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Longitudinal Study of Changes in Ammonia, Carbon Dioxide, Humidity and Temperature in Individually Ventilated Cages Housing Female and Male C57BL/6N Mice during Consecutive Cycles of Weekly and Bi-Weekly Cage Changes

Authors :
Martina Andersson
Karin Pernold
Niklas Lilja
Rafael Frias-Beneyto
Brun Ulfhake
Source :
Animals, Vol 14, Iss 18, p 2735 (2024)
Publication Year :
2024
Publisher :
MDPI AG, 2024.

Abstract

Housing conditions are essential for ensuring animal welfare and high-quality research outcomes. In this study, we continuously monitored air quality—specifically ammonia, carbon dioxide, relative humidity, and temperature—in Individually Ventilated Cages (IVCs) housing five female or male C57BL/6N mice. The cages were cleaned either weekly or bi-weekly, and the data were collected as the mice aged from 100 to 348 days. The survival rate remained above 96%, with body weight increasing by 35–52% during the study period. The ammonia levels rose throughout the cleaning cycle, but averaged below 25 ppm. However, in the older, heavier mice with bi-weekly cage cleaning, the ammonia levels reached between 25 and 75 ppm, particularly in the males. While circadian rhythms influenced the ammonia concentration only to a small extent, the carbon dioxide levels varied between 800 and 3000 ppm, increasing by 30–50% at night and by 1000 ppm with body weight. Humidity also correlated primarily with the circadian rhythms (10% higher at night) and, to a lesser extent, with body weight, reaching ≥70% in the middle-aged mice. The temperature variations remained minimal, within a 1 °C range. We conclude that air quality assessments in IVCs should be conducted during animals’ active periods, and both housing density and biomass must be considered to optimise welfare.

Details

Language :
English
ISSN :
20762615
Volume :
14
Issue :
18
Database :
Directory of Open Access Journals
Journal :
Animals
Publication Type :
Academic Journal
Accession number :
edsdoj.5be79109045411bbbe469dcb8388779
Document Type :
article
Full Text :
https://doi.org/10.3390/ani14182735