRMS) techniques applied to the analysis of pesticides in fruit-based and vegetable-based matrices and includes HRMS technology as a reliable complementary alternative allowing theAnalysis of a wide range of pesticide in food.
TL;DR: In this paper, the effects of water depth, liquid velocity and the presence, or absence, of sump baffles to improve the CO2 supply transfer were considered in relation to on the power consumption, residence time and mixing in the reactor.
Abstract: The fluid dynamic characterization of a 100 m length × 1 m wide channel raceway photobioreactor was carried out. The effects of water depth, liquid velocity and the presence, or absence, of sump baffles to improve the CO2 supply transfer were considered in relation to on the power consumption, residence time and mixing in the reactor was studied. When operated at a depth of 20 cm, the power consumption was between 1.5 and 8.4 W m?3 depending on the forward velocity, with higher values occurring when the baffle was in place. Residence times and the degree of mixing at each section of the raceway (paddlewheel, bends, channels and sump) were measured experimentally. Mixing occurred mainly in the sump, paddlewheel and bends, with a maximum dispersion coefficient of 0.07 m2 s?1. These sections, however, only contributed a small fraction to the total volume of the raceway. Bodenstein numbers from 200 to 540 for the channel sections indicated plug-flow characteristics. Mixing times ranged from 1.4 to 6 h, with the presence of the baffle greatly increasing these times despite higher specific power consumption. A total of 15–20 circuits of the raceway were needed to achieve complete mixing without the baffle, compared to 30–40 cycles with the baffle. Vertical mixing was very poor whereas axial mixing was similar to that achieved in closed photobioreactors. The methodologies applied were shown to be useful in determining the fluid dynamics of a raceway photobioreactor. Equations useful in simulating the power consumption as a function of the design and operation parameters have been validated.
TL;DR: Results demonstrate that photosynthetic efficiency is modified as a function of culture conditions, and can be used to determine the proximity of culture Conditions to optimal values, and is a powerful tool for the optimal design and management of microalgae-based processes, especially outdoors.
Abstract: In this paper, the influence of culture conditions (irradiance, temperature, pH, and dissolved oxygen) on the photosynthesis rate of Scenedesmus almeriensis cultures is analyzed. Short-run experiments were performed to study cell response to variations in culture conditions, which take place in changing environments such as outdoor photobioreactors. Experiments were performed by subjecting diluted samples of cells to different levels of irradiance, temperature, pH, and dissolved oxygen concentration. Results demonstrate the existence of photoinhibition phenomena at irradiances higher than 1,000 μE/m2 s; in addition to reduced photosynthesis rates at inadequate temperatures or pH—the optimal values being 35 °C and 8, respectively. Moreover, photosynthesis rate reduction at dissolved oxygen concentrations above 20 mg/l is demonstrated. Data have been used to develop an integrated model based on considering the simultaneous influence of irradiance, temperature, pH, and dissolved oxygen. The model fits the experimental results in the range of culture conditions tested, and it was validated using data obtained by the simultaneous variation of two of the modified variables. Furthermore, the model fits experimental results obtained from an outdoor culture of S. almeriensis performed in an open raceway reactor. Results demonstrate that photosynthetic efficiency is modified as a function of culture conditions, and can be used to determine the proximity of culture conditions to optimal values. Optimal conditions found (T = 35 °C, pH = 8, dissolved oxygen concentration <20 mg/l) allows to maximize the use of light by the cells. The developed model is a powerful tool for the optimal design and management of microalgae-based processes, especially outdoors, where the cultures are subject to daily culture condition variations.
TL;DR: MORPGEASA, a Pareto-based hybrid algorithm that combines evolutionary computation and simulated annealing, is proposed and analyzed for solving these multi-objective formulations of the VRPTW and the results obtained show the good performance of this hybrid approach.
TL;DR: Simulations showed the energy required to increase mass transfer and reduce oxygen concentrations was more than compensated for by increased biomass and potential energy yields, and maintenance of mass transfer by sparging may be necessary even when CO2 is not required.
TL;DR: This paper conducted an extensive review and empirical analysis of a broad variety of classic and recent controversies and issues related with the use of Structural Equation Models (SEM) in order to identify problematic questions and prescribe a compendium of solutions for its suitable application.
