INFLUENCE OF FORMIC-ACID ON THE MICROFLORA IN DIFFERENT SEGMENTS OF THE GASTROINTESTINAL-TRACT .5. INVESTIGATIONS ABOUT THE NUTRITIVE EFFICACY OF ORGANIC-ACIDS IN THE REARING OF PIGLETS

After a feeding trial of 41 days 45 weaned cross-bred piglets (German Landrace x Pietrain) were slaughtered and the influence of formic acid additions to the feed on the microorganism counts of Lactobacillus/Bifidobacterium, Eubacteria, Bacteroidaceae, E. coli and Enterococci in duodenum, jejunum, ileum, caecum and colon was investigated. Beside a negative control the feed was supplemented with 0.6 %, 1.2 %, 1.8 % and 2.4 % formic acid. In the segments of the small intestine the microorganism counts of Lactobacillus/Bifidobacterium, Eubacteria and Bacteroidaceae decreased slightly by the addition of formic acid. In the 1.8 % formic acid group the E. coli counts in duodenum and also the Enterococcus counts in duodenum and jejunum were significantly higher. In caecum contents the Lactobacillus/Bifidobacterium, Eubacteria and E. coli were significantly lowered by the formic acid supplementation. The counts of Lactobacillus/Bifidobacterium and E. coli in the colon contents were also significantly decreased in all formic acid groups.