Basic Research On Feeding Microenvironment And Animal Welfare In Laboratory Animal Room With IVC System

With the progress and development of human social civilization,experimental animal science has become an important discipline.At present,experimental animals play an important role in the research of various laws of nature,especially in the experiment of biomedical field.In order to make the experimental results of animal experiments more reliable,we should first focus on ensuring the quality of experimental animals.Therefore,it is indispensable to pay attention to the breeding microenvironment and animal welfare of experimental animals.Basically,the general environment in the laboratory animal room represents the living environment of experimental animals,which can not truly reflect the impact of the environment on experimental animals.At the same time,due to the slow development of experimental animal ethics in China and the existing animal welfare evaluation indicators are mostly constructed from the starting point of industry interests,the evaluation system of experimental animal welfare needs to be improved.In this paper,KM mice were taken as the research object and an IVC system laboratory animal room in the experimental animal center of Hunan University of Chinese medicine was taken as the research site.The breeding microenvironment of experimental animals in the laboratory animal room with IVC system was studied by measuring the wind speed,temperature,relative humidity,ammonia concentration,cleanliness and noise in the general environment in the laboratory animal room and IVC cage.The indexes of abdominal heat flow,ammonia concentration in IVC cage,type of bedding and mouse behavior were selected to study the welfare of experimental animals.At last,from the perspective of air conditioning and ventilation,CFD is used to simulate the environment of the laboratory animal room with up supply and down return convective air-conditioning system and air carrying energy radiant air-conditioning system(ACERS)and the breeding microenvironment inside the IVC cage.The measurement results of environmental parameters in the laboratory animal room and IVC cage show that the general environment in the laboratory animal room with IVC system and the breeding microenvironment in the IVC cage are two relatively independent environments,but they are also related.The more mice are fed in the IVC cage,the higher the temperature in the cage is,and the maximum temperature can be 2℃higher than the general environment.Due to the existence of the drinking water system in the IVC cage,the relative humidity is slightly higher than the general environment,and the excessive wind speed at the air outlet of the cage is easy to cause aerodynamic noise;The analysis of animal welfare indexes shows that there is a moderate correlation between abdominal heat flow and health status of mice,and the correlation coefficient can reach 0.786.The difference of ammonia production capacity of mice between different seasons can reach 2～5 times,so the cage change interval can be adjusted seasonally;The CFD simulation results show that the distribution of wind speed,temperature,relative humidity and ammonia concentration in the laboratory animal room with IVC system and the ACERS is relatively homogeneous.With the up supply and down return convective air-conditioning system,the wind speed at the air outlet and the ground in the laboratory animal room with IVC system can reach 1.4m/s and 0.8m/s respectively,which is easy to roll up the ground dust,resulting in the number of dust particles in the room exceeding the standard.At the same time,it was found that excessive local wind speed and ammonia accumulation under the air outlet were easy to occur in the IVC cage.The maximum wind speed in the mouse activity area could reach 0.4m/s and the ammonia concentration could reach 6mg/m~3.This paper studies the breeding microenvironment and animal welfare,and puts forward corresponding suggestions,which provides a feasible direction and reference for improving the breeding microenvironment and animal welfare of experimental animals.