First evaluation of associated gut microbiota in wild thick-lipped grey mullets (Chelon labrosus, Risso 1827)

The need for species diversification in Mediterranean aquaculture has promoted the culture of omnivorous and herbivorous species. Within this context, it is worth noting the high potential presented by the species of the family Mugilidae (mullets), which is considered a priority within the current strategies of European aquaculture (Alexander et al. 2015). One of the mullets with potential for use in aquaculture is the thick-lipped grey mullet (Chelon labrosus), due to its great adaptability to different culture conditions, omnivorous profile, high osmoregulatory capacity, and resistance to environmental variations (Pujante et al., 2018). However, there is a lack of information regarding the composition and functions of its intestinal microbiota. Documenting the bacteria present in healthy individuals is the first step to understanding the impacts of microbial manipulation in aquaculture systems (Tarnecki et al., 2016). In this sense, the knowledge of bacterial diversity from healthy wild fish in their natural environment is essential. Furthermore, the study of the functionality of the intestinal microbiota of wild fish provides information on its capacity to adapt to different culture conditions. Thus, this study aimed to characterize the intestinal microbiota of wild C. labrosus and explore its potential functionality on the host. Predicted functions of intestinal microbiota showed the most abundant those related to amino acid metabolism, carbohydrate metabolism, energy metabolism, membrane transport, and cell replication and repair. Furthermore, the analysis revealed microbial functional genes related to the elimination of environmental toxins. These functions of intestinal microbiota might provide beneficial effects for the host.This work was funded by Project Agl-2017-83260R supported by the Agencia Estatal de Investigación (MINECO, Spanish Government), and by the Project Bluemaro (PID2020 116136 RB100) of the Ministry of Science and Innovation of Spain

Antimicrobial and Toxic Activity of Citronella Essential Oil (Cymbopogon nardus), and Its Effect on the Growth and Metabolism of Gilthead Seabream (Sparus aurata L.)

Aquaculture procedures usually induce stress that affects the physiological status of fish. For this reason, the inclusion of additives in fish feeds to palliate stress might be a good alternative. This study aimed to assess the antimicrobial activity of citronella (Cymbopogon nardus) essential oil (CEO) against bacterial pathogens and to determine its dietary impact on the growth performance of Sparus aurata. In vitro tests confirmed that CEO possesses antimicrobial activity against several fish-specific pathogens. For the in vivo tests, three experimental groups were fed for 60 days with different concentrations of CEO: CTRL (0 mL kg(-1) fish feed); CEO1 (1 mL kg(-1) fish feed); and CEO2 (2 mL kg(-1) fish feed). At the end of the experiment, the physiological status was characterized. Subsequently, the specimens of the CTRL and CEO2 groups were subjected to a challenge with an injection of Poly I:C for immune stimulation. Although S. aurata individuals tolerated CEO inclusion without compromising growth performance, it significantly reduced glycogen in the CEO2 group, concomitant to an increment of total peripheral leucocytes. Moreover, different hematological profiles' responsive patterns against an inflammatory stimulus were observed. In conclusion, our results suggest that the use of CEO as a fish feed additive can prevent bacterial outbreaks and improve potential in vivo disease resistance in S. aurata without negatively affecting growth

First Evaluation of Associated Gut Microbiota in Wild Thick-Lipped Grey Mullets (Chelon labrosus, Risso 1827)

This study aimed to characterize the intestinal microbiota of wild thick-lipped grey mullets (Chelon labrosus) and explore its potential functionality on the host. Intestinal contents of anterior and posterior sections from wild fish were collected and DNA was extracted. Subsequently, the V3–V4 regions of 16S rRNA were sequenced using the Illumina technology and results were analyzed by bioinformatics pipeline. The functional profile of the microbial community was analyzed using PICRUSt software. Shannon and Simpson diversity indices were significantly higher in the posterior section of wild specimens. The overall taxonomic composition suggests a certain homogeneity in the anterior section of the intestine and heterogeneity in the posterior section. Due to this, no statistical differences were detected at any level among both intestinal sections. Predicted functions of intestinal microbiota showed the most abundant were those related to amino acid metabolism, carbohydrate metabolism, energy metabolism, membrane transport, and cell replication and repair. Furthermore, the analysis revealed microbial functional genes related to the elimination of environmental toxins.This work was financed by the Project ‘Design and evaluation of probiotics and feed in uncoupled aquaponic system of fishes, plants and microalgae’ (grant #Agl-2017-83260R) granted by Agencia Estatal de Investigación (MINECO, Spanish Government), and by the Project Bluemaro (PID2020 116136 RB100) of the Ministry of Science and Innovation of Spain. Partial funding for open access charge: Universidad de Málag

