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- The effects of stocking density on physiological traits in Holothuria forskali broodstockPublication . Sousa, João; Félix, Pedro M.; Brito, Ana C.; Venâncio, Eliana; Silva, Francisco Azevedo e; Simões, Tomás; Raposo, Andreia; Neves, Marta; Narciso, Luís; Melo, Ricardo; Pombo, AnaThe high demand of sea cucumbers in international markets, mostly based in Asia, has left a deep impact on the natural stock of many species, leading to an investment in aquaculture techniques in order to mitigate these impacts. This study aimed to determine the effects of stock density in rearing broodstock of Holothuria (Panningoturia) forskali Delle Chiaje, 1823, a common species in the Mediterranean Sea and eastern Atlantic with commercial value. To do so, two different density treatments were selected: 1 kg/m2 and 2 kg/m2. The trial took place over five months and individuals were fed a mixture of frozen microalgae (Tetraselmis sp. and Phaeodactylum tricornutum). At the end of the trial, the effects of stock density on the individuals’ condition were assessed by analysing different variables, namely their fresh and gutted weight, evisceration and mortality rates, gonadosomatic index and oocyte size and even biochemical content, such as protein and lipid content in muscle bands. No significant differences were found between density treatments regarding any of the parameters assessed, aside from mean oocyte diameter. Individuals from the lower-density treatment presented a smaller mean oocyte diameter, supplied with fewer oocytes, than individuals in both the higher-density treatment and the baseline group. Regardless of this one difference, all trial individuals were able to maintain their elevated gonadal developmental stage for a full period of five months past their reproductive peak, with female holothurians subjected to the higher-density treatment showing signs of increasing vitellogenic reserves, a considerable advantage in aquaculture broodstock rearing.
- High dietary protein, n − 3/n − 6 ratio and β-carotene enhances Paracentrotus lividus (Lamarck, 1816) larval developmentPublication . Gomes, Ana S.; Lourenço, Sílvia; Santos, Pedro M.; Neves, Marta; Adão, Pedro; Tecelão, Carla; Pombo, AnaThe nutritional characteristics of microalgae affect the growth, survival and fatty acid composition of sea urchin larvae. This study aimed to evaluate the influence of nutritive characteristics of single microalgal diets in Paracentrotus lividus (Lamarck, 1816) larval development, growth, and condition. Larvae of P. lividus were fed with three monospecific microalgal diets, Rhodomonas sp. (Rho), Dunaliella tertiolecta (Duna) and the diatom Chaetoceros calcitrans (Chae), and their development and growth were analysed until competence. Additionally, the fatty acid (FA) profile of larvae was analysed at competence and compared with the FA profile of the correspondent diet. The three groups of larvae attained competence simultaneously with differences in growth performance. The larvae fed with Chae attained the largest stomach and the shortest post-oral arm. The larvae were able to accumulate long-chain polyunsaturated fatty acids (PUFA), such as docosahexaenoic (DHA, C22:6n − 3), eicosapentaenoic (EPA, C20:5n − 3) and arachidonic (ARA, C20:4n − 6) acids, either by assimilation and retention of dietary FA or by the synthesis from α-linolenic acid (ALA, C18:3n − 3) and linoleic acid (LA, C18:2n − 6). Furthermore, the low DHA/EPA ratio and high EPA/ARA and n − 3/n − 6 ratios of Rho and Chae and the high levels of the β-carotene present in Chae improved larval growth and development. In conclusion, the results indicated that of the three microalgal diets tested, C. calcitrans provided important nutritional characteristics, especially in terms of FA composition and carotenoids, improving P. lividus larval growth and condition.
- Enhancing oxidative stability of sunflower oil by supplementation with prickled broom (Pterospartum tridentatum) ethanolic extractPublication . Neves, Marta; Miranda, Andreia; Lemos, Marco F.L.; Silva, Susana; Tecelão, CarlaThis study aimed to evaluate the effect of ethanolic extract of Pterospartum tridentatum flowers in the stability of sunflower oil. The extract was characterized regarding to its antioxidant activity by the 2,2,1-diphenyl-1-picrylhydrazyl (DPPH) scavenging method (EC50 = 76.3 ± 2.6 μg/mL) and total phenolic content (200 ± 8 mg GAE/g). Extracts were added at 500 mg/L (E1) and 1,000 mg/L (E2), and after 30 days of storage at room temperature, E2 oil showed improved quality parameters,with a reduction of 22.4%,17.2%,and 45.6% in the values of acidity,peroxide,and p-anisidine, respectively.The extract also increased oil stability at 180 °C.After 27 hr, the acidity (0.216 ± 0.016 mg KOH/g) and the total oxidation value (TOTOX) (69.30 ± 0.26) values of E2 oil were significantly lower than the control. These results showed that P. tridentatum effectively improved the shelf-life and thermal stability of sunflower oil,being a promising source of antioxidants for edible oils processing.
