DOI: 10.5061/dryad.ksn02v75q
title: A multicentre study on spontaneous in-cage activity and micro-environmental conditions of IVC housed C57BL/6J mice during consecutive cycles of bi-weekly cage change

description: 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
 (NH3) 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 NH3 ppm across the cage floor revealed x3 higher values for the latrine
 area compared with the opposite area. NH3 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 NH3 ppm. Histopathological analysis revealed no changes to the
 upper airways covarying with recorded NH3 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.
description: Raw data and metadata files used for the manuscript "A
 multicentre study on spontaneous in-cage activity and micro-environmental
 conditions of IVC housed C57BL/6J mice during consecutive cycles of
 bi-weekly cage change". The recording of ammonia
 levels, i.e. NH3 ppm values, from every cage while inserted in the rack
 under airflow conditions, was carried out using an industrial ammonia
 detector device (Dräger X-249am® 8000, Dräger). The IVC cages were
 modified with three holes drilled 1.5 cm above the bedding level along the
 cage's lateral wall corresponding to the rear, middle, and front area
 of the cage floor. The activity of the mice inside the
 home-cage was automatically collected by the DVC system, which consists of
 electronic boards positioned below the cage, using the metric Animal
 Locomotion Index Smoothed (DVC Analytics, Tecniplast S.p.a.).
 Histopathological analysis was performed in compliance with
 previously published protocols. Seven different histopathological entities
 (Table 2) were ranked on a scale from not present (0) to severe
 (5). Bacterial load assessment was done by swabbing the
 animals at the end of the five bi-weekly cage-change cycles, at the end of
 the two cycles of weekly cage change and at the end of the second
 cycle.
description: File 1 Name:
 <strong>weight_age_sex.csv</strong> File 1
 Description: age, sex and weights information for each cage of each
 site File 2 Name:
 <strong>nh3_measurements.csv</strong> File
 2 Description: NH3 ammonia measurements File 3 Name:
 <strong>Histopathology_scoring of signs in SPF and GF
 mice.xlsx</strong> File 3 Description: scores 1-5
 and cell counts executed on 20 SPF and 20 GF animals of both sexes at
 KI. File 4 Name: <strong>Cage, BW, ppmNH3 and
 ln(CFUs).xlsx</strong> File 4 Description: (page
 1) End values ppmNH3, bacterial load after weekly and bi-weekly
 cage-change; (page 2)ppmNH3 across all cycles for each cage at
 KI. File 5 Name: <strong>DVC
 activity_IMG.zip</strong> File 5 Description:
 minute activity measured by DVC at IMG site (Animal Locomotion Index
 Smoothed, DVC Analytics, Tecniplast S.p.a.) File 6
 Name: <strong>DVC activity_KI.zip</strong>
 File 6 Description: minute activity measured by DVC at KI site
 (Animal Locomotion Index Smoothed, DVC Analytics, Tecniplast
 S.p.a.) File 7 Name: <strong>DVC
 activity_KI_phase_2.zip</strong> File 7
 Description: minute activity measured by DVC at KI site (Animal Locomotion
 Index Smoothed, DVC Analytics, Tecniplast S.p.a.) File
 8 Name: <strong>DVC activity_LUMC.zip</strong>
 File 8 Description: minute activity measured by DVC at LUMC site
 (Animal Locomotion Index Smoothed, DVC Analytics, Tecniplast
 S.p.a.) File 9 Name: <strong>DVC
 activity_UGA.zip</strong> File 9 Description:
 minute activity measured by DVC at UGA site (Animal Locomotion Index
 Smoothed, DVC Analytics, Tecniplast S.p.a.) File 10
 Name: <strong>README.txt</strong> File 10
 Description: README file with all the relevant information of the
 dataset