Journal Article

Investigating unsaturated fat, monensin, or bromoethanesulfonate in continuous cultures retaining ruminal protozoa. I. Fermentation, biohydrogenation, and microbial protein synthesis

Gilligan, L.E, Sylvester, J.T, Karnati, S.K.R, Firkins, J.L, Ribeiro, C.V.D.M

2009

Overview

Methane is an end product of ruminal fermentation that is energetically wasteful and contributes to global climate change. Bromoethanesulfonate, animal-vegetable fat, and monensin were compared with a control treatment to suppress different functional groups of ruminal prokaryotes in the presence or absence of protozoa to evaluate changes in fermentation, digestibility, and microbial N outflow. Four dual-flow continuous culture fermenter systems were used in 4 periods in a 4 x 4 Latin square design split into 2 subperiods. In subperiod 1, a multistage filter system (50-μm smallest pore size) retained most protozoa. At the start of subperiod 2, conventional filters (300-μm pore size) were substituted to efflux protozoa via filtrate pumps over 3 d; after a further 7 d of adaptation, the fermenters were sampled for 3 d. Treatments were retained during both subperiods. Flow of total N and digestibilities of NDF and OM were 18, 16, and 9% higher, respectively, for the defaunated subperiod but were not different among treatments. Ammonia concentration was 33% higher in the faunated fermenters but was not affected by treatment. Defaunation increased the flow of nonammonia N and bacterial N from the fermenters. Protozoal counts were not different among treatments, but bromoethanesulfonate increased the generation time from 43.2 to 55.6 h. Methanogenesis was unaffected by defaunation but tended to be increased by unsaturated fat. Defaunation did not affect total volatile fatty acid production but decreased the acetate:propionate ratio; monensin increased production of isovalerate and valerate. Biohydrogenation of unsaturated fatty acids was impaired in the defaunated fermenters because effluent flows of oleic, linoleic, and linolenic acids were 60, 77, and 69% higher, and the ratio of vaccenic acid:unsaturated FA ratio was decreased by 34% in the effluent. This ratio was increased in both subperiods with the added fat diet, indicating an accumulation of intermediates of biohydrogenation. However, the flow of 18:2 conjugated linoleic acid was unaffected by defaunation or by treatments other than added fat. The flows of trans-10, trans-11, and total trans-18:1 fatty acids were not affected by monensin or faunation status.

• Publisher: American Dairy Science Association,Am Dairy Sci Assoc
• Subject: Alkanesulfonates / Alkanesulfonates - pharmacology / ammonia / Ammonia - analysis / analysis / Animals / Anti-Infective Agents / Anti-Infective Agents - pharmacology / Antiprotozoal Agents / Antiprotozoal Agents - pharmacology / Bacteria / Bacteria - drug effects / Bacteria - metabolism / biohydrogenation / bromoethanesulfonate / Cattle / chemistry / continuous systems / Culture Techniques / Dietary Fats, Unsaturated / Dietary Fats, Unsaturated - metabolism / drug effects / Eukaryota / Eukaryota - drug effects / Eukaryota - metabolism / Eukaryota - physiology / Fatty Acids, Volatile / Fatty Acids, Volatile - analysis / feed additives / Female / Fermentation / Fermentation - drug effects / functional diversity / Gastrointestinal Contents / Gastrointestinal Contents - chemistry / generation time / Hydrocarbons, Brominated / Hydrocarbons, Brominated - pharmacology / Hydrogenation / Hydrogenation - drug effects / in vitro digestibility / in vitro studies / metabolism / Methane / Methane - metabolism / methane production / microbial activity / monensin / Monensin - pharmacology / neutral detergent fiber / nitrogen / Nitrogen - analysis / Nitrogen - metabolism / organic matter / parasitology / pharmacology / physiology / Protein Biosynthesis / Protein Biosynthesis - drug effects / protein synthesis / Rumen / Rumen - metabolism / Rumen - parasitology / rumen fermentation / rumen microorganisms / rumen protozoa / unsaturated fatty acids / volatile fatty acids