- Enrichment of sunflower oil with ultrasound-assisted extracted bioactive compounds from Crithmum maritimum L.Publication . Sousa, Gabriela; Alves, Mariana I.; Neves, Marta; Tecelão, Carla; Ferreira-Dias, SuzanaCrithmum maritimum L., or sea fennel, is an edible halophyte plant, rich in phenolic compounds with antioxidant and antimicrobial activities, that naturally grows in Mediterranean coasts. This study aims to incorporate bioactive compounds extracted from lyophilized Crithmum maritimum to sunflower oil assisted by ultrasounds (UAE), to improve its biological value and oxidative stability. UAE conditions were optimized as a function of time (5–20 min) and lyophilized plant concentration (5–20% m/v). The experiments were dictated by a central composite rotatable matrix. Oxidation products were not influenced by UAE conditions. Acidity, chlorophyll, and carotenoid contents were affected by both factors, while total phenols, flavonoids, and antioxidant activity (FRAP method) only increased with plant concentration. Response surfaces were fitted to these experimental results. Flavonoids were highly related with oil antioxidant activity. No sensory defects were detected in supplemented oil (12.5% m/v plant/5 min UAE). The oxidative stability of this oil was evaluated at 60 °C/12 days. Chlorophylls, phenols, radical scavenging (DPPH), and antioxidant activities decreased over time but were always higher than the values in nonsupplemented oil (8.6 and 7‐fold with FRAP and DPPH, respectively). C. maritimum presented high amounts of bioactive compounds with antioxidant activity, adequate for sunflower oil supplementation by UAE.
- Effects of ocean acidification and warming on the development and biochemical responses of juvenile shrimp Palaemon elegans (Rathke, 1837)Publication . Maia, Simão; Marques, Sónia C.; Dupont, Sam; Neves, Marta; Pinto, Henrique J.; Reis, João; Leandro, Sérgio M.Anthropogenic CO2 emissions have led to the warming and acidification of the oceans. Although, there is a growing of evidence showing that simultaneous occurrence of ocean acidification and ocean warming are threats to marine organisms, information on their combined effect on coastal shrimp species remains scarce. The purpose of this study was to estimate the combined effects of seawater acidification and warming on growth-related traits and biochemical responses of P. elegans juveniles. In this work, shrimp were exposed for 65 days at 4 experimental conditions: pH 8.10 * 18 ◦C, pH 7.80 * 18 ◦C, pH 8.10 * 22 ◦C, pH 7.80 * 22 ◦C. The results showed that low pH decreases the lipid content by ~13% (p < 0.05). Higher temperature reduced the condition factor by ~11%, the protein content by ~20%, the PUFA by ~8,6% and shortened moulting events by 5 days (p > 0.05) while the SFA increased ~9.4%. The decrease in condition factor and protein was however more prominent in organisms exposed to the combination of pH and temperature with a decrease of ~13% and ~21%, respectively. Furthermore, essential fatty acids as EPA and DHA also decreased by ~20% and ~6.6% in low pH and higher temperature condition. Despite this study suggest that warming may have a greater impact than acidification, it has been shown that their combined effect can exacerbate these impacts with consequences for the shrimp’s body size and biochemical profile.
