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- 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.
- Evaluation of fatty acids profile as a useful tool towards valorization of by-products of agri-food industryPublication . Ferreira, Rui; Lourenço, Sílvia; Lopes, André; Andrade, Carlos; Câmara, José S.; Castilho, Paula; Perestelo, RosaWorldwide, the food industry generates a large number of by-products from a wide variety of sources. These by-products represent an interesting and economical source of added value components with potential functionalities and/or bioactivities, which might be explored for industrial purposes, encouraging and promoting the circular economy concept. In this context, the current work aimed to evaluate the fatty acids (FAs) profile using gas chromatography–flame ionization detector (GC–FID) and Fourier Transform Infrared (FTIR), as well as the determination of related health lipid indices (e.g., atherogenic (AI) and thrombogenic (TI)) as a powerful strategy to investigate the potential applications of different agri-food by-products for human nutrition and animal feeding. This work results showed that polyunsaturated fatty acids (PUFAs) are the predominant group in grape pomace (72.7%), grape bunches (54.3%), and brewer’s spent grain (BSG, 59.0%), whereas carrot peels are dominated by monounsaturated fatty acids (MUFAs, 47.3%), and grape stems (46.2%), lees (from 50.8 to 74.1%), and potato peels (77.2%) by saturated fatty acids (SFAs). These findings represent a scientific basis for exploring the nutritional properties of agri-food by-products. Special attention should be given to grape pomace, grape bunches, and BSG since they have a high content of PUFAs (from 54.3 to 72.7%) and lower AI (from 0.11 to 0.38) and TI (from 0.30 to 0.56) indexes, suggesting their potential to provide a variety of health benefits against cardiovascular diseases including well-established hypotriglyceridemia and anti-inflammatory effects, products to which they are added.
- Morphometric approach to the development of Paracentrotus lividus larvae fed with different microalgae dietsPublication . Lourenço, Sílvia; Gomes, Ana Sofia; Santos, Pedro M.; Raposo, Andreia; Ferreira, Susana; Pombo, Ana
- A morphometric approach to the development of Paracentrotus lividus larvae fed with different microalgae dietsPublication . Lourenço, S.; Gomes, A.S.; Santos, Pedro Castelo Filipe Moreira dos; Raposo, A.; Ferreira, S.M.F.; Pombo, AnaParacentrotus lividus is the most valuable sea urchin species in the European roe markets. Its economic value has been driving an intense exploration of wild populations leading to their over-exploitation in several areas of the Mediterranean and eastern Atlantic coast. The full production of P. lividus in aquaculture can potentially supply the European market for sea urchin roe reducing the impact over the wild populations. However, the low survival rates of sea urchin planktonic stages represent a critical bottleneck for the full cycle production for commercial purposes. Together with the zootechnical challenges, the selection of a suitable microalgal diet is fundamental to overcome this challenge. In the present study, we conducted two larvae rearing experiments testing the effect of five microalgae diets in the larvae development, age at competence and survival. The experimental diets tested were: Rhodomonas baltica (rho); Phaedactylum tricornutum (phae); Chaetoceros calcitrans (chae); a mix diet of rho and phae (1:1); and a mixed diet of rho and chae (1:1). The larvae were reared in closed system in triplicate tanks (50 L) at a density of 4 larvae/mL with seawater temperature ranging between 18.5 and 20°C. The daily feed concentration was adapted to the larval stage of development and standardized to the ratio between microalgae biovolume. Larvae samples were regularly collected to measure larvae body length, body width, post-oral arm length and the rudiment length. Linear models were fitted to the larval measurements and the model residuals were analyzed as an indication of larvae body condition. The larval survival was assessed volumetrically every two days. The results showed that the larvae fed with rho attained age at competence (at 18 days post fecundation, DPF, in experiment I and at 16 DPF at experiment II) earlier than larvae fed with phae, chae or with the mixed diets. On the other hand, the larvae fed with the rho and chae mixed diet presented higher survival rate (32 %). Moreover, the preliminary analysis of the linear model residuals showed that the mixed diet promoted the development of larvae with better condition. These results indicated that the rho diet promoted a reduction of the planktonic phase albeit with costs in terms of larval condition and survival rate.
- Before and after a disease outbreak: tracking a keystone species recovery from a mass mortality eventPublication . Gizzi, Francesca; Jiménez, Jesús; Schäfer, Susane; Castro, Nuno; Costa, Sónia; Lourenço, Sílvia; José, Ricardo; Canning-Clode, João; Monteiro, JoãoMass mortality events involving marine taxa are increasing worldwide. The long-spined sea urchin Diadema africanum is considered a keystone herbivore species in the northeastern Atlantic due to its control over the abundance and distribution of algae. After a first registered mass mortality in 2009, another event off the coasts of Madeira archipelago affected this ecologically important species in summer 2018. This study documented the 2018 D. africanum mass mortality event, and the progress of its populations on the southern coast of Madeira island. A citizen science survey was designed targeting marine stakeholders to understand the extent and intensity of the event around the archipelago. Underwater surveys on population density prior, during and after the mass mortality, permitted an evaluation of the severity and magnitude of the event as well as urchin population recovery. A preliminary assessment of causative agents of the mortality was performed. The event was reported in the principal islands of the archipelago reducing the populations up to 90%. However, a fast recovery was registered during the following months, suggesting that the reproductive success was not compromised. Microbiological analyses in symptomatic and asymptomatic individuals, during and after the event, was not conclusive. Nevertheless, the bacteria Aeromonas salmonicida, or the gram-negative bacteria, or the interaction of different types of bacteria may be responsible for the disease outbreak. Further studies are needed to assess the role of pathogens in sea urchin mass mortalities and the compound effects that sea urchins have in local habitats and ecological functioning of coastal marine ecosystems.
