Figure 1
Concept of the study. (a) Transfer of the multi-laboratory approach into a single-laboratory situation. In the multi-laboratory situation, the integration of different laboratory environments in one study results in a heterogenous study population. In the single-laboratory approach, the animals are tested in the same laboratory, but in different mini-experiments spread over three time points (t1–t3). Between mini-experiments, uncontrollable factors of the laboratory environment may vary in the same way as they may vary between laboratories in the multi-laboratory approach. Thereby, the heterogeneity of the study population is enhanced, resembling the logic of the multi-laboratory approach. (b) Overview of the study design: Strain differences were repeatedly investigated in four independent replicate experiments in both a conventional (Con, red) and a mini-experiment design (Mini, blue). In the conventional design, all animals of one replicate experiment (e.g. Con 1) were tested at one specific point in time. In the mini-experiment design, by contrast, one replicate experiment (e.g. Mini 1) was split in three mini-experiments (Mini 1a, Mini 1b, and Mini 1c), all organised in the same way. Please note, whenever mice of a conventional replicate experiment were tested, also one mini-experiment of the corresponding mini-experiment replicate experiment was conducted to control for potential time-point specific background effects. Experimental phase: EPM Elevated Plus Maze, OF Open Field test, NC Novel Cage test, Barrier Barrier test, PB Puzzle Box test, FCMs + FTMs Collection of faecal samples for assessment of corticosterone and testosterone metabolites, SC Sucrose Consumption test, NT Nest test, HCB Home cage behaviour. In addition, body weights were taken.
