Unravelling the Role of Rumen Microbial Communities, Genes, and Activities on Milk Fatty Acid Profile Using a Combination of Omics Approaches

Milk products are an important component of human diets, with beneficial effects for health, but also one the major sources nutritionally undesirable saturated fatty acids (SFA). Recent discoveries showing importance rumen microbiome on dairy cattle metabolism and performance highlight that milk composition, potentially SFA content, may be associated microorganisms, their genes activities. Understanding these mechanisms can used development cost-effective strategies production less SFA. This work aimed to compare between cows producing contrasting FA profile identify responsible metabolic-related microbial mechanisms. Forty eight Holstein were fed same total mixed ration under housing conditions. fluid samples collected from all analysis acid profiles (by gas chromatography), abundances communities whole-genome-shotgun metagenomics), metabolome (using 500 MHz nuclear magnetic resonance). The following groups: (i) 24 High-SFA (66.9–74.4% FA) vs. Low-SFA (60.2–66.6%% cows, (ii) 8 extreme (69.9–74.4% (60.2–64.0% compared. Rumen more characterized by higher lactic bacteria Lactobacillus, Leuconostoc , Weissella acetogenic Proteobacteria Acetobacter Kozakia, Mycobacterium two fungi ( Cutaneotrichosporon Cyphellophora ), at a lesser extent Methanobrevibacter protist Nannochloropsis . Cows carrying correlated had concentrations butyrate, propionate tyrosine lower xanthine hypoxanthine in rumen. Abundances able explain 76 94% variation most abundant FA. Metagenomics metabolomics analyses highlighted diet, differ metabolic activities relation adaptation reduced pH, carbohydrate fermentation, protein synthesis metabolism.