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09:00-09:45 Session 1: Plenary Lecture
From Molecular Ecology to Planetary Health.

ABSTRACT. Exposure to long-range transported industrial chemicals such as persistent organic pollutants (POPs) and other pollutants such as mercury pose a risk to the overall health and populations of Arctic wildlife and Northerners. Since local communities are relying on the same marine food web as marine mammals in the Arctic, it requires a One Health approach to understand the holistic ecosystem health including that of the environment, animals and humans. Given the long marine food chains and the biomagnification of most contaminants, top predators such as Inuits, polar bears and toothed whales end up with extremely high exposures posing risks of effects at population-level. Here I give a overview of the current knowledge on POPs and mercury in the Arctic environment, molecular effects and the consequences for animals and humans in terms of adverse health effects. Finally, I discuss the future perspectives of planetary health in relation to other stressors such as climate change and zoonotic infectious diseases.

09:50-10:50 Session 1: Oral Presentations
New approaches in the detection and ecotoxicity of nanoplastics in aquatic organisms.
PRESENTER: François Gagné

ABSTRACT. The ubiquity of plastic materials in the environment has raised the issue of potential ecotoxicological problems in aquatic organisms. Furthermore, this is worsened by the long-term degradation of plastics at the micro (5 mm-0.1 µm) and nanoscale (<100 nm), becoming bioavailable, internalized in cells and toxic such as oxidative stress. The presence of these polymers in the cytoplasm introduces crowding leading to “biophysical changes” in protein networks and soluble/membrane receptors involved in metabolism. Size exclusion chromatography and flow cytometry methodologies were recently developed and makes use of fluorescent probes for plastics such as Nile Red and molecular rotor probe (joluidine). Biophysical changes of plastic nanoparticles involve the formation of liquid crystals, protein condensation (plaques) and fractal changes in enzyme activities induced by crowding protein networks were recently proposed. The fractal changes result from changes in protein networks, acting as percolation clusters, leading to reduced dimensions of chemical reactions at the levels of energy metabolism. These changes lead to protein denaturation and recycling from the geometrical structure of nanoparticles. These endpoints were used to investigate the presence and effects of plastic nanoparticles in both marine and freshwater bivalves at polluted (anthropogenic) sites likely sources of plastic contamination. These tools should better our understanding on the fundamental toxic properties of plastic polymers in the environment.

Physiological combined effects of microplastic and heat waves in the Mediterranean coral Astroides calycularis
PRESENTER: Verdiana Vellani

ABSTRACT. Anthropogenic stressors are negatively influencing marine organisms, both directly and indirectly. Among them heatwaves and microplastic are recognized as global threats, especially in the Mediterranean basin where environmental changes are happening at faster rates. In this study, the combined effects of heatwaves and microplastics on respiration and excretion rates were studied in the Mediterranean coral Astroides calycularis. Colonies were exposed to 4 conditions (presence/absence of microplastics and ambient/increased temperature) for 4 weeks under laboratory conditions, with 1°C/week increasing temperature (26°C->29°C). During the exposure, oxygen consumption was measured for each colony i using respiration chambers. An aliquot of seawater was collected from each chamber for the ammonia excretion analysis, and mortality rate was also measured. ANCOVA (polyps/colony as covariate) was applied to highlight significant interactions between microplastics and heatwaves on physiological rates during a 4 weeks exposure, while ANOVA was used for testing differences in the mortality rate. Mortality was not significantly different among conditions and physiological rates increased with temperature. Respiration and excretion rates showed a bell-shape trend, with higher values after 3 weeks, at 29 °C, probably due to the proximity to the warm sublethal thresholds, being around 24-29 °C according to the literature. The decrease detected for both rates after four weeks could be due to acclimatisation to laboratory conditions or to adaptation: if the latter case, reducing metabolic rates is a strategy for energy conservation to better survive in a stressful scenario. Temperature was the main factor that affected metabolic rates, while the presence of microplastics reduced respiration rate only after 3 weeks of exposure. Our data suggest that temperature between 27 °C and 29 °C is probably within a zone of metabolic thermal compensation for the species.

