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Vadroňová M, Šťovíček A, Jochová K, Výborná A, Tyrolová Y, Tichá D, Homolka P, Joch M. Combined effects of nitrate and medium-chain fatty acids on methane production, rumen fermentation, and rumen bacterial populations in vitro. Sci Rep 2023; 13:21961. [PMID: 38081855 PMCID: PMC10713576 DOI: 10.1038/s41598-023-49138-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2023] [Accepted: 12/05/2023] [Indexed: 12/18/2023] Open
Abstract
This study investigated the combined effects of nitrate (NT) and medium-chain fatty acids (MCFA), including C8, C10, C12, and C14, on methane (CH4) production, rumen fermentation characteristics, and rumen bacteria using a 24 h batch incubation technique. Four types of treatments were used: control (no nitrate, no MCFA), NT (nitrate at 3.65 mM), NT + MCFA (nitrate at 3.65 mM + one of the four MCFA at 500 mg/L), and NT + MCFA/MCFA (nitrate at 3.65 mM + a binary combination of MCFA at 250 and 250 mg/L). All treatments decreased (P < 0.001) methanogenesis (mL/g dry matter incubated) compared with the control, but their efficiency was dependent on the MCFA type. The most efficient CH4 inhibitor was the NT + C10 treatment (- 40%). The combinations containing C10 and C12 had the greatest effect on bacterial alpha and beta diversity and relative microbial abundance (P < 0.001). Next-generation sequencing showed that the family Succinivibrionaceae was favored in treatments with the greatest CH4 inhibition at the expense of Prevotella and Ruminococcaceae. Furthermore, the relative abundance of Archaea decreased (P < 0.05) in the NT + C10 and NT + C10/C12 treatments. These results confirm that the combination of NT with MCFA (C10 and C12 in particular) may effectively reduce CH4 production.
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Affiliation(s)
- Mariana Vadroňová
- Department of Microbiology, Nutrition and Dietetics, Faculty of Agrobiology, Food and Natural Resources, Czech University of Life Sciences, Kamýcká 129, 165 00, Prague, Czech Republic
- Department of Nutrition and Feeding of Farm Animals, Institute of Animal Science, Přátelství 815, 104 00, Prague, Czech Republic
| | - Adam Šťovíček
- Department of Microbiology, Nutrition and Dietetics, Faculty of Agrobiology, Food and Natural Resources, Czech University of Life Sciences, Kamýcká 129, 165 00, Prague, Czech Republic
| | - Kateřina Jochová
- Department of Microbiology, Nutrition and Dietetics, Faculty of Agrobiology, Food and Natural Resources, Czech University of Life Sciences, Kamýcká 129, 165 00, Prague, Czech Republic
- Department of Nutrition and Feeding of Farm Animals, Institute of Animal Science, Přátelství 815, 104 00, Prague, Czech Republic
| | - Alena Výborná
- Department of Nutrition and Feeding of Farm Animals, Institute of Animal Science, Přátelství 815, 104 00, Prague, Czech Republic
| | - Yvona Tyrolová
- Department of Nutrition and Feeding of Farm Animals, Institute of Animal Science, Přátelství 815, 104 00, Prague, Czech Republic
| | - Denisa Tichá
- Department of Microbiology, Nutrition and Dietetics, Faculty of Agrobiology, Food and Natural Resources, Czech University of Life Sciences, Kamýcká 129, 165 00, Prague, Czech Republic
- Department of Nutrition and Feeding of Farm Animals, Institute of Animal Science, Přátelství 815, 104 00, Prague, Czech Republic
| | - Petr Homolka
- Department of Microbiology, Nutrition and Dietetics, Faculty of Agrobiology, Food and Natural Resources, Czech University of Life Sciences, Kamýcká 129, 165 00, Prague, Czech Republic
- Department of Nutrition and Feeding of Farm Animals, Institute of Animal Science, Přátelství 815, 104 00, Prague, Czech Republic
| | - Miroslav Joch
- Department of Microbiology, Nutrition and Dietetics, Faculty of Agrobiology, Food and Natural Resources, Czech University of Life Sciences, Kamýcká 129, 165 00, Prague, Czech Republic.
- Department of Nutrition and Feeding of Farm Animals, Institute of Animal Science, Přátelství 815, 104 00, Prague, Czech Republic.
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Patra AK, Puchala R. Methane mitigation in ruminants with structural analogues and other chemical compounds targeting archaeal methanogenesis pathways. Biotechnol Adv 2023; 69:108268. [PMID: 37793598 DOI: 10.1016/j.biotechadv.2023.108268] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2023] [Revised: 09/20/2023] [Accepted: 09/30/2023] [Indexed: 10/06/2023]
Abstract
Ruminants are responsible for enteric methane production contributing significantly to the anthropogenic greenhouse gases in the atmosphere. Moreover, dietary energy is lost as methane gas without being available for animal use. Therefore, many mitigation strategies aiming at interventions at animals, diet, and microbiota have been explored by researchers. Specific chemical analogues targeting the enzymes of the methanogenic pathway appear to be more effective in specifically inhibiting the growth of methane-producing archaea without hampering another microbiome, particularly, cellulolytic microbiota. The targets of methanogenesis reactions that have been mainly investigated in ruminal fluid include methyl coenzyme M reductase (halogenated sulfonate and nitrooxy compounds), corrinoid enzymes (halogenated aliphatic compounds), formate dehydrogenase (nitro compounds, e.g., nitroethane and 2-nitroethanol), and deazaflavin (F420) (pterin and statin compounds). Many other potential metabolic reaction targets in methanogenic archaea have not been evaluated properly. The analogues are specifically effective inhibitors of methanogens, but their efficacy to lower methanogenesis over time reduces due to the metabolism of the compounds by other microbiota or the development of resistance mechanisms by methanogens. In this short review, methanogen populations inhabited in the rumen, methanogenesis pathways and methane analogues, and other chemical compounds specifically targeting the metabolic reactions in the pathways and methane production in ruminants have been discussed. Although many methane inhibitors have been evaluated in lowering methane emission in ruminants, advancement in unravelling the molecular mechanisms of specific methane inhibitors targeting the metabolic pathways in methanogens is very limited.
