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- Avaliação do potencial antiviral de extratos em robalos (Dicentrarchus labrax) infetados com o vírus da necrose nervosa (VNN)Publication . Vaz, Mariana Catarina Cameira; Baptista, Teresa Maria CoelhoUm dos grandes impasses ao desenvolvimento da aquacultura está relacionado com infeções virais, as quais causam perdas económicas significativas. O vírus da necrose nervosa (VNN) é responsável por elevadas taxas de mortalidade em larvas e juvenis, em importantes espécies de peixes. Atualmente, não existe um tratamento completamente eficaz contra esta infeção, e como tal é necessário que sejam aplicadas medidas preventivas, como é o caso da integração de extratos antivirais para controlar e minimizar o impacto desta infeção. Este estudo teve como objetivo avaliar a aplicabilidade de extratos com potencial antiviral, extrato 469 (12 mg/kg) e (6 mg/kg), 558 (306 mg/kg) e (153 mg/kg), 488 (2000 mg/kg) fornecidos a robalos (Dicentrarchus labrax) com 5,30 ± 1,23g, durante 52 dias. Seguido de uma infeção por imersão com TCID50 =106/mL do genótipo RGNNV. Numa análise sobre como o sistema imunitário do D. labrax reage a uma infeção com VNN, não se verificou stress nutricional relacionado com as diferentes dietas fornecidas, pela expressão semelhante do gene hsp-90 entre tratamentos. Quando analisada a expressão do irf3, responsável pela redução da replicação viral, verificou-se uma regulação estatisticamente positiva nos extratos 469 (12 mg/kg), 469 (6 mg/kg), 558 (306 mg/kg) e 488 (2000 mg/kg). Depois da infeção, a quantidade de vírus no tecido cerebral revelou que o extrato 469 (6 mg/kg) foi o único que apresentou diferenças significativas com o menor número de partículas virais (1,56 x 104), coincidente com a elevada expressão do irf3 neste mesmo extrato, antes da infeção. A expressão do ighm, confirmou que nenhum dos extratos teve capacidade de neutralizar partículas virais, o que se verificou pela mortalidade registada. Estes resultados sugerem que a concentração ideal que reduza a quantidade de partículas virais, e com capacidade de neutralização, poderá encontra-se no extrato 469 entre 6 a 12 mg/kg. São necessários mais estudos para perceber exatamente como funciona a modulação do sistema imunitário na presença do VNN e como ocorre a interação do patógeno-hospedeiro. O fornecimento de imunoestimulantes antivirais, podem ser uma estratégia promissora para preparar o sistema imunológico dos peixes e prevenir danos irreversíveis.
- Functional and molecular mmune response of rainbow trout (Oncorhynchus mykiss) following challenge with Yersinia ruckeriPublication . Fajardo, Carlos; Santos, Paulo; Passos, Ricardo; Vaz, Mariana; Azeredo, Rita; Machado, Marina; Fernández-Boo, Sergio; Baptista, Teresa; Costas, BenjaminCurrently, aquaculture production of rainbow trout (Oncorhynchus mykiss) is a multibillion dollar industry; nevertheless, the development of this sector has not been exempt from pitfalls related to the recurrent presence of pathogens of bacterial origin. This is the case of Yersinia ruckeri, the etiologic agent of the infectious pathology known as Enteric Red Mouth Disease (ERM), causing serious economic losses that can be as high as 30–70% of production. Although several studies have been performed regarding pathogen features and virulence factors, more information is needed about the host defense mechanism activation after infection. Given this perspective, this study aimed to evaluate rainbow trout’s short-term innate immune response against infection with Y. ruckeri. A series of factors linked to the innate immune response were evaluated, including determination of hematological parameters, oxidative stress biomarkers, and analysis of the expression of immunerelated genes. Results showed a significant decrease in several hematological parameters (white blood cell count, hematocrit, neutrophils, monocytes, lymphocytes, and thrombocytes) and oxidative stress indicators (SOD) between the control and infected groups. In addition, there were significant differences in the level of gene expression between infected individuals and the control group. Most of these genes (il-1b, il-8, il-10, tnf-a1, tnf-a2, socs3, mmp-9, cath, hsp-70, saa, fer, pcb) were upregulated within the first 24 h following infection. Results from this study showed more insights into the short-term immune response of rainbow trout to infection with Y. ruckeri, which may be useful for the establishment of biomarkers that may be used for the early detection of ERM.
- Lidocaine supplementation in clove-oil and 2-phenoxyethanol anesthesia for gilthead seabream (Sparus aurata)Publication . Tchobanov, Carolina F.; Vaz, Mariana; Pires, Damiana; Passos, Ricardo; Antunes, Luís M.; Baptista, TeresaAnimal welfare and reducing stress during procedures are key objectives for success in animal production. Anesthesia has been used for procedures to reduce animal stress and its negative impact on welfare. This study aimed first to refine the concentrations of the anesthetic clove-oil (CO) and lidocaine (L) in gilthead seabream (Sparus aurata) juveniles (56.0 ± 15.09 g) and then combine clove-oil and 2-phenoxyethanol (2PHE) with the refined concentration of lidocaine. The concentrations of clove-oil (30, 45, and 60 mg L− 1), and the concentrations of lidocaine (2.5, 5, and 7.5 mg L− 1), were evaluated in the refinement trial. Based on these results, a second trial was performed with 45 mg L− 1 CO or 0.4 mL L− 1 2PHE as anesthetics alone or combined with 2.5 mg L− 1 of lidocaine. Results from this work showed an improvement in induction times for 2-phenoxyethanol when lidocaine was added (2PHE 179.53 ± 63.21 s; 2PHE + L 130.65 ± 40.16 s). Recovery time also showed a reduction for clove-oil when lidocaine was used (CO 349.90 ± 123.69 s; CO + L 250.11 ± 51.99 s). The use of lidocaine showed better results, reducing lactate and histological progressive alterations. Lidocaine showed stress-induced oxidative alterations when it was combined with 2-phenoxyethanol. Lidocaine exposure increased ALT, AST, histological regressive alterations for both anesthetics, and gene expression of hsp70 in the gills when clove-oil was used. Further studies are necessary to comprehend the synergistic effects of lidocaine when combined with synthetic and natural anesthetics and to discern potential acute or chronic toxic responses in fish. These insights will be crucial for refining anesthesia protocols and ensuring the well-being of aquatic species in aquaculture practices and research settings.