Procedimiento de preparación, conservación, y uso en peces, del probiótico SHEWANELLA PUTREFACIENS PDP 11 para el control de enfermedades y la mejora en el crecimiento

Número de solicitud 201100385Procedimiento de preparación, conservación, y uso en peces, del probiótico Shewanella putresfaciens Pdp11 para el control de enfermedades y la mejora en el crecimiento. Preferentemente, el probiótico, compuesto por células enteras de la cepa Pdp11, se cultiva en TSAs durante 24 h a 22ºC. La preparación de una suspensión del probiótico, preferentemente sin proceso previo de liofilización o de inactivación física o química, se realiza mediante su incorporación en una matriz de alginato, preferentemente alginato sádico al 0,5%. La suspensión preparada se puede conservar sin pérdida significativa de viabilidad durante 20 - 30 días a 4ºC. Los productos alimenticios para peces son preparados mediante la adición en agitación de la suspensión de probiótico y, adicionalmente, CaCl2 50 mM, preferentemente mediante atomización.Universidad de Málaga (50%). Universidad de Almería (50%

Preparado de bacterias probióticas para su administración oral a peces cultivados basado en la encapsulación en hidrogeles de alginato

Número de solicitud: 201100469La invención consiste en un preparado para la administración oral del probiótico Shewanella PDP11 a peces. El preparado se caracteriza por contener células bacterianas viables de la cepa CECT 7627 encapsuladas en un hidrogel basado en alginato cálcico en forma de partículas esféricas de morfología uniforme y tamaño modificable para adaptarse a peces de distinto tamaño. Las cápsulas contienen aditivos organolépticos y/o nutricionales que actúan como atrayentes para los animales. El preparado mantiene viables a las bacterias durante periodos prolongados, es estable en medios acuáticos, y soporta el paso por el tubo digestivo de los peces, sobre los que ejerce efectos biológicos favorables. Su administración por vía oral es independiente del alimento habitual, evitando así la inactivación del microorganismo durante la fabricación del pienso.Universidad de Almerí

Cultivated and Wild Juvenile Thick-Lipped Grey Mullet, Chelon labrosus: A Comparison from a Nutritional Point of View

The thick-lipped grey mullet (Chelon labrosus) is a nominee fish species for aquaculture diversification in Spain because it is an omnivore and euryhaline species, but limited knowledge about the nutritional attributes of this species is available. This study aimed to characterize the chemical composition of wild and cultured fish. The muscle proximate composition, and fatty acid and amino acid profiles were assessed. The cultivated specimens showed a higher lipid content and lower protein and ash contents compared with the wild specimens. The predominant tissue fatty acids in both the wild and cultivated fish were palmitic acid (16:0), oleic acid (18:1n-9) and docosahexaenoic acid (DHA, 22:6n-3). A higher content of arachidonic acid (ARA, 20:4n-6), eicosapentaenoic acid (20:5n-3) and DHA were detected in the muscle of wild mullets, while the fish supplied with commercial pellets showed higher quantities of monounsaturated fatty acids, and lower quantities of saturated fatty acids and polyunsaturated fatty acids (PUFAs). Regarding PUFAs, n-3 fatty acids were predominant in wild mullets, while n-6 and n-9 were more abundant in farmed fish. In terms of amino acid composition, except for histidine in wild specimens, the amino acid amounts were higher than the FAO/WHO standard. In conclusion, C. labrosus may contribute to improving the dietary intake of highly polyunsaturated n-3 fatty acids, with a benefit to human health, owing to that fact that a 100-g fillet portion of cultivated and wild C. labrosus can provide 770 mg and 1160 mg of EPA and DHA, respectively, which exceeds the 250 mg dietary daily intake recommended by the FAO/WHO

Dietary Use of the Microalga Chlorella fusca Improves Growth, Metabolism, and Digestive Functionality in Thick-Lipped Grey Mullet (Chelon labrosus, Risso 1827) Juveniles