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Affiliation(s)
- Amlan Kumar Patra
- American Institute for Goat Research, Langston University, Langston, OK 73050, USA.
| | - Ryszard Puchala
- American Institute for Goat Research, Langston University, Langston, OK 73050, USA; Applied Physiology Unit, Military Institute of Hygiene and Epidemiology, Kozielska 4, Warsaw, Poland
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Li W, Cui Z, Jiang Y, Aisikaer A, Wu Q, Zhang F, Wang W, Bo Y, Yang H. Dietary Guanidine Acetic Acid Improves Ruminal Antioxidant Capacity and Alters Rumen Fermentation and Microflora in Rapid-Growing Lambs. Antioxidants (Basel) 2023; 12:antiox12030772. [PMID: 36979020 PMCID: PMC10044800 DOI: 10.3390/antiox12030772] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2023] [Revised: 03/13/2023] [Accepted: 03/15/2023] [Indexed: 03/30/2023] Open
Abstract
Guanidine acetic acid (GAA) has been reported to improve growth performance, nutrient utilization, and meat quality in livestock. This study aimed to investigate whether coated GAA (CGAA) in comparison with uncoated GAA (UGAA) could have different effects on rumen fermentation, antioxidant capacity, and microflora composition in the rumen. Seventy-two lambs were randomly arranged in a 2 × 3 factorial experiment design with two diets of different forage type (OH: oaten hay; OHWS: oaten hay plus wheat silage) and three GAA treatments within each diet (control, diet without GAA addition; UGAA, uncoated GAA; CGAA, coated GAA). The whole feeding trial lasted for 120 days. The lambs in the OH group presented lower total volatile fatty acid (VFA), alpha diversity, Firmicutes, NK4A214_group, and Lachnospiraceae_NK3A20_group than those on the OHWS diet in the last 60 days of the feeding stage (p < 0.05). Regardless of what GAA form was added, dietary GAA supplementation increased the total VFA, microbial crude protein (MCP), adenosine triphosphate (ATP), and antioxidant capacity in rumen during lamb feedlotting (p < 0.05). However, molar propionate proportion, acetate:propionate ratio (A:P), and relative Succiniclasticum abundance decreased with GAA addition in the first 60 days of the growing stage, while the molar butyrate proportion and NK4A214_group (p < 0.05) in response to GAA addition increased in the last 60 days of feeding. These findings indicated that dietary GAA enhanced antioxidant capacity and fermentation characteristics in the rumen, but the addition of uncoated GAA in diets might cause some dysbacteriosis of the rumen microbiota.
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Affiliation(s)
- Wenjuan Li
- State Key Laboratory of Animal Nutrition, College of Animal Science and Technology, China Agricultural University, Beijing 100193, China
| | - Zhaoyang Cui
- State Key Laboratory of Animal Nutrition, College of Animal Science and Technology, China Agricultural University, Beijing 100193, China
| | - Yaowen Jiang
- State Key Laboratory of Animal Nutrition, College of Animal Science and Technology, China Agricultural University, Beijing 100193, China
| | - Ailiyasi Aisikaer
- State Key Laboratory of Animal Nutrition, College of Animal Science and Technology, China Agricultural University, Beijing 100193, China
| | - Qichao Wu
- State Key Laboratory of Animal Nutrition, College of Animal Science and Technology, China Agricultural University, Beijing 100193, China
| | - Fang Zhang
- State Key Laboratory of Animal Nutrition, College of Animal Science and Technology, China Agricultural University, Beijing 100193, China
| | - Weikang Wang
- State Key Laboratory of Animal Nutrition, College of Animal Science and Technology, China Agricultural University, Beijing 100193, China
| | - Yukun Bo
- Zhangjiakou Animal Husbandry Technology Promotion Institution, Zhangjiakou 075000, China
| | - Hongjian Yang
- State Key Laboratory of Animal Nutrition, College of Animal Science and Technology, China Agricultural University, Beijing 100193, China
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Romero P, Huang R, Jiménez E, Palma-Hidalgo JM, Ungerfeld EM, Popova M, Morgavi DP, Belanche A, Yáñez-Ruiz DR. Evaluating the effect of phenolic compounds as hydrogen acceptors when ruminal methanogenesis is inhibited in vitro – Part 2. Dairy goats. Animal 2023; 17:100789. [PMID: 37087998 DOI: 10.1016/j.animal.2023.100789] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2022] [Revised: 03/17/2023] [Accepted: 03/20/2023] [Indexed: 03/31/2023] Open
Abstract
Most mitigation strategies to reduce enteric methane (CH4) production in the rumen induce an excess of rumen dihydrogen (H2) that is expelled and consequently not redirected to the synthesis of metabolites that can be utilised by the ruminant. We hypothesised that phenolic compounds can be potential H2 acceptors when added to the diet, as they can be degraded to compounds that may be beneficial for the animal, using part of the H2 available when ruminal methanogenesis is inhibited. We performed four in vitro incubation experiments using rumen inoculum from Murciano-Granadina adult goats: Experiment 1 examined the inhibitory potential of Asparagopsis taxiformis (AT) at different concentrations (0, 1, 2, 3, 4 and 5% of the substrate on a DM basis) in 24 h incubations; Experiment 2 investigated the effect of a wide range of phenolic compounds (phenol, catechol, resorcinol, hydroquinone, pyrogallol, phloroglucinol, gallic acid and formic acid) at different doses (0, 2, 4, and 6 mM) on rumen fermentation for 24 h; Experiment 3 evaluated the combined effect of each phenolic compound at 6 mM with AT at 2% DM in sequential batch cultures for 5 days; and Experiment 4 examined the dose-response effect of phloroglucinol at different concentrations (0, 6, 16, 26 and 36 mM) combined with AT in sequential batch cultures for 5 days. Results from Experiment 1 confirmed that AT at 2% DM substantially inhibited CH4 production while significantly increasing H2 accumulation and decreasing the acetate:propionate ratio. Results from Experiment 2 showed that phenolic compounds did not negatively affect rumen fermentation at any dose. In Experiment 3, each phenolic compound at 6 mM combined with AT at 2% DM inhibited CH4 production. Phloroglucinol numerically decreased H2 accumulation and significantly increased total gas production (TGP), volatile fatty acid (VFA) production and the acetate:propionate ratio. In Experiment 4, phloroglucinol at increasing doses supplemented with AT at 2% DM significantly decreased H2 accumulation and the abundances of archaea, protozoa and fungi abundances, and increased TGP, total VFA production and the acetate:propionate ratio in a dose-dependent way. In conclusion, combined treatment with AT and phloroglucinol was successful to mitigate CH4 production while preventing the accumulation of H2, leading to an increase in acetate and total VFA production and therefore an improvement in rumen fermentation in goats.
