Fig 1.
Overview of the procedures for single- and group-housed cohorts: (a) = tail; (b) = forceps; (c) = tube. Behavioral analysis (except the NT) of mice started at week 9 and lasted until the animals were euthanized at 10 weeks.
Table 1.
Statistical results concerning the factors ‘housing’ and ‘handling’.
Fig 2.
A) Nest building test, 24 h (n of cages = 36, 24 mice/handling method). A significant overall effect (p < 0.05) revealed regarding the factor ‘handling’. Furthermore, a significant difference in the nest building performance is seen by the last week of housing and handling, indicating the role of experience. B) Behavioral scoring of aggression-associated parameters, (n = 54, 18/handling method). There was a significant overall effect concerning the number of attacks: forceps-handled group-housed mice had an increase in the number of attacks compared to the other handling methods (p < 0.01). C) Body weight, (n = 72, 24/handling method). No difference in the development was found regarding the factor ‘housing’ or ‘handling’. Asterisks indicate the level of significance (* p ≤ 0.05; ** p ≤ 0.01; *** p ≤ 0.001).
Fig 3.
A) Stress induced hyperthermia, (cages n = 36, 24 mice/handling method). Effect of handling treatment on the SIH in 8th week. A higher temperature difference was found for forceps-handled animals compared to tube- and tail-handled mice (p < 0.05). B) Light/dark box test, (n = 36, 12/handling method). Evaluation of anxiety behavior regarding the factor ‘handling’ in a LDB test. Tube-handled mice had diminished anxiety behavior represented by the latency to the first exit. C) Hotplate test, (n = 36, 12/handling method). Asterisks indicate the level of significance (* p ≤ 0.05; ** p ≤ 0.01; *** p ≤ 0.001).
Fig 4.
A-B) Open field, (n = 36, 18/group). Behavior of C57BL/6N mice in the OF. Group-housed mice stayed more distant to the walls (A), consequently they spent more time in the center (B). C) Fecal corticosterone metabolites (FCM), week 7–3, (n = 36, 18/group). Group-housed mice had higher FCM levels (** p = 0.002). Asterisks indicate the level of significance (* p ≤ 0.05; ** p ≤ 0.01; *** p ≤ 0.001).