The adaptability of mice to the environment and the ability to resist diseases are worse than those of other experimental animals, but there are many varieties and strains of mice, and each variety and strain has its own special requirements, so a clean and comfortable living environment should be given according to the actual situation. Rats of different grades should live in corresponding facilities.
The critical temperature of mice is low temperature 10℃, high temperature is 37℃, and the temperature neutral range is 30 ~ 33℃. The control of feeding environment should meet the following requirements: the temperature is 65438 08 ~ 29℃; Relative humidity 40 ~ 70%; It is best to control the temperature at 18 ~ 22℃ and the humidity at 50 ~ 60%. Generally, the temperature in the mouse feeding box is higher than the environment 1 ~ 2℃, and the humidity is 5 ~ 10%.
The temperature and humidity should be kept relatively stable, and the daily temperature difference should not exceed 3℃, otherwise it will directly affect the growth, production and reproduction of mice, and even lead to diseases in mice, thus affecting the experimental results. In places with poor building conditions, the relative stability of temperature and humidity can be adjusted by air conditioners, humidifiers and heating in the north. In order to keep the indoor air fresh, the ammonia concentration should not exceed 20ppm, and the air exchange frequency should reach 10 ~ 20 times/hour.
At present, non-toxic plastic mouse boxes, stainless steel wire cage covers and metal cage frames are widely used in China. Cages are generally movable and can be disinfected in various ways. It is a good method to control the feeding of second-and third-grade mice in a clean laminar flow framework. The cage box should not only ensure that mice have room to move, but also prevent mice from biting their teeth and breaking the mouse box to escape, which is convenient for cleaning and disinfection. Cages with filter caps can reduce microbial pollution, but the concentration of harmful gases such as ammonia in cages is high, which sometimes affects the accuracy of experimental results. Drinking fountains can be made of glass bottles and plastic bottles, and metal or glass drinking pipes are installed on the cork, with a capacity of 250ml or 500ml.
Cushion is a kind of bedding in direct contact with the living environment of mice, which has the functions of moisture absorption (urine), warmth retention, nesting and so on. Therefore, the padding should be hygroscopic, non-toxic, non-irritating, dust-free and inedible to make animals feel comfortable. The liner must be disinfected to remove potential pathogens and harmful substances. Generally, it is advisable to use wood shavings or sawdust from broad-leaved forest as bedding, and it can also be used after corncob processing, crushing and dust removal.
It is forbidden to use cork (pine, juniper and fir) shavings as padding in the experiment. These shavings emit volatile substances with aromatic smell, which can cause damage to liver cells and greatly interfere with pharmacological and toxicological experiments.
There are specialized padding manufacturers abroad to produce padding, but the padding industry in China has yet to be developed. At present, most experimental animals in China use wood processing by-products, such as sawdust and wood shavings, whose sources and tree species are difficult to control, which brings many adverse effects to the quality control of experimental animals.
Second, feed and drinking water
1. feed
The mice should be fed full-nutrition pellet feed, and the feed should contain a certain proportion of crude fiber, so that the molded feed has a certain hardness and the mice can grind their teeth. At the same time, the nutritional components should remain relatively stable, and any change in feed formula or dosage form should be recorded in the file as a major event.
Different kinds of mice have different nutritional standards. For example, the feed of purebred mice and breeding mice contains more protein than that of ordinary mice, and DBA mice need a feed with high protein and low fat.
2. Drinking water
The water metabolism of mice is quite fast, so it is necessary to ensure enough drinking water. The standard of first-class animal drinking water should not be lower than the hygienic standard of urban drinking water. The drinking water of second-class animals must be disinfected. Hydrochloric acid can also be used to acidify water (pH 2.5 ~ 3.0), so that mice can drink acidified water, which can inhibit the growth of bacteria and kill them to some extent, and its bactericidal effect can meet the requirements. The drinking water of Class III and IV animals is sterilized by high pressure and high temperature.
Third, general feeding management.
The feeding and management of rats is very complicated, which requires the breeder to have a high sense of responsibility, check the condition of rats at any time, and correct the problems immediately when found. In order to make the feeding work orderly, all operations must be arranged as a whole, and fixed operating procedures must be established, so that the breeder will not miss an operation and it is convenient for managers to check at any time.