Chemical characterization and toxicity evaluation of bioplastics leachates in early larval stages and adult mussels, Mytilus galloprovincialis
PRESENTER: Elena Fabbri

ABSTRACT. Similarly to conventional plastics, bioplastics contain additives such as plasticizers, stabilizers, etc (intentionally added substances, IAS) and side products or breakdown products (non-intentionally added substances, NIAS), which may be released during weathering processes, producing mixtures whose biological effects are poorly known. In the present work, leachates were obtained from three bio-based plastics, polylactic acid glasses (PLA), bio-polyethylene terephthalate mineral water bottles (BPT), unknown bioplastic-based supermarket bags (SB) and one conventional polymer, i.e. tire rubber (TR). The chemical nature of plastics was confirmed by Py-GC-MS and ATR-FTIR. Fragmented plastic items were incubated in artificial sea water (35 PSU, pH 8) for 14 days at 18°C in the dark. The main organic chemicals found by GC-MS and HPLC-MS/MS in the leachates were catalysts and stabilizers in TR and NIAS in SB. BPA was found at 4.8 µg/L in leachates from TR, 0.5 from SB and 0.3 from PLA and BPT. NIAS found in SB leachates probably derived from poly(butylene adipate-co- terephthalate). Trace metals higher than in controls were: Al, Fe, Zn, Pb, Cr, As in leachates from TR; Fe, Cu, Ni, Pb, As from SB; Cu, Mn from PLA and BPT. Leachates (12 dilutions, from 100% to 0.6%) were tested for embryotoxicity and sublethal effects in mussels. TR and SB leachates caused embryos deformities at 1%, and were lethal at 10% concentration. Adult mussels were exposed to leachates at a concentration as low as 0.6% for 7 days, then 9 biomarkers were assessed. Haemocyte lysosome membrane stability was reduced and lysosome enlarged by TR and SB leachates. Lipofuscins significantly increased in digestive glands after exposure to TR and SB leachates, indicating oxidative stress. Overall, data on mixture composition represents a crucial contribution in this field, enabling scientists to relate plastic leachates and toxicity. The presence of non-priority NIAS is worth of consideration.

09:50-10:50 Session 2: Oral Presentations
Short-term effects of the strobilurin fungicide Dimoxystrobin on zebrafish gills: a morpho-functional study.

ABSTRACT. In the last decades, the hazards posed by the increasing and extensive application of fungicides have become an issue of great concern. Strobilurins which account for 20% of the global market are the most sold fungicides and are found in all environmental compart. Dimoxystrobin, belonging to strobilurins, has been classified as very toxic and listed on the Third Watch List under the Water Framework Directive by European Union, fulfilling the criteria for prioritization requirements. Dimoxystrobin poses a significant risk to the aquatic habitats being bioaccumulative, toxic, and owning endocrine-disrupting properties. However, the information is insufficient, and much more effort is required to gather comprehensive data for aquatic species. Hence, understanding the mechanisms through which Dimoxystrobin disrupts the normal physiological processes will help elucidate its actual environmental hazard. Here we used zebrafish (Danio rerio), a well-recognized model species, to investigate the effects of this fungicide on gills, a multifunctional and highly sensitive organ widely used for ecotoxicological evaluation. Furthermore, since the zebrafish genome has remarkable similarities to humans, our results have a high translational value and can help assess potential risks to human health. To realize a realistic exposure scenario, two low and environmentally relevant concentrations (6.56 and 13.13 µg/L) were used based on the predicted concentrations in freshwater. We analyzed gills' histological alterations and the expression patterns of key enzymes involved in physiological processes after short-term exposure (96 h). We demonstrated for the first time that, Dimoxystrobin alters the morphology and function of the gills, thus affecting the general health status of fish and posing a serious risk to non-target organisms. Given the scarcity of reports, our results provide a basis for future policy design and the development of early warning protocols.

