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Novel and abundant members of the porcine intestinal microbiota respond to dietary interventions

A feeding trial was performed, in which the effect of 4 fermentable carbohydrates (inulin, lactulose, wheat starch and sugar beet pulp) on the intestinal microbiota of weaning piglets was analyzed. Cultivation and molecular 16S ribosomal RNA targeted approaches revealed that the addition of fermentable CHOs (= prebiotics) led to a significant enrichment of lactobacilli in the ileum, namely Lactobacillus reuteri- and amylovorus-related strains.

In an attempt to obtain porcine isolates related to Lactobacillus amylovorus, we screened isolates from piglet intestine grown on Lactobacillus-specific MRS agar for hybridization to a phylotype-specific fluorescent 16S rRNA-targeted DNA probe. Six isolates were obtained and further characterized by phenotypic and molecular taxonomic methods. The isolates were Gram-positive, catalase-negative, facultatively anaerobic rods.

They had similar phenotypic characteristics and displayed genomic DNA relatedness values of >78%, indicating that they belong to a single species. Comparative 16S rRNA gene sequence analysis demonstrated that the novel isolates were members of Lactobacillus rRNA group I. Based on 16S rRNA sequence identity, L. kitasatonis (99%), L. crispatus (98%), and L. amylovorus (97%) were the nearest relatives of the new isolates, but their DNA relatedness was found to be lower than 49%.

One of the isolates, strain OTU171_001 was further characterized using physiological and biochemical tests. Together, the results allowed genotypic and phenotypic differentiation of strain OTU171_001 from those related species that showed 16S rRNA gene sequence similarity values greater than 97%. Strain OTU171_001 T merits species status, and the name Lactobacillus sobrius sp. nov. has been proposed with the type strain OTU171_001T.

Reported by

Wageningen University
Hesselink van Suchtelenweg 4
6703CT Wageningen
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