Browsing by Author "Oliva-Teles, Aires"
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- European Sea Bass (Dicentrarchus labrax) immune status and disease resistance are impaired by arginine dietary supplementationPublication . Azeredo, Rita; Perez-Sanchez, Jaume; Sitja-Bobadilla, Ariadna; Fouz, Belen; Tort, Lluis; Aragao, Claudia; Oliva-Teles, Aires; Costas, BenjaminInfectious diseases and fish feeds management are probably the major expenses in the aquaculture business. Hence, it is a priority to define sustainable strategies which simultaneously avoid therapeutic procedures and reinforce fish immunity. Currently, one preferred approach is the use of immunostimulants which can be supplemented to the fish diets. Arginine is a versatile amino acid with important mechanisms closely related to the immune response. Aiming at finding out how arginine affects the innate immune status or improve disease resistance of European seabass (Dicentrarchus labrax) against vibriosis, fish were fed two arginine-supplemented diets (1% and 2% arginine supplementation). A third diet meeting arginine requirement level for seabass served as control diet. Following 15 or 29 days of feeding, fish were sampled for blood, spleen and gut to assess cell-mediated immune parameters and immune-related gene expression. At the same time, fish from each dietary group were challenged against Vibrio anguillarum and survival was monitored. Cell-mediated immune parameters such as the extracellular superoxide and nitric oxide decreased in fish fed arginine-supplemented diets. Interleukins and immune-cell marker transcripts were down-regulated by the highest supplementation level. Disease resistance data were in accordance with a generally depressed immune status, with increased susceptibility to vibriosis in fish fed arginine supplemented diets. Altogether, these results suggest a general inhibitory effect of arginine on the immune defences and disease resistance of European seabass. Still, further research will certainly clarify arginine immunomodulation pathways thereby allowing the validation of its potential as a prophylactic strategy.
- Skin mucus and blood plasma as non-lethal sources of malnutrition protein biomarkers in meagre (Argyrosomus regius)Publication . Oliveira, Joana; Raposo de Magalhães, Cláudia; Schrama, Denise; Rodrigues, Pedro M.; Barata, Marisa; Soares, Florbela; Pousão-Ferreira, Pedro; Oliva-Teles, Aires; Couto, AnaDeveloping dietary formulations for aquaculture that meet nutritional requirements is essential to production, as nutrition is key for fish growth and health. However, novel dietary formulations may induce malnutrition, which is complex to evaluate and often requires animal sacrifice. Therefore, finding reliable non-lethal biomarkers to diagnose malnutrition in fish is important. This study aimed to obtain vital information on potential non-lethal biomarkers from blood plasma and skin mucus to assess the fish's nutritional status using meagre (Argyrosomus regius) juveniles. For that purpose, a nutritional challenge was performed with fish fed a fish meal (FM) and fish- oil (FO) based control diet (55.1 % FM; 11 % FO, CTRL), a challenging diet (15 % FM; 7 % FO, CD), and a highly challenging diet (5 % FM; 5 % FO, ED), which, despite being nutritionally complete, may pose digestive and physiological challenges to carnivorous species. Diets significantly affected blood parameters, except for leukocyte counts, peroxidase activity, and immunoglobulin levels. Overall, blood parameters showed potential as non-lethal biomarkers to accurately identify signs of malnutrition. Meagre's plasma and skin mucus proteomes provided crucial information on the species' reaction to malnutrition, and 29 proteins connected to various physiological functions such as metabolism, development and immunity showed potential as non-lethal biomarkers. Significance: The significance of this study lies in the establishment of potential non-lethal biomarkers for diagnosing malnutrition in fish. The results demonstrate that immunological, haematological, and biochemical parameters measured in fish blood can reveal signs of nutritional deficiencies. The findings further highlight that the proteomes of plasma and skin mucus provide valuable information about the fish's nutritional status. Notably, 29 proteins identified in this study, associated with various physiological functions, exhibit biomarker potential and warrant consideration in future research in the field of aquaculture nutrition. Moreover, the research provides critical insights into the proteome of meagre (Argyrosomus regius), enhancing our understanding of the species and contributing to the future improvement of its aquaculture production.