Physiological responses of Mytilus galloprovincialis exposed to neonicotinoids: Calypso 480SC and thiacloprid
PRESENTER: Maria Pagano

ABSTRACT. This work aimed to assess the risk posed by the neonicotinoid pesticide thiacloprid on Mytilus galloprovincialis, a non-target organism. Mussels were exposed to the commercial pesticide formulation Calypso 480 SC (40.4% thiacloprid) and the active molecule thiacloprid (purity 99.9%, Sigma Aldrich). An acute exposure to sublethal concentrations of Calypso (10, 50 and 100 mg/L) and thiacloprid (1, 5 and 10 mg/L) was performed for 3 and 7 days, whereas a sub-chronic exposure to Calypso (7.77 and 77.70 mg/L) and thiacloprid (4.5 and 450 g/L) was carried out for 10 and 20 days. Acute exposure showed significant changes in electrolytes ions, LDH enzyme activity and glucose concentration in haemolymph. The thiacloprid-exposed mussels showed a significant imbalance in CAT activity in the digestive gland and gills. Calypso caused a significant decrease in SOD activity in gills and CAT activity in both tissues. Results of histological analyses showed severe damage in both the digestive gland and gills in a time- and concentration-dependent manner. Sub-chronic exposure to Calypso showed significantly increased mortality rate in the cells of both hemolymph and the digestive gland, while digestive gland cells were no longer able to regulate cell volume. Exposure significantly reduced hemolymph parameters, affected the enzymatic activities of SOD of the digestive gland and that of CAT in gills, and also caused histopathological alterations in the digestive gland and gills. Main histological damages detected in mussels. Sub-chronic exposure to thiacloprid affected hemolymph biochemical parameters, cell viability in the digestive gland, antioxidant biomarkers in the digestive gland and gills. In addition, thiacloprid caused histological damage to the digestive gland and gills. This study attempts to improve the limited information on the effects of neonicotinoids on aquatic organisms, highlighting how prolonged exposure to low concentrations is harmful to non-target organisms

Complex contaminant mixture and omics responses in Atlantic cod: a time- and dose-response study

ABSTRACT. Understanding responses to contaminant mixtures is a pressing challenge in environmental toxicology. In this study, we used an omics-based strategy to investigate the response to a mixture of ten contaminants representing both legacy organochlorines and contaminants of emerging concern in equimolar concentrations (with trans-nonachlor and chlorpyrifos at 1/10 of the rest) at eight different doses. Juvenile Atlantic cod (Gadus morhua) were exposed by intraperitoneal injection, and various tissues were sampled on day 2, 5 and 12 after the start of the experiment (total n=219). RNA-seq was performed on all liver samples from days 0, 2 and 5, whereas proteomics was performed on doses 0, 3, and 7 from day 5, and on all doses from day 12, and lipidomics was performed on liver microsomes from doses 0, 3, and 7 from all time points, and on plasma samples from doses 0, 3, and 7 only from day 12. RNA-seq revealed a cluster of estrogen-responsive transcripts of which some were induced on day 2 and 5, but only at the higher doses (6-8 on day 2, 7-8 on day 5), although some were also down-regulated at the lower doses. Genes involved in lipid metabolism showed a similar pattern. Among proteins identified in day 12 liver samples the top predicted canonical pathways show a biphasic activation of the LXR/RXR pathway, synaptogenesis signaling, and fatty acid ß-oxidation. A decrease in phosphatidyl lipids was seen in the liver microsomes on day 12. Non-monotonic dose-response curves were observed for several genes and proteins involved in reproductive function, lipid metabolism and phospholipid regulation. suggesting that non-monotonic dose-response analysis can improve the toxicological and regulatory assessment of mixtures.

The study was a part of the dCod 1.0 project, funded by the Research Council of Norway (project 248840) under the Centre for Digital Life Norway program (248810).

10:50-11:30Coffee Break
11:30-13:10 Session 1: Oral Presentations
A new route: do tire particles and associated-chemicals have an effect on Pacific oyster (Crassostrea gigas) physiology and reproduction?

