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Fonoll X, Zhu K, Aley L, Shrestha S, Raskin L. Simulating Rumen Conditions Using an Anaerobic Dynamic Membrane Bioreactor to Enhance Hydrolysis of Lignocellulosic Biomass. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2024; 58:1741-1751. [PMID: 38184844 DOI: 10.1021/acs.est.3c06478] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2024]
Abstract
An anaerobic dynamic membrane bioreactor (AnDMBR) mimicking rumen conditions was developed to enhance the hydrolysis of lignocellulosic materials and the production of volatile fatty acids (VFAs) when treating food waste. The AnDMBR was inoculated with cow rumen content and operated at a 0.5 day hydraulic retention time, 2-4 day solids retention time, a temperature of 39 °C, and a pH of 6.3, characteristics similar to those of a rumen. Removal rates of neutral detergent fiber and acid detergent fiber of 58.9 ± 8.4 and 69.0 ± 8.6%, respectively, and a VFA yield of 0.55 ± 0.12 g VFA as chemical oxygen demand g volatile solids (VS)fed-1 were observed at an organic loading rate of 18 ± 2 kg VS m-3 day-1. The composition and activity of the microbial community remained consistent after biofilm disruption, bioreactor upset, and reinoculation. Up to 66.7 ± 5.7% of the active microbial populations and 51.0 ± 7.0% of the total microbial populations present in the rumen-mimicking AnDMBR originated from the inoculum. This study offers a strategy to leverage the features of a rumen; the AnDMBR achieved high hydrolysis and fermentation rates even when treating substrates different from those fed to ruminants.
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Affiliation(s)
- Xavier Fonoll
- Department of Civil and Environmental Engineering, University of Michigan, Ann Arbor, Michigan 48109, United States
- Energy Research & Innovation, Great Lakes Water Authority, 9300 W Jefferson Avenue, Detroit, Michigan 48209, United States
| | - Kuang Zhu
- Department of Civil and Environmental Engineering, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Lucy Aley
- Department of Civil and Environmental Engineering, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Shilva Shrestha
- Department of Civil and Environmental Engineering, University of Michigan, Ann Arbor, Michigan 48109, United States
- Department of Environmental Health and Engineering, Johns Hopkins University, Baltimore, Maryland 21205, United States
| | - Lutgarde Raskin
- Department of Civil and Environmental Engineering, University of Michigan, Ann Arbor, Michigan 48109, United States
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Inhibitory Effect Mediated by Deoxynivalenol on Rumen Fermentation under High-Forage Substrate. FERMENTATION 2022. [DOI: 10.3390/fermentation8080369] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Deoxynivalenol (DON) is a type B trichothecene mycotoxin produced by Fusarium fungi. To investigate its ruminal degradability and its effect on rumen fermentation, a 2 × 5 factorial experiment was conducted in vitro with two feed substrates with different forage levels (high forage (HF), forage-to-concentrate = 4:1; low forage (LF), forage-to-concentrate = 1:4) and five DON additions per substrate (0, 5, 10, 15, and 20 mg/kg of dry matter). After 48 h incubation, the DON degradability in the HF group was higher than in the LF group (p < 0.01), and it decreased along with the increase in DON concentrations (p < 0.01), which varied from 57.18% to 29.01% at 48 h. In addition, the gas production rate, total VFA production and microbial crude protein decreased linearly against the increase in DON additions (p < 0.05). Meanwhile, the proportion of CH4 in the fermentation gas end-products increased linearly, especially in the HF group (p < 0.01). In brief, rumen microorganisms presented 29–57% of the DON degradation ability and were particularly significant under a high-forage substrate. Along with the increasing DON addition, the toxin degradability decreased, showing a dose-dependent response. However, DON inhibited rumen fermentation and increased methane production when it exceeded 5 mg/kg of dry matter.
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Schilde M, von Soosten D, Hüther L, Kersten S, Meyer U, Zeyner A, Dänicke S. Dose-Response Effects of 3-Nitrooxypropanol Combined with Low- and High-Concentrate Feed Proportions in the Dairy Cow Ration on Fermentation Parameters in a Rumen Simulation Technique. Animals (Basel) 2021; 11:1784. [PMID: 34203718 PMCID: PMC8232248 DOI: 10.3390/ani11061784] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2021] [Revised: 06/09/2021] [Accepted: 06/10/2021] [Indexed: 11/17/2022] Open
Abstract
Methane (CH4) from ruminal feed degradation is a major pollutant from ruminant livestock, which calls for mitigation strategies. The purpose of the present 4 × 2 factorial arrangement was to investigate the dose-response relationships between four doses of the CH4 inhibitor 3-nitrooxypropanol (3-NOP) and potential synergistic effects with low (LC) or high (HC) concentrate feed proportions (CFP) on CH4 reduction as both mitigation approaches differ in their mode of action (direct 3-NOP vs. indirect CFP effects). Diet substrates and 3-NOP were incubated in a rumen simulation technique to measure the concentration and production of volatile fatty acids (VFA), fermentation gases as well as substrate disappearance. Negative side effects on fermentation regarding total VFA and gas production as well as nutrient degradability were observed for neither CFP nor 3-NOP. CH4 production decreased from 10% up to 97% in a dose-dependent manner with increasing 3-NOP inclusion rate (dose: p < 0.001) but irrespective of CFP (CFP × dose: p = 0.094). Hydrogen gas accumulated correspondingly with increased 3-NOP dose (dose: p < 0.001). In vitro pH (p = 0.019) and redox potential (p = 0.066) varied by CFP, whereas the latter fluctuated with 3-NOP dose (p = 0.01). Acetate and iso-butyrate (mol %) decreased with 3-NOP dose, whereas iso-valerate increased (dose: p < 0.001). Propionate and valerate varied inconsistently due to 3-NOP supplementation. The feed additive 3-NOP was proven to be a dose-dependent yet effective CH4 inhibitor under conditions in vitro. The observed lack of additivity of increased CFP on the CH4 inhibition potential of 3-NOP needs to be verified in future research testing further diet types both in vitro and in vivo.
