Browsing by Author "Bandarra, Narcisa M."
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- Antioxidant and anti-inflammatory extracts from sea cucumbers and tunicates induce a pro-osteogenic effect in Zebrafish LarvaePublication . Carletti, Alessio; Cardoso, Carlos; Lobo-Arteaga, Jorge; Sales, Sabrina; Juliao, Diana; Ferreira, Inês; Chainho, Paula; Dionísio, Maria Ana; Gaudêncio, Maria J.; Afonso, Cláudia; Lourenço, Helena; Cancela, M. Leonor; Bandarra, Narcisa M.; J. Gavaia, PauloBone metabolic disorders such as osteoporosis are characterized by the loss of mineral from the bone tissue leading to its structural weakening and increased susceptibility to fractures. A growing body of evidence suggests that inflammation and oxidative stress play an important role in the pathophysiological processes involved in the rise of these conditions. As the currently available therapeutic strategies are often characterized by toxic effects associated with their long-term use, natural antioxidants and anti-inflammatory compounds such as polyphenols promise to be a valuable alternative for the prevention and treatment of these disorders. In this scope, the marine environment is becoming an important source of bioactive compounds with potential pharmacological applications. Here, we explored the bioactive potential of three species of holothurians (Echinodermata) and four species of tunicates (Chordata) as sources of antioxidant and anti-inflammatory compounds with a particular focus on polyphenolic substances. Hydroethanolic and aqueous extracts were obtained from animals' biomass and screened for their content of polyphenols and their antioxidant and anti-inflammatory properties. Hydroethanolic fractions of three species of tunicates displayed high polyphenolic content associated with strong antioxidant potential and anti-inflammatory activity. Extracts were thereafter tested for their capacity to promote bone formation and mineralization by applying an assay that uses the developing operculum of zebrafish (Danio rerio) to assess the osteogenic activity of compounds. The same three hydroethanolic fractions from tunicates were characterized by a strong in vivo osteogenic activity, which positively correlated with their anti-inflammatory potential as measured by COX-2 inhibition. This study highlights the therapeutic potential of polyphenol-rich hydroethanolic extracts obtained from three species of tunicates as a substrate for the development of novel drugs for the treatment of bone disorders correlated to oxidative stress and inflammatory processes.
- Can Senegalese sole post-larvae effectively grow on low dietary DHA and lipid levels during weaning?Publication . Pinto, Wilson; Engrola, S.; Santos, André; Bandarra, Narcisa M.; Dias, Jorge; Conceicao, LuisSenegalese sole (Solea senegalensis) is a highly-valuable flatfish species with interest for diversification of aquaculture in Mediterranean countries. Unlike other fish species known to have a high dietary DHA requirement during the larval stage, several studies have suggested dietary DHA could play a minor role for Senegalese sole during the early developmental stages. This suggestion was recently supported by studies that indicated an ability of Senegalese sole to biosynthesise DHA from its precursors during the larval period. However, it is still uncertain if Senegalese sole post-larvae can effectively grow on low dietary DHA levels during weaning. Moreover, recent studies focusing on the juvenile phase of Senegalese sole have suggested a possible impairment of this species to efficiently digest or absorb high dietary lipid levels. Yet, if a reduction of dietary lipid levels would affect a normal development of Senegalese sole during the early stages remains to be established. Therefore, this study aimed at determining if a reduction of dietary DHA and lipid levels would affect Senegalese sole performance and lipidme-tabolism duringweaning and post-larval period. In this study, Senegalese sole post-larvae were reared according to four dietary treatments: low lipid levels (treatments LFAT and LFAT_DHA) and moderate lipid levels (MOD-FAT and MODFAT_DHA). DHA levels in LFAT_DHA and MODFAT_DHA diets were higher than in LFAT and MOD-FAT diets, respectively. Subsequently, effects of experimental diets on Senegalese sole post-larval growth, survival, fatty acid composition and histopathological condition of intestinal and liver tissues were evaluated. Results showed that feeding on diets with low DHA and lipid levels significantly reduced the growth performance of Senegalese sole post-larvae. However, at the end of the experimental period, no significant differences were observed for post-larval survival in response to dietary treatments. In overall, this study disadvises that weaning diets for Senegalese sole post-larvae should contain low DHA and lipid levels, as a reduction of these levels may compromise post-larval growth performance.Statement of relevance: Determining essential fatty acid requirements in marine fish larvae is of utmost importance for the aquaculture industry, contributing to fulfil the growth potential of farmed species. In the case of Senegalese sole, a highly valued species farmed in Mediterranean countries, it may have the capacity to biosynthesise DHA from its precursors during the larval stage. However, the inclusion of DHA-rich oils in weaning diets is costly, considerable savings could be achieved by replacing DHA-rich oils by common fish oils in weaning diets for this species. Furthermore, Senegalese sole has also been shown a poor ability to deal with high dietary lipid levels during the juvenile stage. However, no studies have addressed this capacity in Senegalese sole larvae. This study comprises an evaluation on the effects of reducing dietary DHA and lipid levels during Senegalese sole weaning by integrating an assessment of these effects on post-larval growth, survival, fatty acid composition and histopathological condition. (C) 2016 Elsevier B.V. All rights reserved.