ABSTRACT. The presence of tire particles in seawater and Oceans potentially represent the 93% by mass of the aquatic plastic contamination by 2040. This might have consequences on organisms, like physical injuries and health repercussions due to chemical risk following the leaching of tires-associated chemicals. The present study proposes an exhaustive analysis on the potential effects of tire particles and related leachates on physiology and reproduction of the Pacific oyster Crassostrea gigas, a sessile bivalve mollusk species with relevant ecological and economical roles. Following the exposures to different tire particles and leachate concentrations, chemical, ecophysiological, cellular and molecular analyses (RNA-sequencing, 16S) were performed to evaluate alterations at different organization levels in adults’ tissues and gametes. Results highlighted no significant differences between groups in ecophysiological parameters and haemocytes features. Regarding molecular analysis, few changes in gills and digestive gland microbial composition between treatments have been found. Conversely, transcriptional profiling evidenced significant modifications between groups especially in oysters treated with the highest concentration of tire particles and leachates, with common alterations of pathways involved in xenobiotic metabolism, bile and fatty acid metabolism, oxidative phosphorylation and glycolysis. Transcriptional sex-dependent responses to each treatment were also found. Regarding possible effects on oyster reproduction, the exposures to leachates significantly reduced the percentage of motile spermatozoa compared to the control treatment. Transcriptomic study performed in oocytes showed also the impairment of genes involved in different biological processes like hormone signaling, reproduction, development, immune response and inflammation without consequences on female gamete quality.

Microplastics and sea urchins: from the laboratory to the marine environment
PRESENTER: Carola Murano

ABSTRACT. Plastic pollution has become a problem of global concern and strongly impacts marine ecosystems. However, the interaction between living organisms and plastic debris including microplastics (MPs, <5mm) are still not fully explored. We present here our recent recent findings about the capability of the Mediterranean sea urchin Paracentrotus lividus to internalize MPs in a selective size-dependent manner and the resulting severe immunological alterations. Moreover, we obtained evidence that the biofilms naturally occurring on MPs play a key role affecting uptake/biodistribution and altering the redox homeostasis of organs/immune cells in sea urchins. Presence of MPs in natural populations of P. lividus from the Gulf of Naples has also been assessed. The data show significant occurrence of MPs, mostly microfibers (MFs; >90%) both in gonads, coelomic fluid and digestive system with an average of 2.6 items/individual, in adult sea urchin specimens sampled in all four sites in the Gulf of Naples (Ischia, Rocce Verdi, Capo Miseno, Nisida). The highest number of MFs was found in those retrieved from Rocce Verdi (4.88 items/individual) followed by those from Nisida (3.28 items/individual), while the lowest in those from Ischia (0.60 items/individual). Fourier Transform Infrared spectroscopy (µ-FTIR) analysis revealed that both polyester and cotton-based MFs were found. The origin of such polymers could be mainly attributable to fragmentation of fishing lines and/or release of sewages discharges from municipal sewage treatment plants. Overall, these findings suggest that sea urchins may represent a suitable bioindicator to monitor the presence of MPs and in particular MFs in benthic environments. In addition, the extent of MP contamination in local sea urchin populations provides insights into the potential risks for other species as well as for humans, following their consumption.

Morphological and molecular evidence of the impact of biodegradable microplastics on the sea urchin Paracentrotus lividus embryos
PRESENTER: Thomas Viel

ABSTRACT. Plastic represents a ubiquitous material in our lifes and its uncorrected disposal is causing serious problem for the environment, being plastic litter detected in all environmental compartments. Several efforts are currently focused on improving its recycling process and producing environmentally friendly solutions. In recent years, biodegradable polymers/plastics have been proposed to reduce the environmental impact in some specific applications like in the packaging sector. Research studies are ongoing to improve biodegradable polymers manufacturing and characteristics, but few data are available about their behavior and toxicity on marine organisms. We investigated the effects biodegradable microplastics, realized at lab scale by milling polymeric films of Polybutylene succinate (PBS), Poly(butylene succinate-co-butylene adipate (PBSA), Polycaprolactone (PCL), Poly-β-hydroxybutyrate (PHB) and Polylactic acid (PLA) on the sea urchin Paracentrotus lividus embryos at morphological and molecular levels. Our results showed that PCL, PHB and PLA were able to induce delay and malformations in P. lividus embryos by affecting the expression levels of several genes involved in stress response, differentiation/development, skeletogenesis and detoxification process. These findings open new perspectives for understanding the role of biodegradable polymers on different marine organisms.

