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Andersson M, Pernold K, Lilja N, Frias-Beneyto R, Ulfhake B. 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. Animals (Basel) 2024; 14:2735. [PMID: 39335324 PMCID: PMC11428529 DOI: 10.3390/ani14182735] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2024] [Revised: 09/11/2024] [Accepted: 09/16/2024] [Indexed: 09/30/2024] Open
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.
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Affiliation(s)
- Martina Andersson
- Department of Comparative Medicine, Karolinska Institutet, 171 77 Stockholm, Sweden
| | - Karin Pernold
- Department of Comparative Medicine, Karolinska Institutet, 171 77 Stockholm, Sweden
- Department of Laboratory Medicine, Karolinska Institutet, 171 77 Stockholm, Sweden
| | - Niklas Lilja
- Department of Comparative Medicine, Karolinska Institutet, 171 77 Stockholm, Sweden
| | - Rafael Frias-Beneyto
- Department of Laboratory Medicine, Karolinska Institutet, 171 77 Stockholm, Sweden
- Department of Comparative Medicine, Karolinska University Hospital, 171 76 Solna, Sweden
| | - Brun Ulfhake
- Department of Comparative Medicine, Karolinska Institutet, 171 77 Stockholm, Sweden
- Department of Laboratory Medicine, Karolinska Institutet, 171 77 Stockholm, Sweden
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Cho E, Walsh CA, D'Angelo-Gavrish NM, Wilson SR, Cirillo PA, Smith PC. Effects of Housing Density on Reproductive Performance, Intracage Ammonia, and Welfare of Mice Continuously Housed as Breeders in Standard Mouse and Rat Caging. JOURNAL OF THE AMERICAN ASSOCIATION FOR LABORATORY ANIMAL SCIENCE : JAALAS 2023; 62:116-122. [PMID: 36878483 PMCID: PMC10078924 DOI: 10.30802/aalas-jaalas-22-000069] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/15/2022] [Revised: 09/02/2022] [Accepted: 10/30/2022] [Indexed: 03/08/2023]
Abstract
Maintaining compliance with cage density recommendations in The Guide for the Care and Use of Laboratory Animals precludes continuous trio breeding in standard-sized mouse cages. This study evaluated and compared several parameters of reproductive performance, intracage ammonia concentration, and fecal corticosterone levels in 2 strains of mice, C57BL/6J (B6) and B6.129S(Cg)-Stat1tm1Dlv/J (STAT1-/-), housed as continuous breeding pairs or trios in standard-sized mouse cages, and continuous breeding trios in standard-sized rat cages. Reproductive performance data indicated that STAT1-/- trios raised in rat cages weaned significantly more pups per litter than did STAT1-/- trios raised in mouse cages, and B6 mice had higher pup survival rates at weaning than did STAT1-/- mice in mouse cages housing continuous breeding trios. In addition, the Production Index was significantly higher for B6 breeding trios in rat cages than for B6 trios in mouse cages. Intracage ammonia concentration increased with cage density, with significantly higher ammonia concentrations in mouse cages housing trios compared with rat cages housing trios. However, fecal corticosterone levels did not differ significantly regardless of genotype, breeding configuration, or cage size, and daily health checks revealed no clinical abnormalities under any of the conditions evaluated. These results suggest that, although continuous trio breeding in standard-sized mouse cages does not seem to compromise mouse welfare, it offers no advantage in reproductive performance compared with pair breeding, and in some cases, it might be disadvantageous in this regard. Further, high intracage ammonia in mouse cages containing breeding trios might necessitate more frequent cage changes.
