Skin mucus proteins of rainbow trout (Oncorhynchus mykiss) in response to mucosal vaccination and challenge with Flavobacterium psychrophilum.
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ABSTRACT:
SUBMITTER: Hoare R
PROVIDER: S-EPMC9299601 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:Aquatic pathogens are a major concern for fish hatchery production, fisheries management, and conservation, and disease control needs to be addressed. Two important salmonid pathogens are Myxobolus cerebralis and Flavobacterium psychrophilum that cause whirling disease and bacterial coldwater disease (BCWD), respectively. Innate disease resistance is a potential option for reducing disease-related mortality in hatchery-reared rainbow trout (Oncorhynchus mykiss, Walbaum). Two experiments were conducted to assess pathogen resistance of first-generation (F1) rainbow trout created by crossing M. cerebralis- and F. psychrophilum-resistant strains. In the first experiment, we exposed two rainbow trout strains and one F1 cross to six treatments: control (no exposure), mock injection, F. psychrophilum only, M. cerebralis only, F. psychrophilum then M. cerebralis, and M. cerebralis then F. psychrophilum. Results indicated that the F1 cross was not resistant to either pathogen. In the second experiment, we exposed five rainbow trout strains and four rainbow trout crosses to F. psychrophilum. The second experiment indicated that at least one rainbow trout cross was F. psychrophilum-resistant. Achieving dual resistance may be possible using selective breeding but only some multigenerational strains are suitable candidates for further evaluation.
| S-EPMC9314901 | biostudies-literature
Project description:Rainbow trout that were resistant or susceptible to Flavobacterium psychrophilum infection were compared with respect to their microbial composition by using 16S rRNA V3-V4 sequencing. The differences occurred in gills, where resistant fish displayed a greater abundance of the phylum Proteobacteria and a smaller proportion of Firmicutes relative to those of susceptible fish.
| S-EPMC7082464 | biostudies-literature
Project description:Rainbow trout (1000 fish) was exposed to the bacterial pathogen F. psychrophilum by simple bath challenge without any pre-treatment with hydrogen peroxide. Samples (fin clip for Affymetrix QTL analysis) were taken from 167 moribund fish during the course of infection. When mortality/morbidity ended (day 40) we euthanized a total of 197 specimens of the remaining fish and took samples for DNA (QTL analysis) and assigned the status: Survivor. For gene expression analysis we took samples from gill, spleen and liver between day 11 and 15 from fish with clinical signs (CS) and no clinical signs (NCS), whereas samples from survivors were taken at day 40.
2023-11-01 | GSE216505 | GEO
Project description:Here, we report the complete genome sequence of Flavobacterium psychrophilum FPRT1, isolated from the spleen and kidney of diseased rainbow trout (Oncorhynchus mykiss). Whole-genome sequencing was performed using the PacBio RS II platform, which yielded a circular chromosome of 2,795,347 bp harboring 2,895 protein-coding genes.
| S-EPMC7996460 | biostudies-literature
Project description:Flavobacterium psychrophilum is the causative agent of bacterial cold-water disease in salmonids and rainbow trout fry syndrome. This pathogen has attained a global presence and can spread both horizontally and vertically. However, it was not documented in Korea before September 2018. In this study, the objectives were to characterize Flavobacterium psychrophilum strain FPRT1, isolated from diseased rainbow trout genotypically and phenotypically. We also conducted various investigations to better understand its impact and assess potential control measures. We acquired fifty rainbow trout (approximately 70 g in weight) and transferred them to a laboratory aquarium. During the initial acclimation period, we observed mortality and examined affected fish for clinical signs. We isolated the bacterium from the spleen of infected rainbow trout using tryptone yeast extract salts agar supplemented with glucose, naming this FPRT1. Antibiotic susceptibility testing was carried out, and from the result, we selected enrofloxacin to administer to the trout orally to reduce mortality. To evaluate pathogenicity, we exposed the trout to FPRT1 at different water temperatures (8, 15, and 22 °C). Genomic analysis was conducted to identify the serotype and relatedness of FPRT1 to European strains. Affected fish displayed clinical signs, such as ulcerative lesions in the mandible, anemia with pale gills, exophthalmia, and increased mucus secretion. Internal symptoms included pale liver and enlarged spleen. FPRT1 was susceptible to erythromycin, enrofloxacin, florfenicol, oxytetracycline, and gentamicin, but resistant to oxolinic acid and sulfamethoxazole/trimethoprim. Oral administration of enrofloxacin resulted in a decrease in mortality from 28% to 6%. Pathogenicity tests revealed varying mortality rates due to FPRT1 at different temperatures. The highest rates were observed at 8 °C (ranging from 43% to 100%) for both intraperitoneal and intramuscular injections, and lower rates occurred at 22 °C (ranging from 0% to 30%), with intramuscular injections displaying higher susceptibility. Genomic analysis identified FPRT1 as serotype 2 and indicated its close genetic relationship with European strains based on the core genome and dispensable genome. The substantial genomic similarity between our strain and European strains suggests the possibility of bacterial spread through the importation of fertilized eggs from Europe. In conclusion, this study highlights the introduction of the previously undocumented pathogen (F. psychrophilum) into Korean rainbow trout populations. The detection of this pathogen and its pathogenicity assessment is not only important for understanding its impact on local aquaculture but also for establishing surveillance and control measures to prevent further transmission and outbreaks in the region.
