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Mitchell KE, Wenner BA, Lee C, Park T, Socha MT, Kleinschmit DH, Firkins JL. Supplementing branched-chain volatile fatty acids in dual-flow cultures varying in dietary forage and corn oil concentrations. I: Digestibility, microbial protein, and prokaryotic community structure. J Dairy Sci 2023; 106:7530-7547. [PMID: 37532627 DOI: 10.3168/jds.2022-23165] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2022] [Accepted: 03/17/2023] [Indexed: 08/04/2023]
Abstract
Branched-chain amino acids are deaminated by amylolytic bacteria to branched-chain volatile fatty acids (BCVFA), which are growth factors for cellulolytic bacteria. Our objective was to determine the dietary conditions that would increase the uptake of BCVFA by rumen bacteria. We hypothesized that increased forage would increase cellulolytic bacterial abundance and incorporation of BCVFA into their structure. Supplemental polyunsaturated fatty acids, supplied via corn oil (CO), should inhibit cellulolytic bacteria growth, but we hypothesized that additional BCVFA would alleviate that inhibition. Further, supplemental BCVFA should increase neutral detergent fiber degradation and efficiency of bacterial protein synthesis more with the high forage and low polyunsaturated fatty acid dietary combination. The study was an incomplete block design with 8 dual-flow continuous cultures used in 4 periods with 8 treatments (n = 4 per treatment) arranged as a 2 × 2 × 2 factorial. The factors were: high forage (HF) or low forage (LF; 67 or 33%), without or with supplemental CO (3% dry matter), and without or with 2.15 mmol/d (which included 5 mg/d of 13C each of BCVFA isovalerate, isobutyrate, and 2-methylbutyrate). The isonitrogenous diets consisted of 33:67 alfalfa:orchardgrass pellet, and was replaced with a concentrate pellet that mainly consisted of ground corn, soybean meal, and soybean hulls for the LF diet. The main effect of supplementing BCVFA increased neutral detergent fiber (NDF) degradability by 7.6%, and CO increased NDF degradability only in LF diets. Supplemental BCVFA increased bacterial N by 1.5 g/kg organic matter truly degraded (6.6%) and 0.05 g/g truly degraded N (6.5%). The relative sequence abundance decreased with LF for Fibrobacter succinogenes, Ruminococcus flavefaciens, and genus Butyrivibrio compared with HF. Recovery of the total 13C dose in bacterial pellets decreased from 144 µg/ mg with HF to 98.9 µg/ mg with LF. Although isotope recovery in bacteria was greater with HF, BCVFA supplementation increased NDF degradability and efficiency of microbial protein synthesis under all dietary conditions. Therefore, supplemental BCVFA has potential to improve feed efficiency in dairy cows even with dietary conditions that might otherwise inhibit cellulolytic bacteria.
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Affiliation(s)
| | - B A Wenner
- Elanco Animal Health, Greenfield, IN 46140
| | - C Lee
- Department of Animal Sciences, The Ohio State University, Wooster, OH 44691
| | - T Park
- Department of Animal Science and Technology, Chung-Ang University, Anseong, Gyeonggi-do, Korea 17546
| | - M T Socha
- Zinpro Corporation, Eden Prairie, MN 55344
| | | | - J L Firkins
- Department of Animal Sciences, The Ohio State University, Columbus, OH 43035
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Sujani S, White RR, Firkins JL, Wenner BA. Network analysis to evaluate complexities in relationships among fermentation variables measured within continuous culture experiments. J Anim Sci 2023; 101:skad085. [PMID: 37078886 PMCID: PMC10158529 DOI: 10.1093/jas/skad085] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2023] [Accepted: 04/17/2023] [Indexed: 04/21/2023] Open
Abstract
The objective of this study was to leverage a frequentist (ELN) and Bayesian learning (BLN) network analyses to summarize quantitative associations among variables measured in 4 previously published dual-flow continuous culture fermentation experiments. Experiments were originally designed to evaluate effects of nitrate, defaunation, yeast, and/or physiological shifts associated with pH or solids passage rates on rumen conditions. Measurements from these experiments that were used as nodes within the networks included concentrations of individual volatile fatty acids, mM and nitrate, NO3-,%; outflows of non-ammonia nitrogen (NAN, g/d), bacterial N (BN, g/d), residual N (RN, g/d), and ammonia N (NH3-N, mg/dL); degradability of neutral detergent fiber (NDFd, %) and degradability of organic matter (OMd, %); dry matter intake (DMI, kg/d); urea in buffer (%); fluid passage rate (FF, L/d); total protozoa count (PZ, cells/mL); and methane production (CH4, mmol/d). A