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Affiliation(s)
- Ellen Cho
- Yale School of Medicine, Department of Comparative Medicine, New Haven, Connecticut
| | - Courtney A Walsh
- Yale School of Medicine, Department of Comparative Medicine, New Haven, Connecticut
| | | | - Steven R Wilson
- Yale School of Medicine, Department of Comparative Medicine, New Haven, Connecticut
| | - Patricia A Cirillo
- Yale School of Medicine, Department of Comparative Medicine, New Haven, Connecticut
| | - Peter C Smith
- Yale School of Medicine, Department of Comparative Medicine, New Haven, Connecticut;,
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Jones T, Thaweethai T, Molk D, Ingram L, Palley LS, Jarrell D. Evaluation and Refinement of a Spot-change-only Cage Management System for Mice. JOURNAL OF THE AMERICAN ASSOCIATION FOR LABORATORY ANIMAL SCIENCE : JAALAS 2022; 61:650-659. [PMID: 36328418 PMCID: PMC9732769 DOI: 10.30802/aalas-jaalas-22-000023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/09/2022] [Revised: 04/21/2022] [Accepted: 07/14/2022] [Indexed: 11/06/2022]
Abstract
Maximizing operational efficiency while maintaining appropriate animal housing conditions is a continuous focus of research animal care programs. Our institution's longstanding approach to cage-change management included scheduled cage changes every 2 wk, with spot changes if cages met established visual criteria during the intervening period. This 2-wk plus spot changing (2WS) practice for mice housed in IVC was problematic during the COVID-19 pandemic when the need arose to minimize workload to reduce on-site staffing out of concern for employee health and possible absenteeism. With the approval of the IACUC, a spot-change-only (SCO) process was adopted, with the requirement to evaluate microenvironmental parameters under both practices to confirm acceptable equivalence. These parameters (humidity, temperature, and ammonia) were evaluated in a controlled study that found no significant difference between the 2 groups. Ammonia levels did not exceed 10 ppm in any group throughout the study. To assess operational differences between these 2 approaches, we collected cage-change data and employee feedback from facilities operating under these schemes. The SCO method required fewer cage changes than did the 2WS method (10.3% per day with 2WS and 8.4% per day with SCO). Despite this benefit, through a Plan-Do-Check-Act process that has been regularly employed at our institution, employee feedback identified important operational challenges associated with the SCO practice. The SCO approach was thus refined into a scheduled spot change (SSC) practice that builds on the SCO model by incorporating a scheduled focused cage evaluation period. Based on subsequent feedback, the SSC was found to retain the efficiency benefits afforded by the SCO model and simultaneously alleviated staff and operational concerns. This result underscores the importance of integrating staff feedback with a performance standard-based approach when assessing cage-change management.
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Affiliation(s)
- Tim Jones
- Center for Comparative Medicine, Massachusetts General Hospital, Boston, MA;,
| | - Tanayott Thaweethai
- Biostatistics Center, Massachusetts General Hospital, Boston MA; Department of Medicine, Harvard Medical School, Boston MA
| | - Denise Molk
- Center for Comparative Medicine, Massachusetts General Hospital, Boston, MA
| | - Laurie Ingram
- Center for Comparative Medicine, Massachusetts General Hospital, Boston, MA
| | - Lori S Palley
- Center for Comparative Medicine, Massachusetts General Hospital, Boston, MA
| | - Donna Jarrell
- Center for Comparative Medicine, Massachusetts General Hospital, Boston, MA
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Ulfhake B, Lerat H, Honetschlager J, Pernold K, Rynekrová M, Escot K, Recordati C, Kuiper RV, Rosati G, Rigamonti M, Zordan S, Prins JB. 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. PLoS One 2022; 17:e0267281. [PMID: 35613182 PMCID: PMC9132304 DOI: 10.1371/journal.pone.0267281] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2021] [Accepted: 04/05/2022] [Indexed: 11/19/2022] Open
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 (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.