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Affiliation(s)
- P Romero
- Estación Experimental del Zaidín (CSIC), Profesor Albareda, 1, 18008 Granada, Spain
| | - R Huang
- Université Clermont Auvergne, INRAE, VetAgro Sup, UMR Herbivores, F-63122 Saint-Genès Champanelle, France
| | - E Jiménez
- Estación Experimental del Zaidín (CSIC), Profesor Albareda, 1, 18008 Granada, Spain
| | - J M Palma-Hidalgo
- Estación Experimental del Zaidín (CSIC), Profesor Albareda, 1, 18008 Granada, Spain
| | - E M Ungerfeld
- Centro Regional de Investigación Carillanca, Instituto de Investigaciones Agropecuarias INIA, Temuco 4880000, Chile
| | - M Popova
- Université Clermont Auvergne, INRAE, VetAgro Sup, UMR Herbivores, F-63122 Saint-Genès Champanelle, France
| | - D P Morgavi
- Université Clermont Auvergne, INRAE, VetAgro Sup, UMR Herbivores, F-63122 Saint-Genès Champanelle, France
| | - A Belanche
- Estación Experimental del Zaidín (CSIC), Profesor Albareda, 1, 18008 Granada, Spain; Departamento de Producción Animal y Ciencia de los Alimentos, Universidad de Zaragoza, Miguel Servet 177, 50013 Zaragoza, Spain
| | - D R Yáñez-Ruiz
- Estación Experimental del Zaidín (CSIC), Profesor Albareda, 1, 18008 Granada, Spain.
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Kong F, Liu Y, Wang S, Zhang Y, Wang W, Yang H, Lu N, Li S. Nutrient Digestibility, Microbial Fermentation, and Response in Bacterial Composition to Methionine Dipeptide: An In Vitro Study. BIOLOGY 2022; 11:biology11010093. [PMID: 35053091 PMCID: PMC8772947 DOI: 10.3390/biology11010093] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/15/2021] [Revised: 01/05/2022] [Accepted: 01/06/2022] [Indexed: 11/20/2022]
Abstract
Simple Summary The rumen microbiota plays an important role in maintaining microbiota homeostasis and promoting milk production synthesis through utilizing amino acids and non-protein nitrogen. Furthermore, various nitrogen sources have shown distinct effects on microbial growth rates. The methionine dipeptide (MD) is a bioactive peptide consisting of two methionine (Met) residues linked by a peptide bond. Although the role of MD in milk protein synthesis is established, little is known about its role in bacterial fermentation. The present study demonstrates that the various nitrogen sources could reshape microbiota differently, and MD could be more efficient than free Met in the rumen to support acetate producer growth. Our study provides some new insights into the relationship between ruminal microbiota of dairy cows and small peptides and points to potential strategies to effectively enhance the health condition and digestion ability of dairy cows. Abstract It is well known that the methionine dipeptide (MD) could enhance the dairy cows milking performance. However, there is still a knowledge gap of the effects of MD on the rumen fermentation characteristics, microbiota composition, and digestibility. This experiment was conducted to determine the effect of different nitrogen sources with a total mixed ration on in vitro nutrient digestibility, fermentation characteristics, and bacterial composition. The treatments included 5 mg urea (UR), 25.08 mg methionine (Met), 23.57 mg MD, and no additive (CON) in fermentation culture medium composed of buffer solution, filtrated Holstein dairy cow rumen fluid, and substrate (1 g total mixed ration). Nutrient digestibility was measured after 24 h and 48 h fermentation, and fermentation parameters and microbial composition were measured after 48 h fermentation. Digestibility of dry matter, crude protein, neutral detergent fiber (NDF), and acid detergent fiber (ADF) in the MD group at 48 h were significantly higher than in the CON and UR groups. The total volatile fatty acid concentration was higher in the MD group than in the other groups. In addition, 16S rRNA microbial sequencing results showed MD significantly improved the relative abundances of Succinivibrio, Anaerotruncus, and Treponema_2, whereas there was no significant difference between Met and UR groups. Spearman’s correlation analysis showed the relative abundance of Succinivibrio and Anaerotruncus were positively correlated with gas production, NDF digestibility, ADF digestibility, and acetate, propionate, butyrate, and total volatile fatty acid concentrations. Overall, our results suggested that the microbiota in the fermentation system could be affected by additional nitrogen supplementation and MD could effectively enhance the nutrient utilization in dairy cows.