frequentist network (ELN) derived using a graphical LASSO (least absolute shrinkage and selection operator) technique with tuning parameters selected by Extended Bayesian Information Criteria (EBIC) and a BLN were constructed from these data. The illustrated associations in the ELN were unidirectional yet assisted in identifying prominent relationships within the rumen that were largely consistent with current understanding of fermentation mechanisms. Another advantage of the ELN approach was that it focused on understanding the role of individual nodes within the network. Such understanding may be critical in exploring candidates for biomarkers, indicator variables, model targets, or other measurement-focused explorations. As an example, acetate was highly central in the network suggesting it may be a strong candidate as a rumen biomarker. Alternatively, the major advantage of the BLN was its unique ability to imply causal directionality in relationships. Because the BLN identified directional, cascading relationships, this analytics approach was uniquely suited to exploring the edges within the network as a strategy to direct future work researching mechanisms of fermentation. For example, in the BLN acetate responded to treatment conditions such as the source of N used and the quantity of substrate provided, while acetate drove changes in the protozoal populations, non-NH3-N and residual N flows. In conclusion, the analyses exhibit complementary strengths in supporting inference on the connectedness and directionality of quantitative associations among fermentation variables that may be useful in driving future studies.
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Affiliation(s)
- Sathya Sujani
- School of Animal Sciences, Virginia Tech, Blacksburg, VA 24061, USA
| | - Robin R White
- School of Animal Sciences, Virginia Tech, Blacksburg, VA 24061, USA
| | - Jeffrey L Firkins
- Department of Animal Sciences, The Ohio State University, Columbus, OH 43210, USA
| | - Benjamin A Wenner
- Department of Animal Sciences, The Ohio State University, Columbus, OH 43210, USA
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Li MM, Ghimire S, Wenner BA, Kohn RA, Firkins JL, Gill B, Hanigan MD. Effects of acetate, propionate, and pH on volatile fatty acid thermodynamics in continuous cultures of ruminal contents. J Dairy Sci 2022; 105:8879-8897. [PMID: 36085109 DOI: 10.3168/jds.2022-22084] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2022] [Accepted: 06/09/2022] [Indexed: 11/19/2022]
Abstract
To investigate the effects of acetate, propionate, and pH on thermodynamics of volatile fatty acids (VFA) in the rumen, a dual-flow continuous culture study was conducted to quantify production of major VFA, interconversions among the VFA, and H2 and CH4 emissions in a 4 × 4 Latin square design. The 4 treatments were (1) control: pH buffered to an average of 6.75; (2) control plus 20 mmol/d of infused acetate (InfAc); (3) control plus 7 mmol/d of infused propionate (InfPr); and (4) a 0.5-unit decline in pH elicited by adjustment of the buffer (LowpH). All fermentors were fed 40 g of a pelleted diet containing whole alfalfa pellets and concentrate mix pellets (50:50) once daily. After 7 d of treatment, sequential, continuous infusions of [2-13C] sodium acetate (3.5 mmol/d), [U-13C] sodium propionate (2.9 mmol/d), and [1-13C] sodium butyrate (0.22 mmol/d) were carried out from 12 h before feeding for 36 h. Filtered liquid effluent (4 mL) was sampled at 0, 2, 4, 6, 8, 12, 16, and 22 h after feeding, and assessed for VFA concentrations, with another filtered sample (20 mL) used to quantify aqueous concentrations of CH4 and H2. Headspace CH4 and H2 gases were monitored continuously. Ruminal microbes were isolated from the mixed effluent samples, and the microbial community structure was analyzed using the 16S rRNA amplicon sequencing technique. The digestibility of neutral detergent fiber, acid detergent fiber, and starch and microbial C sequestrated from VFA were not affected by treatments. The LowpH treatment increased net propionate production and decreased H2 and CH4 headspace emissions, primarily due to shifts in metabolic pathways of VFA formation, likely due to the observed changes in bacterial community structure. Significant interconversions occurred between acetate and butyrate, whereas interconversions of other VFA with propionate were relatively small. The InfAc and InfPr treatments increased net acetate and propionate production, respectively; however, interconversions among VFA were not affected by pH, acetate, or propionate treatments, suggesting that thermodynamics might not be a primary influencer of metabolic pathways used for VFA formation.
