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 aim of this study was to evaluate the efficacy of two probiotic strains Bifidobacterium longum subsp. infantis CECT7210 (Laboratorios Ordesa S.L.) and Lactobacillus rhamnosus HN001 combined or not with a prebiotic mixture of oligofructose and inulin against Salmonella typhimurium. A total of 96 piglets (28 days) were distributed into 32 pens assigned to 5 treatments: one non-challenge (control diet, CTR+) and four challenged: control diet (CTR-), or supplemented with probiotic (>3x1010cfu/kg each, PRO), prebiotic (5%, PRE) or their combination (SYN). After one adaptation week, animals were inoculated with Salmonella. Feed intake, weight and clinical signs were recorded. On days 4 and 8 post-inoculation (PI), one animal per pen was euthanized and samples collected for Salmonella counts, fermentation products, ileal histomorphology and serum inflammatory markers. After the challenge, feed intake was decreased (P = 0.001) more markedly in the SYN group with a lower final weight (P = 0.009). PRE and SYN groups showed more liquid ileal consistency on day 8PI (P = 0.009). A higher percentage of animals receiving PRO became negative to Salmonella in feces at the end of the study (65% PRO vs 0% CTR-, P = 0.028). Animal receiving PRE did not reach countable levels in feces any time during the trial (vs 23.2% for CTR-group, P = 0.013). Histologically, on day 4PI a decrease in the ileal villous/crypts ratio was found in challenged animals (P < 0.001), being PRO able to improve the recovery from this damage at day 8PI (P = 0.008). Animals receiving PRE had higher number of intraepithelial lymphocytes (IEL) on day 8PI (P = 0.028). In conclusion, the probiotic strains were able to promote a faster clearance of the pathogen from the gut with a faster recovery of damaged histological architecture. The prebiotic reduced Salmonella colonization and stimulated the local immune response. However, these beneficial effects disappeared when they were administered in a synbiotic form.

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.