PROFILING OF GUT METHANOGENIC ARCHAEA IN LACTATING PIGLETS USING ILLUMINA-BASED 16S rRNA GENE SEQUENCING: EFFECTS OF DIETARY PECTIN

Methane-producing archaea play a key ecological role within the digestive system of humans and animals: they feed off of hydrogen and other byproducts of bacterial metabolism thus regulating carbohydrate fermentation in the gut. Although it is well established that diet is an important determinant of gut microbiota composition, to date there are only limited data describing how gut methanogens are affected by diet in humans. In this study, we investigated the archaeal community in the feces of neonatal piglets fed either a control or a pectin-containing milk diet (10.0 g/L) using 16S rRNA gene deep sequencing and real-time PCR. We sought to determine if pectin supplementation could affect the archaeal population in the gut of such a model animal. Analysis of the archaeal community revealed that in control piglets the dominant methanogens were members of the genus Methanobrevibacter, followed byMethanosphaera cuniculi. The diet composition had no clear impact on the total number of either methanogens or total archaea, as assessed by real-time PCR. The main effect of pectin supplementation was on the relative composition of the fecal methanogenic species,with a reduction of the Methanobrevibacter spp. proportion and an increase of Methanosphaera cuniculi relative abundance. The response on the population structure level appeared to be individual, as different piglets responded differently to pectin supplementation. The putative impact of this microbial shifts on the health of the host is unknown, anyway this study provides new information on the physiological significance of some fiber used in human nutrition.