Project description:Stocking density is considered as a key factor determining the productivity of fish aquaculture systems. The transcriptomic response to crowding stress is, however, still poorly investigated. We aimed at the identification of potential biomarker genes via microarray analyses to get insight into molecular pathways modulated through density-induced stress in farmed rainbow trout Oncorhynchus mykiss. Transcriptome profiling in liver, kidney, and gills was complemented with behaviarol observation and analysis of classical plasma parameters. Individuals of two trout strains were exposed for eight days to definite stocking densities, 1 kg/m³ (low density); 10 kg/m³ (moderate); 18 kg/m³ (elevated); and 35 kg/m³ (high). Whereas stocking density had no significant effect on cortisol levels, plasma glucose levels were elevated in trout kept at high density. Pathway enrichment analyses confirmed the upregulation of HIF1a signaling in liver contributing to glucose homeostasis during stress conditions, while mTOR and PI3K/AKT signaling pathways were downregulated. Further perturbed hepatic pathways were involved in protein ubiquitination and the biosynthesis of cholesterol, retinol and glutathione. Three stocking density conditions were investigated: an uncrowded âmoderateâ density (MD: 10 kg trout/m³) , an elevated density (ED: 18 kg/m³ ), and high density (HD: 35 kg/m³). The experiment was performed twice with two strains of Steelhead rainbow trout (Troutlodge and Born trout), randomly assigned to identical glass tanks with MD (30 and 34 individuals), ED (60 and 64 individuals), and HD (120 and 140 individuals). Trout were sampled 8 d after experimental onset.
Project description:Rainbow trout (Oncorhynchus mykiss) is one of the economically important cold-water fish cultivated in the world. The outbreak of infectious hematopoietic necrosis (IHN) seriously restricted the development of rainbow trout farming industry and caused huge economic losses. Fish skin is the largest mucosal immune organ, providing the first line of defense against pathogen invasion. However, the immune mechanisms associated with fish skin remain unclear. To systematically identify skin mucosal immune genes induced by infectious hematopoietic necrosis virus (IHNV) infection, trout transcriptome profiles following IHNV challenge were examined. Transcriptome analysis identified 6905 differentially expressed genes (DEGs) and revealed numerous immune-related DEGs involved in cytokine-cytokine receptor interactions, NOD-like receptor signaling, RIG-I-like receptor signaling, Toll-like receptor signaling, JAK-STAT signaling, Chemokine signaling pathway, and TNF signaling pathway, and the expression of these DEGs was significantly up-regulated in T48Skm group, including NOD1, NLRC3, NLRC5, TLR3, TLR7/8, TRIM25, DHX58, IFIH1, IRF3/7, STAT1, TRAF3, MX1, and HSP90A1. Additionally, highly interactive DEGs network involving immune-related terms and pathways was shown using protein-protein interaction network. The expression patterns of 12 DEGs were further verified by quantitative real-time PCR, which confirmed the reproducibility and reliability of transcriptome sequencing data. These findings expand our understanding of the innate immune system of rainbow trout skin infected with IHNV, and lay a foundation for further studies of the immune molecular mechanism and disease resistance breeding.
Project description:Infectious hematopoietic necrosis virus (IHNV) can cause widespread death of rainbow trout (Oncorhynchus mykiss), understanding the molecular mechanisms that occur in the rainbow trout in response to IHNV infection will be useful to decrease IHN-related morbidity and mortality in trout aquaculture. However, the molecular mechanisms of rainbow trout in response to IHNV are very limited. This study performed analysis of mRNAs and miRNAs based on RNA-seq technology on the intestine of rainbow trout infected with IHNV and control. There were 80 differentially expressed miRNAs that regulated 3355 target mRNAs, which overlapped with differentially expressed mRNAs obtained from RNA-seq. The expression patterns of DEGs and miRNAs differentially expressed were validated by qRT-PCR. GO enrichment and KEGG pathway analyses of the potential target genes of the DE miRNAs, revealed DEGs were mainly enriched in immune-related pathways such as Toll-like receptor signaling pathway, RIG-I-like receptor signaling pathway and IL-17 signaling pathway. These findings improve our understanding of the molecular mechanisms of IHNV infection. The study analyzed the immune regulatory target gene pairs and signal pathways of rainbow trout intestine against IHNV infection at the transcriptional level, and provided basic data for the study of rainbow trout against IHNV immune regulatory.