1. Feeding
Mice have a small stomach and eat at any time, so they are animals with the habit of eating more meals. The feed intake of adult rats is generally 3 ~ 7g/ day, and that of young rats is generally 1 ~ 3g/ day. Feed should be added 3 ~ 4 times a week, and there should always be enough fresh and dry feed in the hopper of the rat cage. In a large group of mice, feed should be added two days a week, and other times can be added at any time according to the situation.
According to the growth and development characteristics of mice at different stages, there should be different feeding standard. Due to the frequent mating and reproduction of breeding mice and production mice, especially the production of breeding mice is heavy and consumes a lot of energy, so in addition to supplying enough blocks, we should regularly feed a small amount of sunflower seeds, malt and soft materials to mix eggs. The supply of sunflower seeds is 0.5 ~ 1g/ day/adult rat. However, wheat teeth and soft materials are often eliminated because of the difficult control of microbial conditions, and they are committed to the complete nutrition of granular materials, that is, to switch to vitamin mixtures.
Feed water
Water is supplied by a drinking bottle, and the water is changed 2-3 times a week. The water consumption of adult rats is generally 4 ~ 7 ml/day. In order to ensure continuous drinking, the bottle stopper should be checked frequently to prevent animals from drowning due to bottle stopper leakage or rats from dehydration due to blocked drinking pipes. In the process of water absorption, food particles and saliva in the mouth can flow back into the water bottle. In order to avoid microbial contamination of water bottles, water bottles and suction pipes should be cleaned when changing water. It is strictly forbidden to continue to use unsterilized water bottles.
3. Cleaning and disinfection
Gaskets should be replaced at least twice a week. When replacing the padding, remove the feeding box together and pour the padding into the special room to prevent indoor dust and pollution. The bedding of animals above the first grade should be sterilized under high pressure before use.
Keep the indoor and outdoor culture clean, and the doors, windows, walls and floors are dust-free.
Adhere to the system of small disinfection every month and large disinfection once every quarter. That is, use 0. 1% bromogeramine spray air for disinfection once a month, 3% for outdoor disinfection and 0.2% for peracetic acid spray disinfection once a quarter. Cages and utensils should be thoroughly disinfected at least once a month, and other utensils in the rat room should also be disinfected when used. It can be autoclaved or soaked in 0.2% peracetic acid.
There should be a rotating room. After being used in the feeding room for one year, all the mice moved in, and the original feeding room was thoroughly decorated and disinfected.
4. Animal health appearance inspection
This is a routine job to check the health of animals. The criteria for judging the health status of mice by appearance are: ① strong appetite; 2 bright eyes and quick response; ③ Smooth body hair, plump muscles and strong mobility; ④ The body has no scar, the tail is not bent, and there is no secretion and deformity in the natural cavity; ⑤ The feces are black and wheat-shaped.
5. Gender discrimination
The sex of adult rats is easy to distinguish, and the scrotum of male rats is obvious; The female mouse can see the vaginal opening and five pairs of nipples.
Young rats or young rats are mainly judged by the distance between the external genitalia and the anus, and the nearest one is female and the far one is male. In addition, there is a hairless groove between the anus and genitals of female rats, while there is long hair between the anus and genitals of male rats. In addition, female mice have significantly more nipples than male mice.
6. Disease prevention
As an experimental animal, it should be healthy and disease-free before the experiment, so it is necessary to actively prevent diseases, and once it gets sick, it will lose its significance as an experimental animal. Attention should be paid to the following points in the feeding process:
(1) The mice suspected of infectious diseases should be removed in the whole box, and then the disease should be detected before taking corresponding measures.
(2) In order to keep animals healthy, it is necessary to establish a closed epidemic prevention system to reduce the chances of mice being infected. That should pay attention to the following points:
(1) Newly introduced animals must be isolated in the isolation room, and can only be kept with the original rats after being observed to be disease-free.
② The breeders must abide by the feeding management rules when entering or leaving the feeding area, and shower, change clothes, wash their hands and carry out necessary local disinfection according to the requirements of different feeding areas.
③ Non-feeding personnel are prohibited from entering the feeding area.
④ Strictly prevent wild animals (rats and cockroaches) from entering the feeding area.