The management of the litters through practices of early-socialization and environmental enrichment has been shown to improve piglet’s adaptation at weaning, reducing stress response. We hypothesized that changes in the neonatal environment of piglets could also modulate the maturation of intestinal microbiota and gene expression at weaning. In a commercial farm, 14 maternity sows and their litters were allotted to two treatments: a control treatment (commercial conditions, CTR) and an enriched treatment (ENR) in which piglets from two litters were mixed 14 days post-partum by removing fences. Moreover, the farrowing pen was fitted with hanging objects. Piglets were mixed after weaning (d28) according to their body size, as in commercial practice, but keeping experimental groups. Faecal and jejunum samples were collected from 7 piglets/treatment before (d26) and after (d31) weaning. Faecal microbiome was analyzed by sequencing the 16S RNA gene (Illumina MiSeq®) and OpenArray® technology was used for gene expression analysis. No significant changes promoted by treatments were found in microbiota structure during lactation. However, dissimilarities were observed after weaning (Penvfit = 0.04) although we were not able to detect significant changes in particular taxa. Weaning had an evident impact in the microbiota structure with increases in α-diversity and a clear decrease in Lactobacillaceae family. Regarding intestinal gene expression, a higher expression of the TLR2 gene was registered in CTR piglets after weaning (P = 0.03). The weaning process itself was associated with changes in the expression of numerous genes related to barrier function, digestive enzymes and nutrient transport. Results confirm that early socialization of piglets and an enriched neonatal environment during lactation, can have an impact on the maturation of the intestinal microbiota after weaning. These effects could be mediated by a differential stress response and changes in the cross-talk between the host and the intestinal microbiota.

The effect of long-term administration of two different Bacillus strains was tested on 90 breeding sows (Landrace x Yorkshire) that were randomly allotted into three treatments: a control group (CON), supplemented with 5x108 cfu/kg B. subtilis 25841 (PR1), or 5x108 cfu/kg B. amyloliquefaciens 25840 (PR2). Reproductive parameters were registered along three reproductive full cycles. Fecal samples were taken along the third cycle from the sows (on days 8 and 21 of lactation) and from the piglets (on days 21 and 33 (12 post-weaning)). Fecal microbiota was analyzed by sequencing the 16S RNA gene (Illumina MiSeq®) and jejunum samples, obtained from piglets on day 21, analyzed for gene expression (52 genes by OpenArray® plate). Supplemented sows showed higher number of born piglets per litter (P = 0.01) and PR2 sows a higher number of born alive (P = 0.01). Regarding sows’ fecal microbiota, changes were found in community structure (ANOSIM test, P = 0.08) with changes at phylum level (Firmicutes:Bacteroidetes: 3.7, 5.3 and 4.6 for CON, PR1 & PR2, P = 0.10) and at family level (Prevotellaceae: 9.4, 7.3, 7.3% (P = 0.03) and Ruminococcaceae: 16.1, 13.1, 13.7% (P = 0.04)). Several genera were also modified including Prevotella, Ruminococcus and Megasphaera. Regarding the microbiota of piglets, the administration of probiotics to their mothers was associated to structural changes in piglets’ fecal community during lactation (PEnvfit=0.05) but not after weaning, although relevant changes were observed between both periods (PEnvfit< 0.001). The expression of different genes was clearly modified by weaning but we were not able to detect changes related to the probiotic in any of the genes analyzed. In conclusion, the addition of B. subtilis 25841 and B. amyloliquefaciens 25840 were shown to enhance the sow reproductive performance in terms of prolificacy, with a clear impact on the gut microbial ecosystem of the sows and shifts in the microbiota structure of suckling piglets.

The aim of the present study was to explore the evolution of piglet gut microbiota from birth to weaning. Moreover, it was hypothesized that different farm environments could condition this process. Two farms, distinct in their use of antibiotics, and 10 litters per farm were selected. A total of 100 fecal samples were obtained from the same pig of each litter on d2, d7, d14 and d21 of lactation and d14 after weaning. The DNA was extracted by using the PSP® Spin Stool DNA Kit and sequencing of the 16S rRNA gene (V3-V4 region) performed by Illumina MiSeq Platform. Bioinformatics and biostatistical analysis were performed with QIIME and the open-source software R v3.5.3. (phyloseq package). Alpha diversity was strongly affected by age (P< 0.001), with an increasing richness of species through time. Beta diversity decreased after weaning (P< 0.001), suggesting a convergent evolution among individuals. Regarding the structure of the microbiota, a clear clustering of the samples according to age was observed (P< 0.001). A progressive decrease was observed as the piglets aged for Clostridiaceae, Enterobacteriaceae, Fusobacteriaceae, Pasteurellaceae and Streptococcaceae (P< 0.001). In contrast, Lachnospiraceae (P=0.003), Lactobacillaceae (P=0.003) and Veillonellaceae (P=0.025) increased along the d7–d14 period, but decreased afterwards. Campylobacteraceae, Erysipelotrichaceae, Ruminococcaceae (P< 0.001) and Prevotellaceae (P=0.005) gradually increased with age reflecting the change from a milk-oriented microbiome towards a butyrate-producing one. Regarding the impact of the farm, differences in species richness were found and also a distinct microbial structure (ANOSIM: P=0.025) associated to changes in some particular taxonomic groups. In conclusion, during the transition from birth to weaning, the pig microbiota showed a relevant succession of microbial groups towards a more stable ecosystem better adapted to the dry feed. In this relevant early-age process differences between farms seems to have a limited impact.