Project description:Infectious hematopoietic necrosis virus (IHNV) can cause widespread death of rainbow trout (Oncorhynchus mykiss), understanding the molecular mechanisms that occur in the rainbow trout in response to IHNV infection will be useful to decrease IHN-related morbidity and mortality in trout aquaculture. However, the molecular mechanisms of rainbow trout in response to IHNV are very limited. This study performed analysis of mRNAs and miRNAs based on RNA-seq technology on the intestine of rainbow trout infected with IHNV and control. There were 80 differentially expressed miRNAs that regulated 3355 target mRNAs, which overlapped with differentially expressed mRNAs obtained from RNA-seq. The expression patterns of DEGs and miRNAs differentially expressed were validated by qRT-PCR. GO enrichment and KEGG pathway analyses of the potential target genes of the DE miRNAs, revealed DEGs were mainly enriched in immune-related pathways such as Toll-like receptor signaling pathway, RIG-I-like receptor signaling pathway and IL-17 signaling pathway. These findings improve our understanding of the molecular mechanisms of IHNV infection. The study analyzed the immune regulatory target gene pairs and signal pathways of rainbow trout intestine against IHNV infection at the transcriptional level, and provided basic data for the study of rainbow trout against IHNV immune regulatory.
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:Gynogenetic development in fish is induced by activation of eggs with irradiated spermatozoa followed by exposure of the activated eggs to the temperature or high hydrostatic pressure (HHP) shock that prevents 1st cell cleavage. Produced specimens are fully homozygous fish also known as Doubled Haploids. Gynogenetic DH individuals might be used aquaculture and developmental biology unfortunately; the potential application of DHs is limited by a rather low survival rate of such specimens. However, observed variation in the survival rates of the gynogenetic embryos originated from different clutches suggests that eggs from some females have increased ability for gynogenetic development than others. Taking into account that first 10 cell cleavages in the fish embryos rely on the maternal RNA, it is tempting to assume that the ova showing such a vast difference in potential for gynogenesis may have also had different biological characteristics including alterations in maternal gene expression profiles. If so, then genes that up- or down –regulated expression in eggs increases competence for gynogenetic development in trout might be considered as candidate genes for gynogenesis in rainbow trout. Thus, the main goal of the project is identification of genes that increase ability of rainbow trout eggs for gynogenetic development. Within the project, we tried to verify following hypotheses: 1. Eggs from different females have different potential for gynogenesis in rainbow trout. 2. Eggs with different ability for gynogenetic development with all maternal inheritance have different biological characteristics including morphology and anti-ROS enzyme activities. 3. Eggs with increased competence for gynogenesis have altered transcriptomic profiles. 4. There are some particular genes that altered expression in trout eggs enable development of gynogenetic embryos. Gynogenetic rainbow trout specimens were produced in the course of activation of eggs with UV-irradiated spermatozoa and High Hydrostatic Pressure shock (HHP) applied around 1st cell cleavage. Eggs from several females were used in the experiment. Survival rates of gynogenetic rainbow trout was monitored since fertilization. Quality of eggs was examined by assessment of their morphology and activity of anti-ROS (reactive oxygene species) enzymes. Transcriptome of eggs showing increased and decreased developmental competence for gynogenesis was analyzed using RNA-seq approach and results compared to find out any alterations related to survival of gynogenetic trout.
Project description:Stocking density is considered as a key factor determining the productivity of fish aquaculture systems. The transcriptomic response to crowding stress is, however, still poorly investigated. We aimed at the identification of potential biomarker genes via microarray analyses to get insight into molecular pathways modulated through density-induced stress in farmed rainbow trout Oncorhynchus mykiss. Transcriptome profiling in liver, kidney, and gills was complemented with behaviarol observation and analysis of classical plasma parameters. Individuals of two trout strains were exposed for eight days to definite stocking densities, 1 kg/m³ (low density); 10 kg/m³ (moderate); 18 kg/m³ (elevated); and 35 kg/m³ (high). Whereas stocking density had no significant effect on cortisol levels, plasma glucose levels were elevated in trout kept at high density. Pathway enrichment analyses confirmed the upregulation of HIF1a signaling in liver contributing to glucose homeostasis during stress conditions, while mTOR and PI3K/AKT signaling pathways were downregulated. Further perturbed hepatic pathways were involved in protein ubiquitination and the biosynthesis of cholesterol, retinol and glutathione.