Browsing by Author "Rodrigues, V."
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- Can dietary aromatic amino acid supplementation be beneficial during fish metamorphosis?Publication . Pinto, W.; Rodrigues, V.; Dinis, Maria Teresa; Aragão, C.Aromatic amino acids (AA, phenylalanine and tyrosine) are the precursors of thyroid hormones, which regulate metamorphosis in all vertebrates. In fish, this is a critical developmental stage where physiological requirements for aromatic AA may increase. Therefore, it is possible that dietary aromatic AA supplementation may be beneficial to accomplish a successful transition from larvae to the juvenile stage. This work aimed to assess the effect of dietary aromatic AA supplementation on tyrosine metabolism in species with an accentuated (Senegalese sole, Solea senegalensis) and a less marked (gilthead seabream, Sparus aurata) metamorphosis. For this purpose, either species were fed Artemia and subsequently received or not an aromatic AA supplement through tube-feeding, together with a L-[U-14C] tyrosine marker, throughout metamorphosis. Tyrosine was elected as a tracer since the metabolic fate of this aromatic AA is directly linked to the production of thyroid hormones and metamorphosis. Results showed that dietary phenylalanine supplementation did not increase tyrosine retention in Senegalese sole larvae during metamorphosis, suggesting that this species may not be able to biosynthesise tyrosine from phenylalanine at a sufficient rate to supply its physiological requirements until after metamorphosis. Furthermore, dietary tyrosine supplementation effectively increased tyrosine availability in Senegalese sole body fluids at metamorphosis, most likely for coping with metamorphosis-related processes, such as production of thyroid hormones. Therefore, dietary tyrosine supplementation may be beneficial for Senegalese sole during metamorphosis. On the other hand, results indicated that gilthead seabream larvae do not seem to require an additional supply of aromatic AA during metamorphosis, probably because the physiological requirements for tyrosine do not increase during this developmental stage. The different results observed for Senegalese sole and gilthead seabream are probably related to the complexity of metamorphosis that each species undergoes and to the needs for production of thyroid hormones, which seems to affect aromatic AA requirements during this critical stage of development. These findings may be important for physiologists, fish nutritionists and for the flatfish aquaculture industry.
- Dietary lipid quality regulates bone composition and metabolism in gilthead seabream (Sparus aurata) juvenilesPublication . Dias, J.; Rodrigues, V.; Colen, Rita; Rosa, Joana; Viegas, Michael; Cardeira Da Silva, João; Cancela, Leonor; Gavaia, Paulo J.; Laizé, VincentReplacement of significant amounts of marine fish oils by vegetable oils is a major trend in the aquaculture feed industry. However, knowledge on the mechanisms underlying the nutritional regulation of bone metabolism is extremely scarce in fish. We speculate that changes in the dietary ratio of fatty acids may modulate tissue eicosanoids production and affect bone formation in fastgrowing gilthead seabream, an important fish species for aquaculture in the Mediterranean region.
- Effect of variable levels of dietary cholesterol and plant sterols on the growth performance and bone metabolism in gilthead seabream (Sparus aurata) juvenilesPublication . Dias, J.; Colen, Rita; Rodrigues, V.; Aragão, C.; Engrola, S.; Viegas, Michael; Laizé, Vincent; Gavaia, Paulo J.; Cancela, LeonorCholesterol is found in all animal tissues and is an important component of biological cell membranes with functions such as precursor to bile acids, hormones and vitamins. Fish meal and fish oil are cholesterol-rich ingredients. Replacement of these marine-derived ingredients by plant proteins and vegetable oils tends to reduce dietary cholesterol levels.
- Improving vector-borne disease control in AlbufeiraPublication . Sá, R.; Dinis, V.; Edmundo, A.; Costa, I. Carvalho; Figueiredo, V.; Almeida, S.; Fonseca, A.; Lopes, C.; Rodrigues, V.; Correia, M.The Albufeira Health Centre (CSA) comprises various functional units within primary healthcare. Recognizing the limited awareness of colleagues regarding the Vector Surveillance Network (REVIVE), responsible for entomological surveillance of mosquitoes, ticks, and sandflies, the Public Health Unit (USP) initiated a project to improve coordination and knowledge sharing. Implemented in April 2023, the project involved a multidisciplinary team. Informational materials on vector surveillance and control, clinical guidance for common vector-borne diseases (VBDs), tick collection protocols, and specimen registration forms were distributed. A video highlighting entomological surveillance and strategies for prevention and control was disseminated. To date, the project has recorded 45 views of the video (51%). A questionnaire distributed among the target population revealed that only 20% had knowledge of the epidemiological importance of vectors in the Algarve region. None were familiar with REVIVE or its work. Furthermore, participants were not acquainted with the Aedes albopictus mosquito species. Regarding ticks, 20% felt confident in tick removal, but none were aware of the tick genera in the Algarve region. Only 20% were aware of notifiable vector-borne diseases through SINAVE. Training sessions on this topic were suggested. The project emphasized the significance of communication and collaboration among healthcare professionals in the prevention and control of vector-borne diseases. It highlighted the need for continuous education on VBDs, surveillance techniques, and control measures. This innovative project can serve as a model for healthcare centres and countries, contributing to global efforts to improve the response to vector-borne diseases. The project's outreach extended to the Municipal Albufeira Animal Welfare Centre. A new questionnaire will be distributed to gather additional insights and enhance the impact of the project.
- Nutritional modulation of innate immune parameters in the epidermal mucus of Senegalese sole (Solea senegalensis)=Influência da dieta nos parâmetros da resposta imunitária inata do muco de linguado (Solea senegalensis)Publication . Rodrigues, V.; Dinis, Maria Teresa; Dias, J.; Ribeiro, L.Fish are in constant interaction with their habitat and potential pathogens. Fish epidermis acts as the first line of defense, since mucus secreted by mucous cells contains innate immune parameters, such as enzymes and antimicrobial proteins. Knowledge about the mechanisms of immune defense at the skin and mucus level in fish is still scarce. This study was undertaken to evaluate the role of nutritional factors as tools to enhance the immune parameters in the mucus of Senegalese sole (Solea senegalensis). Homogenous groups of Senegalese sole (initial body weight: 92.8 ± 1.52g) were fed: a control diet (CTRL); the CTRL diet supplemented with vitamin C (1000 mg/kg) (VIT C); and a diet identical to CTRL but in which 70% of the dietary fat was originated from coconut oil (COC), identified as a potential immunostimulant. After a period of 4 and 6 weeks of experimental feeding, fish mucus was sampled for quantification of lysozyme, alkaline phosphatase, proteases, lipid antioxidation (TBARS) and antimicrobial activity. Growth performance and lysozyme activity was not affected by dietary treatments, while the proteolytic activity and lipid oxidation was affected positively by both dietary treatments. Alkaline phosphatase activity was only affected by diets rich in coconut oil. Epidermal mucus of sole showed antibacterial activity against a series of marine pathogen bacteria. Highest inhibitory action was associated to mucus extracts derived from coconut oil fed fish. The modulation of selected mucus immune parameters through dietary factors is possible in Senegalese sole. A four weeks period of feeding seems enough to induce such changes. Further research is needed to determine the processes associated to such modulation and evaluate to what extent these beneficial changes contribute to an enhanced immune response of sole.