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 of maraena whitefish (Coregonus maraena) exposed to inconvenient temperatures. The present study compares the physiological impact of either acute or gradual temperature rise from 18 °C to 24 °C on maraena whitefish in aquaculture. We analysed microarray-based transcriptome profiles in liver, spleen and kidney and identified a common set of diagnostic biomarkers each indicating thermal stress induced by acute or gradual temperature rise in the selected tissues. We identified common and unique tissue- and stress mode-specific pathways reflecting metabolic, cell signalling and immunologic crossroads to cope with thermal stress.
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.