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Affiliation(s)
- Meng M Li
- Department of Dairy Science, Virginia Tech, Blacksburg 24061; State Key Laboratory of Animal Nutrition, College of Animal Science and Technology, China Agricultural University, Beijing, P. R. China, 100193
| | - S Ghimire
- Department of Dairy Science, Virginia Tech, Blacksburg 24061
| | - B A Wenner
- Department of Animal Sciences, The Ohio State University, Columbus 43210
| | - R A Kohn
- Animal and Avian Sciences, University of Maryland, College Park 20742
| | - J L Firkins
- Department of Animal Sciences, The Ohio State University, Columbus 43210
| | - B Gill
- Department of Geosciences, Virginia Tech, Blacksburg 24061
| | - M D Hanigan
- Department of Dairy Science, Virginia Tech, Blacksburg 24061.
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Roman-Garcia Y, Mitchell KE, Lee C, Socha MT, Park T, Wenner BA, Firkins JL. Conditions stimulating neutral detergent fiber degradation by dosing branched-chain volatile fatty acids. III: Relation with solid passage rate and pH on prokaryotic fatty acid profile and community in continuous culture. J Dairy Sci 2021; 104:9868-9885. [PMID: 34253360 DOI: 10.3168/jds.2021-20336] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2021] [Accepted: 06/02/2021] [Indexed: 01/03/2023]
Abstract
Our objectives were to evaluate potential interactions in culture conditions that influence how exogenously dosed branched-chain VFA (BCVFA) would be recovered as elongated fatty acids (FA) or would affect bacterial populations. A 2 × 2 × 2 factorial arrangement of treatments evaluated 3 factors: (1) without versus with BCVFA (0 vs. 2 mmol/d each of isobutyrate, isovalerate, and 2-methylbutyrate; each dose was partially substituted with 13C-enriched tracers before and during the collection period); (2) high versus low pH (ranging diurnally from 6.3 to 6.8 vs. 5.7 to 6.2); and (3) low versus high particulate-phase passage rate (kp; 2.5 vs. 5.0%/h) in continuous cultures administered a 50:50 forage:concentrate diet twice daily. Samples of effluent were collected and composited before harvesting bacteria from which FA and DNA were extracted. Profiles and enrichments of FA in bacteria were evaluated by gas chromatography and isotope-ratio mass spectrometry. The 13C enrichment in bacterial FA was calculated as percentage recovery of dosed 13C-labeled BCVFA. Dosing BCVFA increased the even-chain iso-FA, preventing the reduced concentration at higher kp and potentially as a physiological response to decreased pH. However, decreasing pH decreased recovery of 13C in these even-chain FA, suggesting greater reliance on isobutyrate produced from degradation of dietary valine. The iso-FA were decreased, whereas anteiso-FA and 16:0 increased with decreasing pH. Thus, 2-methylbutyrate still appeared to be important as a precursor for anteiso-FA to counter the increased rigidity of bacterial membranes that had more saturated straight-chain FA when pH decreased. Provision of BCVFA stimulated the relative sequence abundance of Fibrobacter and Treponema, both of which require isobutyrate and 2-methylbutyrate. Numerous bacterial community members were shifted by low pH, including increased Prevotella and genera within the phylum Proteobacteria, at the expense of members within phylum Firmicutes. Because of relatively few interactions with pH and kp, supplementation of BCVFA can stimulate neutral detergent fiber degradability via key fibrolytic bacteria across a range of conditions. Decreasing pH shifted bacterial populations and their FA composition, suggesting that further research is needed to distinguish pH from dietary changes.