Abstract: Purpose – Structural equation modelling (SEM) is a method that is very frequently applied by marketing and business researchers to assess empirically new theoretical proposals articulated by means of complex models. It is, therefore, a logical thought that the quality of the new advances in marketing and business theory depends, in part, on how well SEM is applied. This study aims to conduct an extensive review and empirical analysis of a broad variety of classic and recent controversies and issues related with the use of SEM, in order to identify problematic questions and prescribe a compendium of solutions for its suitable application.Design/methodology/approach – The main analyses were conducted on a sample of 191 SEM‐based papers and 472 applications, i.e. all the SEM‐based studies published in four leading marketing journals during the period 1995‐2007.Findings – Despite the maturity of SEM, its application in marketing research still has notable room for improvement. This is a general conclusion bas...
TL;DR: The procedure MT-PSA outperforms SPEA2 in the benchmarks here considered, with respect to the solution quality and execution time, and Computational results obtained on Solomon's benchmark problems show that the island-based parallelization produces Pareto-fronts of higher quality that those obtained by the sequential versions without increasing the computational cost.
Abstract: The Capacitated Vehicle Routing Problem with Time Windows (VRPTW) consists in determining the routes of a given number of vehicles with identical capacity stationed at a central depot which are used to supply the demands of a set of customers within certain time windows. This is a complex multi-constrained problem with industrial, economic, and environmental implications that has been widely analyzed in the past. This paper deals with a multi-objective variant of the VRPTW that simultaneously minimizes the travelled distance and the imbalance of the routes. This imbalance is analyzed from two perspectives: the imbalance in the distances travelled by the vehicles, and the imbalance in the loads delivered by them. A multi-objective procedure based on Simulated Annealing, the Multiple Temperature Pareto Simulated Annealing (MT-PSA), is proposed in this paper to cope with these multi-objective formulations of the VRPTW. The procedure MT-PSA and an island-based parallel version of MT-PSA have been evaluated and compared with, respectively, sequential and island-based parallel implementations of SPEA2. Computational results obtained on Solomon's benchmark problems show that the island-based parallelization produces Pareto-fronts of higher quality that those obtained by the sequential versions without increasing the computational cost, while also producing significant reduction in the runtimes while maintaining solution quality. More specifically, for the most part, our procedure MT-PSA outperforms SPEA2 in the benchmarks here considered, with respect to the solution quality and execution time.
TL;DR: The aim of the study was to compare the potential classification accuracy provided by pan-sharpened orthoimages from both GeoEye-1 and WorldView-2 (WV2) VHR satellites over urban environments and found the ideal choice would be variable depending on both each satellite and target class.
Abstract: The latest breed of very high resolution VHR commercial satellites opens new possibilities for cartographic and remote-sensing applications. In fact, one of the most common applications of remote-sensing images is the extraction of land-cover information for digital image base maps by means of classification techniques. The aim of the study was to compare the potential classification accuracy provided by pan-sharpened orthoimages from both GeoEye-1 and WorldView-2 WV2 VHR satellites over urban environments. The influence on the supervised classification accuracy was evaluated by means of an object-based statistical analysis regarding three main factors: i sensor used; ii sets of image object IO features used for classification considering spectral, geometry, texture, and elevation features; and iii size of training samples to feed the classifier nearest neighbour NN. The new spectral bands of WV2 Coastal, Yellow, Red Edge, and Near Infrared-2 did not improve the benchmark established from GeoEye-1. The best overall accuracy for GeoEye-1 close to 89% was attained by using together spectral and elevation features, whereas the highest overall accuracy for WV2 83% was achieved by adding textural features to the previous ones. In the case of buildings classification, the normalized digital surface model computed from light detection and ranging data was the most valuable feature, achieving producer's and user's accuracies close to 95% and 91% for GeoEye-1 and VW2, respectively. Last but not least and regarding the size of the training samples, the rule of ‘the larger the better' was true but, based on statistical analysis, the ideal choice would be variable depending on both each satellite and target class. In short, 20 training IOs per class would be enough if the NN classifier was applied on pan-sharpened orthoimages from both GeoEye-1 and WV2.
TL;DR: In this paper, an optimal controller for distributing the energy consumption rate inside a building and preserving, at the same time, the user welfare is proposed, which is based on the Lagrangian dual method.
TL;DR: The combination of nitrogen depletion and light stress was proved to contribute to lipid enhancement and showed an important change in the fatty acids profile and an increase in the neutral lipids content.
TL;DR: The use of sophisticated software tools has allowed successful screening analysis, determining several hundreds of analytes, and assisted in the structural elucidation of unknown compounds in a timely manner.
