Sixty weaned piglets (33 d, 7.96 ± 1.09 kg BW) were divided into 4 groups with 15 pigs each and fed identical diets in which meal was coarsely ground (CM), coarsely ground and pelleted (CP), finely ground and pelleted (FP), or coarsely ground and extruded (CE) for 4 wk. At the end of the trial the pigs were killed and samples of the digesta were taken from the stomach, the end of the small intestine, and the cecum for microbiological, DM, pH, and lactic acid analyses. Differences (P < 0.05) regarding the counts of bacteria were mainly found between the CM and the FP group, but the CP and the CE diet mostly resulted in intermediate values. Pigs fed the CM diet had the highest numbers of lactobacilli in the stomach content (P < 0.01) and the cecal digesta (P < 0.05). Perhaps due to a more efficient stomach barrier, characterized by high lactobacilli counts and a marked pH gradient in the stomach content (cardia, 5.15 ± 0.475; pylorus, 2.83 ± 1.06; P < 0.01), the lowest counts of coliform bacteria were found in the distal part of the small intestine in pigs fed the CM diet (P < 0.05).
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