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The Lagunas de Campillos Natural Reserve and adjacent ponds are fundamentally surrounded by regularly fertilized crop fields and livestock industry, producing leachates which can be found in the ponds. The interest in this Site of European Importance and the RAMSAR wetland complex lies in the habitats within it, which are included in the Directive on Habitats of Community Interest. It is essential to determine the trophic status of the ponds and the quality of these habitats, as well as whether corrective measures need to be established in order to maintain a good environmental status. To characterize and compare the ponds, different parameters were measured, such as conductivity, pH, nutrient concentration, Chl-a concentration, phytoplankton composition, phytoplankton abundance (<20 µm), and the quantification of heterotrophic microorganisms indicating contamination of the aquifers. The obtained results showed that all ponds, except a mesotrophic pond, are eutrophic or even hypertrophic, with high levels of total nitrogen (>8 mg L−1), total phosphorous (>165 μg L−1), and chlorophyll-a concentration. These findings explain the high densities of phytoplankton observed, with the predominant presence of small cells (<3.6 μm ESD). In addition, concentrations of heterotrophs and coliforms are, in some ponds, higher than expected. Eutrophication hinders ecological functions and ecosystem services, which finally affects biodiversity and human wellbeing. Five of the six analyzed ponds are within various protection figures for their essential importance to local and migrating avifauna. Therefore, ponds' status analysis and the implementation of measures for maintaining ecosystem services and trophic state are fundamental for the sustainable management of the studied area. [ABSTRACT FROM AUTHOR]

Simple Summary: The use of functional feeds in aquaculture is currently increasing. In this study, we investigated the impact of a diet containing Chlorella fusca and ethanol-inactivated Vibrio proteolyticus in Chelon labrosus. After 90 days of feeding, we assessed how this diet affected the fish's gut microbiota and gene expression related to metabolism, stress, and the immune system. We also tested the immune response after submitting fish to challenges with Aeromonas hydrophila and polyinosinic–polycytidylic acid (poly I:C). Results showed that the combined dietary administration influenced the microbial community in the fish's intestines, but it did not change the way these microorganisms functioned. In terms of gene expression, we observed significant variations in several genes in different fish organs from fish fed the combination of microalgae and probiotics. Notably, the combined diet seemed to enhance the fish's ability to regulate stress and immune-related genes, suggesting that it could improve their resistance to stress and infections. Overall, the present study sheds light on how this diet affects both the gut microbiota and gene expression in C. labrosus, potentially benefiting their health and immune response. The use of functional feeds in aquaculture is currently increasing. This study aimed to assess the combined impact of dietary green microalgae Chlorella fusca and ethanol-inactivated Vibrio proteolyticus DCF12.2 (CVP diet) on thick-lipped grey mullet (Chelon labrosus) juvenile fish. The effects on intestinal microbiota and the transcription of genes related to metabolism, stress, and the immune system were investigated after 90 days of feeding. Additionally, the fish were challenged with Aeromonas hydrophila and polyinosinic–polycytidylic acid (poly I:C) to evaluate the immune response. Microbiota analysis revealed no significant differences in alpha and beta diversity between the anterior and posterior intestinal sections of fish fed the control (CT) and CVP diets. The dominant genera varied between the groups; Pseudomonas and Brevinema were most abundant in the CVP group, whereas Brevinema, Cetobacterium, and Pseudomonas were predominant in the CT group. However, microbial functionality remained unaltered. Gene expression analysis indicated notable changes in hif3α, mhcII, abcb1, mx, and tnfα genes in different fish organs on the CVP diet. In the head kidney, gene expression variations were observed following challenges with A. hydrophila or poly I:C, with higher peak values seen in fish injected with poly I:C. Moreover, c3 mRNA levels were significantly up-regulated in the CVP group 72 h post-A. hydrophila challenge. To conclude, incorporating C. fusca with V. proteolyticus in C. labrosus diet affected the microbial species composition in the intestine while preserving its functionality. In terms of gene expression, the combined diet effectively regulated the transcription of stress and immune-related genes, suggesting potential enhancement of fish resistance against stress and infections. [ABSTRACT FROM AUTHOR]

Some of the characteristics of probiotics used in aquaculture are the antagonistic activity against pathogens and the activation of the immune response. Moreover, some probiotics with common antigens to pathogens can produce antibodies that react with these pathogens. One of those potential probiotics is Vibrio proteolyticus DCF12.2, a strain with the capacity to produce antibodies in soles (Solea senegalensis) that react with Photobacterium damselae subsp. piscicida and Vibrio harveyi antigens. Therefore, the objective of the work was to determine the capacity of DCF12.2 to activate the immune response in the sole, providing protection against both pathogens. For this purpose, DCF12.2 was administered to cultured soles by intraperitoneal injection, bath, and diet. The DCF12.2 strain activated the gene expression related to the fish immune response and increased the antibody production with cross-reaction to P. damselae subsp. piscicida and V. harveyi cells. Challenges with P. damselae subsp. piscicida resulted in a 30–40% relative percent survival (RPS) through DCF12.2 treatments. After challenge with V. harveyi, only intraperitoneal treatment protected the fish (67% RPS). In conclusion, the DCF12.2 strain showed great potential to be used to prevent diseases caused by both pathogens, and indicates a way to use probiotics as live vaccines. [ABSTRACT FROM AUTHOR]

