Effect of lactulose on rabbits fed on a low residue diet.

The effect of lactulose (Duphalac) was tested for four months on six rabbits on a low residue diet representative of the diet ingested by the peoples of western civilization. A control group of six rabbits simply had the low residue diet and they developed a very low fecal output, with a mean wet fecal weight measured at monthly intervals varying between 2 and 4.6 gm.; increased transit times of 48 hours and intracolonic pressures which increased over four months from a colonic motility index (CMI) of 12,261 to a CMI of 28,084 in response to neostigmine. The rabbits on diet and lactulose did not develop diarrhea but produced three times the wet fecal weight of the rabbits on diet alone, with a range of mean values from 9.4-12.4 gm.; transit times remained at 24 hours which is normal transit time for rabbits on regular laboratory diet; intracolonic pressures in response to neostigmine rose only from a CMI of 11,652 to a CMI of 14,263 during the four months on diet with lactulose.