| S-EPMC10609541 | biostudies-literature
Project description:Flavobacterium psychrophilum, the etiological agent of bacterial coldwater disease and rainbow trout fry syndrome, causes considerable losses in salmonid aquaculture globally. Systemic F. psychrophilum infections in rainbow trout (Oncorhynchus mykiss) lead to a range of clinical signs, including ulcerative lesions in the skin and muscle and splenitis. Previous studies offered an integrative analysis of the skeletal muscle response to F. psychrophilum infection in rainbow trout. However, little is known about the molecular mechanism of immune response in the spleen, which is an important immune organ of rainbow trout. Here, we investigated the time-course splenic transcriptome profiles in uninfected rainbow trout (CK) and F. psychrophilum-infected rainbow trout at day 3 and day 7 (D3, D7) by RNA-seq analyses. Among the 7,170 differentially expressed genes (DEGs) in the three comparisons (D3 vs. CK, D7 vs. CK, D3 vs. D7), 1,286 DEGs showed consistent upregulation or downregulation at D3 and D7 and were associated with pattern recognition, acute-phase response, complement cascade, chemokine and cytokine signaling, and apoptosis. The Real time quantitative PCR (RT-qPCR) analysis of eight DEGs confirmed the accuracy of the RNA-Sequencing (RNA-seq) data. Our results reflected a general process from pathogen recognition to inflammatory cytokine generation and delineated a putative Toll-like receptor signaling pathway in rainbow trout spleen, following F. psychrophilum infection. Taken together, these results provide new insights into the molecular mechanism of the immune response to F. psychrophilum infection and are a valuable resource for future research on the prevention and control of bacterial coldwater disease during salmon culture.
| S-EPMC9396386 | biostudies-literature
Project description:Flavobacterium psychrophilum affects salmonid health worldwide and causes economic losses. The genetic diversity of the pathogen must be considered to develop control methods. However, previous studies have reported both high and low levels of genetic diversity. The present longitudinal study aimed at assessing the genetic diversity of F. psychrophilum at a small temporal and geographic scale. Four farms located on the same watershed in France were studied. Rainbow trout (Oncorhynchus mykiss) batches were monitored, and apparently healthy individuals were sampled over 1 year. A total of 288 isolates were recovered from fish organs (gills and spleen) and eggs. Pulsed field gel electrophoresis revealed high genetic diversity. Multilocus sequence typing performed on a selection of 31 isolates provided congruent results, as follows: 18 sequence types (STs) were found, of which 13 were novel. The mean gene diversity (H = 0.8413) was much higher than that previously reported for this host species, although the sampling was restricted to a single watershed and 1 year. Seven isolates out of 31 were assigned to clonal complex ST10 (CC-ST10), which is the predominant clonal complex in the main salmonid production areas. A split decomposition tree reflected a panmictic population. This finding is important for aquaculture veterinarians in their diagnostic procedure, as the choice of adequate antibiotic treatment is conditioned by the correct identification of the causative agent. Furthermore, this study expands our knowledge on genetic diversity required for the development of an effective vaccine against F. psychrophilumIMPORTANCE The bacterium Flavobacterium psychrophilum is a serious pathogen in many fish species, especially salmonids, that is responsible for considerable economic losses worldwide. In order to treat infections and to develop vaccines, the genetic diversity of this bacterium needs to be known. We assessed the genetic diversity of F. psychrophilum isolates from apparently healthy rainbow trout raised in several fish farms in the same watershed in France. Two different genotyping methods revealed high diversity. The majority of isolates were unrelated to clonal complex sequence type 10 (CC-ST10), the clonal complex that is predominant worldwide and associated with disease in rainbow trout. In addition, we found 13 novel sequence types. These results suggest that a diverse subpopulation of F. psychrophilum may be harbored by rainbow trout.