- Somatic growth and gonadal development of Paracentrotus lividus (Lamarck, 1816) fed with diets of different ingredient sourcesPublication . Lourenço, Sílvia; Cunha, Beatriz; Raposo, Andreia; Neves, Marta; Santos, Pedro M.; Gomes, Ana S.; Tecelão, Carla; Ferreira, Susana M. F.; Baptista, Teresa; Gonçalves, Sílvia C.; Pombo, AnaSea urchins’ gonads are a delicacy highly appreciated worldwide. In Europe, Paracentrotus lividus is one of the most valuable edible sea urchin species and a desired target for aquaculture. One of the challenges of echinoculture is to increase the sea urchins’ growth rate during the on-growing phase and reducing the production cycle required to obtain sea urchins of commercial size (test diameter ≈ 50 mm). The present study aimed to evaluate the growth and gonad development of P. lividus urchins fed with three dry diets for 15 weeks. The diets were formulated with ingredients of three different sources: an algae-based, a fishmeal-based and a cereals-based diet. The somatic growth was assessed by biometric indicators like the linear and specific growth rates. The gonadal development was assessed by the gonadal somatic index (GSI), gametogenesis level, proximate composition and fatty acids profile. The results obtained showed high growth rates in all the three diets tested (0.44% per day). The sea urchins fed with the cereals diet presented the highest GSI (8.22%) with higher proportion of gonads in growing and premature stages. The proximate composition of the sea urchins’ gonads was significantly affected by diet and sea urchins’ sex, particularly the lipid content. Concomitantly, fatty acids (FA) profile of the gonads was influenced by both diet and sea urchins’ sex with saturated and polyunsaturated FA playing an important role in this differentiation.
- Optimization of ultrasound-assisted extraction of bioactive compounds from Pelvetia canaliculata to sunflower oilPublication . Sousa, Gabriela; Trifunovska, Marija; Antunes, Madalena; Miranda, Isabel; Moldão-Martins, Margarida; Alves, Vitor D.; Vidrih, Rajko; Lopes, Paula Allen; Aparicio, Luis; Neves, Marta; Tecelão, Carla; Ferreira-Dias, SuzanaIn this study, Pelvetia canaliculata L. macroalga, collected from the Atlantic Portuguese coast, was used as a source of bioactive compounds, mostly antioxidants, to incorporate them in sunflower oil with the aim of increasing its biological value and oxidative stability. The lyophilized alga was added to the oil, and ultrasound‐assisted extraction (UAE) was performed. Algae concentration and UAE time varied following a central composite rotatable design (CCRD) to optimize extraction conditions. The following parameters were analyzed in the oils: oxidation products, acidity, color, chlorophyll pigments, carotenoids, flavonoids, total phenolic content, antioxidant activity by DPPH (2,2‐diphenyl‐1‐picrylhydrazyl) and FRAP (ferric reducing antioxidant power) assays, and sensory analysis. Extraction conditions did not affect the acidity and the amount of oxidation products in the oil. Chlorophylls and carotenoid contents increased with algae concentration, while flavonoid extraction did not depend on algae content or UAE time. Total phenolics in the oil were highly related only to FRAP antioxidant activity. Storage experiments of supplemented oil (12.5% algae; 20 min UAE) were carried out under accelerated oxidation conditions at 60 °C/12 days. Antioxidant activity (FRAP) of supplemented oil was 6‐fold higher than the value of non‐supplemented oil. Final samples retained 40% of their initial antioxidant activity. The presence of algae extracts contributed to the increased oxidative stability of sunflower oil.
- Physicochemical and nutritional characterization of the leaves, flowers and fruits of Chorão da praia (Carpobrotus edulis) from Portuguese west shoresPublication . Neves, Marta; Antunes, Madalena; Azevedo, Zélia M.; Freitas, Victor; Rocha, João M.; Tecelão, CarlaLeaves, flowers and fruits from the edible halophyte Chorão da praia (Carpobrotus edulis), harvested in Portuguese west shores, were characterized regarding their proximate composition, phenolic compounds and antioxidant activity. Flowers and leaves had similar protein content (5.42±0.15 and 5.22 ±0.13 % DW, respectively), being higher than fruits (4.67±0.22 %). No significant differences were observed in the lipid fraction, ranging from 1.70 ± 0.12 in flowers to 1.90 ± 0.16 % DW in leaves. Fruits presented the highest value of total carbohydrates (71.5±1.2 % DW), whereas ash was more abundant in leaves (32.00 ± 0.35 % DW) that also showed the highest chlorophylls content, comprising 52.0±7.2 μg/g chl a and 26.2±8.2 μg/g chl b. Similar levels of total carotenoids were observed in leaves and flowers (5.7±1.6 and 4.6±1.4 μg/g DW, respectively), being significantly higher than fruits (2.8±0.2 μg/g