In recent years, a clear emphasis has been placed on replacing fishmeal and fish oil in aquafeeds with other alternative ingredients, including algae, particularly in low trophic omnivorous fish species. This work aimed at evaluating the effects of moderate dietary supplementation with the green microalga Chlorella fusca on growth, metabolism, and digestive functionality in juvenile thick-lipped grey mullet (Chelon labrosus). Fish were fed a control diet (CT) or a diet containing 15% C. fusca (C-15) biomass during 90 days. C. labrosus fed with the C-15 diet showed higher growth performance (in terms of final weight and length, weight gain, and specific growth rate) than the control group. Somatic indices and muscle proximate composition were similar at the end of the feeding trial. Regarding fatty acids profile, C. fusca-fed fish showed a selective retention of docosahexaenoic acid (DHA) in the liver, and arachidonic acid (ARA), eicosapentaenoic acid (EPA), and DHA in the muscle. Dietary inclusion of this microalga significantly increased intestinal total alkaline protease, leucine aminopeptidase, and alkaline phosphatase activities in specimens fed with C-15 diet. Furthermore, intestine histological analysis revealed the absence of damage signs on gut morphology in fish fed the microalgae supplemented diet. Thick-lipped grey mullets fed the C-15 diet increased plasma glucose and decreased plasma lactate. Overall, the effects observed on liver (lipid metabolism, glycolysis and glycogenolysis) enzyme activities, together with adequate fatty acid profile, metabolic response, and gut morphology, and a significant increase in the intestinal mucosa's digestive and absorptive capacity, could explain the positive effects on growth performance obtained in fish fed the microalgae-supplemented diet. In conclusion, the results obtained showed that C. fusca is suitable as dietary ingredient for feeding thick-lipped grey mullet juveniles

Molecular Diversity and Biochemical Content in Two Invasive Alien Species: Looking for Chemical Similarities and Bioactivities

The biochemical composition, molecular diversity, and two different bioactivities of Asparagopsis armata and Rugulopteryx okamurae (two alien species with different invasive patterns in the southern Iberian Peninsula) were analyzed through spectrophotometric methods and Fourier transform ion cyclotron mass spectroscopy (FT-ICR-MS). A total of 3042 molecular formulas were identified from the different extracts. The dH2O extracts were the most molecularly different. A. armata presented the highest content of nitrogenous compounds (proteins, CHON) and sulphur content, whereas R. okamurae was rich in carbonated compounds (total carbon, lipids, CHO, and CHOP). Antioxidant capacity and phenolic content were higher in R. okamurae than in A. armata. Antimicrobial activity was detected from both species. A. armata showed capacity to inhibit human and fish pathogens (e.g., Staphylococcus aureus or Vibrio anguillarum), whereas R. okamurae only showed inhibition against human bacteria (Staphylococcus aureus and Cutibacterium acnes). In R. okamurae, molecules with a great number of pharmaceutical activities (e.g., anti-inflammatory or antitumoral), antibacterial, biomaterial, and other utilities were found. The main molecules of A. armata had also pharmaceutical applications (e.g., antimalarian, antithrombotic, anti-inflammatory, or antiarthritis). The valorization of these species can help to counteract the environmental effects of the bioinvasions.This research was funded by the BLUEMARO Project from the Science and Innovation Ministry of the Spanish Government (grant number PID2020-116136RB-I00) and by the Start-up funding for junior research groups of the Carl von Ossietzky University Oldenburg, “pharmaDOM”. Partial funding for open access charge: Universidad de Málaga

Instituto de Biotecnología y Desarrollo Azul de la Universidad de Málaga: una apuesta por una Acuicultura Azul

Noventa investigadores de la Universidad de Málaga pertenecientes a 21 grupos de investigación, se han organizado en un Instituto de Biotecnología y Desarrollo Azul, IBYDA. El objetivo del IBYDA es la investigación, la docencia, el desarrollo y la transferencia de conocimiento en el marco del desarrollo circular o azul; incluyendo el análisis económico de los proyectos, el modelado de diferentes escenarios, y su aplicación a la gestión y planificación del territorio. Así mismo, el instituto ofrecerá infraestructuras acuícolas y servicios, y promoverá el emprendimiento. La actividad transversal central del IBYDA es la Acuicultura Multitrófica como implementación de la estrategia de Biorrefinería, es decir, el aprovechamiento de distintos tipos de residuos para el cultivo de organismos, cuya biomasa se empleará para la obtención de productos de alto valor añadido.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tec

Role of the capsule of Photobacterium damsela subsp. piscicida in protection against phagocytosis and killing by gilt-head seabream (Sparus aurata, L) macrophages

The role of the capsule in Photobacterium damsela subsp. piscicida (formerly Pasteurella piscicida) as a virulence factor was evaluated by determining the phagocytic and bactericidal activities of macrophages of gilt-head seabream. Five capsulated strains of P. damsela subsp. piscicida pathogenic for gilt-head seabream and one strain (EPOY-8803-II) described as noncapsulated and avirulent for this fish species were used in the study. Significant di#erences (P<0·025) in the percentages and index of phagocytosis between the EPOY-8803-II strain and capsulated strains were observed, the noncapsulated strain being phagocytosed to a greater degree (86·4%). The induction of the synthesis of a capsule in strain EPOY-8803-II produced a significant reduction in the phagocytic percentage and index for this strain. However, no significant di#erences (P<0·1) in the bactericidal activity of seabream macrophages were obtained between capsulated and noncapsulated strains. 1998 Academic Press Limite