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- Evaluating the Potential of the Defatted By-Product of Aurantiochytrium sp. Industrial Cultivation as a Functional FoodPublication . Reboleira, João; Félix, Rafael; Félix, Carina; Melo, Marcelo M. R. de; Silva, Carlos M.; Saraiva, Jorge A.; Bandarra, Narcisa M.; Teixeira, Bárbara; Mendes, Rogério; Paulo, Maria C.; Coutinho, Joana; Lemos, Marco F. L.While Aurantiochytrium sp. is an increasingly popular source of polyunsaturated fatty acids (PUFAs), its extraction generates high amounts of waste, including the spent, defatted residue. The composition and bioactivities of this by-product could prove to be a major part of the sustainable valorisation of this organism within the framework of a circular economy. In this study, the defatted biomass of commercial Aurantiochytrium sp. was nutritionally characterised, and its amino acid profile was detailed. Additionally, the antioxidant and prebiotic potentials of an enzymatically digested sample of defatted Aurantiochytrium sp. were evaluated under a set of miniaturised in vitro assays. The nutritional profile of the spent Aurantiochytrium biomass revealed a protein and dietary-fibre rich product, with values reaching 26.7% and 31.0% for each, respectively. It also held high concentrations of glutamic and aspartic acid, as well as a favourable lysine/arginine ratio of 3.73. The digested samples demonstrated significant Weissela cibaria and Bifidobacterium bifidum growth-enhancing potential. Residual ferric reducing antioxidant power (FRAP) activity was likely attributed to antioxidant amino acids or peptides. The study demonstrated that some of the nutritional and functional potential that reside in the defatted Aurantiochytrium sp. waste encourages additional studies and the development of food supplements employing this resource’s by-products under a biorefinery framework.
- Non-lethal heat shock induces cross-tolerance to different stressors in two strains of Brachionus koreanus (Rotifera: Monogononta): Mechanisms of increased tolerance to hydrogen peroxidePublication . Granada, Luana; Morão, Inês F.C.; Lemos, Marco F. L.; Bossier, Peter; Novais, Sara C.The rotifer Brachionus sp. is of great importance for aquaculture, as the reproduction cycle under rearing conditions of many economically important species larvae depends on the use of rotifers as first live feed. Establishing a protocol that results in an improved tolerance of rotifers to environmental stressors will allow for a more stable rotifer production. The exposure to non-lethal heat shocks (NLHS) already proved to enhance the tolerance, not only to heat stress, but also to other stressors in several aquatic species, by activating the heat shock response and epigenetic mechanisms. This study aimed to determine the potential of a single NLHS to induce tolerance to different abiotic stressors in two strains of B. koreanus (MRS10 and IBA3) and to evaluate possible molecular mechanisms involved in the achievement of increased tolerance to hydrogen peroxide induced by NLHS. Cross-tolerance was achieved for both strains, namely to high salinity, cadmium chloride, and hydrogen peroxide. Scale-up tests resulted in increased tolerance to hydrogen peroxide only for MRS10. During the exposure to this substance, heat-shocked MRS10 rotifers showed an up-regulation of genes related to oxidative stress response and histone modifications, increased production of HSP70, and higher levels of total acetylation of histone H3. A single NLHS proved to induce epigenetic effects when rotifers were exposed to other stressor later in life. However, further studies should elucidate if the NLHS conditions used in this study can yield a persistent outcome, allowing the establishment of tolerant rotifer strain lines and, consequently, a more stable production.
- Trace Elements in Edible Rocky Shore Species: Effect of Sewage Discharges and Human Health Risk ImplicationsPublication . Cabral-Oliveira, Joana; Pratas, João; Mendes, Susana; Pardal, Miguel A.Sewage pollution is a worldwide concern and can result in increasing levels of trace elements in the environment that can pose serious risks both to wildlife and human health. This highlights the importance of studying the role of sewage discharges in the contamination of aquatic systems, especially in rocky shores, since part of our food resources is directly collected from coastal waters. For this purpose, the accumulation of trace elements (Cu, Zn, Pb, Ni, Co, Cd, Fe, Mn, and As) by edible molluscs (Mytilus galloprovincialis, Patella ulyssiponensis, and Phorcus lineatus) was compared between one sewage-impacted area and two reference areas. This study suggests that the concentrations of trace elements in the soft tissues of the selected molluscs can be affected by the presence of sewage discharges, and that limpets seem to be the best bioindicator. Moreover, the sewage pollution increased the concentrations of As in the mollusc species, emphasizing its potential damaging effects on natural systems and on edible species.
