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- Chemical composition, fatty acids profile and cholesterol content of commercialized marine fishes captured in Northeastern AtlanticPublication . Nogueira, Natacha; Cordeiro, Nereida; Aveiro, Maria JoãoInformation available on the chemical composition and nutritional value of commercialized marine fish is very limited. The aim of this study was to investigate major nutrients of raw fish muscle and liver. Protein, moisture ash and lipid content were estimated for 14 commercialized species captured in Northeastern Atlantic. Proximate compositions were found to be varied among the studied species. Cluster analysis revealed two major groups based on proximate composition. Pontinus kuhlii and Trachurus picturatus formed one group, while the second group was formed by ten other species. Protein content was high in all species, varying between 18.51% in Phycis phycis and 32.69 % in Diplodus sargus. Fat content, on the other hand, was low and fish could be considered lean (lipid content <4%). Muscle fatty acid compositions consisted of 26.2-35.8% saturated fatty acids (SFA), 10.5-37.6% monounsaturated fatty acids (MUFA) and 28.7-57.5% polyunsaturated fatty acids (PUFA). Fish livers presented lower amounts of PUFA’s than muscles, mainly due to a reduction of the docosahexaenoic acid (DHA) content. Cholesterol content in liver revealed significant differences, ranging from 0.05 ±0.01 mg/g in Scorpaena scrofa to 7.58 ±0.19 mg/g in Aphanopus carbo. In fish muscle, cholesterol was low and was not correlated with lipids, fatty acids or PUFA content of the muscle.
- Lipid and fatty acid composition of wild Almaco Jack Seriola rivoliana at two maturation stagesPublication . Fernandes, Igor; Nogueira, Natacha; Faria, Graça; Fernandes, Tomásia; Faria, Marisa; Cordeiro, NereidaAlmaco jack (Seriola rivoliana) is an emergent marine finfish that presents high market value. In order to study the feasibility of the exploitation of this marine resource for human consumption the evaluation of the nutritional characteristics of this species has attracted the attention of the scientific community. The lipid characteristics and fatty acid composition were evaluated in muscle, liver and gonad tissues of wild Almaco jack from Atlantic Ocean at two different maturation stages. According to results, the lipid content was found higher at pre-spawning stage (21.78 - 36.17%) and highest proportion being exhibited in the liver. Palmitic acid was predominant among the saturated fatty acids (35.42 - 47.80%) and oleic acid was detected as the main monounsaturated acid (25.26 - 36.55%). Higher amounts of ω3 polyunsaturated fatty acids (PUFAs) were identified in gonads of resting females, of which more than 84% was accounted by docosahexaenoic acid (12.62%). Muscle and liver of resting females presented the highest ω3/ω6 ratios. The Hypocholesterolemic/Hypercholesterolemic index was higher in gonads of both maturation stages (0.97 and 1.05). The results showed that wild Almaco jack at resting stage were a better source of oleic acid and ω3 PUFAs and that liver and gonads present good nutritional by-products.
- Inclusion of low levels of blood and feathermeal in practical diets for gilthead seabream (Sparus aurata)Publication . Nogueira, Natacha; Cordeiro, Nereida; Andrade, Carlos; Aires, TiagoRendered animal protein ingredients, such as feather meal and blood meal, are promising animal protein sources for the replacement of fish meal often proved to combine synergistically. Three practical diets containing similar amounts of PD/ED (22.0 mg/kJ) but differing in the amount of digestible protein were tested in sea bream juveniles of initial body weight 41.81±1.12 g. FBCM diet (40%PD) and FBM diet (42%PD) contained similar percentages of blood and feather meal (10% and 5%, respectively) but differed in the proportion of soybean / rapeseed meal. Although growth performance and feed utilization were very similar in all treatments, chemical composition showed that blood and feather meal supplementation increased significantly whole-body lipid content compared with fishmeal diet (P205A). Liver lipid content was significantly lower in fish fed FBCM diet. Whole-body fatty acids composition was similar between treatments, ranging between 242.57±14.17 mg g-1 in FBM diet and 274.62±23.95 mg g-1 for FBCM diet. Palmitic acid, oleic acid, linoleic acid; EPA and DHA were the most abundant fatty acids in both polar and neutral lipid fractions of the fish. Economical evaluation indicated that the incorporation of blood and feather meal as a substitute of fish meal decreased feed costs leading to a better economic conversion ratio.