- Early immune modulation in European Seabass (Dicentrarchus labra) juveniles in response to Betanodavirus infectionPublication . Vaz, Mariana; Pires, Damiana; Pires, Pedro; Simões, Marco; Pombo, Ana; Santos, Paulo; Carmo, Beatriz do; Passos, Ricardo; Costa, Janina Z.; Thompson, Kim D.; Baptista, TeresaThe early host–pathogen interaction between European seabass (Dicentrarchus labrax) and Betanodavirus was examined by using juvenile fish infected intramuscularly with RGNNV (red-spotted grouper nervous necrosis virus). The time course selected for sampling (0–144 h post-infection (hpi)) covered the early stages of infection, with hematological, antioxidant and immunological responses examined. Early activation of the host’s immune system was seen in the first few hours post-infection (6 to 9 hpi), as evidenced by an increase in tnfa, cd28 and c3 expression in the head kidney of infected fish. Most hematological parameters that were examined showed significant differences between sampling times, including differences in the number of thrombocytes and various leukocyte populations. The plasma lysozyme concentration decreased significantly over the course of the trial, and most antioxidant parameters examined in the liver showed significant differences over the infection period. At 144 hpi, peak expression of tnfa and il-1b coincided with the appearance of disease symptoms, peak levels of virus in the brain and high levels of fish mortality. The results of the study show the importance of analyzing the early interactions between European seabass and Betanodavirus to establish early indicators of infection to prevent more severe outcomes of the infection from occurring.
- Principais Patógenos que Afetam Peixes Cultivados em PortugalPublication . Pires, Damiana; Vaz, Mariana; Pires, Pedro; Passos, Ricardo; Carmo, Beatriz; Santos, Paulo; Tomás, Mafalda; Ferreira, Susana M. F.; Baptista, TeresaA mortalidade de peixes que ocorre nas explorações aquícolas, devida à ação de agentes patogénicos, constitui ainda um dos maiores entraves ao desenvolvimento económico do sector. Tendo em conta a sua origem, as doenças podem subdividir-se em não infeciosas e infeciosas, sendo estas últimas as de maior importância e a principal causa de perdas económicas elevadas. As doenças infeciosas agrupam-se em três categorias, de acordo com a sua etiologia viral, bacteriana e parasítica. Estas doenças são muitas vezes indicadoras de condições fisiológicas e patológicas, resultantes de alimentação inadequada, infeções subclínicas, ou condições ambientais adversas. Quando simultaneamente existem condições favoráveis para a multiplicação do patógeno e condições adversas para os peixes, observa-se o desenvolvimento da doença. Entre as condições adversas que podem diminuir a resposta imune dos peixes cultivados, provocando uma maior predisposição aos patógenos, enumeram-se: densidade elevada, baixos níveis de oxigénio, stress alimentar, stress provocado pelo transporte, acumulação de compostos azotados, alterações de pH, entre outros. Estas situações, tendo em conta as consequências, merecem uma atenção redobrada por parte dos aquicultores.
- 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.
- Pelvetia canaliculata as an aquafeed supplement for gilthead seabream Sparus aurata: A biorefinery approach for seaweed biomass valorisationPublication . Pires, Damiana; Passos, Ricardo; Carmo, Beatriz do; Tchobanov, Carolina F.; Forte, Sara; Vaz, Mariana; Antunes, Madalena; Tecelão, Carla; Baptista, TeresaFor sustainable and economically viable aquaculture, it is necessary to search for alternative sources of aquafeeds. Algae have been studied because of their bioactive compounds with several activities such as antioxidants. The direct incorporation of the macroalgae Pelvetia canaliculata in sunflower oil to increase oxidative stability and biological value results in waste with high nutritional value that may be used as an ingredient in aquaculture feed. This study aimed to evaluate the effect of incorporating algae powder (PEL 1%, PEL 10%) and algae waste obtained after sunflower oil supplementation (WO 1%, WO 10%) in aquafeeds for gilthead seabream. We studied the growth performance, haematological profile, oxidative stress and metabolic parameters, and intestine histomorphology. Experimental diets did not influence growth performance or somatic indexes, and barely affected the haematological profile. Catalase showed higher activity in seabream fed with PEL10 than with control diet. Total glutathione had a higher activity in fish fed with both WO diets. Plasmatic levels of cholesterol were higher in PEL1 and WO10. Triglyceride levels were higher in WO1 and total lipids were higher in both WO diets. The histomorphology of the intestine was slightly modulated by experimental diets but was not affected negatively. In general, supplementation with Pelvetia powder and algal waste oil may be used as an aquafeed for gilthead seabream according to the results obtained for growth, some haematological parameters, catalase and total glutathione, intestinal villi length, and the number of total and acid goblet cells.