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Affiliation(s)
- Matthias Schilde
- Institute of Animal Nutrition, Friedrich-Loeffler-Institut (FLI), Federal Research Institute for Animal Health, 38116 Braunschweig, Germany; (D.v.S.); (L.H.); (S.K.); (U.M.); (S.D.)
| | - Dirk von Soosten
- Institute of Animal Nutrition, Friedrich-Loeffler-Institut (FLI), Federal Research Institute for Animal Health, 38116 Braunschweig, Germany; (D.v.S.); (L.H.); (S.K.); (U.M.); (S.D.)
| | - Liane Hüther
- Institute of Animal Nutrition, Friedrich-Loeffler-Institut (FLI), Federal Research Institute for Animal Health, 38116 Braunschweig, Germany; (D.v.S.); (L.H.); (S.K.); (U.M.); (S.D.)
| | - Susanne Kersten
- Institute of Animal Nutrition, Friedrich-Loeffler-Institut (FLI), Federal Research Institute for Animal Health, 38116 Braunschweig, Germany; (D.v.S.); (L.H.); (S.K.); (U.M.); (S.D.)
| | - Ulrich Meyer
- Institute of Animal Nutrition, Friedrich-Loeffler-Institut (FLI), Federal Research Institute for Animal Health, 38116 Braunschweig, Germany; (D.v.S.); (L.H.); (S.K.); (U.M.); (S.D.)
| | - Annette Zeyner
- Institute of Agricultural and Nutritional Sciences, Group Animal Nutrition, Martin Luther University Halle-Wittenberg, 06120 Halle (Saale), Germany;
| | - Sven Dänicke
- Institute of Animal Nutrition, Friedrich-Loeffler-Institut (FLI), Federal Research Institute for Animal Health, 38116 Braunschweig, Germany; (D.v.S.); (L.H.); (S.K.); (U.M.); (S.D.)
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4
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Evaluation of iso-α-acid and β-acid extracts from hops (Humulus lupulus L.) on fermentation by rumen microbes in dual-flow continuous culture fermenters. Anim Feed Sci Technol 2020. [DOI: 10.1016/j.anifeedsci.2019.114385] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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5
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Brandao VLN, Marcondes MI, Faciola AP. Comparison of microbial fermentation data from dual-flow continuous culture system and omasal sampling technique: A meta-analytical approach. J Dairy Sci 2020; 103:2347-2362. [PMID: 31954580 DOI: 10.3168/jds.2019-17107] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2019] [Accepted: 11/08/2019] [Indexed: 12/28/2022]
Abstract
Although the omasal sampling technique (OST) has been successfully used to estimate ruminal fermentation and nutrient flow, alternatives to invasive animal trials should be pursued and evaluated. The objective of this study was to evaluate carbohydrate and N metabolisms using a meta-analytical approach to compare 2 methods: dual-flow continuous culture system (DFCCS) and OST. To be included, studies needed to report diet chemical composition and report at least 1 of the dependent variables of interest. A total of 155 articles were included, in which 97 used the DFCCS and 58 used the OST. The independent variables used were dietary nonfiber carbohydrate concentration, neutral detergent fiber (NDF) degradability, true crude protein (CP) degradability, and efficiency of microbial protein synthesis (EMPS). In addition, 12 dependent variables were used. Statistical analyses were performed using the Mixed procedure of SAS (SAS Institute Inc., Cary, NC). A random coefficients model was used considering study as a random effect and including the possibility of covariance between the slope and the intercept. The effect of method (DFCCS or OST) was included and tested in the estimates of the intercept, linear, and quadratic effects of the independent variable. There was no method effect when NDF degradability was regressed with total volatile fatty acids concentration, true CP degradability, and EMPS. Molar proportions of acetate and propionate were quadratically associated with NDF degradability. When NDF degradability was regressed with acetate and propionate there was a method effect, differing only in the intercept (β0) estimate. True organic matter digestibility, bacterial N/total N, efficiency of N utilization, total volatile fatty acid concentration, and molar proportion of butyrate linearly increased as dietary nonfiber carbohydrate concentration increased, and none of these variables were affected by method. Concentration of ammonia N had a linear and positive association with true CP degradability. This was the only variable that had a method effect when regressed with true CP degradability, differing only in the estimate of the intercept (β0). As EMPS increased, efficiency of N utilization also increased, and it was affected by method. Overall, the majority of DFCCS responses were similar to OST. When a method effect was observed, it was mainly on the estimate of the intercept, demonstrating that the magnitude of these responses was different. However, the relationships between independent and dependent variables were similar across methods.
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Affiliation(s)
- V L N Brandao
- Department of Animal Sciences, University of Florida, Gainesville 32611
| | - M I Marcondes
- Department of Animal Science, Federal University of Viçosa, Viçosa, MG, Brazil, 36570900
| | - A P Faciola
- Department of Animal Sciences, University of Florida, Gainesville 32611.
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Gutierrez-Gomez C, Vera N, Allende R, Williams P, Astudillo R, Ávila-Stagno J. Linseed and glycerol in forage diets effect methane production and rumen fermentation parameters in a Rusitec semi-continuos system. ANIMAL PRODUCTION SCIENCE 2020. [DOI: 10.1071/an18710] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Context
The use of oilseeds as a feed ingredient has been proposed to improve fatty acid profiles and reduce methane (CH4) emissions. Glycerol has been used as a common additive in ruminant feeding systems with variable effects on CH4 production. The effects of the combination of these ingredients remain unknown.
Aims
The aim of this study was to assess the effects of feeding linseed and increasing concentrations of glycerol in forage diets supplemented with corn grain on nutrient disappearance, CH4 production and rumen fermentation parameters.
Methods
Experimental diets were: control (70:30% hay:corn); linseed (70:15 :15% hay:corn:linseed); 5% glycerol (70:10:15:5% hay:corn:linseed:glycerol); 10% glycerol (70:5:15:10% hay:corn:linseed:glycerol). Diets were incubated in a completely randomised design with four replicates per treatment in a Rusitec apparatus for 15 days (10 days adaptation, 5 days sampling).
Key results
Total VFA production (VFA, mmol/day) was quadratically increased due to glycerol concentration in the diets (P = 0.009). Acetate:propionate (A:P) decreased by the inclusion of linseed (P < 0.001) and glycerol into the diets (P < 0.001). Linseed inclusion in the diet reduced CH4 production, mg/DM disappeared (P = 0.004) by up to 36%. These effects were not altered by the addition of glycerol into the diets. Ammonia nitrogen (NH3-N) production increased 2-fold in the linseed-added diets, but this effect was partially reverted by increasing glycerol concentrations in the diets (P < 0.001). Crude protein (CP) disappearance increased (P < 0.001) in the linseed added diets, with no effect of glycerol addition. Neutral detergent fibre (aNDFom; P = 0.005) disappearance was increased by the addition of linseed to the diet.
Conclusions
The use of linseed in ruminant diets reduces CH4 emissions but increases NH3-N production in a Rusitec system. This latter effect is partially reverted by glycerol inclusion in the diet. Propionate production increases with the inclusion of glycerol, but does not alter CH4 production. Including linseed increases the in vitro CP disappearance without affecting DM total disappearance.