| S-EPMC7783352 | biostudies-literature
Project description:The health and environmental risks associated with antibiotic use in aquaculture have promoted bacterial probiotics as an alternative approach to control fish infections in vulnerable larval and juvenile stages. However, evidence-based identification of probiotics is often hindered by the complexity of bacteria-host interactions and host variability in microbiologically uncontrolled conditions. While these difficulties can be partially resolved using gnotobiotic models harboring no or reduced microbiota, most host-microbe interaction studies are carried out in animal models with little relevance for fish farming. Here we studied host-microbiota-pathogen interactions in a germ-free and gnotobiotic model of rainbow trout (Oncorhynchus mykiss), one of the most widely cultured salmonids. We demonstrated that germ-free larvae raised in sterile conditions displayed no significant difference in growth after 35 days compared to conventionally-raised larvae, but were extremely sensitive to infection by Flavobacterium columnare, a common freshwater fish pathogen causing major economic losses worldwide. Furthermore, re-conventionalization with 11 culturable species from the conventional trout microbiota conferred resistance to F. columnare infection. Using mono-re-conventionalized germ-free trout, we identified that this protection is determined by a commensal Flavobacterium strain displaying antibacterial activity against F. columnare. Finally, we demonstrated that use of gnotobiotic trout is a suitable approach for the identification of both endogenous and exogenous probiotic bacterial strains protecting teleostean hosts against F. columnare. This study therefore establishes an ecologically-relevant gnotobiotic model for the study of host-pathogen interactions and colonization resistance in farmed fish.
| S-EPMC7875404 | biostudies-literature
Project description:Rainbow trout fry syndrome (RTFS) is a disease caused by the Gram-negative bacterium Flavobacterium psychrophilum, responsible for significant economic losses in salmonid aquaculture worldwide. The diversity of F. psychrophilum isolates and the inherent difficulties in vaccinating juvenile fish has hampered the development of a vaccine for RTFS. Disease episodes tend to occur between 10-14 °C with necrotic lesions often seen on the skin surrounding the dorsal fin and tail. At present no commercial vaccines are available for RTFS in the UK, leaving antibiotics as the only course of action to control disease outbreaks. The current work was performed as a pilot study to assess the efficacy of a polyvalent, whole cell vaccine containing formalin-inactivated F. psychrophilum, to induce protective immunity in rainbow trout fry. Duplicate groups of 30 trout (5 g) were immersed in 1 L of the vaccine for 30 s. Samples were taken 4 h, day 2 and 7 post-vaccination (pv) of skin mucus, tissues for histology and gene expression analysis; serum and histology samples were taken 6 weeks pv. A booster vaccination was given at 315 degree days (dd) also by immersion. Challenge was by immersion with a heterologous isolate of F. psychrophilum 630 dd post primary vaccination. The vaccine provided significant protection to the trout fry with a RPS of 84% (p < 0.0001). Detection of increased numbers of IgT positive cells in systemic organs, up-regulation of IgT expression in hind-gut and an increase in total IgT in serum was observed in vaccinated fish; however a functional role of IgT in the observed protection remains to be demonstrated.
| S-EPMC5563058 | biostudies-literature
Project description:Yersinia ruckeri is the causative agent of enteric redmouth disease in salmonids. In fish, the intestine represents an important site of nutrient uptake, host-pathogen interactions, and defense. The posterior intestine can be inflamed, reddened, and filled with an opaque, yellowish fluid during Y. ruckeri infection. Herein, we report an investigation on the proteome alteration in the posterior intestinal mucosa of rainbow trout (Oncorhynchus mykiss) after exposure to Y. ruckeri. The intestinal mucosal proteins were identified and quantified by a shotgun proteomic approach by applying data-independent quantification with sequential windowed acquisition of all theoretical mass spectra (SWATH). A total of 437 proteins were found to be differentially up- or downregulated in the posterior intestine. Gene ontology of upregulated proteins pointed to their involvement into exopeptidase, endopeptidase, and hydrolase activities, while the downregulated proteins were involved in lipid metabolism, actin binding, and translation processes. Additionally, upregulated proteins were predicted to be involved in lysosome, oxidative phosphorylation, and metabolic pathways, while downregulated proteins were implicated in focal adhesion, regulation of actin cytoskeleton, protein digestion and absorption pathways. This study showed that Y. ruckeri infection can alter protein abundance involved in serine-type carboxypeptidase, cysteine and aspartic-type endopeptidases, metallopeptidases, antioxidant defense, calcium ion binding, glycolytic and carbohydrate metabolic processes in the proteome of the intestinal mucosa of rainbow trout.
| S-EPMC6637484 | biostudies-literature