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Affiliation(s)
- Y Roman-Garcia
- Department of Animal Sciences, The Ohio State University, Columbus 43210
| | - K E Mitchell
- Department of Animal Sciences, The Ohio State University, Columbus 43210
| | - C Lee
- Ohio Agricultural Research and Development Center, Wooster 44691
| | - M T Socha
- Zinpro Corporation, Eden Prairie, MN 55344
| | - T Park
- Department of Animal Sciences, The Ohio State University, Columbus 43210
| | - B A Wenner
- Department of Animal Sciences, The Ohio State University, Columbus 43210
| | - J L Firkins
- Department of Animal Sciences, The Ohio State University, Columbus 43210.
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Roman-Garcia Y, Mitchell KE, Denton BL, Lee C, Socha MT, Wenner BA, Firkins JL. Conditions stimulating neutral detergent fiber degradation by dosing branched-chain volatile fatty acids. II: Relation with solid passage rate and pH on neutral detergent fiber degradation and microbial function in continuous culture. J Dairy Sci 2021; 104:9853-9867. [PMID: 34147227 DOI: 10.3168/jds.2021-20335] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2021] [Accepted: 05/02/2021] [Indexed: 11/19/2022]
Abstract
To support improving genetic potential for increased milk production, intake of digestible carbohydrate must also increase to provide digestible energy and microbial protein synthesis. We hypothesized that the provision of exogenous branched-chain volatile fatty acids (BCVFA) would improve both neutral detergent fiber (NDF) degradability and efficiency of microbial protein synthesis. However, BCVFA should be more beneficial with increasing efficiency of bacterial protein synthesis associated with increasing passage rate (kp). We also hypothesized that decreasing pH would increase the need for isobutyrate over 2-methylbutyrate. To study these effects independent from other sources of variation in vivo, we evaluated continuous cultures without (control) versus with BCVFA (0 vs. 2 mmol/d each of isobutyrate, isovalerate, and 2-methylbutyrate), low versus high kp of the particulate phase (2.5 vs. 5.0%/h), and high versus low pH (ranging from 6.3 to 6.8 diurnally vs. 5.7 to 6.2) in a 2 × 2 × 2 factorial arrangement of treatments. Diets were 50% forage pellets and 50% grain pellets administered twice daily. Without an interaction, NDF degradability tended to increase from 29.7 to 35.0% for main effects of control compared with BCVFA treatments. Provision of BCVFA increased methanogenesis, presumably resulting from improved NDF degradability. Decreasing pH decreased methane production. Total volatile fatty acid (VFA) and acetate production were decreased with increasing kp, even though true organic matter degradability and bacterial nitrogen flow were not affected by treatments. Decreasing pH decreased acetate but increased propionate and valerate production, probably resulting from a shift in bacterial taxa and associated VFA stoichiometry. Decreasing pH decreased isobutyrate and isovalerate production while increasing 2-methylbutyrate production on a net basis (subtracting doses). Supplementing BCVFA improved NDF degradability in continuous cultures administered moderate (15.4%) crude protein diets (excluding urea in buffer) without major interactions with culture pH and kp.
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Affiliation(s)
- Y Roman-Garcia
- Department of Animal Sciences, The Ohio State University, Columbus 43210
| | - K E Mitchell
- Department of Animal Sciences, The Ohio State University, Columbus 43210
| | - B L Denton
- Department of Animal Sciences, The Ohio State University, Columbus 43210
| | - C Lee
- Ohio Agricultural Research and Development Center, Wooster 44691
| | - M T Socha
- Zinpro Corporation, Eden Prairie, MN 55344
| | - B A Wenner
- Department of Animal Sciences, The Ohio State University, Columbus 43210
| | - J L Firkins
- Department of Animal Sciences, The Ohio State University, Columbus 43210.
