RESUMO
Genetic background in animal models is an intrinsic research variable in biomedical research. Although inbred strains offer genetic uniformity, the outbred stocks, known for genetic variability are often used to develop animal models of human disease. The genetic variability is considered to be even higher when outbred stocks are obtained from different sources. In order to examine the degree of variability of an outbred stock obtained from various sources, Sprague Dawley (SD) rat lines obtained from two sources were evaluated for their growth characteristics. The SD rats from Charles River laboratories (CRL) and Harlan Laboratories (HAR) were monitored for weight gain from the age of 6 weeks to 24 weeks. Food intake was monitored between 13 and 24 weeks. Body composition, organ weights, tibial lengths and blood parameters were measured. There was no difference observed in food intake per 100 gram body weight at most of the time points. CRL rats showed higher body fat mass (49.6%), higher gross liver weights (22.2%), lower testicular weights (30.8%) and lower cholesterol levels (25.4%) than HAR rats. Phenotypic differences may be attributed to genetic heterogeneity of the SD outbred stock between the two sources and represent a significant research variable impacting studies especially related to metabolic diseases. Therefore, in order the minimize research variables for those studies where genetic diversity is not a basis for experimental design, the use of single source genetically uniform inbred animal models is highly recommended over the use of outbred stocks.
Assuntos
Fibrossarcoma/veterinária , Neoplasias Mandibulares/veterinária , Coelhos , Animais , Dentística Operatória , Diagnóstico Diferencial , Feminino , Fibrossarcoma/diagnóstico , Fibrossarcoma/patologia , Fibrossarcoma/cirurgia , Neoplasias Mandibulares/diagnóstico , Neoplasias Mandibulares/patologia , Neoplasias Mandibulares/cirurgiaRESUMO
This paper provides a review of reproductive characteristics of hamsters, guinea pigs, gerbils, hamsters, rats, and mice, as well as rabbits and chinchillas. It is not intended to be a source of the facts of reproduction (which can be readily found in many references) but rather to highlight some of the unique characteristics of the various species and common problems that clients may present to theriogenologists. This paper includes information regarding sexing, mating, gestation, parturition, lactation, and comments regarding spays and neuters.