Simple Summary: The aquaculture industry is constantly looking for alternative ingredients to fishmeal and terrestrial-plant feedstuffs. Here, we have studied the effects of the combined administration of Chlorella fusca and ethanol-inactivated Vibrio proteolyticus DCF12.2 in the diet of the thick-lipped grey mullet (Chelon labrosus), a promising candidate species for aquaculture diversification. The combined diet enhanced growth performance, n-3 polyunsaturated fatty acids, and fish lipid quality. Furthermore, the experimental diet increased several metabolic enzymes' activity, as well as the intestinal absorption capacity. It can thus be concluded that the experimental diet composed of C. fusca and V. proteolyticus was suitable for feeding C. labrosus. This study aimed to evaluate the combined effect of dietary Chlorella fusca and ethanol-inactivated Vibrio proteolyticus DCF12.2 (C + V diet) in Chelon labrosus juveniles, highlighting their nutritional, physiological, and morphological effects. The results showed that the combined dietary inclusion of C. fusca and V. proteolyticus significantly enhanced growth performance and feed utilization compared to the control group. The C + V diet increased the fish lipid quality index (FLQ), n-3 polyunsaturated fatty acids, and n-3/n-6 ratio, which might be beneficial in terms of human nutrition. The C + V diet considerably increased carbohydrate metabolic activity by statistically boosting plasma glucose. The dietary inclusion of C. fusca in conjunction with V. proteolyticus increased metabolic enzyme activity as well as intestinal absorption capacity compared to that found in the control group. In conclusion, the experimental diet was suitable for feeding C. labrosus, increasing their growth and the nutritional characteristics of the muscle and intestine, without causing tissue damage. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

This work concerns the case study of a Mediterranean Ramsar salt lake (Fuente de Piedra, southern Spain) that receives the treated wastewater of the local village treatment plant. The wastewater goes through a system of canals, water dams, and three semi-natural ponds that were built in 2005. This work aims to investigate the capacity of the system to assimilate the impact of wastewater effluents on Lake Fuente de Piedra. For this, four points were sampled on 27-29 April 2016, at the inlet and the outlet points of the first and the third semi-natural ponds, with three replicates each. Temperature, pH, and conductivity at the inlet were 19.62 °C, 7.99, and 3262.67 μS/cm, respectively, and increased through the pond system by 7.59%, 8.04%, and 37.34%, respectively. Phytoplankton concentration indicators decreased from the inlet point to the outlet point (chlorophyll a from >500 to <20mg/L), as did the biovolume (from >5 × 1010 to 4.3 × 109 μm³/mL). Zooplankton biovolume, in contrast, increased three orders of magnitude from the inlet (3.5 × 107 μm³/mL) to the outlet point (1.6 × 109 μm³/mL). Heterotrophic bacteria (1.29 × 105 cfu/mL) and faecal enterococci (1033 ± 351 cfu/100 mL) were high at the inlet point, but decreased at the outlet point by almost three orders of magnitude. Total phosphorous and total nitrogen decreased 40.3% and 23.1% through the pond system. The results showed an improvement in water quality in its passage through the built system. Additionally, as permanent wetlands with acceptable water quality, the water system attracts wild fauna during the dry summer, leading to the conclusion that these semi-natural or artificial wetlands should be extrapolated to other aquatic ecosystems (Mediterranean wetlands) that receive contributions of residual waters. Better functioning of the treatment plant is desirable to improve the conservation of the Ramsar and adjacent wetlands systems. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Simple Summary: The thick-lipped grey mullet (Chelon labrosus) has good potential for aquaculture diversification in Europe. However, research studies about this species are scarce, particularly focusing on the nutritional attributes of wild and cultivated thick-lipped grey mullets that might help to optimize its feeding regime. In order to determine the nutritional composition of thick-lipped grey mullet juveniles, wild and cultivated specimens were collected and compared. To do so, the liver fatty acids, muscle proximate composition, fatty acids and amino acids were analyzed. The wild specimens had higher levels of polyunsaturated fatty acids and a higher content of eicosapentaenoic (EPA) and docosahexaenoic (DHA) acids than the farmed specimens. Furthermore, all the amino acid scores were above 100% compared to the Food and Agriculture Organization of the United Nations/World Health Organization (FAO/WHO) standard. This study provides new knowledge and contributes to understanding the nutritional attributes of wild and cultured C. labrosus and helps to design diets according to their nutritional demands. 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. [ABSTRACT FROM AUTHOR]

Impacts on wetlands are becoming more pressing every day. Among them, habitat loss, overexploitation of aquifers and changes in land use are considered the most important. However, the impacts linked to wastewater discharges are increasing worldwide. In this context, this study analyses the impacts of input of wastewater to a Mediterranean Ramsar temporary wetland (Fuente de Piedra, south of Spain). To this end, systematic sampling was carried out in the Charcón stream which receives water from a wastewater treatment plant (WWTP) and discharges it into the wetland. The results showed a slight decrease in the nutrient concentrations, particularly for nitrogen compounds. Heterotrophic and fecal bacteria concentration, as well as phytoplankton and zooplankton abundance and biomass, all significantly decreased from the treatment plant to the wetland. When comparing the effect of this discharge with other similar occurring to the same wetland, it was evident that the Charcón stream was responsible for a greater impact. At this point, it is relevant to note that the main difference among both treated wastewater discharges lies in the different water retention time once the wastewater was released from the WWTP. In fact, we recommend an increase in the water retention time by building seminatural ponds, together with the use of biofilters, which will notably contribute to improve the processes of assimilation of nutrients and to decrease the impact generated in the wetland by this spill. [ABSTRACT FROM AUTHOR]