Study On The Growth And Reproducibility Of Clean Level Wistar Rats

[Objective] The clean level experimental animal is very widely used in diseases research, new drugdevelopment and biosecurity evaluation as animal models supporting the biomedical and life scienceresearch. The standardized experimental animal production is the essence to estabulish the experimentalanimal qulity ensuring system,which guarantees the accuracy and repeatability of the animal experiment.In this paper the growth and reproductive ability of clean level Wistar rats was studied for helping theirstandardized large scale production, selection and use.[Methods] A total of90（60♀vs.30♂）bloodExpanded Wistar rats were chosen in a barrier system with mating program of2♀×l♂for reproduction. Theparmeters of growth and reproducibility as well as the food consumption were tested. The body weight of60rats（30♀vs.30♂）from the second litter were measured every week.[Results]The growth curve ofclean level Wistar rats showed “S” type and everlasting grow during the first year after birth；With thedevelopment of age in days, the absolute growth value emerged parabolic distribution between1to13weeks, while females and males respecetively reach summit value in5week and6week. The averageconception rate of female rats was94.2％, The average survival rate of young mice was89.3%. Comparedto pre-mate, the daily consumption of food and water in duration of pregnancy and suckling period aredestincly increase.[Conclusion] The female and male rats separately reach sexual maturity in5week and6week while body maturity in11week and12week; The reproducibility was related to the fetal times,with the increase of pregnancies,the birth weight was increased and delivery interval gradually waswidening, but the litter size was gradually decreased. The survive ratio of first delivery was the lowest. TheMating pregnancy rate and the litter size reached to the peck on the second delivery. Clean level Wistar ratswere suitable for continual reproduction till4thlitters and the second litter is the best for breeding．Theconsumption of Female rats in suckling period need more food and the consumption of food and water areall more than pregnancy period.