Project description:Through 8 generations of selection, our group has developed a strain of rainbow trout that exhibits high growth rates on an economically and environmentally sustainable all plant protein, high-soy diet. The selected strain also shows superior performance in bacterial and viral disease challenges compared to commercial trout strains, and even a strain specifically selected over many generations for viral and bacterial disease resistance. The selection criteria was strictly focused on performance on plant-based diets, and therefore the physiological mechanisms responsible for the strain’s superior disease resistance remain unresolved. To better characterize the physiological mechanism behind the superior performance of the selected strain we compared the intestinal gene expression of the select strain to that of a commercial control line of trout during an experimental bacterial infection with Flavobacterium psychrophilum (Fp) (CSF 259-93), the causative agent of bacterial cold water disease (BCWD) in salmonids. At 65 days post hatch, all female rainbow trout from the select and commercial strain were stocked separately into four 150L tanks each, at a density of 45 fish per tank. For both strains of trout, three tanks of fish were experimentally infected with Fp by intramuscular injection and one control tank was mock challenged by sham injection. Sampling was conducted at 5 days post challenge (dpc) (Early Infection) and 21 dpc (Late/Recovered Infection). Two intestinal samples from each tank were pooled and two pools from each tank were utilized for RNAseq library preparation. The select strain of trout showed significantly better survival rates (Log-Rank Test, p < 0.0001) over the 21 day infection period, with 70 and 95 % mortality among the select and commercial strain, respectively. Reads from the RNAseq samples were quantified at the transcript level prior to evaluating differential transcript usage and differential gene expression between the strains of trout, infection time points, and disease status.
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.
Project description:In rainbow trout (Oncorhynchus mykiss), the effect of a paternal and a maternal high carbohydrate/low protein diet was assessed on progeny. To this purpose, two-year old males and females rainbow trout were fed either a control diet or a high carbohydrate/low protein diet for an entire reproductive cycle for females and for 5 months for males. Crossed-fertilizations were carried out in order to obtain 4 groups of offspring. Before the first feeding, whole fry transcriptomes were compared to detect any impact of the parental diet on offspring metabolism.
Project description:Newly hatched rainbow trout were exposed to the PAHs retene and fluoranthene semistatically for 1, 3, 7 and 14 days. Fry were exposed to the PAHS alone or as a binary mixture. At sample, hearts were excised, pooled and prepared for microarray analysis. We also investigated body burden of the two PAHs and how the whole organisms respond biometrically following exposure. Transcriptomic responses were confirmed using qPCR.
Project description:Infectious hematopoietic necrosis virus (IHNV) is a virus of the genus Novirhabdovirus and the causative agent of infectious hematopoietic necrosis (IHN), one of the most serious threats to salmonid fishes. IHN outbreaks can cause more than 80% mortality rates in certain cases. Studying the transcriptional responses to the secondary immunization with a live attenuated IHNV vaccine will help us understand how fish previously immunized respond when they encounter again the same pathogen and how effective this type of vaccination is.This experiment was aimed at understanding the transcriptomic response of rainbow trout to an IHNV secondary nasal vaccination.
Project description:High-throughput proteomics was used to determine the role of the fish liver in defense responses to bacterial infection, done using a rainbow trout (Oncorhynchus mykiss) model following infection with Aeromonas salmonicida, the causative agent of furunculosis. The vertebrate liver has multifaceted roles in innate immunity, metabolism, and growth; we hypothesize this tissue serves a dual function in supporting host defense in parallel to metabolic adjustments that promote effective immune function. While past studies have reported mRNA responses to A. salmonicida in salmonids, the impact of bacterial infectionon the liver proteome remains uncharacterized in fish.
Project description:Sex steroids play a key role in triggering sec differentiation in fish and the use of exogenous hormone treatment leads to partial or complete sex reversal. This phenomenon has attracted attention since the discovery taht even low environmental doses of exogenous steroids can adversely affect gonad morphology (ovotestis development) and induce reproductive failure. Modern genomic-based technologies have enhanced opportunities to find mechanisms of action (MOA) and dentify biomarkers for the toxic action of a compound. The goal of this study are to improve the understanding of feminization in fish by analyzing gene expression patterns in the gonads of rainbow trout fry after a chronic exposure to several doses (0.01, 0.1, 1 and 10 ?g/L) of ethynylestradiol (EE2) and to offer target genes as potential biomarkers of ovotestis development. An all-male population of Rainbow trout fry was exposed during 76 days (from 60 to 136 days post-fertilization (dpf)) to five nominal concentrations of 17?-ethynylestradiol (0-solvent control-, 0.01, 0.1, 1 and 10 ?g EE2/L of water), using 3 tanks per condition. In total, 30 samples were analyzed independantly: 6 samples per concentration tested (two samples per tank, three tanks per concentration), each sample being a pool of 10 pairs of gonads.
Project description:The effect of rainbow trout plasma on the conditionally pathogenic gram-negative bacterium A. hydrophila, the causative agent of septicemia, has been studied. It has been shown that the native blood plasma of conditionally healthy cultured trout does not have an antimicrobial effect on bacteria. However, the high-molecular fraction of plasma of trout conditionally immunized with F. psychrophilum had an antimicrobial effect on A. hydrophila. It has been shown that the plasma of supposedly immunized trout prevents the reproduction of bacteria and disrupts their morphology. Using HPLC-MS/MS, we investigated potentially immune plasma proteins that adhere to the surface of bacteria. Proteins that remained on the surface of bacteria after a series of washings were studied. The results of the research may be useful for studying immune proteins of teleost fish and other vertebrates recognizing PAMPs of Gram-negative bacteria and for the cross-resistance of trout between phylogenetically unrelated bacterial species.