Implications
Care should be taken with the use of oilseeds in ruminant diets as it can reduce CH4 emissions but may cause important increases in NH3 emissions. Inclusion of glycerol may partially overcome this latter issue.
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Capelari M, Johnson KA, Latack B, Roth J, Powers W. The effect of encapsulated nitrate and monensin on ruminal fermentation using a semi-continuous culture system. J Anim Sci 2018; 96:3446-3459. [PMID: 29800454 DOI: 10.1093/jas/sky211] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2018] [Accepted: 05/24/2018] [Indexed: 01/18/2023] Open
Abstract
Because enteric methane (CH4) production from ruminants represents a source of greenhouse gas emissions and an energy loss for the host animal alternatives to minimize emissions is a current research priority. Seven 37-d trials tested the effect of encapsulated nitrate (EN) and sodium monensin (MON) in diets commonly fed to dairy (DAIRY; 50:50 forage to concentrate; four trials) and beef cattle (BEEF; 15:85 forage to concentrate; three trials) on rumen fermentation and CH4 production using a semi-continuous fermentation system. A 3 × 2 factorial arrangement was used and additives (0, 1.25, and 2.5% of EN; 0 and 4 mg/L of MON) were tested alone and combined (EN + MON) totaling six treatments. Rumen fluid was pooled from five nonadapted lactating cows fed 50:50 forage to concentrate diet 3 h after morning feeding, and 1 L of processed inoculum was transferred to 2.2-L vessels. Treatment diets were added to nylon bags which remained in the anaerobic fermentation of mixed rumen microorganisms for 48 h. Nitrate decreased CH4 production in DAIRY (24.7 vs. 32.1 mM/d; P < 0.01) and BEEF trials (33.5 vs. 43.5 mM/d; P < 0.01). Methane production was decreased by MON in DAIRY (26.3 vs. 32.1; P < 0.01) and BEEF (26.6 vs. 43.5 mM/d; P < 0.01). The combination of EN + MON further decreased CH4 in DAIRY (21.3 vs. 32.1 mM/d; P = 0.03) and BEEF (19.3 vs. 43.5 mM/d; P = 0.01). Nitrate did not affect major VFA production in DAIRY and BEEF trials, but significantly decreased digestion of protein (96.8 vs. 97.6%; P < 0.01) and starch (79.0 vs. 80.4%; P < 0.01) in DAIRY and NDF (29.3 vs. 32.5%; P < 0.01) and starch (88.5 vs. 90.3%; P < 0.01) in BEEF. Monensin significantly affected VFA pattern with an increase in propionate (P < 0.01) and a decrease on acetate (P < 0.01) production with consequent decrease on acetate-to-propionate ratio in DAIRY (1.6 vs. 2.0; P < 0.01) and BEEF (1.6 vs. 1.9; P < 0.01). Monensin decreased NDF digestion in BEEF only (29.3 vs. 32.5 %; P < 0.01). Significant concentrations of nitrate and nitrite were detected only for EN and EN + MON (P < 0.01). Nitrate and MON effectively decreased CH4 production when fed separately and the combination of additives additively decreased CH4 production.
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Affiliation(s)
- Matheus Capelari
- Department of Animal Science, Michigan State University, East Lansing, MI
| | - Kristen A Johnson
- Department of Animal Science, Washington State University, Pullman, WA
| | - Brooke Latack
- Department of Animal Science, Michigan State University, East Lansing, MI
| | - Jolene Roth
- Department of Animal Science, Michigan State University, East Lansing, MI
| | - Wendy Powers
- Division of Agriculture and Natural Resources, University of California, Oakland, CA
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8
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Salfer IJ, Staley C, Johnson HE, Sadowsky MJ, Stern MD. Comparisons of bacterial and archaeal communities in the rumen and a dual-flow continuous culture fermentation system using amplicon sequencing. J Anim Sci 2018. [PMID: 29529208 DOI: 10.1093/jas/skx056] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Dual-flow continuous culture (CC) fermenters are commonly used to study rumen fermentation in vitro. Research using culture-based and oligonucleotide techniques has shown that certain microbial populations within fermenters may be maintained at abundances similar to those observed in vivo. In this study, bacterial and archaeal communities in the rumen of dairy cattle and in a dual-flow CC fermentation system were compared using high-throughput amplicon sequencing targeting the V4 hypervariable region of 16S rRNA. We hypothesized that the in vitro system harbored a comparable bacterial and archaeal community to that observed in the rumen. Members of the Bacteroidetes and Firmicutes made up the 2 most abundant phyla in the rumen, inoculum, and fermenters and did not differ among sample types (P > 0.10). Similarly, Prevotellaceae, the most abundant family in all 3 sample types, did not differ based on source (P = 0.80). However, beta diversity analyses revealed that bacterial and archaeal communities differed between fermenters and rumen samples (P ≤ 0.001), but fermenter bacterial and archaeal communities stabilized by day 4 of each period. While the overall bacterial and archaeal community differs between natural rumens and those detected in in vitro fermenter systems, several prominent taxa were maintained at similar relative abundances suggesting that fermenters may provide a suitable environment in which to study shifts among the predominant members of the microbial community.
