[Changes of bacterial flora from hindguts of piglets after oral administration of lactobacillus amylovorus S1 as a probiotic strain].

Changes of bacterial flora from hindguts of piglets from 7 to 35 days of age (two weeks after weaning) were studied after oral administration of L. amylovorus S1, using molecular techniques based on 16S rDNA gene. Six litters of neonatal piglets were divided randomly into control group and treatment group. At 7, 9, 11 days of age, piglets in treatment group received 1, 2 and 3mL preparation of S1 (5 x 10(9) CFU/mL) through oral administration, respectively. On D 7, 14, 21, 24 and 35, one piglet from each litter was slaughtered and samples of hindguts were collected for analysis. The results showed that high G + C mol% bacteria in hindguts of piglets disappeared after weaning and restored gradually two weeks later. Sequencing analysis indicated that most of these high G + C mol% bacteria blonged to Lactobacillus spp. . Statistical analysis showed that treatment with S1 had no marked effect on diversity index of predominant bacteria from hindguts in piglets. By comparing the bands in DGGE profiles between two groups, a specific band in treatment group was found in profiles from piglets at 14 days of age, sequence matched with that showed 95 % similarity to Clostridium disporicum. At 35 days of age, another specific band appeared in control group, which was identified to be Streptococcus suis (99% ).