In:
PLOS ONE, Public Library of Science (PLoS), Vol. 17, No. 5 ( 2022-5-25), p. e0267281-
Abstract:
Mice respond to a cage change (CC) with altered activity, disrupted sleep and increased anxiety. A bi-weekly cage change is, therefore, preferred over a shorter CC interval and is currently the prevailing routine for Individually ventilated cages (IVCs). However, the build-up of ammonia (NH 3 ) during this period is a potential threat to the animal health and the literature holds conflicting reports leaving this issue unresolved. We have therefor examined longitudinally in-cage activity, animal health and the build-up of ammonia across the cage floor with female and male C57BL/6 mice housed four per IVC changed every other week. We used a multicentre design with a standardised husbandry enabling us to tease-out features that replicated across sites from those that were site-specific. CC induce a marked increase in activity, especially during daytime (~50%) when the animals rest. A reduction in density from four to two mice did not alter this response. This burst was followed by a gradual decrease till the next cage change. Female but not male mice preferred to have the latrine in the front of the cage. Male mice allocate more of the activity to the latrine free part of the cage floor already the day after a CC. A behaviour that progressed through the CC cycle but was not impacted by the type of bedding used. Reducing housing density to two mice abolished this behaviour. Female mice used the entire cage floor the first week while during the second week activity in the latrine area decreased. Measurement of NH 3 ppm across the cage floor revealed x3 higher values for the latrine area compared with the opposite area. NH 3 ppm increases from 0–1 ppm to reach ≤25 ppm in the latrine free area and 50–100 ppm in the latrine area at the end of a cycle. As expected in-cage bacterial load covaried with in-cage NH 3 ppm. Histopathological analysis revealed no changes to the upper airways covarying with recorded NH 3 ppm or bacterial load. We conclude that housing of four (or equivalent biomass) C57BL/6J mice for 10 weeks under the described conditions does not cause any overt discomfort to the animals.
Type of Medium:
Online Resource
ISSN:
1932-6203
DOI:
10.1371/journal.pone.0267281
DOI:
10.1371/journal.pone.0267281.g001
DOI:
10.1371/journal.pone.0267281.g002
DOI:
10.1371/journal.pone.0267281.g003
DOI:
10.1371/journal.pone.0267281.g004
DOI:
10.1371/journal.pone.0267281.g005
DOI:
10.1371/journal.pone.0267281.g006
DOI:
10.1371/journal.pone.0267281.g007
DOI:
10.1371/journal.pone.0267281.g008
DOI:
10.1371/journal.pone.0267281.g009
DOI:
10.1371/journal.pone.0267281.g010
DOI:
10.1371/journal.pone.0267281.g011
DOI:
10.1371/journal.pone.0267281.g012
DOI:
10.1371/journal.pone.0267281.g013
DOI:
10.1371/journal.pone.0267281.g014
DOI:
10.1371/journal.pone.0267281.g015
DOI:
10.1371/journal.pone.0267281.g016
DOI:
10.1371/journal.pone.0267281.g017
DOI:
10.1371/journal.pone.0267281.g018
DOI:
10.1371/journal.pone.0267281.t001
DOI:
10.1371/journal.pone.0267281.t002
DOI:
10.1371/journal.pone.0267281.s001
DOI:
10.1371/journal.pone.0267281.r001
DOI:
10.1371/journal.pone.0267281.r002
DOI:
10.1371/journal.pone.0267281.r003
DOI:
10.1371/journal.pone.0267281.r004
Language:
English
Publisher:
Public Library of Science (PLoS)
Publication Date:
2022
detail.hit.zdb_id:
2267670-3
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