Extracellular vesicles (EVs) are cell-derived membrane-surrounded vesicles that carry bioactive molecules. Among EVs, outer membrane vesicles (OMVs), specifically produced by Gram-negative bacteria, have been extensively characterized and their potential as vaccines, adjuvants or immunotherapeutic agents, broadly explored in mammals. Nonetheless, Gram-positive bacteria can also produce bilayered spherical structures from 20 to 400 nm involved in pathogenesis, antibiotic resistance, nutrient uptake and nucleic acid transfer.
View Article and Find Full Text PDFThis study aims to assess the effects of different dietary n-6/n-3 long-chain polyunsaturated fatty acid ratios and CHO content in the immune response of gilthead seabream. For that purpose, gilthead sea bream juveniles (initial body weight = 47.5 g) were fed for 84 days with four isoproteic (47% crude protein) and isolipidic (18% crude lipids) diets with high (20%) or low (5%) level of gelatinized starch (HS or LS diets, respectively) and included approximately 2.
View Article and Find Full Text PDFDisease outbreaks are a common problem in aquaculture, with serious economic consequences to the sector. Some of the most important bacterial diseases affecting aquaculture are caused by Gram-negative bacteria including spp. (vibriosis), (photobacteriosis), spp.
View Article and Find Full Text PDFThis study aimed to determine the effects of dietary inclusion of larvae (yellow worms) meal (TM) on meagre fish () whole-body fatty acids (FA) profile and hepatic and intestine oxidative status. For that purpose, fish were fed for 9 weeks a fishmeal-based diet (control) or diets including 10%, 20%, or 30% TM. With the increase in dietary TM level, whole-body oleic acid, linoleic acid, monounsaturated FA, and n-6 polyunsaturated FA (PUFA) increased while saturated FA (SFA), n-3 PUFA, n-3 long chain-PUFA, SFA:PUFA ratio, n3:n6 ratio, and FA retention decreased.
View Article and Find Full Text PDFInsect meal (IM), recently authorized for use in aquafeeds, positions itself as a promising commodity for aquafeed inclusion. However, insects are also rich in chitin, a structural polysaccharide present in the exoskeleton, which is not digested by fish, resulting in lower fish performance. Through the application of a dietary pressure, this study aimed to modulate European sea bass gut microbiota towards the enrichment of chitinolytic bacteria to allow the isolation of novel probiotics capable of improving the use of IM-containing diets, overcoming chitin drawbacks.
View Article and Find Full Text PDFAdjuvants that would help optimize fish vaccines against bacterial and viral pathogens are highly demanded by the aquaculture sector. Flagellin has been proposed as an immunostimulant and an adjuvant for more than a decade. However, the adjuvant ability of flagellins with hypervariable region deleted is still unclear in fish.
View Article and Find Full Text PDFhas been documented in the past years as an effective probiotic for different aquacultured species, with recognized beneficial effects on water quality, fish growth and immune status. Furthermore, its potential as a vaccine adjuvant has also been explored in different species. In the current work, we have used spores as delivery vehicles for the presentation of the VP2 protein from infectious pancreatic necrosis virus (IPNV).
View Article and Find Full Text PDFThe aquaculture industry is one of the fastest-growing sectors in animal food production. However, farming of carnivorous fish strongly relies on the use of wild fish-based meals, a practice that is environmentally and economically unsustainable. Insect-based diets constitute a strong candidate for fishmeal substitution, due to their high nutritional value and low environmental footprint.
View Article and Find Full Text PDFAquaculture has been one of the fastest-growing food industry sectors, expanding at the pace of consumers' demands. To promote safe and effective fish growth performance strategies, and to stimulate environmentally friendly solutions to protect fish against disease outbreaks, new approaches are needed to safeguard fish welfare, as well as farmers and consumers interests. Here, we tested the use of cyanobacterial extracellular vesicles (EVs) as a novel nanocarrier system of heterologous proteins for applications in fish.
View Article and Find Full Text PDFStimulation of the fish immune system using immunostimulants is an environmentally friendly strategy to minimize bacterial outbreaks in aquaculture. Different biological and synthetic immunostimulants can enhance non-specific innate immune responses by directly activating immune cells. An example are Bacillus spp.
View Article and Find Full Text PDFThe disruption of pathogen communication or quorum-sensing (QS) via quorum-quenching (QQ) molecules has been proposed as a promising strategy to fight bacterial infections. spp. have recognizable biotechnology applications, namely as probiotic health-promoting agents or as a source of natural antimicrobial molecules, including QQ molecules.