Abstract: Since the so-called emerging contaminants were established as a new group of pollutants of environmental concern, a great effort has been devoted to the knowledge of their distribution, fate and effects in the environment. After more than 20 years of work, a significant improvement in knowledge about these contaminants has been achieved, but there is still a large gap of information on the growing number of new potential contaminants that are appearing and especially of their unpredictable transformation products. Although the environmental problem arising from emerging contaminants must be addressed from an interdisciplinary point of view, it is obvious that analytical chemistry plays an important role as the first step of the study, as it allows establishing the presence of chemicals in the environment, estimate their concentration levels, identify sources and determine their degradation pathways. These tasks involve serious difficulties requiring different analytical solutions adjusted to purpose. Thus, the complexity of the matrices requires highly selective analytical methods; the large number and variety of compounds potentially present in the samples demands the application of wide scope methods; the low concentrations at which these contaminants are present in the samples require a high detection sensitivity, and high demands on the confirmation and high structural information are needed for the characterisation of unknowns. New developments on analytical instrumentation have been applied to solve these difficulties. Furthermore and not less important has been the development of new specific software packages intended for data acquisition and, in particular, for post-run analysis. Thus, the use of sophisticated software tools has allowed successful screening analysis, determining several hundreds of analytes, and assisted in the structural elucidation of unknown compounds in a timely manner.
TL;DR: In this article, the authors obtained ordering properties for coherent systems with possibly dependent identically distributed components based on a representation of the system reliability function as a distorted function of the common component reliability function.
Abstract: In this paper, we obtain ordering properties for coherent systems with possibly dependent identically distributed components. These results are based on a representation of the system reliability function as a distorted function of the common component reliability function. So, the results included in this paper can also be applied to general distorted distributions. The main advantage of these results is that they are distribution-free with respect to the common component distribution. Moreover, they can be applied to systems with component lifetimes having a non-exchangeable joint distribution. Copyright © 2012 John Wiley & Sons, Ltd.
TL;DR: New insights are offered into the mechanisms involved in the biodegradation of organic matter and help to prioritize the parameters that contribute at critical stages of the process.
TL;DR: In this paper, the authors examined the direct and indirect effects of different BSC features on runoff and erosion in a semi-arid ecosystem under conditions of natural rainfall, and they found that the hydrological response of BSCs varies depending on rainfall properties, which determine the process governing overland flow generation.
Abstract: Biological soil crusts (BSCs) cover non-vegetated areas in most arid and semiarid ecosystems. BSCs play a crucial role in the redistribution of water and sediments and, ultimately, in the maintenance of ecosystem function. The effects of BSCs on water infiltration are complex. BSCs increase porosity and micro-topography, thus enhancing infiltration, but, at the same time, they can increase runoff by the secretion of hydrophobic compounds and clogging of soil pores upon wetting. BSCs confer stability on soil surfaces, reducing soil detachment locally; however, they can also increase runoff, which may increase sediment yield. Although the key role of BSCs in controlling infiltration–runoff and erosion is commonly accepted, conflicting evidence has been reported concerning the influence of BSCs on runoff generation. Very little is known about the relative importance of different BSC features such as cover, composition, roughness, or water repellency, and the interactions of these attributes in runoff and erosion. Because BSC characteristics can affect water flows and erosion both directly and indirectly, we examined the direct and indirect effects of different BSC features on runoff and erosion in a semiarid ecosystem under conditions of natural rainfall. We built structural equation models to determine the relative importance of BSC cover and type and their derived surface attributes controlling runoff and soil erosion. Our results show that the hydrological response of BSCs varies depending on rainfall properties, which, in turn, determine the process governing overland flow generation. During intense rainfalls, runoff is controlled not only by rainfall intensity but also by BSC cover, which exerts a strong direct and indirect influence on infiltration and surface hydrophobicity. Surface hydrophobicity was especially high for lichen BSCs, thus masking the positive effect of lichen crust on infiltration, and explaining the lower infiltration rates recorded on lichen than on cyanobacterial BSCs. Under low intensity, rainfall volume exerts a stronger effect than rainfall intensity, and BSC features play a secondary role in runoff generation, reducing runoff through their effect on surface micro-topography. Under these conditions, lichen BSCs presented higher infiltration rates than cyanobacterial BSCs. Our results highlight the significant protective effect against erosion exerted by BSCs at the plot scale, enhancing surface stability and reducing sediment yield in both high- and low-magnitude rainfall events.
