Avaliação do índice reprodutivo: ratas hairless (Rattus norvegicus)

Abstract

Several works with small rodents have been carried out since the creation of the Wistar Institute, in 1894, located in Pennsylvania. However, the use of animals in the field of science is nothing new, because in order to promote the development of medicine, the technique of vivisection and dissection has been used as a comparison to human physiology since ancient times. Thus, rats (Rattus norvegicus) became good study models due to their short life cycle and docility. In the literature, the Hairless lineage counts as an animal with little maternal care, as it is described as an animal that produces less milk. In addition to the lack of fur, it ends up not warming the puppies as they should. However, in the vivarium of the Dois Irmãos State Park (PEDI) it was empirically noted that the rats, in addition to being more productive, also always weaned the entire litter in a healthy way. Therefore, the present work aimed to prove, through statistical analysis, whether this fact was true or not. A total of 78 rats were used, 60 of which had normal fur and 18 had the Hairless gene mutation. The animals were distributed in 26 polypropylene boxes that contained two females and one male. These were divided into three experimental groups, group 01 being at least a normal female and a normal male; group 02 two hairless females; group 03 normal females and the male Hairless. Data were obtained on the number of animals born, weaned, deaths, transferred, number of births and number of offspring per birth. Data were analyzed using the Statistical Analysis System Software (SAS®, version 9.3; SAS® Institute Inc., Cary, NC, USA). Tables 01 and 02 show that the results did not differ. With this, it can be seen that the Hairless rats of the PEDI are as productive as the non-mutant rats. However, several factors may have influenced the results, such as climate, luminosity and genetic interaction. Therefore, further studies are recommended to be carried out on site.