Several reports have demonstrated the effects of orally administered B. subtilis on the intestinal microflora, body weight gain, and increased feed efficiency of animals and birds 3s 42 These results indicate that ingestion of live B. subtilis cells can actually improve the intestinal microflora. When weanling piglets were fed diet including spores of B. subtilis (natto), the changes in intestinal microflora varied depending upon the region of the intestine examined.38 In the jejunum, numbers of streptococcus spp. and Bifidobacteriim spp. 1 ed, while no difference wa observed in the colon when compared with the control diet group. When turkeys were fed subtilis culture, body weight gain and cumulative feed efficiency sig nificantly increased, both by 2.5%.39 When chickens were given B. subtilis, the detection rate of the intestinal pathogen Campylobacter jejuni decreased in the laboratory portion of the experiment 40 The cell number of Salmonella typhimurium also decreased. In the field trial, feeding a B. subtilis strain decreased the cell number and/or detection rates of intestinal Enterobacteriaceae, Clostridium perfringens, an Campylobacter sp. When sows and gilts were fed an experimental diet containin B. subtilis, the number and/or detection rates of fecal Bifidobacterium spp. an Lactobacillus spp. increased, but Streptococcus spp., Enterobacteriaceae, Clost ium perfringens, and Bacteroidaceae decreased The diarrhea rate of piglets up to 10 days old and mortality rate up to 25 days old also decreased. When mice were intubated with intact and autoclaved B. subtilis (natto) spores for 8 days, only intact spores changed the fecal microflora, and the patterns of the changes differed depend