Examinando por Autor "Vicente- Gil, Samuel"

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Effect of β-glucans on rainbow trout (Oncorhynchus mykiss) IgM+ B cells
(Elsevier, 2024-08) Martín, Diana; Ordás, M. Camino; Morel, Esther; Nuñez- Ortiz, Noelia; Díaz- Rosales, Patricia; Vicente- Gil, Samuel; Zarza, Carlos; Jensen, Linda; Tafalla, Carolina
β-glucans are carbohydrates present in the cell wall of many fungi, which are often used as immunostimulants in feeds for farmed species. Their capacity to activate innate immune responses directly acting on innate cell populations has been widely documented in fish. However, whether they can affect the functionality of adaptive immune cells has been scarcely explored. In this context, in the current work, we have determined the effects of β-glucans on rainbow trout blood IgM+ B cells in the presence or absence of 2,4,6-trinitrophenyl hapten conjugated to lipopolysaccharide (TNP-LPS), a model antigen. For this, rainbow trout peripheral blood leukocytes were incubated with different doses of β-glucans or media alone in the presence or absence of TNP-LPS for 48 h. The size, levels of expression of surface MHC II, antigen processing and phagocytic capacities and proliferation of IgM+ B cells were then studied by flow cytometry. The number of IgM-secreting cells in the cultures was also estimated by ELISpot. β-glucans significantly decreased the levels of surface MHC II expression and the antigen processing capacities of these cells, especially in the presence of TNP-LPS, while they increased their phagocytic activity. On their own, β-glucans slightly activated the proliferation of IgM+ B cells but reduced that induced by TNP-LPS. In contrast, β-glucans significantly increased the number of cells secreting IgM in the cultures. This effect of β-glucans on the IgM-secreting capacity of B cells was also confirmed through a feeding experiment, in which the IgM-secreting capacity of blood leukocytes obtained from fish fed a β-glucan-supplemented diet for one month was compared to that of leukocytes obtained from fish fed a control diet. Altogether, these findings contribute to increase our knowledge regarding the effects of β-glucans on fish adaptive responses.
The oral delivery of Bacillus subtilis spores modulates skin and intestinal mucus responses in rainbow trout (Oncorhynchus mykiss).
(Elsevier, 2024-08) Vicente- Gil, Samuel; Nogales-Mérida, Silvia; Gonçalves, Gabriela; Serra, Claudia R; Ordás, M. Camino; Tafalla, Carolina; Díaz- Rosales, Patricia
Bacillus subtilis is a spore-forming microorganism, recognized as a safe probiotic strain. Its endospores are easily produced at a large scale, can be dehydrated and maintain their characteristics after long-term storage, providing great advantages for their application in aquafeeds. Nonetheless, knowledge on the effects that B. subtilis provokes on fish mucosal immunity is still scarce. In this context, the aim of this work was to explore the effects of the oral administration of B. subtilis spores to rainbow trout (Oncorhynchus mykiss) for 30 days on the intestinal and skin mucus, focusing on a range of immune and enzymatic parameters. Thus, fish supplemented with B. subtilis spores showed increased levels of total immunoglobulin (Ig) in intestinal and skin mucus, as well as IgM levels in both mucus and serum. B. subtilis spores induced an increase of peroxidase activities in mucus from both sources. Although superoxide dismutase (SOD) activity was not affected by the spores, NO production significantly decreased in skin mucus. Finally, the bactericidal activity of the intestinal and skin mucus was significantly higher in fish fed the probiotic spores. The results obtained demonstrate that the dietary supplementation with B. subtilis spores enhances mucosal defense mechanisms by increasing immunological parameters of the intestinal and skin mucus.