Non-invasive stress assay: identification and comparrison of methodologies during handling, sampling or transfer of fish
Fish are daily used as experimental model in a multitude of studies. Non-invasive procedures to handle, sample or transfer fish are required in order to reduce disturbance in the tanks to a minimum. On the contrary, when these procedures are carried out careless and become invasive, they provoke a rising of the level of stress which lead to detrimental effects on growth, reproduction, immunological function and on the survival of fish.
Among experiments reported in the literature, differences in the procedures used to anesthetize fish (i.e. the anesthetic type and doses), or in the environmental conditions (i.e. water temperature and light condition), have not only an effect on the experimental outcome, but also become a source of variability in the data collected. Thus, experiments made in different facilities often generate results that are impossible to compare. Unfortunately, there are not any specific guidelines about how to address these issues.
Due to the increasing concern of the welfare of farmed fishes, and their level of stress, there is much interest in assessing the stress level of fishes. In response to acute and chronic stress, the fish interrenal synthesizes cortisol, and the concentration of which in plasma is commonly used to indicate stress level. However, blood sampling procedure, where it is not cause of death, is a potential stressor itself for the single fish as well as for all the population in the thank. This makes fish unable to be used any further in the experiment. Fortunately, less invasive stress markers are available. For examples, stress derived cortisol levels can be measured in the outlet water. In addition, the state of the fish can also be assessed by measure of oxygen consumption, feed intake and or behavior observation.
In this experiment, we aim to test different 3 different doses of anesthetic (MS222) in the seawater Atlantic salmon holding thank and measure differences in the stress caused after transferring all fish into a twin thank. Measure of cortisol released in the water, oxygen consumption and behavior observations will be collected for 6 hours. After, one of the three doses (the lowest) will be selected for a second experiment where fish will be anesthetized in the holding thank, but this time in complete darkness. During the transfer into a new twin tank, tree fish per tank will be sacrificed in order to study the effect of sampling of slightly anaesthetized fish in darkness on blood parameters. Other data will be collected as described previously
REFINEMENT: Animals’ distress will be reduced to the minimum and unnecessary pain will be avoided. Therefore, when transported in the experimental tanks fish will be slightly anesthetized.
REPLACEMENT: The experimental models were chosen in order to use farmed instead of wild stocks. Furthermore, using Atlantic salmon is critical to improve fish welfare, the quality of the product and the farmers’ economic benefits.
REDUCTION: The number/biomass of fish is chosen in order to have stable behavior in the tanks, strong analytical results, and good oxygen and cortisol measure in the tanks.
Among experiments reported in the literature, differences in the procedures used to anesthetize fish (i.e. the anesthetic type and doses), or in the environmental conditions (i.e. water temperature and light condition), have not only an effect on the experimental outcome, but also become a source of variability in the data collected. Thus, experiments made in different facilities often generate results that are impossible to compare. Unfortunately, there are not any specific guidelines about how to address these issues.
Due to the increasing concern of the welfare of farmed fishes, and their level of stress, there is much interest in assessing the stress level of fishes. In response to acute and chronic stress, the fish interrenal synthesizes cortisol, and the concentration of which in plasma is commonly used to indicate stress level. However, blood sampling procedure, where it is not cause of death, is a potential stressor itself for the single fish as well as for all the population in the thank. This makes fish unable to be used any further in the experiment. Fortunately, less invasive stress markers are available. For examples, stress derived cortisol levels can be measured in the outlet water. In addition, the state of the fish can also be assessed by measure of oxygen consumption, feed intake and or behavior observation.
In this experiment, we aim to test different 3 different doses of anesthetic (MS222) in the seawater Atlantic salmon holding thank and measure differences in the stress caused after transferring all fish into a twin thank. Measure of cortisol released in the water, oxygen consumption and behavior observations will be collected for 6 hours. After, one of the three doses (the lowest) will be selected for a second experiment where fish will be anesthetized in the holding thank, but this time in complete darkness. During the transfer into a new twin tank, tree fish per tank will be sacrificed in order to study the effect of sampling of slightly anaesthetized fish in darkness on blood parameters. Other data will be collected as described previously
REFINEMENT: Animals’ distress will be reduced to the minimum and unnecessary pain will be avoided. Therefore, when transported in the experimental tanks fish will be slightly anesthetized.
REPLACEMENT: The experimental models were chosen in order to use farmed instead of wild stocks. Furthermore, using Atlantic salmon is critical to improve fish welfare, the quality of the product and the farmers’ economic benefits.
REDUCTION: The number/biomass of fish is chosen in order to have stable behavior in the tanks, strong analytical results, and good oxygen and cortisol measure in the tanks.