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Affiliation(s)
- I J Salfer
- Department of Animal Science, University of Minnesota, St. Paul, MN
| | - C Staley
- BioTechnology Institute, Department of Soil, Water, and Climate, University of Minnesota, St. Paul, MN.,Department of Plant and Microbial Biology, University of Minnesota, St. Paul, MN
| | - H E Johnson
- Department of Animal Science, University of Minnesota, St. Paul, MN
| | - M J Sadowsky
- BioTechnology Institute, Department of Soil, Water, and Climate, University of Minnesota, St. Paul, MN.,Department of Plant and Microbial Biology, University of Minnesota, St. Paul, MN
| | - M D Stern
- Department of Animal Science, University of Minnesota, St. Paul, MN
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Cabeza-Luna I, Carro M, Fernández-Yepes J, Molina-Alcaide E. Effects of modifications to retain protozoa in continuous-culture fermenters on ruminal fermentation, microbial populations, and microbial biomass assessed by two different methods. Anim Feed Sci Technol 2018. [DOI: 10.1016/j.anifeedsci.2018.04.004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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10
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Ruh KE, Heins BJ, Salfer IJ, Gardner RD, Stern MD. Comparison of warm season and cool season forages for dairy grazing systems in continuous culture. Transl Anim Sci 2018; 2:125-134. [PMID: 32704696 PMCID: PMC7200886 DOI: 10.1093/tas/txy014] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2018] [Accepted: 04/03/2018] [Indexed: 11/16/2022] Open
Abstract
The objective of this study was to compare warm-season annual grasses to cool-season perennial (CSP) grasses for ruminal nutrient digestibility and N metabolism in a dual-flow continuous culture fermentation system. Dietary treatments were 1) fresh alfalfa, 2) CSP grasses and legumes, 3) brown-midrib sorghum-sudangrass (BMRSS), and 4) teff grass from an organic dairy production system. Eight dual-flow continuous culture fermenters were used during two consecutive 10-d periods consisting of 7 d for stabilization followed by 3 d of sampling. Fermenter samples were collected on days 8, 9, and 10 for analysis of pH, NH3-N, and VFA. Apparent DM, OM, NDF, and ADF digestibility were on average lesser (P < 0.05) in CSP grasses and legumes and warm-season annual grasses compared with alfalfa. True DM and OM digestibility were lesser (P < 0.05) for CSP grasses and legumes and warm-season annual grasses compared with fresh alfalfa. Total VFA were not affected (P > 0.05) by forage. The NH3-N concentrations were highest (P < 0.05) with alfalfa compared with the other CSP grasses and legumes and warm-season annual grasses. CP digestibility was not affected (P > 0.05) by forage treatment. Flow of NH3-N was greatest (P < 0.05) for alfalfa, reflecting the greatest NH3-N concentration. Flow of total N was greatest (P < 0.05) for alfalfa, intermediate for teff, and lowest for CSP grasses and legumes and BMRSS. Flows of bacterial N, efficiency of bacterial N, non-NH3-N, and dietary N were not affected (P > 0.05) by forage source. Overall, fermentation of warm-season grasses was similar to the cool-season grasses and legumes which indicate dairy producers may use warm-season grasses without concerns about negative impact on rumen health.
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Affiliation(s)
- Kathryn E Ruh
- Department of Animal Science, University of Minnesota, St. Paul, MN
| | - Bradley J Heins
- Department of Animal Science, University of Minnesota, St. Paul, MN
| | - Isaac J Salfer
- Department of Animal Science, The Pennsylvania State University, University Park, PA
| | - Robert D Gardner
- Department of Bioproducts and Biosystems Engineering, University of Minnesota, St. Paul, MN
| | - Marshall D Stern
- Department of Animal Science, University of Minnesota, St. Paul, MN
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11
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Dai X, Weimer PJ, Dill-McFarland KA, Brandao VLN, Suen G, Faciola AP. Camelina Seed Supplementation at Two Dietary Fat Levels Change Ruminal Bacterial Community Composition in a Dual-Flow Continuous Culture System. Front Microbiol 2017; 8:2147. [PMID: 29163431 PMCID: PMC5675879 DOI: 10.3389/fmicb.2017.02147] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2017] [Accepted: 10/20/2017] [Indexed: 12/26/2022] Open
Abstract
This experiment aimed to determine the effects of camelina seed (CS) supplementation at different dietary fat levels on ruminal bacterial community composition and how it relates to changes in ruminal fermentation in a dual-flow continuous culture system. Diets were randomly assigned to 8 fermenters (1,200–1,250 mL) in a 2 × 2 factorial arrangement of treatments in a replicated 4 × 4 Latin square with four 10-day experimental periods that consisted of 7 days for diet adaptation and 3 days for sample collection. Treatments were: (1) no CS at 5% ether extract (EE, NCS5); (2) no CS at 8% EE (NCS8); (3) 7.7% CS at 5% EE (CS5); and (4) 17.7% CS at 8% EE (CS8). Megalac was used as a control to adjust EE levels. Diets contained 55% orchardgrass hay and 45% concentrate, and fermenters were equally fed a total of 72 g/day (DM basis) twice daily. The bacterial community was determined by sequencing the V4 region of the 16S rRNA gene using the Illumina MiSeq platform. Sequencing data were analyzed using mothur and statistical analyses were performed in R and SAS. The most abundant phyla across treatments were the Bacteroidetes and Firmicutes, accounting for 49 and 39% of the total sequences, respectively. The bacterial community composition in both liquid and solid fractions of the effluent digesta changed with CS supplementation but not by dietary EE. Including CS in the diets decreased the relative abundances of Ruminococcus spp., Fibrobacter spp., and Butyrivibrio spp. The most abundant genus across treatments, Prevotella, was reduced by high dietary EE levels, while Megasphaera and Succinivibrio were increased by CS supplementation in the liquid fraction. Correlatively, the concentration of acetate was decreased while propionate increased; C18:0 was decreased and polyunsaturated fatty acids, especially C18:2 n-6 and C18:3 n-3, were increased by CS supplementation. Based on the correlation analysis between genera and fermentation end products, this study revealed that CS supplementation could be energetically beneficial to dairy cows by increasing propionate-producing bacteria and suppressing ruminal bacteria associated with biohydrogenation. However, attention should be given to avoid the effects of CS supplementation on suppressing cellulolytic bacteria.
