Hasegawa M, Kurabayashi Y, Ishii T, Yoshida K, Uebayashi N, Sato N, Kurosawa T
Technical Research Laboratory, Dai-Dan Co., Ltd., Saitama, Japan.
Exp Anim. 1997 Oct;46(4):251-7. doi: 10.1538/expanim.46.251.
Recently, a forced-air-ventilated micro-isolation system (FVMIS) has been recognized to accurately maintain microenvironmental conditions inside cages, but the details of the relationship between the concentrations of carbon dioxide (CO2) and oxygen (O2) and the air change rate inside the cages have never been reported. In this study, the proper intra-cage air change rate was examined based on the CO2 concentration and O2 concentration inside the cages measured by changing the ventilation volume inside the closed cages of the FVMIS while housing animals. In the experiments, three 8-week-old Wistar strain male rats weighing 303 g on average were housed in each FVMIS cage (capacity: 0.0223 m3), and the temperature, relative humidity, CO2 concentration and O2 concentration were measured when the air change rate inside the cages was varied from 10 air changes per hour (ACH) to 120 ACH. It proved that the CO2 concentration in the FVMIS cages decreased uniformly with the increase in the air change rate. As a result, 60 ACH was required to maintain the CO2 concentration level inside the FVMIS cages equivalent to or less than that in the conventional housing. Otherwise, when based on the O2 concentration, 50 ACH was required. In consideration of these results and others based on ventilation, airflow, temperature and the ammonia concentration reported previously, we concluded that the proper air change rate inside the FVMIS cages should be approximately 60 ACH.
最近，一种强制通风微隔离系统（FVMIS）已被认可能够准确维持笼内的微环境条件，但笼内二氧化碳（CO₂）和氧气（O₂）浓度与换气率之间关系的细节此前从未有过报道。在本研究中，通过在饲养动物时改变FVMIS封闭笼内的通风量，根据所测的笼内CO₂浓度和O₂浓度来研究合适的笼内换气率。实验中，将3只平均体重303克的8周龄Wistar品系雄性大鼠饲养在每个FVMIS笼（容积：0.0223立方米）中，当笼内换气率从每小时10次换气（ACH）变化到120 ACH时，测量温度、相对湿度、CO₂浓度和O₂浓度。结果表明，FVMIS笼内的CO₂浓度随换气率的增加而均匀下降。因此，需要60 ACH才能将FVMIS笼内的CO₂浓度维持在等于或低于传统饲养环境的水平。否则，基于O₂浓度考虑，需要50 ACH。综合考虑这些结果以及先前报道的基于通风、气流、温度和氨浓度的其他结果，我们得出结论，FVMIS笼内合适的换气率应约为60 ACH。
