Growth performance of piglets during the first two weeks of lactation affects the development of the intestinal microbiota

Summary The aim of this study was to evaluate the effect of newborn piglet weight gain during the first 2 weeks of lactation on the luminal and mucosal microbiota of the ileum and colon. The microbiota from high‐weight‐gain ( HWG ) and low‐weight‐gain ( LWG ) 2‐week‐old piglets was characterized by amplicon length heterogeneity PCR ( LH ‐ PCR ) and compared using diversity indices and multivariate statistical analyses. At birth, LWG piglets weighted in average 0.26 kg less than HWG piglets ( p = .002). The weight difference between LWG and HWG piglets increased with time and reached 2.1 kg after 16 days of lactation ( p < .0001). Based on these growth performance differences, estimated colostrum and milk intake was greater in HWG than in LWG piglets ( p < .0001). Analysis of the LH ‐ PCR data of the microbiota using non‐metric multidimensional scaling ( NMS ) and blocked multiresponse permutation procedure ( MRBP ) revealed that the microbiota of the HWG and LWG piglets tended to differ in ileal mucosa ( p = .097) and differed in colonic lumen ( p = .024). The microbiota of HWG piglets had higher levels of Bacteroidetes , Bacteroides and Ruminoccocaceae , and lower proportions of Actinobacillus porcinus and Lactobacillus amylovorus when compared with those of LWG piglets. As the weight gain of nursing piglets is highly correlated with the amount of ingested colostrum and milk, the results strongly suggest that colostrum and milk intake in the first 2 weeks of life influenced the development of the gut microbiota.