View Article and Find Full Text PDFThe range of metabolic pathways that are dependent on a proper supply of specific amino acids (AA) unveils their importance in the support of health. AA play central roles in key pathways vital for immune support and individual AA supplementation has shown to be able to modulate fish immunity. trials are important tools to evaluate the immunomodulatory role of AA, and the present study was conceived to evaluate methionine and tryptophan roles in immune-related mechanisms aiming to understand their effects in leucocyte functioning and AA pathways.
View Article and Find Full Text PDFAquaculture is responsible for more than 50% of global seafood consumption. Bacterial diseases are a major constraint to this sector and associated with misuse of antibiotics, pose serious threats to public health. Fish-symbionts, co-inhabitants of fish pathogens, might be a promising source of natural antimicrobial compounds (NACs) alternative to antibiotics, limiting bacterial diseases occurrence in aquafarms.
View Article and Find Full Text PDFA healthy gastrointestinal microbiota is essential for host fitness, and strongly modulated by host diet. In aquaculture, a current challenge is to feed carnivorous fish with plant-feedstuffs in substitution of fish meal, an unsustainable commodity. Plants have a limited nutritive value due to the presence of non-starch polysaccharides (NSP) which are not metabolized by fish.
View Article and Find Full Text PDFHere, we present the genome sequences of two environmental strains with broad hydrolytic capacity toward different nonstarch polysaccharides (NSPs) that were isolated from the gut of marine fish fed NSP-rich diets. Several genes that may contribute to the NSP-degrading behavior were identified through analysis.
View Article and Find Full Text PDFThe gastrointestinal microbiota plays a critical role on host health and metabolism. This is particularly important in teleost nutrition, because fish do not possess some of the necessary enzymes to cope with the dietary challenges of aquaculture production. A main difficulty within fish nutrition is its dependence on fish meal, an unsustainable commodity and a source of organic pollutants.
View Article and Find Full Text PDFFor an increased incorporation of plant ingredients in aquafeeds at the expense of fish meal (FM) and fish oil (FO), more knowledge is needed on the effects at the intestine level of dietary vegetable oils (VO) and carbohydrates (CH), and of possible interactions. For that purpose, in this study, the activities of digestive pancreatic enzymes (amylase, lipase, total alkaline proteases), gut microbiota, and histomorphology were assessed in gilthead sea bream (IBW 71.0 ± 1.
View Article and Find Full Text PDFProbiotics benefits in fish farming have been usually inferred appraising the effects observed on the host and not through the direct assessment of probiotic dynamics in the host gut microbiota. To overcome this gap, quantitative PCR (qPCR) can be a powerful approach to study the bacterial dynamics in fish gut microbiota. The presented work proposes four B.
View Article and Find Full Text PDFProkaryote genomes are the result of a dynamic flux of genes, with increases achieved via horizontal gene transfer and reductions occurring through gene loss. The ecological and selective forces that drive this genomic flexibility vary across species. Bacillus subtilis is a naturally competent bacterium that occupies various environments, including plant-associated, soil, and marine niches, and the gut of both invertebrates and vertebrates.
View Article and Find Full Text PDFTeleost innate immune system is a most developed and powerful system in which fish highly rely throughout their lives. Conditions in aquaculture farms are particularly prone to disease, thus, health and welfare ensuring strategies are an urgent call to which nutrition is gradually becoming a most regarded achievement tool. This study intended to evaluate different amino acids' effect on immune-related mechanisms as well as their potential as enhancers of European seabass, Dicentrarchus labrax, leucocyte functioning.
View Article and Find Full Text PDFThe effects of dietary short chain fructooligosaccharides (scFOS) incorporation on hematology, fish immune status, gut microbiota composition, digestive enzymes activities, and gut morphology, was evaluated in gilthead sea bream (Sparus aurata) juveniles reared at 18 °C and 25 °C. For that purpose, fish with 32 g were fed diets including 0, 0.1, 0.
View Article and Find Full Text PDFThe impact of replacing circa 70% fish oil (FO) by a vegetable oil (VO) blend (rapeseed, linseed, palm oils; 20:50:30) in diets for European sea bass juveniles (IBW 96 ± 0.8 g) was evaluated in terms of activities of digestive enzymes (amylase, lipase, alkaline phosphatase, trypsin and total alkaline proteases) in the anterior (AI) and posterior (PI) intestine and tissue morphology (pyloric caeca-PC, AI, PI, distal intestine-DI and liver). For that purpose, fish were fed the experimental diets for 36 days and then liver and intestine were sampled at 2, 6 and 24 h after the last meal.
View Article and Find Full Text PDFSporulation by Bacillus subtilis is a cell density-dependent response to nutrient deprivation. Central to the decision of entering sporulation is a phosphorelay, through which sensor kinases promote phosphorylation of Spo0A. The phosphorelay integrates both positive and negative signals, ensuring that sporulation, a time- and energy-consuming process that may bring an ecological cost, is only triggered should other adaptations fail.
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