- Tryptophan Depletion and Formation of α-Aminoadipic and γ-Glutamic Semialdehydes in Porcine Burger Patties with Added Phenolic-Rich Fruit ExtractsPublication . Ganhão, Rui; Morcuende, David; Estévez, MarioThe effect of added fruit extracts on the oxidation of muscle proteins in porcine burger patties subjected to cooking and chill storage was studied. Extracts from arbutus berries (Arbutus unedo L., AU), common hawthorns (Crataegus monogyna L., CM), dog roses (Rosa canina L., RC), and elmleaf blackberries (Rubus ulmifolius Schott, RU) were prepared, characterized, added to burger patties (3% of total weight), and evaluated as inhibitors of protein oxidation. Negative (no added extract, C) and positive control (added quercetin, 230 mg/kg, Q) groups were also included in the design. Protein oxidation was assessed by means of tryptophan loss using fluorescence spectroscopy (FS) and formation of the specific protein carbonyls αaminoadipic (AAS) and y-glutamic semialdehyde (GGS) using liquid chromatography and mass spectroscopy (LC-MS). Both advanced methodologies (FS and LC-MS) were found to be reliable and specific protein oxidation measurements that allow us to gain chemical insight into protein oxidation. The mechanisms likely involved In the oxidative reactions affecting proteins during cooking and storage of burger patties are profusely discussed. Phenolic-rich fruit extracts protected tryptophan residues against oxidation and Inhibited the formation of both semialdehydes In burger patties during cooking and subsequent chill storage. In general, RC, RU, and AU were the most effective inhibitors of protein oxidation, with this effect being more intense than that of pure polyphenols like quercetin. These fruit extracts could be considered functional ingredients as their antioxidant actions contribute to the enhancement of the nutritional value of the meat products.
- Chemical Characterization and Bio-Screening of Neuroprotective Potential of Brazilian Brown Seaweed Canistrocarpus cervicornis in 6-OHDA-Induced Neurotoxicity ModelPublication . dos Santos, Thalisia Cunha; Obando, Johana Marcela Concha; Silva, Joana; Santos, Ana Luíza Vidal Pimentel; Martins, Roberto Carlos Campos; Cavalcanti, Diana Negrão; Pedrosa, Rui; Alves, CelsoBrazilian native seaweed Canistrocarpus cervicornis (Ochrophyta, Dictyotaceae) is recognized for its chemodiversity, particularly cyclic diterpenes and polysaccharides, yet its relevance to neurological disorders remains unexplored. This study evaluated the neuroprotective potential of a hydroethanolic extract (ECCH), its polar fraction (CCFPol), a dichloromethane extract (ECCD), and eight derived fractions (CCF1–2, CCF3, CCF4, CCF5–6, CCF7, CCF8–10, and CCF11–15). Cytotoxicity was evaluated in SH-SY5Y neuroblastoma cells, and neuroprotection was examined against 6-OHDA–induced toxicity. The mitochondrial membrane potential, ROS and H2O2 generation assays were conducted to explore the mechanisms underlying the observed effects. Among the key findings, the CCF3 fraction exhibited a high content (75.04%) of dolastane-type diterpenoids. Both CCFPol (100 µg/mL) and CCF3 (1 µg/mL) increased cell viability to 68.43 ± 4.60% and 60.61 ± 0.80%, respectively, compared with 6-OHDA–treated cells (50.70 ± 2.71%). Additionally, CCF3 and CCFPol reduced H2O2 levels (200.0 ± 18.19% and 195.5 ± 16.13%, respectively, vs. 6-OHDA-treated cells: 302.2 ± 17.07%) and lowered intracellular ROS (122.6 ± 22.7% and 129.6 ± 19.4%, respectively, vs. 6-OHDA-treated cells: 153.0 ± 32.7%). This is the first study to demonstrate the neuroprotective potential of the C. cervicornis in a 6-OHDA-induced neurotoxicity cellular model, contributing to the understanding of marine bioactive resources and their relevance for neurological research. Additional studies aimed at isolating the active constituents and clarifying their mechanisms of action will further strengthen and expand the biological relevance of this specie as source of neuroprotective agents.
