The source of dietary fat modulates the intestinal microbiota and liver metabolite pattern Gloria Solano‐Aguilar1, Andrew Conchas1, Aleksey Molokin1, Saebyeol Jang1, Sukla Lakshman1, Monica Santin‐Duran1, Masoumeh Sikaroodi2, Patrick Gillevet2, Joseph Urban1. 1USDA, ARS, Beltsville Human Nutrition Research Center, Diet, Genomics, and Immunology Laboratory, Beltsville, MD 20705; 2Microbiome Analysis Center, George Mason University, Manassas, Virginia 20110 The goal of this study was to characterize the intestinal microbiome and host metabolism consequent to feeding an obesogenic diet with different fat sources. We examined the effect of anhydrous milk fat (AMF) and palm oil (PO) on the liver metabolite profile and composition of the intestinal microbiota in juvenile pigs fed either a 10.8% low fat (LF) or 39.5% high fat (HF) diet. Thirty two pigs were randomly allocated to dietary treatments: 1) LF‐PO, 2) LF‐AMF, 3) HF‐PO and 4) HF‐AMF for 18 weeks. Fecal samples were collected every three weeks to determine changes in total coliforms, and commensal Bifidobacterium, Lactobacillus and Bacteroides species by RT‐PCR. Proximal colon contents and liver samples were also collected at necropsy and used, respectively, for metagenomic analysis (Multitag Pyrosequencing) and global metabolite profile analysis (GC/MS and LC/MS/MS platforms) and compared across dietary treatment groups. The only affect on the microbiome was an increase in total coliforms in pig fed HF‐PO. Different metabolite clusters were identified between pigs fed the HF and LF diets , and pigs fed HF‐PO and HF‐AMF diets suggesting significant differences in metabolites induced by the amount and type of fat in the diet. Our data suggested a fat source dependent effect on microbiota and liver metabolite composition. The use of AMF may constitute a better source of dietary fat to prevent the increase in pro‐inflammatory responses positively associated with increases in intestinal coliforms.Grant Funding Source: Supported by DRI #1101