title: Mitigation of in vitro hydrogen sulfide production using bismuth subsalicylate with and without monensin in beef feedlot diets.
abstract: The objective of this study was to determine if a sulfur binder, bismuth subsalicylate (BSS), alone or combined with monensin (MON) could decrease the production of HS by rumen microbes. In Exp. 1, two 24-h batch culture incubations were conducted using a substrate consisting of 50% corn, 40% distillers grains, 9.75% hay, and 0.25% mineral premix, on a DM basis. Five treatments including BSS concentrations of 0% (control), 0.5%, 1%, 2%, and 4% of DM were assigned in 5 replicates to 120-mL serum bottles containing rumen fluid, buffer, and 0.5 g of dietary substrate. Addition of 2% and 4% BSS decreased ( < 0.05) gas production, whereas all concentrations of BSS reduced ( < 0.05) HS production by 18%, 24%, 82%, and 99% for 0.5%, 1%, 2%, and 4% BSS, respectively. Final pH increased ( < 0.05) with 2% and 4% BSS treatments. At 4% of DM, BSS decreased ( < 0.05) total VFA concentration (m) and propionate (mol/100 mol) but increased acetate (mol/100 mol) and acetate to propionate ratio. Concentration of branched-chain VFA increased ( < 0.05) with the addition of 0.5% BSS, compared with the control. On the basis of these results, addition of BSS (1% of DM) and MON (5 mg/kg) were used to assess their effects on metabolism and HS release by rumen microbes in 8 dual flow continuous culture fermenters during two 10-d periods (Exp. 2). Treatments were arranged in a 2 × 2 factorial design. Substrate similar to that used in Exp. 1 was provided at 75 g DM/fermenter daily. Headspace HS concentration was reduced ( < 0.05) by 99% with BSS treatment but was not affected ( = 0.21) by MON. An overall increase ( < 0.05) in fermentation pH was found following addition of BSS. Addition of BSS increased ( < 0.05) digestion of NDF and ADF but decreased ( < 0.05) nonfiber carbohydrate digestion and total VFA concentration. Acetate and propionate (mol/100 mol) increased ( < 0.05) with BSS, whereas butyrate (mol/100 mol) and branched-chain VFA (m) decreased ( < 0.05). Addition of BSS increased ( < 0.05) NH-N concentration and NH-N outflow but decreased ( < 0.05) microbial N outflow. Results from this study showed no response to monensin addition, but BSS markedly reduced HS production and altered microbial fermentation during in vitro rumen fluid incubations.
authors.forename: M
authors.initials: M
authors.lastname: Ruiz-Moreno
authors.forename: E
authors.initials: E
authors.lastname: Binversie
authors.forename: S W
authors.initials: SW
authors.lastname: Fessenden
authors.forename: M D
authors.initials: MD
authors.lastname: Stern
mesh_terms: D000821:Animal Feed / Q000032:analysis*; D000818:Animals; D001729:Bismuth / Q000008:administration & dosage / Q000494:pharmacology*; D002417:Cattle; D004032:Diet / Q000662:veterinary*; D004063:Digestion / Q000502:physiology; D005285:Fermentation; D006859:Hydrogen; D006862:Hydrogen Sulfide / Q000378:metabolism*; D008985:Monensin / Q000008:administration & dosage / Q000494:pharmacology*; D009942:Organometallic Compounds / Q000008:administration & dosage / Q000494:pharmacology*; D012417:Rumen / Q000382:microbiology; D012459:Salicylates / Q000008:administration & dosage / Q000494:pharmacology*
chemical_list: D009942:Organometallic Compounds; D012459:Salicylates; C015715:bismuth subsalicylate; D006859:Hydrogen; D008985:Monensin; D001729:Bismuth; D006862:Hydrogen Sulfide