Comparison of the Microbiome-Metabolome Response to Copper Sulfate and Copper Glycinate in Growing Pigs

SIMPLE SUMMARY: Copper sulfate and copper glycinate have been used as additives for copper supplementation and growth promotion in the swine feed industry. However, their effects on the gut microenvironment, especially for the fecal microbiota and metabolites, still remain unclear, which are the important indicators of gut health. As well as the nutrient digestibility and physiological and biochemical indices of pigs, the effects of copper sulfate and copper glycinate on fecal microbial communities and metabolic profiles were investigated to understand it better in the present study. Our results suggested that copper sulfate and copper glycinate could differentially affect fecal microbiota and metabolites, by which dietary copper glycinate exerted more beneficial effects on the gut health of pigs. ABSTRACT: This study aims to compare the fecal microbiome-metabolome response to copper sulfate (CuSO(4)) and copper glycinate (Cu-Gly) in pigs. Twelve Meishan gilts were allocated into the CuSO(4) group and the Cu-Gly group (fed on a basal diet supplemented with 60 mg/kg copper from CuSO(4) or Cu-Gly) paired in litter and body weight. After a two-week feeding trial, the Cu-Gly group had a higher copper digestibility, blood hemoglobin, and platelet volume and higher levels of plasma iron and insulin-like growth factor-1 than the CuSO(4) group. The Cu-Gly treatment increased the abundance of the Lachnospiraceae family and the genera Lachnospiraceae XPB1014, Corprococcus_3, Anaerorhabdus_furcosa_group, Lachnospiraceae_FCS020_group, and Lachnospiraceae_NK4B4_group and decreased the abundance of the Synergistetes phylum and Peptostreptococcaceae family compared to the CuSO(4) treatment. Moreover, the Cu-Gly group had a lower concentration of 20-Oxo-leukotriene E4 and higher concentrations of butyric acid, pentanoic acid, isopentanoic acid, coumarin, and Nb-p-Coumaroyl-tryptamine than the CuSO(4) group. The abundance of Synergistetes was positively correlated with the fecal copper content and negatively correlated with the fecal butyric acid content. The abundance of the Lachnospiraceae_XPB1014_group genus was positively correlated with the plasma iron level and fecal contents of coumarin and butyric acid. In conclusion, Cu-Gly and CuSO(4) could differentially affect fecal microbiota and metabolites, which partially contributes to the intestinal health of pigs in different manners.