- Quality parameters of wild white trevally (Pseudocaranx dentex) natural spawn kept in captivityPublication . Nogueira, Natacha; Ferreira, Marilyn; Cordeiro, Nereida; Canada, PaulaThe white trevally (Pseudocaranx dentex Bloch & Schneider, 1801) is a widely distributed carangid, commercially exploited in both the Pacific and eastern Atlantic. Most published works refer to the use of hormonal induction with gonadotropin-releasing hormone for egg supply with generally low fecundities and of poor quality. This study aimed to contribute for a better knowledge on the husbandry conditions that allow for natural spawning of white trevally in captivity. Wild white trevallies were kept in captivity for four years until natural spawning occurred. Nine breeders were kept in a 10m3 concrete tank at a density of 5 Kg/m3 , under natural photoperiod and natural water temperature fluctuations. Spawning started when water temperature reached 19 °C and lasted for two months. Viability rates varied between 35 and 79% and the average number of spawned eggs per female was of 280 × 103 . Egg total lipids (16%DW) and fatty acid profile (expressed as a % total detected) remained constant throughout the spawning season and were not correlated with any egg viability parameters. Neutral lipids, a major energy source in marine fish eggs and larvae, accounted for 50% of lipid classes, followed by glycolipids and phospholipids. Within lipid fractions, the neutral lipids presented high amounts of mono unsaturated fatty acids followed by equally high contents of polyunsaturated fatty acids. Docohexaenoic acid (DHA) was mainly found in the phospholipids fraction, though it was present in high amounts in all lipid classes. However, no significant correlations were observed between the DHA content and the egg viability parameters. The percentage of arachidonic acid (Ara) (< 0.1%) was low, possibly due to a deficiency of this fatty acid in the broodstock diet. Polyunsaturated fatty acids content, mostly represented by DHA and eicosapentaenoic acid (EPA), was positively correlated with hatching rate. Correlations observed between chemical composition of the eggs and viability parameters highlight the fact that egg quality is deeply influenced not only by environmental factors but also by broodstock management techniques
- Polystyrene microplastics exposure modulated the content and the profile of fatty acids in the Cladoceran Daphnia magnaPublication . Parolini, Marco; De Felice, Beatrice; Góis, André; Faria, Marisa; Cordeiro, Nereida; Nogueira, NatachaA growing number of studies has shown that the exposure to microplastics (MPs) of different polymeric compositions can induce diverse adverse effects towards several aquatic species. The vast majority of such studies has been focused on the effects induced by the administration of MPs made by polystyrene (PS; hereafter PS-MPs). However, despite the increase in the knowledge on the potential toxicity of PS-MPs, there is a dearth of information concerning their role in affecting energy resources and/or their allocation. The present study aimed at exploring the impact of 21-days expo sure to three concentrations (0.125, 1.25 and 12.5 μg mL−1 ) of PS-MPs of different sizes (1 and 10 μm) on fatty acids (FAs) profile of the freshwater Cladoceran Daphnia magna. The exposure to the highest tested concentration of PS-MPs induced an overall decrease in D. magna total FAs content, independently of the particle size. Moreover, a change in the accumulation of essential FAs by the diet was noted, with an enhanced synthesis of monounsaturated FAs-rich storage lipids. However, a sort of adaptation to counteract the adverse effects and to re-establish the FAs homeostasis was ob served in individuals treated with high PS-MPs concentration, independently of their size. These results indicate that the exposure to PS-MPs could alter the allocation or induce changes in FAs composition in D. magna, with potential long-term consequences on life-history traits of this zooplanktonic species.