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Affiliation(s)
- B. Ulfhake
- Department of Laboratory Medicine, Karolinska Institutet, Stockholm, Sweden
- * E-mail:
| | - H. Lerat
- Université Grenoble-Alpes, UMS hTAG Inserm US046 CNRS UAR2019, Grenoble, France
| | - J. Honetschlager
- Institute of Molecular Genetics of the Czech Academy of Sciences, Prague, Czech Republic
| | - K. Pernold
- Department of Laboratory Medicine, Karolinska Institutet, Stockholm, Sweden
| | - M. Rynekrová
- Institute of Molecular Genetics of the Czech Academy of Sciences, Prague, Czech Republic
| | - K. Escot
- Université Grenoble-Alpes, UMS hTAG Inserm US046 CNRS UAR2019, Grenoble, France
| | - C. Recordati
- Department of Veterinary Medicine and Animal Sciences, University of Milan, Lodi, Italy
- Mouse and Animal Pathology Laboratory, Fondazione Unimi, Milano, Italy
| | - R. V. Kuiper
- Department of Laboratory Medicine, Karolinska Institutet, Huddinge, Sweden
- Norwegian Veterinary Institute, Section Aquatic Biosecurity Research, Oslo, Norway
| | - G. Rosati
- Tecniplast SpA, Buguggiate (Va), Italy
| | | | - S. Zordan
- Tecniplast SpA, Buguggiate (Va), Italy
| | - J.-B. Prins
- Central Animal Facility, PDC, Leiden University Medical Centre, Leiden, The Netherlands
- The Francis Crick Institute, London, United Kingdom
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Stover MG, Villano JS. Evaluation of Various IVC Systems According to Mouse Reproductive Performance and Husbandry and Environmental Parameters. JOURNAL OF THE AMERICAN ASSOCIATION FOR LABORATORY ANIMAL SCIENCE : JAALAS 2022; 61:31-41. [PMID: 34980294 PMCID: PMC8786386 DOI: 10.30802/aalas-jaalas-21-000079] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Revised: 07/29/2021] [Accepted: 09/09/2021] [Indexed: 06/14/2023]
Abstract
IVC systems are marketed for improving the health and management of mouse colonies. The current study compared mouse reproductive performance and husbandry and environmental parameters among 3 high-density (HD) IVC rack systems (RS1, RS2, and RS3), which were present in separate but comparable rooms. Three breeding trios each of Swiss Webster (CFW) and BALB/c mice were placed in each rack (n = 36 female, n = 18 male). Reproductive indices were measured for 3 breeding cycles over 2 generations; indices included time to parturition, litter size and pup weight, survivability, and interbirth interval. Over 18 wk, personnel used scoring systems to evaluate each RS daily to every other week according to cage dirtiness, need for spot changing, ease of cage changing, daily health checks, and cage wash processing. Macroenvironmental parameters (temperature, relative humidity, noise, total particulate matter) were measured weekly over 14 wks. Microenvironmental parameters (temperature, relative humidity, NH₃, CO₂, O₂) of 2 cages each of male and female CFW mice (4 mice/cage) on each RS were measured at 6 time points over 2 wks. RS1 had significantly smaller mean litter sizes of CFW mice (mean ± 1 SD, 6.5 ± 2.9 pups) as compared with both RS2 (9.5 ± 1.7 pups) and RS3 (9.3 ± 3.8 pups). RS1 scored as being significantly easier to process through the cage wash. RS2 had significantly lower room noise levels (46.0 ± 5.0 dBA) but higher humidity (58.6% ± 8.9%) as compared with both RS1 (43.7% ± 9.9%) and RS3 (46.0% ± 12.0%) over the 2-wk cycle, particularly at 8 and 12 d after cage change. In conclusion, in terms of mouse reproductive performance and husbandry and environmental parameters, each system had at least 1 advantage over the other 2. Therefore, various factors should be considered when choosing an IVC system for mice.
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Affiliation(s)
- Mitchel G Stover
- Department of Molecular and Comparative Pathobiology, School of Medicine, and
- Research Animal Resources, Johns Hopkins University, Baltimore, Maryland
| | - Jason S Villano
- Department of Molecular and Comparative Pathobiology, School of Medicine, and
- Research Animal Resources, Johns Hopkins University, Baltimore, Maryland
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