[Intestinal beta-galactosidase in gnotobiotic animals following monoassociation with various E. coli strains].

Germ-free rats were monoassociated by E. coli germs not utilizing (L-) or utilizing lactose (L+) on endo-medium. There was no influence of germ status on the beta-galactosidase activity in the mucosa of the small and large intestine. With standard food, beta-galactosidase activity were to be measured in the chymus of all intestinal segments and in the faeces of germ-free as well as of monoassociated rats. In the chymus of caecum and colon and in the faeces of E. coli(L+)-animals, only, the short-time (12-16 days) application of lactose containing food resulted in an increase of the enzyme activity. Compared with the E. coli(L-)-animals, the lactose content in the chymus of all intestinal segments of this test group was decreased.