Comparison between Coliform Populations at Different Sites of the Intestinal Tract of Pigs

Abstract

The coliform populations collected from different parts of the digestive tract were studied in six healthy pigs sacrificed on day 28 post weaning. Digesta were collected from six defined locations of the intestinal tract of these pigs. These spots were; the proximal and distal parts of the jejunum; ileum; caecum; colon, and rectum. The aim was to study how well the rectal coliform flora reflects the flora at other parts of the intestinal tract. The coliforms at each site were enumerated, and it was found that the number of coliforms per gram digesta increased through the passage of the intestinal tract. The density was highest in the samples collected from rectum. Twenty-four coliform isolates from each site were phenotyped using the PhenePlate system. The phenotypic diversities of the coliforms were quite high at all sites (median diversity indices ranged from 0.85 to 0.88). The coliform floras collected at different sites of the intestinal tract were compared with the rectal flora, and the proportions of identical strains at different sites were fairly high. The homogeneity between the coliform populations of different pigs increased through the intestine, and was highest among the samples collected from rectum. Still, it was concluded that phenotyping several rectal isolates was a relevant method to mirror also the anterior intestinal microflora. However, the results obtained also visualised the complexity of the intestinal bacterial flora, and indicate that important constituents of that flora might be lost if to few isolates are scrutinised. Keywords: pig, intestine, coliform flora, diversity, homogeneity, intestinal stability.