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Affiliation(s)
- Xiaoxia Dai
- Department of Animal Sciences, University of Florida, Gainesville, FL, United States
| | - Paul J Weimer
- Department of Bacteriology, University of Wisconsin-Madison, Madison, WI, United States.,Agricultural Research Service, United States Department of Agriculture, Madison, WI, United States
| | | | - Virginia L N Brandao
- Department of Animal Sciences, University of Florida, Gainesville, FL, United States
| | - Garret Suen
- Department of Bacteriology, University of Wisconsin-Madison, Madison, WI, United States
| | - Antonio P Faciola
- Department of Animal Sciences, University of Florida, Gainesville, FL, United States
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12
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Effect of dried fermentation biomass on microbial fermentation in continuous culture and in vitro intestinal digestibility. Anim Feed Sci Technol 2017. [DOI: 10.1016/j.anifeedsci.2017.05.020] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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13
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Wenner B, de Souza J, Batistel F, Hackmann T, Yu Z, Firkins J. Association of aqueous hydrogen concentration with methane production in continuous cultures modulated to vary pH and solids passage rate. J Dairy Sci 2017; 100:5378-5389. [DOI: 10.3168/jds.2016-12332] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2016] [Accepted: 03/07/2017] [Indexed: 11/19/2022]
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14
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Abecia L, Soto EC, Ramos-Morales E, Molina-Alcaide E. Microbial and chemical composition of liquid-associated bacteria in goats' rumen and fermenters. J Anim Physiol Anim Nutr (Berl) 2014; 98:1001-12. [DOI: 10.1111/jpn.12165] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2013] [Accepted: 12/20/2013] [Indexed: 12/01/2022]
Affiliation(s)
- L. Abecia
- Estación Experimental del Zaidín (CSIC); Granada Spain
| | - E. C. Soto
- Estación Experimental del Zaidín (CSIC); Granada Spain
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15
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Soto E, Molina-Alcaide E, Khelil H, Yáñez-Ruiz D. Ruminal microbiota developing in different in vitro simulation systems inoculated with goats’ rumen liquor. Anim Feed Sci Technol 2013. [DOI: 10.1016/j.anifeedsci.2013.06.003] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Comparison of microbial fermentation of high- and low-forage diets in Rusitec, single-flow continuous-culture fermenters and sheep rumen. Animal 2012; 3:527-34. [PMID: 22444376 DOI: 10.1017/s1751731108003844] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Eight Rusitec and eight single-flow continuous-culture fermenters (SFCCF) were used to compare the ruminal fermentation of two diets composed of alfalfa hay and concentrate in proportions of 80 : 20 (F80) and 20 : 80 (F20). Results were validated with those obtained previously in sheep fed the same diets. Rusitec fermenters were fed once daily and SFCCF twice, but liquid dilution rates were similar in both types of fermenters. Mean values of pH over the 12 h postfeeding were higher (P < 0.001) in Rusitec than in SFCCF, with diet F80 showing higher values (P < 0.001) in both types of fermenters. Concentrations of total volatile fatty acids (VFA) were higher (P < 0.001) in SFCCF than in Rusitec, and in both systems were higher (P = 0.002) for diet F20 than for diet F80. There were significant differences between systems in the proportions of the main VFA, and a fermentation system × diet interaction (P < 0.001) was detected for all VFA with the exception of valerate. No differences (P = 0.145) between the two types of fermenters were detected in dry matter (DM) digestibility, but NDF, microbial N flow and its efficiency were higher (P = 0.001) in SFCCF compared to Rusitec. Whereas pH values and VFA concentrations remained fairly stable through the day in both in vitro systems, pH dropped and VFA increased shortly after feeding in sheep rumen reaching the minimum and maximal values, respectively, about 4 h after feeding. Both in vitro systems detected differences between diets similar to those found in sheep for liquid dilution rate, pH values, DM digestibility, microbial N flow and growth efficiency. In contrast, acetate/propionate ratios were lower for diet F20 than for F80 in sheep rumen (2.73 and 3.97) and SFCCF (3.07 and 4.80), but were higher for diet F20 compared to F80 (4.29 and 3.40) in Rusitec, with values considered to be unphysiological for high-concentrate diets. In vivo NDF digestibility was affected (P = 0.017) by diet, but no differences between diets (P > 0.05) were found in any in vitro system. A more precise control of pH in both types of fermenters and a reduction of concentrate retention time in Rusitec could probably improve the simulation of in vivo fermentation.
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Hristov A, Lee C, Hristova R, Huhtanen P, Firkins J. A meta-analysis of variability in continuous-culture ruminal fermentation and digestibility data. J Dairy Sci 2012; 95:5299-5307. [DOI: 10.3168/jds.2012-5533] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2012] [Accepted: 05/13/2012] [Indexed: 12/18/2022]
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Soto EC, Yáñez-Ruiz DR, Cantalapiedra-Hijar G, Vivas A, Molina-Alcaide E. Changes in ruminal microbiota due to rumen content processing and incubation in single-flow continuous-culture fermenters. ANIMAL PRODUCTION SCIENCE 2012. [DOI: 10.1071/an11312] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
The aim of this study was to investigate the impact of rumen content manipulation and its incubation in an in vitro system on the abundance of some microbial groups and the bacterial diversity of goat rumens. Animals and single-flow continuous-culture fermenters were fed diets differing in forage to concentrate ratio (70 : 30; LC and 30 : 70; HC). Rumen contents were sampled after animals’ adaptation to the experimental diets, processed for inoculum preparation and inoculated into fermenters. Fermenter contents were sampled 1 and 7 days after inoculation. Total bacteria, Fibrobacter succinogenes, fungi and methanogen abundances were lower in the fermenter than in goat rumens, but no differences were found for Ruminococcus flavefaciens. The abundances of all these microorganisms were similar at 1 and 7 days of rumen content incubation in fermenters. Bacterial species richness did not change due to rumen content processing or the in vitro incubation. Shannon–Wiener index and Pielou evenness were lower in the fermenter than in rumen only when the enzyme HaeIII was used in terminal-restriction fragment length polymorphism analysis. Non-metric multidimensional scaling analysis, both in denaturing gradient gel electrophoresis and terminal-restriction fragment length polymorphism, showed a segregation of in vivo and in vitro samples, but no trends of grouping for fermenter samples was observed. The HC diet promoted higher abundance of total bacteria than LC in rumen but not in fermenters. Diet only had an effect on bacterial diversity when the enzyme HaeIII was considered. Rumen content processing and incubation in fermenters caused an important decline of the studied ruminal microbial groups although bacterial community structure and diversity did not significantly change.
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Fiber digestion, VFA production, and microbial population changes during in vitro ruminal fermentations of mixed rations by monensin-adapted and unadapted microbes. Anim Feed Sci Technol 2011. [DOI: 10.1016/j.anifeedsci.2011.06.002] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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20
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Cantalapiedra-Hijar G, Yáñez-Ruiz D, Newbold C, Molina-Alcaide E. The effect of the feed-to-buffer ratio on bacterial diversity and ruminal fermentation in single-flow continuous-culture fermenters. J Dairy Sci 2011; 94:1374-84. [DOI: 10.3168/jds.2010-3260] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2010] [Accepted: 11/05/2010] [Indexed: 11/19/2022]
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21
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Martínez ME, Ranilla MJ, Tejido ML, Saro C, Carro MD. Comparison of fermentation of diets of variable composition and microbial populations in the rumen of sheep and Rusitec fermenters. II. Protozoa population and diversity of bacterial communities. J Dairy Sci 2010; 93:3699-712. [PMID: 20655439 DOI: 10.3168/jds.2009-2934] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2009] [Accepted: 04/25/2010] [Indexed: 11/19/2022]
Abstract
Four ruminally and duodenally cannulated sheep and 8 Rusitec fermenters were used to determine the effects of dietary characteristics on microbial populations and bacterial diversity. The purpose of the study was to assess how closely fermenters can mimic the differences between diets found in vivo. The 4 experimental diets contained forage to concentrate (F:C) ratios of 70:30 (high forage; HF) or 30:70 (high concentrate; HC) with either alfalfa hay (A) or grass hay (G) as the forage. Total bacterial numbers were greater in the rumen of sheep fed HF diets compared with those fed HC diets, whereas the opposite was found in fermenters. The numbers of cellulolytic bacteria were not affected by F:C ratio in any fermentation system, but cellulolytic numbers were 2.7 and 1.8 times greater in sheep than in fermenters for HF and HC diets, respectively. Neither total bacterial nor cellulolytic numbers were affected by the type of forage in sheep or fermenters. Decreasing F:C ratio increased total protozoa and Entodiniae numbers in sheep by about 29 and 25%, respectively, but it had no effect in fermenters. Isotrichidae and Ophryoscolecinae numbers in sheep were not affected by changing F:C ratio, but both disappeared completely from fermenters fed HC diets. Total protozoa and Entodiniae numbers were greater in sheep fed A diets than in those fed G diets, whereas the opposite was found in fermenters. Results indicate that under the conditions of the present study, protozoa population in Rusitec fermenters was not representative of that in the rumen of sheep fed the same diets. In addition, protozoa numbers in fermenters were 121 and 226 times lower than those in the sheep rumen for HF and HC diets, respectively. The automated ribosomal intergenic spacer analysis of the 16S ribosomal DNA was used to analyze the diversity of liquid- and solid-associated bacteria in both systems. A total of 170 peaks were detected in the automated ribosomal intergenic spacer analysis electropherograms of bacterial pellets across the full set of 64 samples, from which 160 were detected in at least 1 individual from each system (sheep or fermenter). Diversity of liquid-associated bacterial pellets was greater with G diets in fermenters but seemed to be unaffected by diet in sheep. Bacterial diversity in solid-associated bacteria pellets was greater for G diets compared with A diets in sheep and fermenters. Different conditions in the fermenters compared with sheep rumen might have caused a selection of some bacterial strains.