- Differential effects of food restriction and warming in the two-spotted goby: impaired reproductive performance and stressed offspringPublication . Lopes, Ana F.; Murdoch, Robyn; Martins-Cardoso, Sara; Madeira, Carolina; Costa, Pedro M.; Félix, Ana S.; Oliveira, Rui F.; Bandarra, Narcisa M.; Vinagre, Catarina; Lopes, Ana R.; Gonçalves, Emanuel J.; Faria, Ana MargaridaClimate change is a growing threat to marine organisms and ecosystems, and it is already modifying ocean properties by, for example, increasing temperature and decreasing pH. Increasing water temperature may also lead to an impairment of primary productivity and an overall depletion of available zooplankton. Understanding how the crossover between warming and zooplankton availability impacts fish populations has paramount implications for conservation and mitigation strategies. Through a cross factorial design to test the effects of ocean temperature and food availability in a temperate marine teleost, Pomatochistus flavescens, we showed that hindered feeding impacted sheltering and avoidance behaviour. Also, low food availability impaired fish reproduction, particularly male reproduction, as the expression of cyp11b1, a gene with a pivotal role in the synthesis of the most important fish androgen, 11-ketotestosterone, was significantly reduced under a low food regime. In contrast, temperature alone did not affect reproductive success, but offspring showed increased saturated fatty acid content (embryos) and increased lipid peroxidation (larvae). Altogether, food availability had a stronger effect on fitness, showing that coping with elevated temperatures, an ability that may be expected in shallow-water fish, can be indirectly impacted, or even overwhelmed, by the effects of ocean warming on primary productivity and downstream ecological processes.
- Exploring Omega-3′s impact on the expression of Bone-Related Genes in Meagre (Argyrosomus regius)Publication . Luján-Amoraga, Leticia; Delgado-Martín, Belén; Lourenço-Marques, Cátia; J. Gavaia, Paulo; Bravo, Jimena; Bandarra, Narcisa M.; Dominguez, David; Izquierdo, Marisol S.; Pousão-Ferreira, Pedro; Ribeiro, LauraDietary supplementation with Omega-3 fatty acids seems to promote skeletal health. Therefore, their consumption at imbalanced or excessive levels has offered less beneficial or even prejudicial effects. Fish produced in aquaculture regimes are prone to develop abnormal skeletons. Although larval cultures are usually fed with diets supplemented with Omega-3 Long Chain Polyunsaturated fatty acids (LC-PUFAs), the lack of knowledge about the optimal requirements for fatty acids or about their impact on mechanisms that regulate skeletal development has impeded the design of diets that could improve bone formation during larval stages when the majority of skeletal anomalies appear. In this study, Argyrosomus regius larvae were fed different levels of Omega-3s (2.6% and 3.6% DW on diet) compared to a commercial diet. At 28 days after hatching (DAH), their transcriptomes were analyzed to study the modulation exerted in gene expression dynamics during larval development and identify impacted genes that can contribute to skeletal formation. Mainly, both levels of supplementation modulated bone-cell proliferation, the synthesis of bone components such as the extracellular matrix, and molecules involved in the interaction and signaling between bone components or in important cellular processes. The 2.6% level impacted several genes related to cartilage development, denoting a special impact on endochondral ossification, delaying this process. However, the 3.6% level seemed to accelerate this process by enhancing skeletal development. These results offered important insights into the impact of dietary Omega-3 LC-PUFAs on genes involved in the main molecular mechanism and cellular processes involved in skeletal development.