Environmental microplastics induce cellular alterations, autophagy and metabolomic disorders in the seaworm Hediste diversicolor
PRESENTER: Tiziana Cappello

ABSTRACT. Microplastics (MPs) have raised global concern in recent years due to their ubiquitous distribution in the marine environment. However, understanding of accumulation and biological impact of environmental MPs is still significantly limited compared to manufactured MPs. To fulfill this gap, the effects of a mixture of environmental MPs collected along the Tunisian beaches were herein assessed in the marine polychaete Hediste diversicolor, following exposure for 14 days. The mixture of environmental MPs was composed by polyethylene (PE), polyethylene vinyl acetate (PEVA), low-density polyethylene (LDPE), high-density polyethylene (HDPE), polypropylene (PP) and polyamide (PA), which concentrations were found to increase in seaworm tissues over time, in the order 1.2–0.45 μm > 3–1.2 μm > 100–3 μm. The ingestion of MPs reduced seaworm survival and growth, and altered neurotransmission and antioxidant pathways. Moreover, environmental MPs provoked cytoskeleton damage and induced autophagy as revealed by immunohistochemical labeling of specific targeted proteins, i.e. tubulin (Tub), microtubule-associated protein light chain 3 (LC3), and sequestosome 1 (p62). Nuclear Magnetic Resonance (NMR)-based metabolomics highlighted a total of 28 metabolites differentially expressed between control and MPs-treated seaworms, which showed elevated levels of amino acids, glucose, ATP/ADP, osmolytes, glutathione, choline and phosphocholine, and reduced concentrations of aspartate, therefore suggesting MPs-induced changes in different metabolic pathways. Overall, findings from this work emphasize that the toxic effects of environmental MPs are closely related to exposure doses and times. Therefore, this study enlarges our understanding of the toxicity and ecological risk of environmental MPs on marine biota, and provides insights on their underlying mechanisms.

Polyethylene microplastics reduce filtration and respiration rates in the Mediterranean sponge Petrosia ficiformis
PRESENTER: Lucia De Marchi

ABSTRACT. Microplastic (MP) pollution represents a distinctive mark of the Anthropocene and it is currently the most common items of marine litter. Polyethylene (PE) represents one of the most abundant plastic compounds in surface waters, significantly contributing to the content of the global plastic waste in the oceans. Despite the increasing efforts to determine ecological impacts of MPs on marine biodiversity, our understanding of their toxicological effects on invertebrate species is still limited. Sponges (Phylum Porifera) are particularly understudied in MP research, despite their key functional roles in ecosystem functioning and as good sentinel species in biomonitoring programs. These filter-feeders extract and retain particles from the water column, across a broad size range. In this study, we carried out a laboratory experiment to assess the uptake of PE-MPs (polyethylene microplastics) by the Mediterranean sponge Petrosia ficiformis, how MPs influence biological key-process after different times of exposure (24h and 72h) and whether they can be subsequently eliminated. Results showed that MP uptake increased with time of exposure, with 30.6% of the inoculated MP particles found in sponge samples after 72h. MPs impaired filtration and respiration rates and these effects were still evident 72h after sponges had been transferred in uncontaminated water. Our study shows that time of exposure represents a key factor in determining MP toxicity in sponges. In addition, our results suggest that sponges could represent a valid tool for the biomonitoring of microparticulate pollutants.

11:30-13:10 Session 4: Oral Presentations
Morphologic and genic effects of waters contaminated with organic pollution on Paracentrotus lividus Lmk: a mesocosm experiment