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Wenner BA, Wagner BK, St-Pierre NR, Yu ZT, Firkins JL. Inhibition of methanogenesis by nitrate, with or without defaunation, in continuous culture. J Dairy Sci 2020; 103:7124-7140. [PMID: 32600762 DOI: 10.3168/jds.2020-18325] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2020] [Accepted: 03/29/2020] [Indexed: 02/02/2023]
Abstract
Within the rumen, nitrate can serve as an alternative sink for aqueous hydrogen [H2(aq)] accumulating during fermentation, producing nitrite, which ideally is further reduced to ammonium but can accumulate under conditions not yet explained. Defaunation has also been associated with decreased methanogenesis in meta-analyses because protozoa contribute significantly to H2 production. In the present study, we applied a 2 × 2 factorial treatment arrangement in a 4 × 4 Latin square design to dual-flow continuous culture fermentors (n = 4). Treatments were control without nitrate (-NO3-) versus with nitrate (+NO3-; 1.5% of diet dry matter), factorialized with normal protozoa (faunated, FAUN) versus defaunation (DEF) by decreasing the temperature moderately and changing filters over the first 4 d of incubation. We detected no main effects of DEF or interaction of faunation status with +NO3-. The main effect of +NO3- increased H2(aq) by 11.0 µM (+117%) compared with -NO3-. The main effect of +NO3- also decreased daily CH4 production by 8.17 mmol CH4/d (31%) compared with -NO3-. Because there were no treatment effects on neutral detergent fiber digestibility, the main effect of +NO3- also decreased CH4 production by 1.43 mmol of CH4/g of neutral detergent fiber degraded compared with -NO3-. There were no effects of treatment on other nutrient digestibilities, N flow, or microbial N flow per gram of nutrient digested. The spike in H2(aq) after feeding NO3- provides evidence that methanogenesis is inhibited by substrate access rather than concentration, regardless of defaunation, or by direct inhibition of NO2-. Methanogens were not decreased by defaunation, suggesting a compensatory increase in non-protozoa-associated methanogens or an insignificant contribution of protozoa-associated methanogens. Despite adaptive reduction of NO3- to NH4+ and methane inhibition in continuous culture, practical considerations such as potential to depress dry matter intake and on-farm ration variability should be addressed before considering NO3- as an avenue for greater sustainability of greenhouse gas emissions in US dairy production.
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Affiliation(s)
- B A Wenner
- Department of Animal Sciences, The Ohio State University, Columbus 43210.
| | - B K Wagner
- Department of Animal Sciences, The Ohio State University, Columbus 43210
| | - N R St-Pierre
- Department of Animal Sciences, The Ohio State University, Columbus 43210
| | - Z T Yu
- Department of Animal Sciences, The Ohio State University, Columbus 43210
| | - J L Firkins
- Department of Animal Sciences, The Ohio State University, Columbus 43210
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Meller RA, Wenner BA, Ashworth J, Gehman AM, Lakritz J, Firkins JL. Potential roles of nitrate and live yeast culture in suppressing methane emission and influencing ruminal fermentation, digestibility, and milk production in lactating Jersey cows. J Dairy Sci 2019; 102:6144-6156. [PMID: 31030922 DOI: 10.3168/jds.2018-16008] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2018] [Accepted: 03/05/2019] [Indexed: 12/11/2022]
Abstract
Concern over the carbon footprint of the dairy industry has led to various dietary approaches to mitigate enteric CH4 production. One approach is feeding the electron acceptor NO3-, thus outcompeting methanogens for aqueous H2. We hypothesized that a live yeast culture (LYC; Saccharomyces cerevisiae from Yea-Sacc 1026, Alltech Inc., Nicholasville, KY) would stimulate the complete reduction of NO3- to NH3 by selenomonads, thus decreasing the quantity of CH4 emissions per unit of energy-corrected milk production while decreasing blood methemoglobin concentration resulting from the absorbed intermediate, NO2-. Twelve lactating Jersey cows (8 multiparous and noncannulated; 4 primiparous and ruminally cannulated) were used in a replicated 4 × 4 Latin square design with a 2 × 2 factorial arrangement of treatments. Cattle were fed diets containing 1.5% NO3- (from calcium ammonium nitrate) or an isonitrogenous control