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Affiliation(s)
- Fanlin Kong
- The State Key Laboratory of Animal Nutrition, Beijing Engineering Technology Research Center of Raw Milk Quality and Safety Control, College of Animal Science and Technology, China Agricultural University, Beijing 100193, China; (F.K.); (S.W.); (W.W.); (H.Y.)
| | - Yanfang Liu
- Beijing Jingwa Agricultural Science & Technology Innovation Center, Beijing 100193, China;
| | - Shuo Wang
- The State Key Laboratory of Animal Nutrition, Beijing Engineering Technology Research Center of Raw Milk Quality and Safety Control, College of Animal Science and Technology, China Agricultural University, Beijing 100193, China; (F.K.); (S.W.); (W.W.); (H.Y.)
| | - Yijia Zhang
- Laboratory of Anatomy of Domestic Animals, College of Veterinary Medicine, China Agricultural University, Beijing 100193, China;
| | - Wei Wang
- The State Key Laboratory of Animal Nutrition, Beijing Engineering Technology Research Center of Raw Milk Quality and Safety Control, College of Animal Science and Technology, China Agricultural University, Beijing 100193, China; (F.K.); (S.W.); (W.W.); (H.Y.)
| | - Hongjian Yang
- The State Key Laboratory of Animal Nutrition, Beijing Engineering Technology Research Center of Raw Milk Quality and Safety Control, College of Animal Science and Technology, China Agricultural University, Beijing 100193, China; (F.K.); (S.W.); (W.W.); (H.Y.)
| | - Na Lu
- Beijing Jingwa Agricultural Science & Technology Innovation Center, Beijing 100193, China;
- Correspondence: (N.L.); (S.L.); Tel.: +86-10-62731254 (S.L.)
| | - Shengli Li
- The State Key Laboratory of Animal Nutrition, Beijing Engineering Technology Research Center of Raw Milk Quality and Safety Control, College of Animal Science and Technology, China Agricultural University, Beijing 100193, China; (F.K.); (S.W.); (W.W.); (H.Y.)
- Correspondence: (N.L.); (S.L.); Tel.: +86-10-62731254 (S.L.)
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Kong F, Lu N, Liu Y, Zhang S, Jiang H, Wang H, Wang W, Li S. Aspergillus oryzae and Aspergillus niger Co-Cultivation Extract Affects In Vitro Degradation, Fermentation Characteristics, and Bacterial Composition in a Diet-Specific Manner. Animals (Basel) 2021; 11:1248. [PMID: 33926015 PMCID: PMC8145302 DOI: 10.3390/ani11051248] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2021] [Revised: 04/22/2021] [Accepted: 04/23/2021] [Indexed: 12/25/2022] Open
Abstract
AOAN may provide enzymes to improve the digestibility of feeds and enhance rumen fermentation. This study determined the effects of AOAN on digestibility, fermentation characteristics, and bacterial composition using in vitro gas recording fermentation system. A total of 30 mg of AOAN was supplemented into 500 mg of TMR, corn silage, oat hay, and alfalfa hay. Fermentation parameters and bacterial communities were determined after 48 h fermentation, and digestibility was determined after 7, 24, 30, and 48 h fermentation. Gas production and dry matter (DM), crude protein (CP), neutral detergent fiber (NDF), and acid detergent fiber (ADF) digestibility were significantly increased by AOAN supplementation at 48 h (p < 0.05), except for digestibility of CP of the TMR (p > 0.05). AOAN increased starch digestibility in corn silage (p < 0.05) and tended to increase that in TMR (0.05 < p < 0.10). AOAN supplementation increased total volatile fatty acid production (p < 0.05). The molar proportions of acetate and acetate to propionate ratio of oat hay and alfalfa hay were increased (p < 0.05). The 16S rRNA analysis revealed that the microbial richness of TMR and oat hay, and microbial evenness of TMR were increased (p < 0.05). AOAN did not affect the α diversity, β diversity, and bacterial composition of the corn silage. The relative abundance of Prevotella was increased and Ruminococcus was decreased in TMR, oat hay, and alfalfa hay. In conclusion, results suggest that AOAN has the potential to improve the utilization of diets differently, including providing enzymes with changing microbiota (TMR, oat hay, and alfalfa hay) or providing enzymes alone (corn silage).
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Affiliation(s)
- Fanlin Kong
- Beijing Engineering Technology Research Center of Raw Milk Quality and Safety Control, The State Key Laboratory of Animal Nutrition, College of Animal Science and Technology, China Agricultural University, Beijing 100193, China; (F.K.); (N.L.); (Y.L.); (S.Z.)
| | - Na Lu
- Beijing Engineering Technology Research Center of Raw Milk Quality and Safety Control, The State Key Laboratory of Animal Nutrition, College of Animal Science and Technology, China Agricultural University, Beijing 100193, China; (F.K.); (N.L.); (Y.L.); (S.Z.)
| | - Yanfang Liu
- Beijing Engineering Technology Research Center of Raw Milk Quality and Safety Control, The State Key Laboratory of Animal Nutrition, College of Animal Science and Technology, China Agricultural University, Beijing 100193, China; (F.K.); (N.L.); (Y.L.); (S.Z.)
| | - Shu Zhang
- Beijing Engineering Technology Research Center of Raw Milk Quality and Safety Control, The State Key Laboratory of Animal Nutrition, College of Animal Science and Technology, China Agricultural University, Beijing 100193, China; (F.K.); (N.L.); (Y.L.); (S.Z.)
| | - Hongqin Jiang
- China Representative Office, Ascor Chimici S.R.L., 201199 Bologna, Italy; (H.J.); (H.W.)
| | - Haomin Wang
- China Representative Office, Ascor Chimici S.R.L., 201199 Bologna, Italy; (H.J.); (H.W.)
| | - Wei Wang
- Beijing Engineering Technology Research Center of Raw Milk Quality and Safety Control, The State Key Laboratory of Animal Nutrition, College of Animal Science and Technology, China Agricultural University, Beijing 100193, China; (F.K.); (N.L.); (Y.L.); (S.Z.)
| | - Shengli Li
- Beijing Engineering Technology Research Center of Raw Milk Quality and Safety Control, The State Key Laboratory of Animal Nutrition, College of Animal Science and Technology, China Agricultural University, Beijing 100193, China; (F.K.); (N.L.); (Y.L.); (S.Z.)
