INFLUENCE OF FORMIC-ACID ON PH-VALUE, DRY-MATTER CONTENT, CONCENTRATIONS OF VOLATILE FATTY-ACIDS AND LACTIC-ACID IN THE GASTROINTESTINAL-TRACT .3.

In 45 weaned cross-breed piglets (German Landrace x Pietrain) slaughtered after a feeding trial of 41 days the influence of formic acid additions to the feed on pH value, concentrations of dry matter, volatile fatty acids and lactic acid in stomach, small intestine, caecum and colon was investigated. Beside an negative control the feed was supplemented with 0.6 %, 1.2 %, 1.8 % and 2.4 % formic acid. With increasing formic acid dosage the dry matter content in stomach was not changed, in the small intestine and caecum it was slightly and in the colon significantly higher. The pH value in the stomach was not influenced. In small intestine, caecum and colon the pH values increased with the dosage of formic acid. The concentrations of volatile fatty acids in the stomach and small intestine were unchanged. In caecum and colon the content of butyric acid was lowered. In the colon the concentrations of acetic, propionic acid and the sum of the volatile fatty acids were diminished by the 1.8 and 2.4 % formic acid supplementation to the feed. In the whole large intestine the proportions of the volatile fatty acids shifted to higher parts of acetic acid at the cost of the part of butyric and largely of propionic acid. The concentrations of lactic acid in small intestine were significantly decreased with increasing formic acid dosage. In stomach, caecum and colon no influence on the lactic acid content by the formic acid supplementation was demonstrated.