A practical guide to unbiased quantitative morphological analyses of the gills of rainbow trout (Oncorhynchus mykiss) in ecotoxicological studies
Fig 5
General experimental design for quantitative stereological analyses of trout gill morphology in ecotoxicological studies.
The paper sections containing the respective sample processing and analysis steps are indicated (5–15). At the end point of the study, fish are euthanized, using a gill-preserving killing method (Section 5). Optional perfusion fixation, excision-, fixation- and volumetry of gills after removal of the gill arch are described in Sections 6–8. Section 9 presents the systematic uniform random (SUR) sampling of representative gill filament specimens for stereological analyses. aAfter SUR sampling of the specimens, it is strongly recommended to store the remaining fixed gills and not discard them until final completion of the study. The subsequent processing steps and analysis methods depend on the individual quantitative stereological parameters of interest (Sections 10–15).