Effect of feeding organic acids on gastrointestinal digesta measurements at various times postweaning in pigs challenged with enterotoxigenic Escherichia coli

Abstract

In Study 1, pigs (n = 54) weaned at 21 ± 2 d were fed a 20% CP corn-soybean meal based diet only (control) or with 1.5% fumaric or 1.5% citric acid. One half of the pigs on each treatment were orally challenged on days 3, 7 or 14 postweaning with 1010E. coli (0157:K88+) to observe the effects on scouring and on intestinal digesta pH, Cl− concentration, VFA and non-volatile acid profiles, and microflora concentrations in the stomach, jejunum, cecum and lower colon when pigs were necropsied 5, 9 or 16 d postweaning. The E. coli challenge increased (P < 0.05) the severity of scouring. Organic acids had no appreciable effects on severity of scouring and intestinal measurements except for fumaric and succinic acid concentrations which were greater in the stomach (P < 0.001) and jejunum (P < 0.05) of pigs fed fumaric acid. The E. coli challenge had no significant effect on pH, Cl− concentration, and lactobacillus or E. coli concentrations, but did increase (P < 0.05) the concentration of lactic acid in the jejunum, and total VFA in the lower colon. From days 5 to 16 postweaning, pH decreased (P < 0.002) in the cecum, Cl− concentration increased (P < 0.03) in the jejunum, lactobacillus counts decreased (P < 0.001) in the jejunum and increased (P < 0.004) in the lower colon, and E. coli counts decreased in the jejunum (P < 0.07), cecum (P < 0.02) and lower colon (P < 0.001). In Study 2, pigs (n = 96) weaned at 21 ± 2 d were similarly fed organic acids as in Study 1 and half of the animals in each treatment were orally challenged with E. coli on day 3 postweaning. During the 15-d experiment, E. coli challenge decreased (P < 0.05) ADG by 20% and increased F:G 19% from 7 to 15 d postweaning and increased (P < 0.001) the severity of scouring between days 4 and 11 postweaning. Feeding organic acids had no measurable effect on growth performance or scouring and did not modify the effects of the postweaning E. coli challenge. Key words: Pigs, pH, organic acids, volatile fatty acids, lactobacillus, Escherichia coli