Acidification of the stomach contents of weaned piglets--effect of feed quantity and composition

The pH in the stomach chyme (5-8 hours past offering the diet) of reared piglets was strongly correlated to the ingested feed quantity, a complete acidification of the stomach contents occurred in restrictively fed piglets (15 g diet/kg BW) only. Feeding ad libitum resulted in comparable low pH values in the fundus and pylorus region only, whereas in the cardiac region high pH values (5-6.5) were observed. Formic acid as feed additive (5 ml/kg diet) did not influence the pH in stomach contents significantly, on the other hand the ingestion of a diet with high CaCO3 content (59 g Ca/kg DM) prevented the acidification of the stomach chyme totally. The variation of pH-values in the different areas within the stomach was caused mainly by the variation of hydrochloric acid concentrations, the influence of lactic acid concentration was negligible.