diet (containing additional urea) and given a top-dress of ground corn without or with LYC, with the fourth week used for data collection. Noncannulated cows were spot measured for CH4 emission by mouth using GreenFeed (C-Lock Inc., Rapid City, SD). The main effect of NO3- decreased CH4 by 17% but decreased dry matter intake by 10% (from 19.8 to 17.8 kg/d) such that CH4:dry matter intake numerically decreased by 8% and CH4:milk net energy for lactation production was unaffected by treatment. Milk and milk fat production were not affected, but NO3- decreased milk protein from 758 to 689 g/d. Ruminal pH decreased more sharply after feeding for cows fed diets without NO3-. Acetate:propionate was greater for cows fed NO3-, particularly when combined with LYC (interaction effect). Blood methemoglobin was higher for cattle fed NO3- than for those fed the control diet but was low for both treatments (1.5 vs. 0.5%, respectively; only one measurement exceeded 5%), indicating minimal risk for NO2- accumulation at our feeding level of NO3-. Although neither apparent organic matter nor neutral detergent fiber digestibilities were affected, apparent N digestibility had an interaction for NO3- × LYC such that apparent N digestibility was numerically lowest for diets containing both NO3- and LYC compared with the other 3 diets. Under the conditions of this study, NO3- mitigated ruminal methanogenesis but also depressed dry matter intake and milk protein yield. Based on the fact that few interactions were detected, LYC had a minimal role in attenuating negative cow responses to NO3- supplementation.
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Affiliation(s)
- R A Meller
- Department of Animal Sciences, The Ohio State University, Columbus 43210
| | - B A Wenner
- Department of Animal Sciences, The Ohio State University, Columbus 43210
| | - J Ashworth
- Department of Animal Sciences, The Ohio State University, Columbus 43210
| | - A M Gehman
- Alltech, 3031 Catnip Hill Pike, Nicholasville, KY 40356
| | - J Lakritz
- Department of Veterinary Clinical Sciences, The Ohio State University, Columbus 43210
| | - J L Firkins
- Department of Animal Sciences, The Ohio State University, Columbus 43210.
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Welty CM, Wenner BA, Wagner BK, Roman-Garcia Y, Plank JE, Meller RA, Gehman AM, Firkins JL. Rumen microbial responses to supplemental nitrate. II. Potential interactions with live yeast culture on the prokaryotic community and methanogenesis in continuous culture. J Dairy Sci 2019; 102:2217-2231. [PMID: 30639000 DOI: 10.3168/jds.2018-15826] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2018] [Accepted: 11/27/2018] [Indexed: 12/21/2022]
Abstract
Nitrates have been fed to ruminants, including dairy cows, as an electron sink to mitigate CH4 emissions. In the NO3- reduction process, NO2- can accumulate, which could directly inhibit methanogens and possibly other microbes in the rumen. Saccharomyces cerevisiae yeast was hypothesized to decrease NO2- through direct reduction or indirectly by stimulating the bacterium Selenomonas ruminantium, which is among the ruminal bacteria most well characterized to reduce both NO3- and NO2-. Ruminal fluid was incubated in continuous cultures fed diets without or with NaNO3 (1.5% of diet dry matter; i.e., 1.09% NO3-) and without or with live yeast culture (LYC) fed at a recommended 0.010 g/d (scaled from cattle to fermentor intakes) in a 2 × 2 factorial arrangement of treatments. Treatments with LYC had increased NDF digestibility and acetate:propionate by increasing acetate molar proportion but tended to decrease total VFA production. The main effect of NO3- increased acetate:propionate by increasing acetate molar proportion; NO3- also decreased molar proportions of isobutyrate and butyrate. Both NO3- and LYC shifted bacterial community composition (based on relative sequence abundance of 16S rRNA genes). An interaction occurred such that NO3- decreased valerate molar proportion only when no LYC was added. Nitrate decreased daily CH4 emissions by 29%. However, treatment × time interactions were present for both CH4 and H2 emission from the headspace; CH4 was decreased by the main effect of NO3- until 6 h postfeeding, but NO3- and LYC decreased H2 emission up to 4 h postfeeding. As expected, NO3- decreased methane emissions in continuous cultures; however, contrary to expectations, LYC did not attenuate NO2- accumulation.
