Intestinal microbiota and expression of genes involved in immunity are modulated in nursing piglets by growth performance in the first week of life

Abstract Text:

Introduction: Growth performance of newborn piglets within a litter can be quite variable during the first weeks of life.  This study was performed to determine the impact of piglet growth on development of intestinal microbiota and immunity.  Material and Methods: Eight litters were used to select, within each litter, the piglets showing the lowest weight gain (LWG) and the highest weight gain (HWG) in their first week of lactation. At 16 days of age, the intestinal microbiota of LWG and HWG piglets were compared by amplicon length heterogeneity PCR. The data were analyzed by nonmetric multidimensional scaling (NMS) and multi-response permutation procedure (MRPP) to determine differences in microbial composition between treatments. Ileal mucosa samples were also taken to extract RNA for microarray analysis and gene expression by quantitative PCR. Results: NMS analyses showed that LWG piglets harbored a distinct microbiota compared to HWG in the ileum and colon contents. In the ileum, the mucosa associated microbiota tended to be different in LWG piglets compared to HWG piglets (MRPP at P < 0.1) whereas in the colon, the luminal microbiota differed significantly (P < 0.05). Expression of several genes involved in innate immunity against microbial pathogens such as MYD88, TLR4, TLR9, NOD2, NOS2, SOD1 and CD74 was significantly (P < 0.05) down-regulated in the ileum of LWG piglets compared to HWG piglets. Conclusion: These results indicate that growth performance in the first week of life affected the establishment of intestinal microbial populations and influenced the gene expression involved in innate immunity against microbial pathogens. As growth performance in the first week of life is closely related to colostrum and milk intake, these results suggest that bioactive factors in colostrum and milk can affect colonisation of bacterial populations in the gut and the intestinal immune response early in life.  

Keywords: immune response, microbiota, intestine, growth, piglets