[The nutritive effect of Bacillus cereus as a probiotic in the raising of piglets. 2. Effect and microbial count, composition and resistance determination of gastrointestinal and fecal microflora].

After a feeding trial of 42 days with 4 x 12 piglets 4 x 6 piglets were slaughtered and the influence of spores of the Bacillus cereus strain FH 1457 S added to the feed on the microorganism counts of Lactobacillus/Bifidobacterium, Eubacteria, Bacteroidaceae, E. coli, Enterococcus and passants (Bacillus cereus) in duodenum, jejunum, ileum, caecum and colon was investigated. Beside a negative control the feed was supplemented with 10(7), 10(8) and 10(9) CFU Bacillus cereus/kg. The feeding trial included two periods each of 21 days. In each period faeces was collected from all animals and the influence on the microorganism counts and also the frequency of resistance of the E. coli and Enterococcus germs against selected antibiotics and chemotherapeutics investigated. The addition of 10(8) CFU Bacillus cereus decreased E. coli counts in duodenum and jejunum, however increased them in ileum, caecum and colon. In the highest dosage the counts of Bacillus cereus in duodenum, caecum, colon and faeces were significantly higher. The addition of Bacillus cereus reduced the counts of E. coli and Enterococcus in faeces in the first period. In the second period the dosage 10(8) CFU showed significant increased counts of E. coli and the sums of microorganisms of the main and satellite flora. The additions had no influence on the frequency of resistance of E. coli and enterococci against the tested antibiotics and synthetic chemotherapeutics. From the addition of Bacillus cereus in this case a selection of factors influencing resistance is not to be expected.