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Affiliation(s)
- C M Welty
- Department of Animal Sciences, The Ohio State University, 2029 Fyffe Ct., Columbus 43210
| | - B A Wenner
- Department of Animal Sciences, The Ohio State University, 2029 Fyffe Ct., Columbus 43210
| | - B K Wagner
- Department of Animal Sciences, The Ohio State University, 2029 Fyffe Ct., Columbus 43210
| | - Y Roman-Garcia
- Department of Animal Sciences, The Ohio State University, 2029 Fyffe Ct., Columbus 43210
| | - J E Plank
- Department of Animal Sciences, The Ohio State University, 2029 Fyffe Ct., Columbus 43210
| | - R A Meller
- Department of Animal Sciences, The Ohio State University, 2029 Fyffe Ct., Columbus 43210
| | - A M Gehman
- Alltech, 3031 Catnip Hill Pike, Nicholasville, KY 40356
| | - J L Firkins
- Department of Animal Sciences, The Ohio State University, 2029 Fyffe Ct., Columbus 43210.
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Wenner BA, Zerby HN, Boler DD, Gebreyes WA, Moeller SJ. Effect of mannan oligosaccharides (Bio-Mos) and outdoor access housing on pig growth, feed efficiency and carcass composition. J Anim Sci 2013; 91:4936-44. [PMID: 23942715 DOI: 10.2527/jas.2013-6582] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The present study was conducted as a 3 × 2 factorial experiment in 7 pen replications conducted using progeny (n = 360) of successive farrowings of 1 Landrace breeding female population. Grower-finisher dietary treatments included the addition of Bio-Mos (BM; at 0.2, 0.1 and 0.05% inclusion rates for phase 1 (30.2 to 63.5 kg), 2 (63.5 to 90.5 kg), and 3 (90.5 to 113.6 kg), respectively), the inclusion of a subtherapeutic antibiotic (AB; tetracycline; at 0.0055% inclusion rate in all dietary phases) and a no additive control (CON) diet. Housing systems were a conventional, indoor (IN) facility providing 1.0 m(2)/pig solid concrete and 0.3 m(2)/pig slatted floor with 12 pigs per pen and an outdoor access (OUT) system providing 1.1 m(2)/pig indoor, bedded concrete, and 1.9 m(2)/pig outdoor solid concrete with 6 pigs per pen. Housing systems analyses acknowledge confounding of space with number of pigs per pen. Daily growth rate (ADG), feed intake (ADFI), feed conversion (G:F), ultrasonic carcass composition, blood hematocrit (1 group), and observed illnesses were measured. Dietary × housing treatment interactions were not observed. Pigs reared in OUT had greater ADFI (0.1 kg/d; P = 0.01) resulting in greater ADG (0.04 kg/d; P < 0.0005) and required fewer days to reach a standard 113.6 kg endpoint (4.0 d; P < 0.0005) but had reduced (poorer) G:F (0.01 kg gain/kg feed; P = 0.05) when compared to IN. Pigs fed BM and CON diets had greater ADG (0.02 kg/d; P < 0.05) and required 3 fewer days to 113.6 kg (P < 0.05) when compared with pigs fed AB. Carcass composition measures were not different across dietary or housing treatments. Hematocrit was 2 units greater (P < 0.05) at the end of the trial (d 84) for OUT housed pigs but not different at the start, d 28, or d 56 of the trial. In the present study, the addition of a subtherapeutic antibiotic in swine finisher diets did not improve pig growth, efficiency, or health whereas the addition of BM did not increase growth performance compared to the CON diet in both housing systems, a finding suggesting the potential for improved gut health and or improved appetite in pigs not fed an antibiotic. Whereas pigs reared OUT had greater growth rate and a more desirable hematocrit level, the observed differences may be attributed to stocking density, number of pigs per pen, or outdoor access, effects that are not able to be fully described under the experimental design.
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Affiliation(s)
- B A Wenner
- Department of Animal Sciences, The Ohio State University, Columbus 43210
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