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Zhang ZW, Wang YL, Chen YY, Zhang LT, Zhang YJ, Liu YQ, Guo YX, Yang HJ. The Dietary Supplemental Effect of Nitroethanol in Comparison with Monensin on Methane Emission, Growth Performance and Carcass Characteristics in Female Lambs. Animals (Basel) 2021; 11:ani11020327. [PMID: 33525565 PMCID: PMC7911303 DOI: 10.3390/ani11020327] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2020] [Revised: 01/17/2021] [Accepted: 01/19/2021] [Indexed: 12/02/2022] Open
Abstract
Simple Summary The objective of present study was to determine the effects of 2-nitroethanol (NEOH) in comparison with monensin on methane (CH4) emission, growth performance and carcass characteristics in female lambs. Both monensin and NEOH are potent CH4 inhibitors that can reduce dietary energy loss. The average daily gain (ADG) and feed conversion rate were improved with monensin and NEOH addition, suggesting that NEOH in comparison with monensin presented a similarly lasting beneficial effect on feed efficiency for female lambs. In addition, monensin and NEOH increased the net muscle percentage to carcass weight (p = 0.03), and they caused a reduction in feed consumption and feed costs resulting in a higher net revenue and economic efficiency. In summary, NEOH in comparison with monensin presented a greater promoting effect on energy utilization in the female feedlotting lambs by inhibiting rumen methanogenesis more efficiently. Abstract This study was conducted to evaluate the dietary supplemental effects of 2-nitroethanol (NEOH) in comparison with monensin on methane (CH4) emission, growth performance and carcass characteristics in female lambs. Sixty female, small-tailed Chinese Han lambs (3.5 ± 0.3 month) were randomly allotted into three dietary treatment groups: (1) Control group, a basal control diet, (2) monensin group, the basal diet added with 40 mg/kg monensin, (3) NEOH group, the basal diet added with 277 mg/kg nitroethanol, and the feedlotting trial lasted for 70 days. Although dietary addition of monensin and NEOH did not affect nutrient digestibility of lambs, both monensin and NEOH decreased the calculated CH4 production (12.7% vs. 17.4% decrease; p < 0.01). In addition, the CH4 production represents less dietary energy loss in the monensin and NEOH group than in the control, indicating that monensin and NEOH are potent CH4 inhibitors that can reduce dietary energy loss. Dietary addition of monensin and NEOH decreased dry matter intake (p < 0.01); however, they increased the ADG of female lambs (p < 0.01). As a result, both monensin and NEOH increased feed conversion efficiency of the feedlotting lambs (p < 0.01), suggesting that feed energy saved from CH4 production promoted the feed efficiency and ADG in the present study. Except for the fact that NEOH addition increased the net muscle percentage to carcass weight (p = 0.03), neither monensin nor NEOH had a significant influence on carcass characteristics of female lambs (p > 0.05). From an economic point of view, NEOH and monensin caused a reduction in feed consumption costs, therefore resulting in a higher net revenue and economic efficiency than the control. In summary, dietary supplementation of NEOH in comparison with monensin presented a more promoting effect on energy utilization in female lambs by inhibiting rumen methanogenesis more efficiently, and NEOH improved the net revenue and economic efficiency more significantly than monensin.
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Affiliation(s)
- Zhen-Wei Zhang
- State Key Laboratory of Animal Nutrition, College of Animal Science and Technology, China Agricultural University, Beijing 100193, China; (Z.-W.Z.); (Y.-L.W.); (Y.-Y.C.); (L.-T.Z.)
- Liaocheng Research Institute of Donkey High-Efficiency Breeding and Ecological Feeding, Liaocheng University, Liaocheng 252059, China
| | - Yan-Lu Wang
- State Key Laboratory of Animal Nutrition, College of Animal Science and Technology, China Agricultural University, Beijing 100193, China; (Z.-W.Z.); (Y.-L.W.); (Y.-Y.C.); (L.-T.Z.)
| | - Yong-Yan Chen
- State Key Laboratory of Animal Nutrition, College of Animal Science and Technology, China Agricultural University, Beijing 100193, China; (Z.-W.Z.); (Y.-L.W.); (Y.-Y.C.); (L.-T.Z.)
| | - Luo-Tong Zhang
- State Key Laboratory of Animal Nutrition, College of Animal Science and Technology, China Agricultural University, Beijing 100193, China; (Z.-W.Z.); (Y.-L.W.); (Y.-Y.C.); (L.-T.Z.)
| | - Ying-Jie Zhang
- College of Animal Science and Technology, Hebei Agricultural University, Baoding 071000, China; (Y.-J.Z.); (Y.-Q.L.)
| | - Yue-Qin Liu
- College of Animal Science and Technology, Hebei Agricultural University, Baoding 071000, China; (Y.-J.Z.); (Y.-Q.L.)
| | - Yun-Xia Guo
- College of Life Science, Hebei Agricultural University, Baoding 071000, China;
| | - Hong-Jian Yang
- State Key Laboratory of Animal Nutrition, College of Animal Science and Technology, China Agricultural University, Beijing 100193, China; (Z.-W.Z.); (Y.-L.W.); (Y.-Y.C.); (L.-T.Z.)
