Effect of weaning diet on the ecology of adherent lactobacilli in the gastrointestinal tract of the pig.

Sixteen pigs were included in an investigation of the effects of weaning and weaning diet on the ecology of adherent Lactobacillus species in the gastrointestinal tract. At 28 d of age four pigs were killed and were designated as the preweaning control (PW). Four pigs remained on the sow (Sow), four pigs were fed a corn-soy-lactose (CSL) diet, and the remaining four pigs were fed a corn-soy (CS) diet. Pigs from the latter three treatments were killed at 38 d of age. Tissue samples were taken from the pars esophagus, ileum, and cecum and the adherent lactobacilli were enumerated using Rogosa SL agar. Bacterial colonies were randomly selected from Rogosa SL agar plates and speciated using cell type, morphology, and substrate fermentation tests. The species data were used to calculate the Shannon, Simpson, and evenness diversity indices. Shannon and Simpson diversity index values when averaged across tissues were lower (P < .05) for PW than for postweaning treatments (Sow, CSL, and CS) and lower (P < .05) when pigs receiving sow's milk (PW and Sow) were compared with pigs receiving the dry diets (CSL and CS). The diversity of adherent Lactobacillus is altered by the form of the diet fed to weanling pigs, and statistical ecological methods provide a powerful way of analyzing the ecology of the gastrointestinal tract.