- Separate and combined effects of cyclic fasting and l-carnitine supplementation in red porgy (Pagrus pagrus, L. 1758)Publication . Nogueira, Natacha; Cordeiro, Nereida; Canada, Paula; Silva, Paula Cruz e; Ozório, Rodrigo O. A.We examined the e¡ects of cyclic fasting in red porgy (Pagrus pagrus) fed di¡erent dietary carnitine levels. Ju venile ¢sh (23.58 3.49 g) were divided into eight groups ^ four groups were fed every day to apparent sa tiation, while the other four were fasted for 7 days every 2 weeks. In each feeding regime, two replicates were fed an L-carnitine non-supplemented diet (46 mg kg 1 ) and the other two groups were fed an L-carnitine sup plemented diet (630 mg kg 1 ). Fish fed 630 mg L-carni tine accumulated two times more L-carnitine in muscle than ¢sh fed 46 mg L-carnitine. Cyclic fasting reduced the growth performance and lipid content in the liver. Carnitine supplementation did not a¡ect performance and body composition, but decreased the n-6 PUFA content. Moreover, the combined e¡ects of fasting and carnitine supplementation were observed on reducing the n-3 fatty acid content. Areas of steatosis were found in the livers of red porgy, but the results revealed that supplementation of L-carnitine in cyclic fasted ¢sh con tributed towards a lower degree of vacuolization than in ¢sh fed to apparent satiation. Regardless of the feed ing regime applied, the spleen of ¢sh fed the L-carni tine-supplemented diet was haemorrhagic and hyper activation of melanomacrophage cells was observed.
- Microalgal-based biopolymer for nano- and microplastic removal: a possible biosolution for wastewater treatmentPublication . Cunha, César; Silva, Laura; Paulo, Jorge; Faria, Marisa; Nogueira, Natacha; Cordeiro, NereidaThe increasing water pollution caused by the presence of nano- and microplastics has shown a need to pursue solutions to remediate this problem. In this work, an extracellular polymeric substance (EPS) producing freshwater Cyanothece sp. strain was exposed to nano- and microplastics. The bioflocculant capacity of the biopolymer produced was evaluated. The influence of different concentrations (1 and 10 mg L-1) of polystyrene nano- and microplastics in the extracellular carbohydrates and in the EPS production was studied. The presence of nano- and microplastics induced a negative effect on the microalgal growth (of up to 47%). The results show that the EPS produced by Cyanothece sp. exhibits high bioflocculant activity in low concentrations. Also, the EPS displayed very favourable characteristics for aggregation, as the aggregates were confirmed to consist of microalga, EPS and both the nano- and microplastics. These results highlight the potential of the microalgal-based biopolymers to replace hazardous synthetic flocculants used in wastewater treatment, while aggregating and flocculating nano- and microplastics, demonstrating to be a multi-purposed, compelling, biocompatible solution to nano- and microplastic pollution.
- Effect of different levels of synthetic astaxanthin on growth, skin color and lipid metabolism of commercial sized red porgy (Pagrus pagrus)Publication . Nogueira, Natacha; Canada, Paula; Caboz, José; Andrade, Carlos; Cordeiro, NereidaA study was undertaken to evaluate the effects of supplementing commercial feeds with Car ophyll® Pink, a gelatin-encapsuled astaxanthin, on growth parameters, lipid composition, pigment concentration and skin color of commercial size red porgy. Three isonitrogenous diets were formulated containing different levels of astaxantin: Ctrl diet (no pigment added), A50 diet (with 50 mg/kg of astaxanthin) and A80 diet (with 80 mg/ kg of astaxanthin). Four groups of fish (386.29 ± 29.50 g initial weight) were grown in triplicate tanks (10 fish per tank). Ctrl, A50 and A80 groups were fed the respective diets to apparent satiation for 180 days, while a fourth group was fed A50 diet for 90 days followed by A80 diet for another 90 days (A50A80). At the end of trial muscle samples were collected for composition analysis, liver and mesenteric fat for lipid composition determination and skin samples for carotenoids quantification. Dietary astaxanthin supplementation had no effect on growth performance and hepatosomatic index. However, A50A80 group displayed a lower muscle protein content and higher fat content when compared to the other groups. There was no clear effect of dietary astaxanthin supplementation on the liver’s and mesenteric fatty acid profile. Although there was no significant effect on skin total carot enoids, the astaxanthin content tended to increase in fish fed astaxanthin supplemented diets, which was reflected on redness values. Accordingly, dietary astaxanthin supplementation (at 50 or 80 mg/kg for 6 months or at 50 mg/kg for 3 months followed by 80 mg/kg for 3 months) influenced positively skin hue and chroma of red porgy on both pectoral and caudal areas, improving the skin color in commercial sized red porgy and achieving hue and chroma values close to those previously reported for wild individuals. The results reported here provide evidence of the applicability of Carophyll® Pink to improve skin color of large size commercial red porgy, but further studies are needed to optimize this carotenoid supplementation in production farming.
