Project description:Non-Saccharomyces yeast such as Debaryomyces hansenii or its cell wall-components are emerging candidates for novel functional aquafeeds, as they contain several microbe-associated molecular patterns (MAMPs) that can activate and modulate the host’s physiological responses and improve fish health and welfare. RNAseq results showed an upregulation in pathways associated with humoral immunity and complement activation in the liver. Considering these data, LAN6 could be a promising functional candidate for aquafeeds to achieve a more resilient salmon during fish farming.
Project description:Recirculation systems (RAS), which reduce water consumption and improve pathogen control are increasingly used in Atlantic salmon aquaculture. Performance and adaptation of fish to new farming environment is actively investigated. Here, responses to crowding stress were compared in salmon reared in two systems (RAS with brackish water and flowthrough with full salinity water) at low and high density.
Project description:Catfish farming remains number one among U.S. aquaculture production. Flavobacterium columnare, the causative agent of columnaris disease, produces substantial mortality during the production of freshwater farmed finfish species. F. columnare is ubiquitous in the aquatic environment, and outbreaks of disease are often triggered during the spring and summer months of the catfish production cycle. As food fish production continues to increase, the frequency of columnaris disease will only continue to rise within the aquaculture industry and thus new preventative measures will be required. Vaccination against different fish pathogens has proven to be an effective disease management practice within the aquaculture industry. To evaluate the immunological effect of bath immunization on catfish with a recombinant F. columnare DNAk protein vaccine, we performed RNA sequencing on skin samples from control and rDNAK immunized catfish at different time intervals. We evaluated the different gene expression patterns between the groups with a focus on identifying differences in innate and adaptive immune function.
Project description:The skin mucus of gilthead sea bream was mapped by 1-DE followed by liquid chromatography coupled to high resolution mass spectrometry using a quadrupole time-of-flight mass analyzer. More than 2000 proteins were identified with a protein score filter of 30. The identified proteins were represented in 418 canonical pathways of the Ingenuity Pathway software. After filtering by canonical pathway overlapping, the retained proteins were clustered in three groups. The mitochondrial cluster contained 59 proteins related to oxidative phosphorylation and mitochondrial dysfunction. The second cluster contained 79 proteins related to antigen presentation and protein ubiquitination pathways. The third cluster contained 257 proteins where proteins related to protein synthesis, cellular assembly, and epithelial integrity were over-represented. The latter group also included acute phase response signaling. In parallel, 2-DE methodology identified six proteins spots of different protein abundance when comparing unstressed fish with chronically stressed fish in an experimental model that mimicked daily farming activities. The major changes were associated with a higher abundance of cytokeratin 8 in the skin mucus proteome of stressed fish, which was confirmed by immunoblotting. Overall, these results indicate that skin mucus is a reliable tissue for alternative or complementary stress phenotyping in fish farming.
Project description:The hypoxia frequently occurs in natural aquatic systems and aquaculture environment due to the natural reasons and human factors such as extreme climate, high density farming, environmental pollution and global warming, which have gradually become a huge threat to aquatic ecosystem functions and aquatic organism survival, causing serious ecological damage and enormous economic losses. Rainbow trout (Oncorhynchus mykiss), as a hypoxia-sensitive fish species, is a good model to study hypoxia stress. The molecular regulation and oxidative stress of rainbow trout still remains unknown in response to environmental hypoxia and reoxygenation stress. In this study, the transcriptome and biochemical indexes of rainbow trout liver in response to hypoxia for different durations were analyzed to highlight the changes in the molecular regulation and oxidative stress.
Project description:Sustainable aquaculture, which entails proportional replacement of fish-based feed sources by plant-based ingredients, is impeded by the poor growth response frequently seen in fish fed high levels of plant ingredients. To evaluate the potential to improve, by means of early nutritional exposure, the growth of fish fed plant-based feed, rainbow trout swim-up fry were fed for 3 weeks either a plant-based diet (diet V, V-fish) or a diet containing fishmeal and fish oil as protein and fat source (diet M, M-fish). After this 3-week nutritional history period, all V- or M-fish received diet M for a 7-month intermediate growth phase. Both groups were then challenged by feeding diet V for 25 days during which voluntary feed intake, growth, and nutrient utilization were monitored (V-challenge). The results of the V-challenge showed a higher growth rate and higher feed intake in fish of nutritional history V compared to M (see PMID:24386155). To identify the molecular mechanisms that govern the enhancement of feed acceptance following early-feed exposure of diet V, we performed microarray expression analysis using swim-up fry collected at the end of early-feeding exposure (diet M and diet V), as well as brain and liver of juveniles sampled at the end of the V-challenge (M-his and V-his), and employing a rainbow trout microarray platform with 8 X 60K probes per slide. Persistently differentially expressed genes were identified by isolating probes that were differentially expressed (fold change ≥ 1.5 and p {nutritional history} ≤ 0.05), both at the end of the early exposure, and in either brain or liver of juvenile trout at the end of the V-challenge. Overall, 1787 (3-week + Brain) and 924 (3-week + Liver) mRNA probes were found to be persistently affected by nutritional history of early-feeding exposure. This positive response is encouraging as a potential strategy to improve the use of plant-based feed in fish, of interest in the field of fish farming and animal nutrition in general. Furthermore, the genes associated with mediating this positive early feeding effect, could serve as potential biomarkers to evaluate increasing acceptability of plant-based diets in fish farming.
Project description:Rainbow trout (Oncorhynchus mykiss) is an important aquaculture fish species that is farmed worldwide, and it is also the most widely cultivated cold water fish in China. This species, a member of the salmonidae family, is an ideal model organism for studying the immune system in fish. Two phenotypes of rainbow trout are widely cultured; wild-type rainbow trout with black skin (WR_S) and yellow mutant rainbow trout with yellow skin (YR_S). Fish skin is an important immune organ, however, little is known about the differences in skin immunity between WR_S and YR_S in a natural flowing water pond aquaculture environment, and very few studies were conducted to investigate the ceRNA mechanism for fish skin.
Project description:Replacement of high-value fish species with cheaper varieties or mislabelling of food unfit for human consumption is a global problem violating both consumers’ rights and safety. For distinguishing fish species in pure samples, DNA approaches are available; however, authentication and quantification of fish species in mixtures remains a challenge. In the present study, a novel high-throughput shotgun DNA sequencing approach applying masked reference libraries was developed and used for authentication and abundance calculations of fish species in mixed samples. Results demonstrate that the analytical protocol presented here can discriminate and predict relative abundances of different fish species in mixed samples with high accuracy. In addition to DNA analyses, shotgun proteomics tools based on direct spectra comparisons were employed on the same mixture. Similar to the DNA approach, the identification of individual fish species and the estimation of their respective relative abundances in a mixed sample also were feasible. Furthermore, the data obtained indicated that DNA sequencing using masked libraries predicted species-composition of the fish mixture with higher specificity, while at a taxonomic family level, relative abundances of the different species in the fish mixture were predicted with slightly higher accuracy using proteomics tools. Taken together, the results demonstrate that both DNA and protein-based approaches presented here can be used to efficiently tackle current challenges in feed and food authentication analyses.