- Production of human milk fat substitutes enriched in omega-3 polyunsaturated fatty acids using immobilized commercial lipases and Candida parapsilosis lipase/acyltransferasePublication . Tecelão, Carla; Silva, Joana; Dubreucq, Eric; Ribeiro, Maria H.; Ferreira-Dias, SuzanaIn human milk fat (HMF), palmitic acid (20-30%), the major saturated fatty acid, is mostly esterified at the sn-2 position of triacylglycerols, while unsaturated fatty acids are at the sn-1,3 positions, conversely to that occurring in vegetable oils. This study aims at the production of HMF substitutes by enzyme-catalyzed interesterification of tripalmitin with (i) oleic acid (system I) or (ii) omega-3 polyunsaturated fatty acids (omega-3 PUFA) (system II) in solvent-free media. Interesterification activity and batch operational stability of commercial immobilized lipases from Rhizomucor miehei (Lipozyme RM IM), Thermomyces lanuginosa (Lipozyme TL IM) and Candida antarctica (Novozym 435) from Novozymes, DK, and Candida parapsilosis lipase/acyltransferase immobilized on Accurel MP 1000 were evaluated. After 24-h reaction at 60 °C, molar incorporation of oleic acid was about 27% for all the commercial lipases tested and 9% with C. parapsilosis enzyme. Concerning omega-3 PUFA, the highest incorporations were observed with Novozym 435 (21.6%) and Lipozyme RM IM (20%), in contrast with C. parapsilosis enzyme (8.5%) and Lipozyme TL IM (8.2%). In system I, Lipozyme RM IM maintained its activity for 10 repeated 23-h batches while for Lipozyme TL IM, Novozym 435 and C. parapsilosis enzyme, linear (half-life time, t1/2 = 154 h), series-type (t1/2 = 253 h) and first-order (t1/2 = 34.5 h) deactivations were respectively observed. In system II, Lipozyme RM IM showed linear deactivation (t1/2 = 276 h), while Novozym 435 (t1/2 = 322 h) and C. parapsilosis enzyme (t1/2 = 127 h), presented series-type deactivation. Both activity and stability of the biocatalysts depended on the acyl donor used.
- Wastewater Valorisation in Sustainable Productive Systems: Aquaculture, Urban, and Swine Farm Effluents HydroponicsPublication . Luz, Tomás M. R.; Ushiña, Damariz; Santos, Ounísia; Ispolnov, Kirill; Aires, Luis M. I.; Sousa, Helena Pala D.; Bernardino, Raul; Vaz, Daniela; Cotrim, Luís; Sebastião, Fernando; Vieira, JuditeThe agricultural sector faces significant challenges related to climate change and population growth, which intensify pressure on natural resources and food security. Sustainable resource-efficient systems, alongside wastewater valorisation, are a promising solution. This study evaluated the reuse potential of aquaculture, urban, and swine farm wastewater in hydroponic cultivation. Trials with leafy vegetables and fruit crops were conducted in aquaponic systems containing two fish species (Koi carp and African catfish) and two small-scale hydroponic systems. Water quality, plant development, and environmental parameters were monitored. Results for the best performance scenarios within each cultivation system showed that in urban wastewater, strawberries yielded 183 ± 74 g/plant, exceeding yields in aquaponics (125 ± 60 g/plant). Lettuce performed better in swine farm wastewater (180 ± 39 g/plant) than in urban (65 ± 6 g/plant), with corresponding water-use efficiencies of 117 and 65 g/L. Aquaponics also supported stable yields, up to 108 ± 1 g/plant for lamb’s lettuce and 10,047 ± 8791 g of papaya fruit per plant. Nutrient recovery in hydroponic systems supplied with urban and swine farm wastewater reached up to 95% for N, P, and K. Overall, these systems demonstrated substantially lower water consumption compared with values commonly reported for conventional agriculture, underscoring their strong sustainability advantages.
