Studies on Germfree Hand-Forced Feeding and Germfree Reproduction in Rats

Present paper reports the results of experiment in raising germfree rats by forced hand feeding which were repeated thirteen times during the period April 1963 to May 1965. Four strains of caesarean derived germfree rats were fed with formula A, B or C diets, which contain protein at a concentration of 4. 3%, 5. 77% and 6. 3% respectively. The results were as follows: 1) Thirteen of 33 newborn germfree rats fed with formula A diet, reached adulthood (13.1%). The highest survival rate (87.5%) was obtained in germfree rats fed with formula C diet. 2) Seven of the eight Wistar germfree rats fed formula C diet became pregnant. The highest conception rate (88%) was obtained in this diet group. 3) The formula given during the period of hand feeding seems to affect the incidence of volvulus of the cecum. Of thirteen rats fed formula A diet, eight animals developed volvulus (62%). From fourteen Wistar rats fed formula C diet, six animals developed volvulus (43%). 4) The abnormality of the teeth occurred only in germfree rats of Gifu hybrid and Donryu strain. No abnormalities of teeth were noticed in germfree rats of Fisher and Wistar strain.