LAUSR

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.