- Production of parsley and pennyroyal with an African catfish-based aquaponics partially fed with yellow mealworms - Tenebrio molitorPublication . Bernardino, Raul; Vieira, Judite; Vaz, Daniela C.; Santos, Ounísia D.; Ribeiro, Vânia S.; Pires, Cristiana L.; Cotrim, Luís; Bernardino, SusanaInsects can be used as alternative protein/food sources. Here, a novel aquaponic system based on the African catfish (Clarias gariepinus) fed with 30% of yellow mealworms (YM) (Tenebrio molitor) as substitute feed to 100% of fish meal (FM) was employed to produce parsley (Petroselinum crispum) and pennyroyal (Mentha pulegium). The two systems implemented (30YW/70FM and 100FM - control) showed identical water quality parameters. The 30YW/70FM operation led to a reduction by 27% of the carbon footprint, relatively to the 100FM system. Plants cultivated in the 30YW/70FM aquaponic system led to lower plant biomass (↓∼75%), as stated by the statistically significant (p < 0.05) lower values of “plant height”, “foliage diameter”, “leaf number”, “biggest leaf length” and “root length”. Moreover, 100FM parsley showed higher levels of greenness (100%) and health status (97%) than the 30YW/70FM plants (↓50% greenness; ↓20% health status). Likewise, 100FM pennyroyal also showed higher levels of greenness (100%) and health status (100%) than 30YW/70FM pennyroyal (↓56 % greenness; ↓59% health status). Also, even if all plants presented equivalent levels of P, K, Ca and Fe, the plants grown in the 30YW/70FM system showed some Cl-accumulation (>7.0 g Cl.kg−1 for parsley and > 4.0 g Cl.kg−1 for pennyroyal, in dry weight) in the leaves and Cu and Mn accumulation in the roots (> 0.4 g.kg−1 in dry weight). The presence of high concentrations of Cl in T. molitor, and consequently in the water and fish faeces, might have caused some abiotic stress and toxicity to plant tissues, reducing plant growth.
- Bioaccumulation and Elimination of Waterborne Mercury in the Midge Larvae, Chironomus riparius Meigen (Diptera: Chironomidae)Publication . Azevedo-Pereira, Henrique M. V. S.; Abreu, Sizenando N.; Lemos, Marco F.L.; Soares, Amadeu M. V. M.Here, mercury kinetics and behavioural effects in the midge larvae under a water-only exposure were assessed. Uptake and elimination of waterborne mercury were described by using a one-compartment kinetic model. Results show that midges were able to readily accumulate the heavy metal (BCF = 450), presenting a fast uptake, up to 13.1 lg Hg g of animal-1 at the end of the exposure period. Elimination was slow, with c.a. 39 % of the mercury in larvae being depurated after 48 h in clean medium. Behaviour did not present differences upon exposure or elimination, but a trend to increase ventilation was noticed during the exposure period.
- Historical separation and present-day structure of common dolphinfish (Coryphaena hippurus) populations in the Atlantic Ocean and Mediterranean SeaPublication . Maggio, Teresa; Allegra, Alessandro; Andaloro, Franco; Barreiros, João Pedro; Battaglia, Pietro; Butler, Christopher M; Cuttitta, Angela; Fontes, Miguel Rodrigues Jorge; Freitas, Rui; Gatt, Mark; Karakulak, F Saadet; Macias, David; Nicosia, Aldo; Oxenford, Hazel A; Saber, Samar; Yildiz, Taner; Sinopoli, Mauro; Vasco Rodrigues, Nuno; Grant, W StewartThe common dolphinfish (Coryphaena hippurus) is an epipelagic, mid-trophic level, highly migratory species distributed throughout the world’s tropical and subtropical oceans in waters greater than 20C. Life-history variables, migratory behaviour, and genetic markers have been used to define major stocks in the central Atlantic Ocean and Mediterranean Sea. Here, we used the mitochondrial DNA gene NADH subunit 1 (688 bp) to test for differences between population groups. A total of 103 haplotypes were detected among 203 fish. Gene diversities in samples were large and similar among populations (mean h ¼ 0.932; range 0.894–0.987), but nucleotide diversities varied widely among samples (range p ¼ 0.004–0.034) and appear to reflect population histories. Principal component analysis revealed two large populations groups, and the analysis of molecular variation and pairwise values of UST resolved population structure within these groups. Populations in the eastern Atlantic and Mediterranean showed the largest amounts of divergence from one another (UCT ¼ 0.331). Adult movement and biophysical barriers to larval dispersal may explain contemporary differences between stocks, but the divergent populations in the Mediterranean Sea are likely due to isolations by cold temperature barriers during Pleistocene glaciations. The geographically large stock groupings require international cooperation in the harvest management and conservation of local dolphinfish population