Breeding experiments of white rats and mice. V. Further data on breeding of rats with descriptions of sixteen rat strains

Abstract

To insure more accurate results in the fields of anatomical, physiological, genetical and medical investigations, it has been necessary to select healthy and purely-bred experimental animals kept under a standardized condition. Their production is a serious and worth-while task for the advance of biology and medicine. To answer this request, the Zoological Laboratory, Faculty of Science, Hokkaido University, has maintained, under the care and direction of Makino, several stocks of rats and mice for research purposes to provide the necessary material for biological and medicai investigations carried on in this laboratory and others. The experience of our laboratory in the breeding and care of rats and mice has brought necessary devices for new cages, new diets, new methods of handling animals.
Sixteen strains (or lines including sublines) of rats have been maintained in our colony: they are the Wistar-albino, WX-albino, Wistar-albino with large litter cast, Wistar-King-A (WKA), Wayne pink-eyed, Lister-albino, Tokyo-albino, Gifu-albino, Castle's black mutant • WKA/Ma and their four sublines, w/Ma • WKA/Ma, wp • w/MaMsMa. The maintainance of each stock has been making by sister-brother mating with particular regards to selection concerning litter size, fertility, growth, body weight and size, and resistance to diseases.
Some devices for breeding and rearing rats, and for new diet were given in this paper in addition to the descriptions of rats for each strain with their general characteristics. The accounts on mice will appear in the following report.