ABSTRACT
The data available for the germfree (GF) gerbil only allow the statement that growth appears to be in the low to normal range, presumably because of its greatly enlarged cecum. Provided that their nutritional requirements are met, GF rats and GF mice reproduce adequately. The females appear to remain productive as long as their conventional (CV) counterparts, although the impression prevails that the number of young born during their reproductive life is somewhat less than in the CV animals. To what extent the increase in life span of GF rats and GF mice is related to their lower oxygen consumption, and to their, allegedly related, lower heart and liver weights, remains a matter of speculation. Cecal enlargement conceivably could also affect life span in a negative way. This potential effect notwithstanding, ad libitum-fed GF mice and GF rats appear to outlive their CV counterparts.
