This study aimed at the characterization of the antioxidant power of polyphenol extracts (PE) obtained from the algae Cystoseira foeniculacea (CYS) (Phaeophyta) and from the halophyte Halocnemum strobilaceum (HAL), growing in the solar saltworks of western Sicily (Italy), and at the evaluation of their anti-microfouling properties, in order to correlate these activities to defense strategies in extreme environmental conditions. The antioxidant properties were assessed in the PE based on the total antioxidant activity test and the reducing power test; the anti-microfouling properties of the two PE were evaluated by measuring the growth inhibition of marine fish and shellfish pathogen bacteria as well as marine surface fouling bacteria and microalgae exposed to the fractions. Similar polyphenol content (CYS 5.88 ± 0.75 and HAL 6.03 ± 0.25 mg gallic acid equivalents (GAE) g⁻¹ dried weight, DW) and similar reducing power percentage (93.91 ± 4.34 and 90.03 ± 6.19) were recorded for both species, even if they exhibited a different total antioxidant power (measured by the percentage of inhibition of the radical 2,2 diphenyl-1-picrylhydrazyl DPPH), with CYS (79.30) more active than HAL (59.90). Both PE showed anti-microfouling properties, being inhibitors of adhesion and growth of marine fish and shellfish pathogen bacteria (V. aestuarianus, V. carchariae, V. harveyi, P. elyakovii, H. aquamarina) and fouling bacteria (V. natriegens, V. proteolyticus, P. iirgensii, R. litoralis) with minimum inhibitory concentrations comparable to the commercial antifouling products used as a positive control (SEA-NINE™ 211N). Only CYS was a significant inhibitor of the microalgae strains tested, being able to reduce E. gayraliae and C. closterium growth (MIC 10 µg·mL⁻¹) and the adhesion of all three strains tested (E. gayraliae, C. closterium and P. purpureum), suggesting its promise for use as an antifouling (AF) product.

Blue mussels (Mytilus edulis L. 1758) are important components of coastal ecosystems and in the economy of rural and coastal areas. The understanding of their physiological processes at key life stages is important both within food production systems and in the management of wild populations. Lipids are crucial molecules for bivalve growth, but their diversity and roles have not been fully characterised. In this study, traditional lipid profiling techniques, such as fatty acid (FA) and lipid class analysis, are combined to untargeted lipidomics to elucidate the lipid metabolism in newly settled spat fed on a range of diets. The evaluated diets included single strains treatments (Cylindrotheca fusiformis CCAP 1017/2 –CYL, Isochrysis galbana CCAP 927/1– ISO, Monodopsis subterranean CCAP 848/1 –MONO, Nannochloropsis oceanica CCAP 849/10– NANNO) and a commercial algae paste (SP). Spat growth was influenced by the diets, which, according to their efficacy were ranked as follows: ISO>NANNO/CYL>SP>MONO. A higher triacylglycerols (TG) content, ranging from 4.23±0.82 μg mg_{ashfree Dry weight (DW)}^-1 at the beginning of the trial (T0) to 51±15.3 μg mg_ashfreeDW^-1 in ISO, characterised significant growth in the spat, whereas, a reduction of TG (0.3±0.08 μg mg_ashfreeDW^-1 in MONO), mono unsaturated FA–MUFA (from 8.52±1.02 μg mgFA_ashfreeDW^-1 at T0 to 2.81±1.02 μg mgFA_ashfreeDW^-1 in MONO) and polyunsaturated FA–PUFA (from 17.57±2.24 μg mgFA_ashfreeDW^-1 at T0 to 6.19±2.49 μg mgFA_ashfreeDW^-1 in MONO) content characterised poor performing groups. Untargeted lipidomics evidenced how the availability of dietary essential PUFA did not influence only neutral lipids but also the membrane lipids, with changes in lipid molecular species in relation to the essential PUFA provided via the diet. Such changes have the potential to affect spat production cycle and their ability to respond to the surrounding environment. This study evidenced the advantages of coupling different lipid analysis techniques, as each technique disclosed relevant information on nutritional requirements of M. edulis juveniles, expanding the existing knowledge on the physiology of this important species.

This study shows a pilot scale protocol aimed to obtain an omega 3-enriched oil after the processing of farmed gilthead sea bream viscera (SBV); this was oil was tested in vitro for bioactivity, attesting to the possibility to turn waste into profit The quality of the oil, in terms of requirements for animal and human consumption, was assessed by determining some chemical parameters, such as peroxide value (PV), thiobarbituric acid reactive substances (TBARS), ρ-anisidine (ρ-AV) content, total oxidation value (TOTOX), and phospholipids and free fatty acid (%), both in crude viscera oil (CVO) and refined viscera oil (RVO). Among the extraction conditions, the higher CVO yields were obtained at 60 °C for 10 min (57.89%) and at 80 °C for 10 min (67.5%), and the resulting oxidation levels were low when utilizing both extraction conditions. RVO, obtained from CVO extracted at 60 °C, showed the highest quality on the basis of the assessed parameters. The ethyl esters of the total fatty acid (TFA) contents extracted from RVO were enriched in the ω-3 polyunsaturated fatty acid fraction (PUFAE) up to almost 56% via short path distillation (SPD). Antioxidant activities and adipogenic properties were tested in vitro. PUFAE protected 3T3 L1 cells from oxidative stress and exerted an anti-adipogenic effect in Dicentrarchus labrax pre-adipocytes, attesting to the beneficial properties for both farmed fish and human health. These results could stimulate the adoption of solutions aimed to recover and utilize aquaculture by-products at a higher scale, turning “waste into profit” and indicating a strategy to reach more sustainable business models in aquaculture resource utilization according to the principles of the circular economy.

Background/Objectives: Gonad histological analysis (GHA) is the traditional method for assessing the gonad maturation status of blue mussels (Mytilus edulis). GHA has some operational disadvantages, such as limited processing outputs, subjectivity in the assessment of transitional stages of gonadal maturation and the need for experienced and trained operators. Lipids could become important indicators of gonadal maturation as they cover many essential functions during such processes in mussels. In this work, blue mussel ovary (BMO) ultrastructure is integrated with liquid chromatography coupled with mass spectrometry (LC-MS) lipidomics fingerprinting to identify suitable markers for ovarian maturation through the application of chemometrics and machine learning approaches. Methods: BMOs are classified here as ripe or non-ripe by means of GHA and the gamete volume fraction (GVF). Receiving operating characteristic (ROC) curves were used to classify the results of the different statistics according to their area under the curve (AUC), and the functional role of important lipids was assessed by lipid ontology enrichment (LiOn) analysis. Results: This approach allowed for the selection of a panel of 35 lipid molecules (AUC > 0.8) that can distinguish non-ripe from ripe BMOs. Ceramide phosphoethanolamine (CerPE) 40:2 was the molecule with the highest classification ability (AUC 0.905), whereas glycerophosphoserine (PS) was the class mostly changing between the two groups. LiOn analysis indicated significant differences in the functional roles of these lipids, highlighting enrichment terms associated with membrane lipids, lysosomes and highly unsaturated triglycerides (TGs) in non-ripe ovaries, whereas terms associated with storage lipids and low-saturated TG characterised ripe BMOs.