DW). Aqueous-ethanolic (1:1, v/v) extract of flowers exhibited the highest total phenolic content (299±8 μg/mg of gallic acid equivalents), by the Folin–Ciocalteu method, as well as the strongest antioxidant activity (3.25±0.21 and 2.38±0.07 μmol/mg of trolox equivalents by the DPPH and FRAP methods, respectively), followed by leaves (1.68±0.16 and 1.36±0.14 μmol/mg) and fruits (0.58±0.13 and 0.71±0.03 μmol/mg). Bulk polyphenol extracts were further purified through Solid-Phase Extraction (SPE), using C18 reversed-phase sorbent Oasis® Prime HLB Extraction cartridges. Polyphenols in purified extracts were initially analyzed by RP-HPLC-DAD and a separation chromatographic method was developed and optimized. The optimal elution program was further used for the separation and identification of polyphenols via RP-HPLC-ESI-MS/MS. Mass spectra unfolded the complete or partial separation of molecular species of polyphenols. Moreover, mass and tandem mass spectra revealed that the most abundant species in all extracts were glycosylated and/or acetylated O-Methyl flavonols. It was observed compounds mainly derived from syringetin and laricitrin. Each of these two aglycones revealed two major compounds: two [MH]- ions with m/z 653 (syringetine derivatives) and two [M-H]- ions with m/z 639 (laricitrin derivatives). In both cases, the MS2 data of the [M-H]- ions showed high intensity fragment ions with m/z 345 and 331, respectively, corresponding to the loose of a glucosyl-alfa-araninofuranoside or an acetylated glucoside [M-308]. Moreover, the MS3 data of the two most intense fragment resulted in successive loss of methyl groups with the first one presenting the highest intensity. Regarding the profile in polyphenols, when comparing leaves, flowers and fruits, one concluded that there are clearly differences in the relative amount of these polyphenols being flowers richer in the syringetin derivatives.
- O Chorão das praias como potencial fonte de compostos bioativos para incorporação em matrizes alimentaresPublication . Fernandes, Wilson; Tecelão, Carla; Neves, MartaO presente estudo pretendeu avaliar o potencial de Carpobrotus edulis L., uma planta invasora do litoral português, como fonte de compostos bioativos para a incorporação em matrizes alimentares. Fez-se a caracterização fitoquímica de espécimes provenientes de diferentes locais da costa oeste de Portugal em termos de: (1) clorofilas e carotenóides totais, (2) compostos fenólicos e (3) atividade antioxidante, tendo-se verificado uma significativa variabilidade geográfica. As plantas colhidas em Peniche Sul foram as que se revelaram mais interessantes em termos de compostos fenólicos e atividade antioxidante, apresentando valores claramente superiores aos dos outros locais. O extrato etanólico destas amostras apresentou um teor de compostos fenólicos de 815+- 0,007 ug/mg e uma atividade antioxidante (34,5 +- 2,7% de inibição do DPPH) equivalente à do antioxidante sintético Trolox testado na mesma concentração (5ug/mL). Os resultados obtidos sugerem assim que C. edulis é uma fonte promissora de compostos bioativos para aplicação alimentar.
- Proximate composition and fatty acid profile of Gilthead seabream (Sparus aurata) fed with Pelvetia canaliculata supplemented diets: An insight towards the valorization of seaweed biomassPublication . Antunes, Madalena; Neves, Marta; Pires, Damiana; Passos, Ricardo; Carmo, Beatriz do; Tchobanov, Carolina F.; Forte, Sara; Vaz, Mariana; Baptista, Teresa; Tecelão, CarlaSeaweeds are a sustainable source of protein and lipids that may be used to replace fish by-products in aquaculture feed. This study aimed at using the macroalgae Pelvetia canaliculata as an ingredient in gilthead seabream (Sparus aurata) feed, either as freeze-dried powder or as algae residue (waste) that was obtained after the supplementation of sunflower oil. The formulated diets and the fish muscle were analyzed concerning the proximate composition and the fatty acid profile. The health lipid indices hypocholesterolemic/ hypercholesterolemic (h/H), atherogenic (AI), thrombogenic (TI), as well as n-3/n-6 and polyunsaturated fatty acid/saturated fatty acid (PUFA/SFA) ratios were calculated. Additionally, the peroxidizability index (PI) was determined. No differences were observed in the proximate composition of fish muscle regardless of the diet used. Fish fed a diet supplemented with 10% of algae waste (W10) stand out for the highest content in oleic acid (C18:1 n-9), and the lowest in both linoleic (C18:2 n-6) and palmitic (C16:0) fatty acids. All fish samples showed values of health lipid indices within the limits recommend for a nutritional balanced diet. These results highlight that fish fed diets supplemented with P. canaliculata are sources of healthy lipids that might be consumed on a regular basis to prevent cardiovascular diseases.