- Correspondence:
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Hua D, Zhao Y, Nan X, Xue F, Wang Y, Jiang L, Xiong B. Effect of different glucogenic to lipogenic nutrient ratios on rumen fermentation and bacterial community in vitro. J Appl Microbiol 2020; 130:1868-1882. [PMID: 32998176 PMCID: PMC8247007 DOI: 10.1111/jam.14873] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2020] [Revised: 09/21/2020] [Accepted: 09/22/2020] [Indexed: 12/22/2022]
Abstract
Aims This study was to investigate the effect of different ratios of glucogenic to lipogenic nutrients on rumen fermentation and the corresponding ruminal bacterial communities. Methods and Results Four diets, including glucogenic diet (G), lipogenic diet (L), two mixed diets: GL1 (G: L = 2 : 1) and GL2 (G:L = 1 : 2), served as substrates and were incubated with rumen fluid in vitro. The results revealed that the gas production, dry matter digestibility and propionate proportion were significantly increased by the G diet than others. The G diet increased the bacterial genera of Succinivibrionaceae_UCG_002, Succinivibrio, Selenomonas_1 and Ruminobacter but decreased some cellulolytic bacteria including the Eubacterium and several genera in family Ruminococcaceae than others. Conclusions When the glucogenic nutrient was above 1/3 of the dietary energy source among the four diets, the in vitro incubation had a higher feed digestibility and lower acetate to propionate ratio. Bacterial genera, including Selenomonas, Succinivibrio, Ruminobacter, certain genera in Ruminococcaceae, Christensenellaceae_R‐7_group and Eubacterium, were more sensitive to the glucogenic to lipogenic nutrients ratio. Significance and Impact of the Study The present study provides a new perspective about the effect of dietary glucogenic to lipogenic ingredient ratios on rumen metabolism by comparing end‐products, gas production and bacterial composition via an in vitro technique.
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Affiliation(s)
- D Hua
- State Key Laboratory of Animal Nutrition, Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, Beijing, China.,Animal Nutrition Group, Department of Animal Sciences, Wageningen University & Research, Wageningen, The Netherlands
| | - Y Zhao
- State Key Laboratory of Animal Nutrition, Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, Beijing, China
| | - X Nan
- State Key Laboratory of Animal Nutrition, Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, Beijing, China
| | - F Xue
- State Key Laboratory of Animal Nutrition, Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Y Wang
- State Key Laboratory of Animal Nutrition, Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, Beijing, China
| | - L Jiang
- Beijing Key Laboratory for Dairy Cattle Nutrition, Beijing Agricultural College, Beijing, China
| | - B Xiong
- State Key Laboratory of Animal Nutrition, Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, Beijing, China
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9
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Zhang Z, Wang Y, Si X, Cao Z, Li S, Yang H. Rumen Methanogenesis, Rumen Fermentation, and Microbial Community Response to Nitroethane, 2-Nitroethanol, and 2-Nitro-1-Propanol: An In Vitro Study. Animals (Basel) 2020; 10:ani10030479. [PMID: 32182983 PMCID: PMC7143717 DOI: 10.3390/ani10030479] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2020] [Revised: 03/01/2020] [Accepted: 03/05/2020] [Indexed: 11/16/2022] Open
Abstract
Nitroethane (NE), 2-nitroethanol (NEOH), and 2-nitro-1-propanol (NPOH) were comparatively examined to determine their inhibitory actions on rumen fermentation and methanogenesis in vitro. Fermentation characteristics, CH4 and total gas production, and coenzyme contents were determined at 6, 12, 24, 48, and 72 h incubation time, and the populations of ruminal microbiota were analyzed by real-time PCR at 72 h incubation time. The addition of NE, NEOH, and NPOH slowed down in vitro rumen fermentation and reduced the proportion of molar CH4 by 96.7%, 96.7%, and 41.7%, respectively (p < 0.01). The content of coenzymes F420 and F430 and the relative expression of the mcrA gene declined with the supplementation of NE, NEOH, and NPOH in comparison with the control (p < 0.01). The addition of NE, NEOH, and NPOH decreased total volatile fatty acids (VFAs) and acetate (p < 0.05), but had no effect on propionate concentration (p > 0.05). Real-time PCR results showed that the relative abundance of total methanogens, Methanobacteriales, Methanococcales, and Fibrobacter succinogenes were reduced by NE, NEOH, and NPOH (p < 0.05). In addition, the nitro-degradation rates in culture fluids were ranked as NEOH (-0.088) > NE (-0.069) > NPOH (-0.054). In brief, the results firstly provided evidence that NE, NEOH, and NPOH were able to decrease methanogen abundance and dramatically decrease mcrA gene expression and coenzyme F420 and F430 contents with different magnitudes to reduce ruminal CH4 production.
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10
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Zhang ZW, Wang YL, Wang WK, Chen YY, Si XM, Wang YJ, Wang W, Cao ZJ, Li SL, Yang HJ. The Antimethanogenic Nitrocompounds Can be Cleaved into Nitrite by Rumen Microorganisms: A Comparison of Nitroethane, 2-Nitroethanol, and 2-Nitro-1-propanol. Metabolites 2019; 10:E15. [PMID: 31881649 PMCID: PMC7023367 DOI: 10.3390/metabo10010015] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2019] [Revised: 12/16/2019] [Accepted: 12/20/2019] [Indexed: 11/16/2022] Open
Abstract
A class of aliphatic short chain nitrocompounds have been reported as being capable of CH4 reduction both in vitro and in vivo. However, the laboratory evidence associated with the metabolic fate of nitrocompounds in the rumen has not been well documented. The present study was conducted to compare in vitro degradation and metabolism of nitroethane (NE), 2-nitroethanol (NEOH), and 2-nitro-1-propanol (NPOH) incubated with mixed rumen microorganisms of dairy cows. After 10 mM supplementation of nitrocompounds, a serious of batch cultures were carried out for 120 h under the presence of two substrates differing in the ratio of maize meal to alfalfa hay (HF, 1:4; LF, 4:1). Compared to the control, methane production was reduced by 59% in NPOH and by >97% in both NE and NEOH, and such antimethanogenic effects were more pronounced in the LF than the HF group. Although NE, NEOH, and NPOH addition did not alter total VFA production, the rumen fermentation pattern shifted toward increasing propionate and butyrate and decreasing acetate production. The kinetic disappearance of each nitrocompound was well fitted to the one-compartment model, and the disappearance rate (k, %/h) of NE was 2.6 to 5.2 times greater than those of NEOH and NPOH. Higher intermediates of nitrite occurred in NEOH in comparison with NPOH and NE while ammonia N production was lowest in NEOH. Consequently, a stepwise accumulation of bacterial crude protein (BCP) in response to the nitrocompound addition was observed in both the HF and LF group. In brief, both NE and NEOH in comparison with NPOH presented greater antimethanogenic activity via the shift of rumen fermentation. In addition, the present study provided the first direct evidence that rumen microbes were able to cleave these nitrocompounds into nitrite, and the subsequent metabolism of nitrite into ammonia N may enhance the growth of rumen microbes or promote microbial activities.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | - Hong-Jian Yang
- State Key Laboratory of Animal Nutrition, College of Animal Science and Technology, China Agricultural University, Beijing 100193, China; (Z.-W.Z.); (Y.-L.W.); (W.-K.W.); (Y.-Y.C.); (X.-M.S.); (Y.-J.W.); (W.W.); (Z.-J.C.); (S.-L.L.)
