Effect of a Lactobacillus Species on Incidence of Diarrhea in Calves and Change of the Microflora Associated with Growth

To evaluate the effect of Lactobacillus plantarum strain Hokkaido, which was isolated from a kind of Japanese pickle, on the incidence of diarrhea in calves and on the intestinal microflora, we performed feeding tests with a milk replacer containing Lactobacillus sp. In Experiment 1, thirty two male Holstein calves were divided into two groups, a control (C) group and LPH group. L. plantarum strain HOKKAIDO was orally administered to the LPH group for 35 days. The diarrhea score and the number of calves with watery or soft stool were significantly (p<0.05) smaller in the LPH group than in the C group. In Experiment 2, ten male Holstein calves were divided into three groups: a control group, LPH group and BOV group. Bovactin ™ was administered to the BOV group and the experimental protocol followed that of Experiment 1. No significant difference was observed in the incidence of diarrhea among the three test groups. However, when the data of Experiments 1 and 2 were pooled, the incidence of diarrhea in the LPH group was significantly (p<0.05) lower than that of the control group. These results indicate that L. plantarum strain Hokkaido reduces the incidence of diarrhea in calves. Analysis of the microflora and measurement of the stool type of the fecal samples that were collected 0, 15 and 28 days after the start of administration were performed using a T-RFLP method and visual analysis, respectively. The clustering of the T-RFLP profiles indicated that when the significance of the distributions of the samples among the clusters was tested, a significant difference (p<0.01) was observed only among the sampling-date groups. The average value of the pairwise Pearson r within each sampling-date group indicated that T-RFLP profiles varied considerably among the calves on day 0 and day 15, while the profiles of day 28 closely resembled each other. From these results, we infer that the intestinal microflora of calves are less settled in the early days of life, and this might partially explain the higher incidence of diarrhea in this period. Bacteria belonging to the class Clostridia were most predominant at all the sampling-date groups. The day 0 samples were characterized by a larger population of bifidobacteria and lactic acid bacteria (LAB). The day 15 samples were characterized by larger populations of LAB and the class Bacteroidia. The day 28 samples were characterized by a larger population of Bacteroides.