- Marine vs freshwater microalgae exopolymers as biosolutions to microplastics pollutionPublication . Cunha, César; Faria, Marisa; Nogueira, Natacha; Ferreira, Artur; Cordeiro, Nereida Maria AbanoMicroalgae can excrete exopolymer substances (EPS) with a potential to form hetero-aggregates with microplastic particles. In this work, two freshwater (Microcystis panniformis and Scenedesmus sp.) and two marine (Tetraselmis sp. and Gloeocapsa sp.) EPS producing microalgae were exposed to different microplastics. In this study, the influence of the microplastic particles type, size and density in the production of EPS and hetero-aggregates potential was studied. Most microalgae contaminated with microplastics displayed a cell abundance decrease (of up to 42%) in the cultures. The results showed that the formed aggregates were composed of microalgae and EPS (homo-aggregates) or a combination of microalgae, EPS and microplastics (hetero-aggregates). The hetero-aggregation was dependent on the size and yield production of EPS, which was species specific. Microcystis panniformis and Scenedesmus sp. exhibited small EPS, with a higher propension to disaggregate, and consequently lower capabilities to aggregate microplastics. Tetraselmis sp. displayed a higher ability to aggregate both low and high-density microplastics, being partially limited by the size of the microplastics. Gloeocapsa sp. had an outstanding EPS production and presented excellent microplastic aggregation capabilities (adhered onto the surface and also incorporated into the EPS). The results highlight the potential of microalgae to produce EPS and flocculate microplastics, contributing to their vertical transport and consequent deposition. Thus, this work shows the potential of microalgae as biocompatible solutions to water microplastics treatment.
- Nannochloropsis gaditana grown outdoors in annular photobioreactors: operation strategiesPublication . Nogueira, Natacha; Nascimento, Francisco J.A.; Cunha, César; Cordeiro, NereidaMicroalgae are a topic of intense research due to their potential applications in bio-based economy. However, sustainable commercial production is still overpriced due to high cultivation costs, harvesting and dewatering processes. In the present study, trials were conducted with the aim to improve daily operation strategies related to microalgae harvesting processes that did not compromise biomass productivity or the biochemical composition of the cultivated microalgae. Two experimental trials were performed in outdoor tubular annular photobioreactors to evaluate the effects of harvesting and medium dilution time (sunrise vs sunset) on Nannochloropsis gaditana biomass productivity, lipid and fatty acid content. Results showed that harvesting time had no significant effect on cell concentration and biomass productivity. Harvesting and medium dilution time did not affect lipid content. However, lipid content in samples collected at sunset was significantly higher than in samples collected at sunrise for both experimental treatments. The fatty acids profiles were mainly composed by polyunsaturated fatty acids, followed by mono-unsaturated fatty acids and saturated fatty acids. Regardless of medium dilution time, harvesting at sunset indicated that lipidic production (higher polyunsaturated fatty acids and lower saturated fatty acids) was favored without affecting the biomass productivity. The current study showed harvesting in the afternoon is a viable option for large production units that use semi-continuous strategy, without compromising biomass cell and lipid productivity.