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Affiliation(s)
- M E Martínez
- Departamento de Producción Animal, Universidad de León, 24007 León, Spain
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Martínez M, Ranilla M, Tejido M, Ramos S, Carro M. Comparison of fermentation of diets of variable composition and microbial populations in the rumen of sheep and Rusitec fermenters. I. Digestibility, fermentation parameters, and microbial growth. J Dairy Sci 2010; 93:3684-98. [DOI: 10.3168/jds.2009-2933] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2009] [Accepted: 04/25/2010] [Indexed: 11/19/2022]
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23
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Effect of inoculated corn silage on rumen fermentation and lipid metabolism in an artificial rumen (RUSITEC). Anim Feed Sci Technol 2009. [DOI: 10.1016/j.anifeedsci.2009.04.019] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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24
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Muetzel S, Lawrence P, Hoffmann EM, Becker K. Evaluation of a stratified continuous rumen incubation system. Anim Feed Sci Technol 2009. [DOI: 10.1016/j.anifeedsci.2008.11.001] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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25
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Molina-Alcaide E, Pascual MR, Cantalapiedra-Hijar G, Morales-García EY, Martín-García AI. Effects of concentrate replacement by feed blocks on ruminal fermentation and microbial growth in goats and single-flow continuous-culture fermenters. J Anim Sci 2008; 87:1321-33. [PMID: 19098232 DOI: 10.2527/jas.2008-1263] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The effect of replacing concentrate with 2 different feed blocks (FB) on ruminal fermentation and microbial growth was evaluated in goats and in single-flow continuous-culture fermenters. Diets consisted of alfalfa hay plus concentrate and alfalfa hay plus concentrate with 1 of the 2 studied FB. Three trials were carried out with 6 rumen-fistulated Granadina goats and 3 incubation runs in 6 single-flow continuous-culture fermenters. Experimental treatments were assigned randomly within each run, with 2 repetitions for each diet. At the end of each in vivo trial, the rumen contents were obtained for inoculating the fermenters. For each incubation run, the fermenters were inoculated with ruminal fluid from goats fed the same diet supplied to the corresponding fermenter flask. The average pH values, total and individual VFA, and NH(3)-N concentrations, and acetate:propionate ratios in the rumen of goats were not affected (P >or= 0.10) by diet, whereas the microbial N flow (MNF) and efficiency were affected (P <or= 0.001), with the greatest values observed for the diet without FB. In fermenters, the diet affected pH (P<0.001), propionate concentrations (P=0.01), acetate:propionate ratio (P=0.03), carbohydrate digestibility (P >or= 0.05), and total (P=0.02), NH(3) (P=0.005), and non-NH(3) (P=0.02) N flows, whereas the efficiency of VFA production was not affected (P=0.75). The effect of diet on MNF and efficiency depended on the bacterial pellet used as a reference. An effect (P<0.05) of diet on the composition of solid- and liquid-associated bacteria was observed. The compositions of liquid-associated bacteria in the fermenter contents and effluent were similar (P=0.05). Differences (P<0.001) between in vivo and in vitro values for most fermentation variables and bacterial pellet compositions were found. Partial replacement of the concentrate with FB did not greatly compromise carbohydrate fermentation in unproductive goats. However, this was not the case for MNF and efficiency. Differences between the results obtained in vivo and in vitro indicate a need to identify conditions in fermenters that allow better simulation of fermentation, microbial growth, and bacterial pellet composition in vivo. Reduced feeding cost could be achieved with the inclusion of FB in the diets of unproductive goats without altering rumen fermentation.
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Affiliation(s)
- E Molina-Alcaide
- Estación Experimental del Zaidín (Consejo Superior de Investigaciones Científicas), Profesor Albareda, 1, 18008 Granada, Spain.
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26
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Seeling K, Boguhn J, Strobel E, Dänicke S, Valenta H, Ueberschär KH, Rodehutscord M. On the effects of Fusarium toxin contaminated wheat and wheat chaff on nutrient utilisation and turnover of deoxynivalenol and zearalenone in vitro (Rusitec). Toxicol In Vitro 2006; 20:703-11. [PMID: 16321500 DOI: 10.1016/j.tiv.2005.10.006] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2005] [Revised: 09/05/2005] [Accepted: 10/15/2005] [Indexed: 11/27/2022]
Abstract
The objective of the present study was to investigate the effects of Fusarium toxin contaminated wheat and wheat chaff (mycotoxin diet) on nutrient degradability and the metabolism of the mycotoxins deoxynivalenol (DON) and zearalenone (ZON) using the rumen simulations technique (Rusitec). A 6 day application period with control wheat and wheat chaff (control diet) was followed by an 8 day sampling phase. During this time three fermenters received the mycotoxin diet (64.9 mg DON/kg dry matter (DM) and 500 microg ZON/kg DM) and the remaining fermenters served as the controls (1.0mg DON/kg DM and 6 microg ZON/kg DM). Feed residues of the bags and samples of the effluent liquids were pooled per fermenter during the last 8 days of the experiment. Additionally, effluents of the mycotoxin fermenters were taken 6, 12 and 24h after the morning feeding on the first day of the sampling phase. The degradation of organic matter (OM; P<0.05), neutral detergent fibre (NDF; P<0.01) and protein (P<0.001) were increased by administration the Fusarium contaminated diet which was accompanied by an increased ammonia concentration (P<0.01) and increased butyrate (P<0.01), isobutyrate (P<0.01) and isovalerate (P<0.05) values of the mycotoxin effluents in relation to the controls. High proportions of ingested DON of 90% (85-93%) and ingested ZON of 93% (80-104%) were recovered at the pooled feed residues and effluents in form of DON and de-epoxy DON, and ZON and alpha-ZOL after administering the Fusarium toxin contaminated feed. While adsorption of DON as DON and de-epoxy DON in the feed particles was only minor (5%), a higher amount of 38% of ingested ZON was recovered as ZON and alpha-ZOL at the feed residues. The total recovery of DON plus de-epoxy DON in effluents as a percentage of DON intake reached 8%, 9% and 22% of ingested DON at 6, 12 and 24h after application of the contaminated diet the first time, whereby the recovery of de-epoxy DON as percentage of DON intake was only 5% at 24h. Concentrations of ZON and metabolites were lower than detection limits in the time dependent effluent samples.
