Project description:We report the hepatic response of broiler chickens to an increase in stocking density. Here we compare gene expression profiles of liver cells via RNA-seq of broiler chicken raised under a high stocking density to broiler chickens raised under a lower stocking density with the objective of this study being to identify biomarkers of stress before the clinical and economic impacts are observed. We found that increasing stocking density seems to have a unique impact on hepatic gene expression prior to eliciting common clinical signs associated with stress. The cellular functions that are most affected appear to be those involved in steroidogenesis and cell movement/migration as identified by RNA-seq analysis of the liver transcriptome. These results could provide a baseline of information that future research to identify genes or molecules that could aid in the detection of negative effects of stressors such as stocking density prior to negative clinical and economic signs presenting themselves.
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: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.
Project description:Stress represents a major factor negatively affecting fish welfare in aquaculture. The objective of the present study was to identify and evaluate informative indicators for the welfare and particular health status of maraena whitefish (Coregonus maraena) farmed at four different stocking densities. Transcriptome profiling revealed that numerous stress-related signaling pathways were activated in liver and kidney under ED and HD conditions, such as ERK/MAPK, mTOR, glucocorticoid receptor, SAPK/JNK and JAK/Stat signalling, as well as p38 and p53 signalling. Moreover, several stress-relevant effector pathways were found to be overexpressed including glycolysis and glycogen degradation. Strikingly, a high number of upregulated genes in kidney and in liver of fish kept at HD (compared to MD fish) were related to immunological processes, such as Acute-phase response signalling, B cell receptor signaling, CD28 signaling in T helper cells, and Interleukin-6 signaling. Four stocking density conditions were investigated: an uncrowded âmoderateâ density (MD: 33 kg trout/m³) , an elevated density (ED: 60 kg/m³ ), a low density (LD: 10 kg/m³ ), and high density (HD: 100 kg/m³). The experiment was performed twice, randomly assigned to identical glass tanks with MD (100 individuals), ED (180 individuals), LD (30 individuals), and HD (300 individuals). Trout were sampled 8 d after experimental onset.