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11
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Muetzel S, Ronimus RS, Lunn K, Kindermann M, Duval S, Tavendale M. A small scale rumen incubation system to screen chemical libraries for potential methane inhibitors. Anim Feed Sci Technol 2018. [DOI: 10.1016/j.anifeedsci.2018.08.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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12
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13
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Anderson RC, Ripley LH, Bowman JGP, Callaway TR, Genovese KJ, Beier RC, Harvey RB, Nisbet DJ. Ruminal Fermentation of Anti-Methanogenic Nitrate- and Nitro-Containing Forages In Vitro. Front Vet Sci 2016; 3:62. [PMID: 27563646 PMCID: PMC4980585 DOI: 10.3389/fvets.2016.00062] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2016] [Accepted: 07/28/2016] [Indexed: 11/20/2022] Open
Abstract
Nitrate, 3-nitro-1-propionic acid (NPA) and 3-nitro-1-propanol (NPOH) can accumulate in forages and be poisonous to animals if consumed in high enough amounts. These chemicals are also recognized as potent anti-methanogenic compounds, but plants naturally containing these chemicals have been studied little in this regard. Presently, we found that nitrate-, NPA-, or NPOH-containing forages effectively decreased methane production, by 35–87%, during in vitro fermentation by mixed cultures of ruminal microbes compared to fermentation by cultures incubated similarly with alfalfa. Methane production was further decreased during the incubation of mixed cultures also inoculated with Denitrobacterium detoxificans, a ruminal bacterium known to metabolize nitrate, NPA, and NPOH. Inhibition of methanogens within the mixed cultures was greatest with the NPA- and NPOH-containing forages. Hydrogen accumulated in all the mixed cultures incubated with forages containing nitrate, NPA or NPOH and was dramatically higher, exceeding 40 μmol hydrogen/mL, in mixed cultures incubated with NPA-containing forage but not inoculated with D. detoxificans. This possibly reflects the inhibition of hydrogenase-catalyzed uptake of hydrogen produced via conversion of 50 μmol added formate per milliliter to hydrogen. Accumulations of volatile fatty acids revealed compensatory changes in fermentation in mixed cultures incubated with the nitrate-, NPA-, and NPOH-containing forages as evidenced by lower accumulations of acetate, and in some cases, higher accumulations of butyrate and lower accumulations of ammonia, iso-buytrate, and iso-valerate compared to cultures incubated with alfalfa. Results reveal that nitrate, NPA, and NPOH that accumulate naturally in forages can be made available within ruminal incubations to inhibit methanogenesis. Further research is warranted to determine if diets can be formulated with nitrate-, NPA-, and NPOH-containing forages to achieve efficacious mitigation in ruminant methane emissions without adversely affecting fermentative efficiency or risking toxicity to animals.
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Affiliation(s)
- Robin C Anderson
- Food and Feed Safety Research Unit, United States Department of Agriculture Agricultural Research Service , College Station, TX , USA
| | - Laura H Ripley
- Food and Feed Safety Research Unit, United States Department of Agriculture Agricultural Research Service , College Station, TX , USA
| | - Jan G P Bowman
- Department of Animal and Range Sciences, Montana State University , Bozeman, MT , USA
| | - Todd R Callaway
- Food and Feed Safety Research Unit, United States Department of Agriculture Agricultural Research Service , College Station, TX , USA
| | - Kenneth J Genovese
- Food and Feed Safety Research Unit, United States Department of Agriculture Agricultural Research Service , College Station, TX , USA
| | - Ross C Beier
- Food and Feed Safety Research Unit, United States Department of Agriculture Agricultural Research Service , College Station, TX , USA
| | - Roger B Harvey
- Food and Feed Safety Research Unit, United States Department of Agriculture Agricultural Research Service , College Station, TX , USA
| | - David J Nisbet
- Food and Feed Safety Research Unit, United States Department of Agriculture Agricultural Research Service , College Station, TX , USA
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14
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Sofyan A, Sakti AA, Herdian H, Khairulli G, Suryani AE, Karti PDMH, Jayanegara A. In vitro gas production kinetics and digestibility of king grass (Pennisetum hybrid) added by organic mineral and natural crude tannin. JOURNAL OF APPLIED ANIMAL RESEARCH 2016. [DOI: 10.1080/09712119.2015.1129339] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Affiliation(s)
- Ahmad Sofyan
- Division of Feed and Animal Nutrition, Research Unit for Chemical Processes Development and Engineering (UPT. BPPTK), Indonesian Institute of Sciences (LIPI), Gading, Playen, Gunungkidul DI. Yogyakarta,Indonesia
| | - Awistaros Angger Sakti
- Division of Feed and Animal Nutrition, Research Unit for Chemical Processes Development and Engineering (UPT. BPPTK), Indonesian Institute of Sciences (LIPI), Gading, Playen, Gunungkidul DI. Yogyakarta,Indonesia
| | - Hendra Herdian
- Division of Feed and Animal Nutrition, Research Unit for Chemical Processes Development and Engineering (UPT. BPPTK), Indonesian Institute of Sciences (LIPI), Gading, Playen, Gunungkidul DI. Yogyakarta,Indonesia
| | - Gumilang Khairulli
- Department of Animal Nutrition and Feed Technology, Faculty of Animal Sciences, Bogor Agricultural University (IPB), Bogor, Indonesia