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Affiliation(s)
- K Seeling
- Institute of Animal Nutrition, Federal Agricultural Research Centre (FAL), Bundesallee 50, 38116 Braunschweig, Germany.
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27
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Boguhn J, Kluth H, Rodehutscord M. Effect of total mixed ration composition on fermentation and efficiency of ruminal microbial crude protein synthesis in vitro. J Dairy Sci 2006; 89:1580-91. [PMID: 16606728 DOI: 10.3168/jds.s0022-0302(06)72225-1] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The goal of this study was to identify dietary factors that affect fermentation and efficiency of microbial crude protein (CP(M)) synthesis in the rumen in vitro. We used 16 total mixed, dairy cow rations with known digestibilities that varied in ingredient composition and nutrient content. Each ration was incubated in a Rusitec (n = 3) for 15 d, and fermentation of different fractions was assessed. Observed extents of fermentation in 24 h were 35 to 47% for organic matter, 25 to 60% for crude protein, 3 to 28% for neutral detergent fiber, and 31 to 45% for gross energy. Organic matter fermentation depended on the content of crude protein and neutral detergent fiber in the ration. We studied net synthesis of CP(M) using an 15N dilution technique and found that 7 d of continuous 15N application are needed to achieve an 15N enrichment plateau in the N of isolated microbes in this type of study. The efficiency of CP(M) synthesis was 141 to 286 g/kg of fermented organic matter or 4.9 to 11.1 g/MJ of metabolizable energy, and these ranges agree with those found in the literature. Multiple regressions to predict the efficiency of CP(M) synthesis by diet data showed that crude protein was the only dietary chemical fraction that had a significant effect. Fat content and the inclusion rate of corn silage in the ration also tended to improve efficiency. We suggest that microbial need for preformed amino acids may explain the crude protein effect. A large part of the variation in efficiency of microbial activity still remains unexplained.
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Affiliation(s)
- J Boguhn
- Institut für Ernährungswissenschaften, Martin-Luther-Universität Halle-Wittenberg, 06099 Halle, Saale, Germany
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28
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Colombatto D, Hervás G, Yang WZ, Beauchemin KA. Effects of enzyme supplementation of a total mixed ration on microbial fermentation in continuous culture, maintained at high and low pH1. J Anim Sci 2003; 81:2617-27. [PMID: 14552391 DOI: 10.2527/2003.81102617x] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
A dual-flow continuous culture system was used to investigate the effects of pH and addition of an enzyme mixture to a total mixed ration (TMR) on fermentation, nutrient digestion, and microbial protein synthesis. A 4 x 4 Latin square design with a factorial arrangement of treatments was used, with four 9-d periods consisting of 6 d for adaptation and 3 d for measurements. Treatments were as follows: 1) high pH with control TMR, 2) high pH with TMR treated with enzyme, 3) low pH with control TMR, and 4) low pH with TMR treated with enzyme. Ranges of pH were 6.0 to 6.6 and 5.4 to 6.0 for high and low, respectively. Fermenters were fed twice daily a TMR consisting of 30% alfalfa hay, 30% corn silage, and 40% rolled corn (DM basis). The silage was milled fresh and the TMR was fed to the fermenters in fresh form (64% DM). The enzyme mixture was a commercial product of almost exclusive protease activity; it was applied daily to the fresh TMR and stored at 4 degrees C for at least 12 h before feeding. Degradability of OM, NDF, ADF, and cellulose was decreased (P < 0.05) by low pH. Hemicellulose and protein degradation were not affected by pH. Enzyme addition increased (P < 0.01) NDF degradability (by 43% and 25% at high and low pH, respectively), largely as a result of an increase in hemicellulose degradation (by 79% and 51% at high and low pH, respectively). This improvement was supported by an increase (P < 0.05) in the xylanase and cellulase activities in the liquid phase of the fermenter contents. Total VFA were decreased (P < 0.05) by low pH, but were not affected by enzyme addition. Total bacterial numbers were increased (P < 0.03) at low pH and tended (P < 0.13) to increase with enzyme addition. Cellulolytic bacteria in effluent fluid were decreased (P < 0.02) at low pH but were unaffected by enzyme addition. Despite a large increase (P < 0.001) in protease activity, protein degradation was only numerically increased by enzyme addition. Microbial protein synthesis was higher (P < 0.10) at high pH but was not affected by enzyme addition. Methane production, expressed as a proportion of total gases, was decreased (P < 0.001) at low pH but was not affected by enzyme addition. It is concluded that it is possible to adapt the continuous culture system to use fresh feeds instead of dried feeds. Overall, the results indicate that the enzyme product used in this study has a potential to increase fiber degradability without increasing methane production.
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Affiliation(s)
- D Colombatto
- Agriculture and Agri-Food Canada, Lethbridge, AB, Canada T1J 4B1.