TL;DR: The excessive current preocupation about body image has resulted in the realization of diets and changes as eating disorders, and further work is needed on the issue by creating tools to detect changes and enhance the design of prevention and intervention programs.
Abstract: Introduction: Nowadays, in developed countries there are standards of beauty based on pro-thin models, which are internalized by adolescents and young people especially in the case of women, assuming it as risk factor for developing changes in body image and perception. Objective: To analyze the current state of research in relation to body image, the sociodemographic variables that influence it, the relationship between body composition, conducting diets, eating disorders, sports and intervention programs and prevention, and the body image. Methods: It was searched in Medline, Isi Web of knowlegde and Dialnet as well as a manual search among the references of selected studies and in different libraries. Results and discussion: A increased socio-cultural influence is associated with a greater perception of body fat, greater body image dissatisfaction and lower self assessment of overall fitness. This leads to a lot of teenagers and young adults to abuse to the restrictive diets and to suffer eating disorders. Numerous studies have analyzed the relationship between sports practice with body image disturbance; there are conflictive results. Moreover it is necessary to design objective tools to detect changes and enhance the design of prevention and intervention programs in order to avoid distortion of body image, especially in those age ranges where the population is more vulnerable to this phenomenon. Conclusions: The excessive current preocupation about body image has resulted in the realization of diets and changes as eating disorders. There are other factors that influence body image and perception as the realization of physical exercise, although the results about the relationship between these factors are contradictory. Therefore, further work is needed on the issue by creating tools to detect changes and enhance the design of prevention and intervention programs.
TL;DR: Oil-rich biomass has been produced from heterotrophic fed-batch and semi-continuous cultures of Chlorella protothecoides in conventional 2-L stirred-tank bioreactors using a modified process based on transesterification of wet biomass paste, with a recovery of nearly 97%.
TL;DR: The economic evaluation shows that when pollution load decreases, the contribution of reactant consumption to the photo-Fenton process costs increase with regard to amortization costs, and 30% total cost reduction can be gained treating higher daily volumes, obtaining competitive costs that vary from 1.1-1.9 €/m(3), depending on the pollution load.
TL;DR: In this paper, the authors analyzed the relationship between environmental protection and mid-term financial performance, focusing on when and why this relationship is positive and differentiating between environmental management practices, environmental proactivity and environmental performance of the organization.
Abstract: Purpose – This paper analyses the relationship between environmental protection and mid-term financial performance, focusing on when and why this relationship is positive. In particular, the paper disaggregates environmental protection, differentiating between environmental management practices, environmental proactivity and environmental performance of the organization.
Design/methodology/approach – It uses a cross-section survey of 2,122 Welsh companies to gather information on environmental practices and the FAME database to collect data on accounting based financial performance. The paper uses regression analysis on a combined sample of 186 Welsh companies to evaluate the effect on performance of different types of environmental protection.
Findings – On the whole, the results show a positive effect of environmental protection on mid-term financial performance. Financial performance has a positive and significant correlation with environmental proactivity and with environmental performance, while it has a no significant relation with environmental management.
Originality/value – The paper presents a disaggregated analysis of environmental protection in relationship with financial performance. The paper differentiates between environmental management practices, environmental proactivity and environmental performance of the organization in their relationship with financial performance.
TL;DR: It seems that butyrate increased the availability of several essential amino acids and nucleotide derivatives, and the energy provision for enteric cells might have been enhanced by a decrease in glucose and amino acid oxidation related to the use ofbutyrate as fuel.
Abstract: Butyrate is a short-chain fatty acid extensively used in animal nutrition since it promotes increases in body weight and other multiple beneficial effects on the intestinal tract. Although such effects have been demonstrated in several species, very few studies have assessed them in fish. On the other hand, little is known about the metabolic processes underlying these effects. In the present work, growth parameters and changes in more than 80 intestinal metabolites (nucleotides, amino acids and derivatives, glycolytic intermediates, redox coenzymes and lipid metabolism coenzymes) have been quantified in juvenile sea bream fed a butyrate-supplemented diet. Results showed a significant increase in the weight of fish receiving butyrate, while metabolomics provided some clues on the suggested effects of this feed additive. It seems that butyrate increased the availability of several essential amino acids and nucleotide derivatives. Also, the energy provision for enteric cells might have been enhanced by a decrease in glucose and amino acid oxidation related to the use of butyrate as fuel. Additionally, butyrate might have increased transmethylation activity. This work represents an advance in the knowledge of the metabolic consequences of using butyrate as an additive in fish diets.