| | - Ade Erma Suryani
- Division of Feed and Animal Nutrition, Research Unit for Chemical Processes Development and Engineering (UPT. BPPTK), Indonesian Institute of Sciences (LIPI), Gading, Playen, Gunungkidul DI. Yogyakarta,Indonesia
| | - Panca Dewi Manu Hara Karti
- Department of Animal Nutrition and Feed Technology, Faculty of Animal Sciences, Bogor Agricultural University (IPB), Bogor, Indonesia
| | - Anuraga Jayanegara
- Department of Animal Nutrition and Feed Technology, Faculty of Animal Sciences, Bogor Agricultural University (IPB), Bogor, Indonesia
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15
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Romero-Pérez A, Okine E, Guan L, Duval S, Kindermann M, Beauchemin K. Effects of 3-nitrooxypropanol on methane production using the rumen simulation technique (Rusitec). Anim Feed Sci Technol 2015. [DOI: 10.1016/j.anifeedsci.2015.09.002] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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16
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Wang M, Wang R, Yang S, Deng JP, Tang SX, Tan ZL. Effects of three methane mitigation agents on parameters of kinetics of total and hydrogen gas production, ruminal fermentation and hydrogen balance usingin vitrotechnique. Anim Sci J 2015. [DOI: 10.1111/asj.12423] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Min Wang
- Key Laboratory for Agro‐Ecological Processes in Subtropical Region, Hunan Research Center of Livestock & Poultry Sciences, South‐Central Experimental Station of Animal Nutrition and Feed Science in the Ministry of AgricultureInstitute of Subtropical Agriculture, The Chinese Academy of Sciences Beijing China
| | - Rong Wang
- Key Laboratory for Agro‐Ecological Processes in Subtropical Region, Hunan Research Center of Livestock & Poultry Sciences, South‐Central Experimental Station of Animal Nutrition and Feed Science in the Ministry of AgricultureInstitute of Subtropical Agriculture, The Chinese Academy of Sciences Beijing China
- College of Animal Science and TechnologyHunan Agricultural University Changsha China
| | - Shan Yang
- Department of Biological and Environmental EngineeringChangsha University Changsha China
| | - Jin Ping Deng
- College of Animal Science and TechnologyHunan Agricultural University Changsha China
| | - Shao Xun Tang
- Key Laboratory for Agro‐Ecological Processes in Subtropical Region, Hunan Research Center of Livestock & Poultry Sciences, South‐Central Experimental Station of Animal Nutrition and Feed Science in the Ministry of AgricultureInstitute of Subtropical Agriculture, The Chinese Academy of Sciences Beijing China
| | - Zhi Liang Tan
- Key Laboratory for Agro‐Ecological Processes in Subtropical Region, Hunan Research Center of Livestock & Poultry Sciences, South‐Central Experimental Station of Animal Nutrition and Feed Science in the Ministry of AgricultureInstitute of Subtropical Agriculture, The Chinese Academy of Sciences Beijing China
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17
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Characterization of bovine ruminal and equine cecal microbial populations enriched for enhanced nitro-toxin metabolizing activity. Anaerobe 2014; 26:7-13. [PMID: 24374155 DOI: 10.1016/j.anaerobe.2013.12.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2013] [Revised: 12/12/2013] [Accepted: 12/17/2013] [Indexed: 11/21/2022]
Abstract
The nitrotoxins 3-nitro-1-propionic acid (NPA) and 3-nitro-1-propanol (NPOH) are produced by a wide variety of leguminous plants, including over 150 different species and varieties of Astragalus potentially grazed by livestock. These toxins are known to be detoxified by at least one ruminal bacterium but detoxification by bacteria from other gut habitats is not known. In the present study, mixed populations of bovine ruminal and equine cecal microbes were enriched for NPA-metabolizing bacteria via consecutive 24-72 h culture in a basal minimal rumen fluid-based medium supplemented with 4.2 mM NPA and H₂ as the energy source. Rates of NPA metabolism by the respective populations increased from 58.4 ± 4.8 and 8.6 ± 11.6 nmol NPA/mL per h during initial culture to 88.9 ± 30.6 and 50.2 ± 30.9 nmol NPA/mL per h following enrichment. Results from 3-tube most probable number tests indicated that numbers of NPA-degrading microbes increased 2.1 and 1.8 log₁₀ units during enrichment from numbers measured pre-enrichment (3.9 × 10³ and 4.3 × 10¹ cells/mL for ruminal and equine cecal populations, respectively). Hydrogen, formate, and to a lesser extent, DL-lactic acid, served as electron donors to the enriched populations and CO₂ or formate were needed to maintain high rates of NPA-metabolism. The NPA-enriched populations were able to metabolize nitrate which, being a preferred electron acceptor, was antagonistic to NPA metabolism. Supplemental NPA was inhibitory to methanogenesis. Fermentation balance estimates indicated that only 47.6% of carbon available in potential substrates was recovered in headspace CO₂, volatile fatty acids or unmetabolized NPA after 72 h incubation of NPA-enriched populations that had metabolized 98% of 8.4 mM added NPA. Overall, these results reveal low level carriage of NPA-metabolizing, CO₂ or formate-requiring bacterial populations in the equine cecum yet support the concept that Denitrobacterium detoxificans-like organisms may well be the functional agents of NPA and NPOH detoxification in the populations studied here.
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