- Motivation and preferences of Portuguese consumers’ towards sea urchin roePublication . Lourenço, Sílvia; Mendes, Susana; Raposo, Andreia; Santos, Pedro M.; Gomes, Ana S.; Ganhão, Rui; Costa, José L.; Gil, Maria M.; Pombo, AnaSea urchin roe is a gastronomic delicacy appreciated worldwide and Portugal is the third largest consumer nation of seafood. However, sea urchin roe is recognized as a seafood by few members of the national coastal communities. Motivated by an increasing interest of gastronomic and aquaculture sectors in producing this seafood, a survey was conducted among the participants of gastronomic festivals aiming to characterize the motivations and preferences regarding sea urchin roe. The results showed that a high percentage of consumers would be willing to eat sea urchin roe in a restaurant, and approximately half of these were not motivated to buy it in the supermarket. The consumers willing to buy sea urchins in the supermarket, would buy it as the whole urchin or the chilled/frozen roe. In conclusion, sea urchin roe can be characterized as a high valued shellfish to be consumed in restaurants.
- Pilot studies for stock enhancement of purple sea urchins (Paracentrotus lividus, Lamarck, 1816): usefulness of refuges and calcein marking for the monitoring of juveniles released into the natural environmentPublication . Correia, Maria João; Lopes, Patrícia Mega; Santos, Pedro M.; Jacinto, David; Mateus, David; Maresca, Francesco; Quintella, Bernardo Ruivo; Cruz, Teresa; Lourenço, Sílvia; Pombo, Ana; Costa, José LinoIn the framework of stock enhancement, field experiments were conducted between March and July 2021 in rocky shores of Central Portugal to test the usefulness of refuges and calcein marking for juvenile sea urchins releases. Individuals with 10–20mmin test diameter were captured in nature and tagged through immersion in a calcein bath with a concentration of 150 mg L 1, during 48 hr. Artificial shelters were used to provide refuge and an acclimatization structure for the released sea urchins, and in situ monitoring was carried out by counting the marked specimens over three months. Results point out to the importance of using shelters to provide protection to sea urchins, and validated the efficiency of the calcein tagging protocol for in situ monitoring. Sea urchins’ test diameter growth during the experiment was estimated to be 0.470mm month 1 (SD = 0.181).
- Population density, reproduction cycle and nutritional value of Sphaerechinus granularis (Echinodermata: Echinoidea) in an oceanic insular ecosystemPublication . Lourenço, Sílvia; José, Ricardo; Neves, Pedro; Góis, André; Cordeiro, Nereida; Andrade, Carlos; Ribeiro, CláudiaSea urchins play an important role in island coastal ecosystems as keystone species and as potential Resources for harvesting and aquaculture. In Southern Europe, the most valuable and harvested species is the European purple sea urchin Paracentrotus lividus, but there is a growing interest to explore other edible Species like the blunt sea urchin Sphaerechinus granularis. The echinoderms biodiversity of Madeira archipelago was previously described, but their local habitat, population densities and size distribution, important to establish their harvest and aquaculture potential, are poorly known. The present study aimed to evaluate S. granularis population in the oligotrophic and narrow insular shelf of Madeira archipelago, mainly regarding its habitat, densities, reproduction season and roe marketable characteristics. Sphaerechinus granularis was found in low densities (0.01 ind./m2) from shallow to deep reefs (5–30 m). The highest densities occurred in shallow waters and breakwaters in association to encrusting algae, turf and erect brown macroalgae. Here, the low primary productivity ecosystem influenced the long reproductive season of the local population. This population showed a relatively high gonadosomatic index (maximum GI of 8), high gonad weight (5.00–12.19 g) with high proportion of bright yellow and orange gonads (37.5–60%) between February and November. Additionally, the high level of total carotenoids, the high PUFA (particularly EPA) content, and the ratio n-6/n-3 close to one support the high nutritional value of S. granularis roe. The trend of incremental GI between September and November and the increasing content of PUFA in autumn suggests this could be the preferential harvesting season. This information is key to evaluate a sustainable exploitation of this living marine resource.
- 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.
- Effects of single and mixed-diatom diets on growth, condition, and survival of larvae of the sea urchin Paracentrotus lividus (Lamarck, 1816)Publication . Gomes, Ana; Lourenço, Sílvia; Santos, Pedro M.; Raposo, Andreia; Mendes, Susana; Gonçalves, Sílvia C.; Ferreira, Susana M. F.; Pombo, AnaThe development of rearing protocols promoting the larval development, pre and postmetamorphosis are key for echinoculture. Mixed diets combining diatom with other microalgae have been used with success and Rhodomonas sp. (Rho)-based diets showed promising results in larval survival. This study was aimed to evaluate the rearing success of Paracentrotus lividus larvae fed with mixed diets combining Rho with two diatoms, Phaedactylum tricornutum (Phae) and Chaetoceros calcitrans (Chae) in two experiments. In experiment I, the effect of the mixed diet of Rho and Phae (Mix I) was compared with monospecific diets of both species, while in experiment II, Rho was combined with Chae (Mix II) and compared with both monospecific diets. In experiment I, larvae fed with Rho I and Mix I diets grew faster than larvae fed with Phae I diet, attained the competence earlier with survival rates of 15-16%. In experiment II, the larvae fed with Rho were larger and the larvae fed with Mix II attained the highest survival rate (32.22%). The analysis of the larval biometric models showed that the larger larvae, with bigger stomachs, and shorter post-oral arm attained the age-at-competence earlier with higher survival rates. In conclusion, the larvae fed with a combination of Rho with the selected diatoms showed identical growth performance and condition to larvae fed with Rho monospecific diet but obtained higher survival rate. These results indicate that mixed-diatoms diets may be more suitable for P. lividus larval rearing.