ABSTRACT. Often our attention is concentrated on chemical pollutants and contaminants of the seawater. However, large part of coastal contamination is due to organic pollution and more than 99 per cent of the organic matter in the ocean is dead, dissolved and extremely dilute. This complex mixture of organic molecules, comprising a solution of degraded macromolecules, has a strong effect on planktonic and benthic coastal communities and plays an active role in the global carbon cycle. The reservoir of organic matter dissolved in sea water is the least understood, considering that 30 per cent of the component molecules have been identified and their effects on animals and plants are only partially known. The tendency of these organic compounds to concentrate at interfaces causes dissolved organic compound (DOC) to adsorb onto particles suspended in sea water. Some DOC components chemically combine with dissolved metals and form complexes, affecting the chemical properties of sea water and the life of coastal biota. In this research we have compared the reproductive performances of the common sea urchin Paracentrotus lividus cultured in open-cycle tanks as compared to other specimens cultured in a recirculating aquaculture systems (RAS), where organic pollution progressively increased during the experiment, even not reaching deadly concentrations, as demonstrated by the results of periodic chemical monitoring of the water in replicate tanks. The specimens were cultured for seven months in the two conditions and finally their gametes were collected and embryos fertilized in vitro were analyzed by Real Time qPCR to identify possible effects of pollution. The fertility of sea urchin was evaluated along with their gonadic state and the gonadosomatic indices. The results indicate that organic pollution may hardly impact the reproductive potential of this species and that chronic effect of stress are revealed by their survival rates and gene expression answers.

Comparative LC-MS Analysis of Bioactive Monoacylglycerols in two Skeletonema marinoi strains

ABSTRACT. Marine microalgae are photosynthetic microorganisms considered as a source of metabolites that can find applications in many fields, from the aquaculture and food industry to their use as bioactive molecules for human health. The exploitation of these organisms has been successful thanks to their short life-cycle and easy growth conditions, the possibility of cultivating them with low costs, and the metabolic plasticity of their genome that allows them to respond to environmental stresses expressing biosynthetic pathways with the production of several metabolites. Diatoms are a microalgal class known to produce a great amount of lipids, like ω-3 and ω-6 Polyunsaturated Fatty Acids (PUFAs). The production of these molecules can represent a great value on the market, considering the huge biomass obtainable and the beneficial effects on human health, such as prevention of inflammation and of cardiovascular diseases, and reduction of cholesterol levels. Monoacylglycerols (MAGs) are lipid composed by glycerol and one fatty acid chain, widely used in the food and cosmetic industries as emulsifiers; indeed, they have been also proposed as PUFAs supplements, showing higher absorption and bioavailability than free or other form of esterified PUFAs. These molecules have been previously reported in the lipidic extract of the diatom Skeletonema marinoi (strain FE7) and showed in vitro antiproliferative activity towards two cancer cell lines (HCT-116 colon cancer and U-937 myeloid leukemia). In this work we extended the investigation to another strain of S. marinoi (FE60), and compared the composition and absolute content of MAGs by UHPLC-ESI-QExative-MS in the two strains. The results showed that although they are clones of the same species and grow in a comparable manner, the MAGs profile is significantly different. This finding opens new questions about the metabolic plasticity of diatoms at the strain level.

Towards sustainable aquaculture systems: biological and environmental impact of replacing fishmeal with Arthrospira platensis (Nordstedt) (spirulina)

ABSTRACT. Improving the sustainability in aquaculture falls within the Farm to Fork Strategy [1], by searching for a strategy to produce healthy and sustainable seafood with benefits for consumers’ and environmental health. Microalgae, such as spirulina (Arthrospira platensis), can supplement diet antioxidants or replace expensive fishmeal with high-quality proteins. However, the high production costs and impacts limit their use in the fish diet. In this study, we analyze the sustainability of a new circular strategy for using spirulina in aquaculture, which involves integrating fish diet with extracts from Arthrospira platensis grown on aquaculture wastewater. We first demonstrated that replacing 5% fishmeal with spirulina (SP5 diet) improves the redox state of muscle tissue of Koi Carp (Cyprinus carpio L.) juveniles (six-week trial). SP5 diet reduced ROS levels, oxidative damage, and susceptibility to oxidants and increased the activity of antioxidant enzymes compared to both a control diet and a high percent spirulina diet. Secondly, we analyzed the environmental impacts of feeding farmed fish with spirulina produced on output wastewater recirculated back from the same farming plant, by using the Life Cycle Assessment (LCA) and the LCA ReCiPe Midpoint (H) methods. We compared the environmental impacts of growing spirulina on aquaculture wastewater and on standard culture medium. Finally, we determined the impacts of aquaculture implants in which fish were fed with a control diet or an SP5 diet, formulated with spirulina grown on aquaculture wastewater (SP5ww) or grown on a standard medium (SP5st). Results indicated that SP5ww had a significantly smaller impact by avoiding the costs related to wastewater disposal and to the use of a standard culture medium. In conclusion, the proposed approach represents a valid solution to improve the sustainability of aquaculture while also improving the welfare of fish.

