title: Effects of a selection of additives on in vitro ruminal methanogenesis and in situ and in vivo NDF digestibility.
abstract: The effects of 18 essential oils, yeast, Quebracho tannin and Quillaja saponin on ruminal methane and gas production (GP) were studied in vitro. A lactating cow diet was incubated with rumen inoculum. Doses of the additives (mg/L) were: essential oils = 500; tannin = 67; yeast = 8.35 and 16.7; and saponin = 300. Lemongrass, estragole, eugenol, geraniol, limonen, thyme oil and thymol produced less gas (overall mean 33.8 mL/200 mg dry matter (DM)) than control (43.6 mL/200 mg DM; P < 0.001). Methane produced (mL/200 mg DM) by guaiacol (10.7), lemongrass (9.6), limonene (11.4), thyme oil (10.9) and thymol (2.1) was lower than control (12.5) (P < 0.001). Methane percentage on total GP was lower (P < 0.001) for cinnamic alcohol (25.4), guaiacol (24.5), thymol (19.7) and vanillin (26.3) than control (28.8). In a second experiment, thymol, guaiacol and yeast were added to the diet of dry fistulated cows to determine in situ neutral detergent fiber digestibility (NDFD) of six forages and in vivo dietary NDFD. Thymol and yeast decreased in situ NDFD after 24 h (33.9% and 33.5% vs. 38.1%; P = 0.008). Thymol decreased in vivo total tract NDFD (40.8% vs. 51.4%; P = 0.02). Differences in GP and methane levels were registered within classes of additives. A careful selection of additives may allow for the manipulation of ruminal fermentation.
authors.affiliation: Dipartimento di Scienze Agrarie e Ambientali, Università degli Studi di Milano, Milan, Italy.
authors.forename: Mario
authors.initials: M
authors.lastname: Pirondini
authors.forename: Stefania
authors.initials: S
authors.lastname: Colombini
authors.forename: Luca
authors.initials: L
authors.lastname: Malagutti
authors.forename: Luca
authors.initials: L
authors.lastname: Rapetti
authors.forename: Gianluca
authors.initials: G
authors.lastname: Galassi
authors.forename: Raffaella
authors.initials: R
authors.lastname: Zanchi
authors.forename: Gianni Matteo
authors.initials: GM
authors.lastname: Crovetto
mesh_terms: D000821:Animal Feed; D000818:Animals; D002417:Cattle; D004043:Dietary Fiber / Q000378:metabolism*; D004063:Digestion / Q000187:drug effects*; D005285:Fermentation; D005503:Food Additives / Q000494:pharmacology*; D005740:Gases; D066298:In Vitro Techniques; D008697:Methane / Q000096:biosynthesis*; D009822:Oils, Volatile / Q000494:pharmacology*; D062605:Quillaja Saponins / Q000494:pharmacology*; D012417:Rumen / Q000378:metabolism* / Q000503:physiopathology; D013634:Tannins / Q000494:pharmacology*; D015003:Yeasts / Q000502:physiology*
chemical_list: D004043:Dietary Fiber; D005503:Food Additives; D005740:Gases; D009822:Oils, Volatile; D062605:Quillaja Saponins; D013634:Tannins; D008697:Methane
keywords: NDF digestibility; additive; essential oil; methane; rumen