title: Evaluation of feeding glycerol on free-fatty acid production and fermentation kinetics of mixed ruminal microbes in vitro.
abstract: Ruminant-derived foods contain high proportions of saturated fats as a result of ruminal biohydrogenation that rapidly saturates and thus limits the availability of free unsaturated fatty acids for assimilation. The objective of this study was to evaluate the effects of glycerol on ruminal free-fatty acid (FFA) production rates and in vitro fermentation kinetics of alfalfa hay. In vitro incubations demonstrated 48% and 77% reductions in rates of FFA accumulation in incubations supplemented with 2% and 20% glycerol as compared to controls. In vitro incubations with alfalfa hay demonstrated that increasing levels of glycerol did not affect NDF digestibility of the hay. Additionally, increasing amounts of glycerol decreased the acetate to propionate ratio in the rumen. These results suggest that inhibiting bacterial fat degradation may promote ruminal passage of total lipid, thereby providing greater proportions of beneficial unsaturated fat for incorporation into beef products.
authors.affiliation: United States Department of Agriculture, Agriculture Research Service, Southern Plains Agriculture Research Center, Food and Feed Safety research Unit, 2881 F&B Road, College Station, TX 77845, USA.
authors.forename: N A
authors.initials: NA
authors.lastname: Krueger
authors.forename: R C
authors.initials: RC
authors.lastname: Anderson
authors.forename: L O
authors.initials: LO
authors.lastname: Tedeschi
authors.forename: T R
authors.initials: TR
authors.lastname: Callaway
authors.forename: T S
authors.initials: TS
authors.lastname: Edrington
authors.forename: D J
authors.initials: DJ
authors.lastname: Nisbet
mesh_terms: D000818:Animals; D001419:Bacteria / Q000187:drug effects* / Q000378:metabolism*; D005230:Fatty Acids, Nonesterified / Q000096:biosynthesis*; D005232:Fatty Acids, Volatile / Q000032:analysis; D005285:Fermentation / Q000187:drug effects*; D005990:Glycerol / Q000494:pharmacology*; D007700:Kinetics; D000455:Medicago sativa / Q000378:metabolism; D012417:Rumen / Q000187:drug effects* / Q000382:microbiology*
chemical_list: D005230:Fatty Acids, Nonesterified; D005232:Fatty Acids, Volatile; D005990:Glycerol