References [1]

The potential of Salicornia ramosissima as a functional feed ingredient strengthening the antioxidant and DNA protection systems in the European sea bass (Dicentrarchus labrax)
PRESENTER: Raquel Marçal

ABSTRACT. Salicornia ramosissima presents interesting nutritional and ecological characteristics, although its application in the context of fish aquaculture is unexplored, namely towards its inclusion in functional feeds. Thus, the antioxidant and DNA protection potential of Salicornia-supplemented diets was assessed in juvenile Dicentrarchus labrax fed, for 2 months, with the supplementation levels of 2.5% (SAL2.5), 5% (SAL5) and 10% (SAL10). In an intermediate evaluation (1 month), it was observed a tissue-specific pattern of antioxidant modulation, depicted in an improved defense capacity of gills (increased GPx and GST activities as well as GSHt content in SAL5), an unresponsiveness of the liver, and an ambivalent response of blood (decreased GST activity in all diets and increased GSHt content in SAL5 and SAL10). No lipid peroxidation (LPO) increment was observed in fish fed with supplemented diets. DNA integrity evaluated in blood cells displayed a slight increase of DNA breaks in SAL5, measured by comet assay, while no chromosomal damage was detected measured by erythrocytic nuclear abnormalities (ENA) assay. With the extension of feeding supplementation for a 2nd month, the antioxidant status showed unclear profiles of variation in all the assessed tissues, in parallel with an LPO increase in gills (SAL2.5 and SAL10) and liver (SAL5). In contrast, all diets improved the DNA integrity in blood cells. Although the circumstantial increase of LPO and decrease of DNA integrity cannot be outright excluded as a signal of toxicity, the most plausible interpretation (legitimized by the combined analysis of all the endpoints assessed) points to a mild oxidative stress induction as a transient step required to trigger cell defenses, but, ultimately, contributing to promote fish stress coping. Overall, the formulation of Salicornia rich functional fish feeds emerges as a challenging but promising topic in aquaculture, pursuing the balance between yield and sustainability.

Dietary soy isoflavone supplementation in rainbow trout: tissue deposition and influence on fillet quality

ABSTRACT. Isoflavones are polyphenols compounds contained in soybean that may act as estrogen receptor agonists or antagonists and potentially affect fish growth performance and fillet quality. A total of 54 rainbow trout (initial weight: 177 g) (18 trout per treatment) were fed three experimental diets containing different concentrations of isoflavones (0, 500, 1500 ppm) for 70 days. At the end of the trial, the quality of trout fillets was evaluated at 1 and 7 days of storage (27 trout per storage time). The levels of isoflavones in diets did not affect trout growth performance during the rearing period. Even biometric indexes, skin and fillet colour, rheological characteristics, proximate composition, fatty acids profile of fillet were not affected by the different dietary treatments. Otherwise, time of storage reduced fillet yield (p<0.01), and skin lightness (p<0.01); red index moved to more negative values (near-zero, however) and yellow index decreased (p<0.01). Fillet pH (p<0.01) and lightness increased (p<0.01), yellow index (p<0.01) and shear force decreased (p<0.01). According to the time of storage, trout fillet showed an increase of water, a loss of crude protein and an increase of total volatile basic nitrogen content (p<0.01). As a result of PUFAs omega-6 decrease (p<0.05), omega-3/omega-6 ratio increased (p<0.05) during storage. The fillet analysis evidenced an accumulation of isoflavones influenced both by dietary isoflavone content (p<0.05) and refrigerated storage time (p<0.05) while fillet lipid oxidation measured by means of thiobarbituric acid reactive substance assay was only affected by the storage time (p<0.05). In conclusion, although a transfer of isoflavones from diet to fillet was observed, rheological and nutritional characteristics, as well as fillet quality were not affected by dietary treatment.

13:10-14:40Lunch Break