title: Effect of direct-fed fibrolytic enzymes on the digestive characteristics of a forage-based diet fed to beef steers.
abstract: A study was conducted to examine the method of delivery of a solution containing cellulases and xylanases on the digestion of a forage-based diet. Five ruminally cannulated beef steers (536 kg BW) were randomly assigned to a control (CON) or one of four enzyme treatments in a 5 x 5 Latin square experiment. Steers were fed a 70:30 (DM basis) grass hay:barley diet. Enzyme-treated rations contained a solution of fibrolytic enzymes at the rate of 1.65 mL/kg of forage DM. Enzyme application treatments were 1) enzyme to forage 24 h before feeding (F-24), 2) enzyme to forage 0 h before feeding (F-0), 3) enzyme to barley 0 h before feeding (B-0), and 4) enzyme infused ruminally 2 h after feeding (RI). Dry matter and NDF intakes were not different (P > .10) across treatments. Ruminal pH was lower and total VFA concentration at 16 h after-feeding was greater (P < .10) for steers fed enzyme treatments compared with CON. Rate of NDF disappearance was greater (P < .05) for enzyme-treated than for untreated grass substrate. Ruminal infusion of enzymes compared with F-24 and F-0 produced lower disappearance of DM at 8 and 32 h (P < .10), NDF at 32 h (P < .10), and DM and NDF at 96 h (P < .05). Rate of DM disappearance of enzyme-treated grass hay was greater (P < .10) for steers fed B-0 than for those fed F-24 and F-0 and for CON than for F-24 and F-0. Total tract digestibility of DM, NDF, and ADF was greater (P < .10) for F-24 and F-0 than for CON. Forage transit time was shorter (P < .10) for B-0 than for F-24 and F-0; however, all other contrasts for particulate passage did not differ (P > .10). Results from this study indicate that direct application of enzymes to forages is capable of improving forage digestion.
authors.affiliation: Department of Animal and Veterinary Science, University of Idaho, Moscow 83844, USA.
authors.forename: G E
authors.initials: GE
authors.lastname: Lewis
authors.forename: C W
authors.initials: CW
authors.lastname: Hunt
authors.forename: W K
authors.initials: WK
authors.lastname: Sanchez
authors.forename: R
authors.initials: R
authors.lastname: Treacher
authors.forename: G T
authors.initials: GT
authors.lastname: Pritchard
authors.forename: P
authors.initials: P
authors.lastname: Feng
mesh_terms: D000818:Animals; D002417:Cattle / Q000378:metabolism* / Q000502:physiology*; D002480:Cellulase / Q000032:analysis / Q000494:pharmacology*; D004032:Diet / Q000662:veterinary*; D004063:Digestion / Q000187:drug effects* / Q000502:physiology; D001467:Hordeum / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D008297:Male; D006109:Poaceae / Q000378:metabolism; D011897:Random Allocation; D012417:Rumen / Q000378:metabolism / Q000502:physiology; D013997:Time Factors; D043325:Xylan Endo-1,3-beta-Xylosidase; D014995:Xylosidases / Q000032:analysis / Q000494:pharmacology*
chemical_list: D014995:Xylosidases; D043325:Xylan Endo-1,3-beta-Xylosidase; D002480:Cellulase