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29
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Noftsger SM, St-Pierre NR, Karnati SKR, Firkins JL. Effects of 2-hydroxy-4-(methylthio) butanoic acid (HMB) on microbial growth in continuous culture. J Dairy Sci 2003; 86:2629-36. [PMID: 12939087 DOI: 10.3168/jds.s0022-0302(03)73858-2] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
2-Hydroxy-4-(methylthio) butanoic acid (HMB) positively affects milk composition and yield, potentially through ruminal actions. Four continuous culture fermenters were used to determine the optimal concentration of HMB for digestibility of organic matter (OM), neutral detergent fiber (NDF), acid detergent fiber (ADF), and hemicellulose and synthesis of microbial N. A highly degradable mix of hay and grain was used as a basal diet to simulate a typical lactation diet. Three concentrations of HMB (0, 0.055, and 0.110%) and one concentration of dl-Met (0.097%) were infused into the fermenters according to a 4 x 4 Latin square design. Digesta samples were collected during the last 3 d of each of the four 10-d experimental periods. Digestibility of OM, hemicellulose, and NDF was largely insensitive to treatment. Digestibility of ADF showed a quadratic effect to supplementation of HMB, with 0.055% having lower digestibility than 0 or 0.110%. Total production of VFA was not influenced by HMB supplementation, but differences in concentration and production of individual VFA were seen. Isobutyrate increased linearly with increasing HMB supplementation. Propionate concentration decreased linearly with increased HMB supplementation, but propionate production showed a quadratic trend (P = 0.13). A higher concentration of acetate was detected for dl-Met compared with the highest HMB concentration. There were trends (P < 0.15) for dl-Met to decrease the production of isobutyrate and to lower the concentration of butyrate when compared with HMB. Microbial efficiency was not different among treatments. The proportion of bacterial N produced from NH3-N decreased linearly with increasing HMB, and bacteria receiving dl-Met synthesized more N from NH3-N than those receiving HMB. These data suggest that supplementation of HMB may have a sparing effect on branched chain volatile fatty acids because the fatty acids are not needed to provide carbon for synthesis of valine, isoleucine and leucine with ammonia. Comparisons of bacterial community structure in the fermenter effluent samples using PCR amplicons containing the ribosomal intergenic spacer region and its flanking partial 16S ribosomal RNA gene showed no distinct banding patterns, though treatments tended to group together. Both Met and HMB affect the rumen microbial population, but Met supplied as dl-Met does not act identically to that supplied as HMB.
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Affiliation(s)
- S M Noftsger
- Department of Animal Sciences, Ohio State University, Columbus 43210, USA
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30
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de Veth MJ, Kolver ES. Diurnal variation in pH reduces digestion and synthesis of microbial protein when pasture is fermented in continuous culture. J Dairy Sci 2001; 84:2066-72. [PMID: 11573787 DOI: 10.3168/jds.s0022-0302(01)74651-6] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Many models of digestion assume steady-state conditions and do not account for diurnal variation in the rumen environment. This experiment examined the relationships between diurnal pH, pasture digestion, and microbial protein synthesis. Four dual-flow continuous culture fermenters were used to test the effect of increasing time at suboptimal pH on parameters of digestion. Fermentation of high quality pasture was controlled at pH 5.4 (suboptimal) for four intervals during each 24-h period (0, 4, 8, and 12 h) according to a 4 x 4 Latin square design. During the remainder of each day, pH was controlled at 6.3 (optimal). Samples were collected during the last 3 d of each of the four 9-d experimental periods. A negative quadratic relationship was observed between time at suboptimal pH and apparent digestibility of organic matter and dry matter. The largest reduction in digestibility of organic matter, dry matter, and neutral detergent fiber was exhibited after 4 h at suboptimal pH. A negative linear relationship was found between time at suboptimal pH and microbial N flow, with the greatest decline in microbial N flow occurring at 12 h at suboptimal pH. These results suggest that the period of time that pH is below optimal may be more critical for digestion than the relationship between mean daily pH and optimal pH. Modeling non-steady-state ruminal conditions to account for diurnal variation in the ruminal environment may improve the prediction of digestion, especially fiber.
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Affiliation(s)
- M J de Veth
- Dexcel (formerly Dairying Research Corporation), Hamilton, New Zealand
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31
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Abstract
The ruminal pH of dairy cows fed high quality pasture is often below values recommended to optimize digestion. Four continuous culture fermenters were used to determine the pH required for the optimal digestion of pasture. High quality pasture was fermented at four controlled levels of pH (5.4, 5.8, 6.2, and 6.6) according to a 4 x 4 Latin square design. Automatic infusion of 5 M NaOH and 5 M HCl controlled pH to +/- 0.1. Digesta samples were collected during the last 3 d of each of the four 9-d experimental periods. Digestion and synthesis of microbial protein were largely insensitive to pH across a broad range of pH (5.8 to 6.6), but a large reduction in both occurred when pH was 5.4. The digestibility of pasture dry matter and synthesis of microbial protein were optimized at pH 6.35 and 6.13, respectively. The proportions of individual volatile fatty acids were not changed as pH increased. Digestion of high quality pasture in continuous culture was comparable to that predicted by the Cornell Net Carbohydrate and Protein System between pH 6.2 and 6.6. However, the model underpredicted organic matter and fiber digestibility between pH 5.4 and 5.8, compared with values obtained in continuous culture. This suggests that when ruminal pH is less than 6.2, the model may over-predict the production response to supplementation of high quality pasture with an effective fiber source.
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Dijkstra J, France J, Davies DR. Different mathematical approaches to estimating microbial protein supply in ruminants. J Dairy Sci 1998; 81:3370-84. [PMID: 9891281 DOI: 10.3168/jds.s0022-0302(98)75902-8] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Many of the amino acids that are available for absorption in ruminants are derived from microbial protein that has been synthesized in the reticulorumen. This paper focuses on the prediction of the microbial protein supply and evaluates different approaches to represent mathematically the process of microbial protein synthesis. In current protein evaluation systems for ruminants, the microbial protein supply is predicted using empirical equations that relate microbial protein production to the amounts of ruminally available energy and nitrogen. In contrast, mechanistic models of rumen function endeavor to describe quantitatively the microbial protein production that is based on underlying identifiable processes. A brief description is presented of two culture techniques used to examine microbial ecosystems, namely, batch culture and chemostat culture. The mathematical equations describing these cultures are helpful in understanding key parameters of microbial production for inclusion in models, including specific growth rate, growth yield, and substrate affinity. The availability of carbohydrates is a primary determinant of microbial protein production in the rumen, and the adequacy of mathematical representations of this relationship in empirical and mechanistic models is assessed. The representation of substrate utilization for nongrowth processes and the relationship between microbial protein production and the availability of various nitrogen sources are discussed. A variable part of the synthesized microbial protein does not reach the duodenum but is degraded in the rumen, and its representation is examined. The prediction of microbial protein supply should be based on a sound representation of the underlying mechanisms, including the interactions among microbes and between microbial activity and substrate degradation.
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Affiliation(s)
- J Dijkstra
- Animal Nutrition Group, Wageningen Institute of Animal Sciences (WIAS), Wageningen Agricultural University, The Netherlands
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