Abstract
This study investigated faecal microbial composition and blood metabolome profile of piglets fed different levels of supplementary zinc oxide (ZnO) after weaning. A dose-response study was conducted with four experimental diets containing 153 (D153), 1022 (D1022), 1601 (D1601), and 2407 (D2407) ppm zinc (Zn) in the feed. At the end of the trial, blood and faeces samples were obtained for analyses. Multivariate analysis of the blood metabolomics dataset and Principal Coordinate Analysis (PCoA) of faecal microbiota data showed that pigs receiving D2407 had a different metabolic and microbial profile to the other groups, whereas no differences were observed in pigs fed with D153, D1022, and D1601. The highest dietary Zn inclusion was associated with significant increase in the abundance of Clostridium sensu stricto, Terrisporobacter, Dorea, and Prevotellaceae_NK3B31_group and a decrease in relative abundances of Methanobrevibacter, Treponema, Megasphaera, and UCG 002 genera. Pearson's correlation analysis showed positive correlations between the abundance of Christensenellaceae R7-group with amino acids metabolism and production of microbial metabolites. The results suggest that only 2407 ppm Zn altered gut microbiota and modulated blood metabolic profile, which may impact the health status of piglets through specific microbial metabolites.