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Xiang R, McNally J, Bond J, Tucker D, Cameron M, Donaldson AJ, Austin KL, Rowe S, Jonker A, Pinares-Patino CS, McEwan JC, Vercoe PE, Oddy VH, Dalrymple BP. Across-Experiment Transcriptomics of Sheep Rumen Identifies Expression of Lipid/Oxo-Acid Metabolism and Muscle Cell Junction Genes Associated With Variation in Methane-Related Phenotypes. Front Genet 2018; 9:330. [PMID: 30177952 PMCID: PMC6109778 DOI: 10.3389/fgene.2018.00330] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2018] [Accepted: 07/31/2018] [Indexed: 01/03/2023] Open
Abstract
Ruminants are significant contributors to the livestock generated component of the greenhouse gas, methane (CH4). The CH4 is primarily produced by the rumen microbes. Although the composition of the diet and animal intake amount have the largest effect on CH4 production and yield (CH4 production/dry matter intake, DMI), the host also influences CH4 yield. Shorter rumen feed mean retention time (MRT) is associated with higher dry matter intake and lower CH4 yield, but the molecular mechanism(s) by which the host affects CH4 production remain unclear. We integrated rumen wall transcriptome data and CH4 phenotypes from two independent experiments conducted with sheep in Australia (AUS, n = 62) and New Zealand (NZ, n = 24). The inclusion of the AUS data validated the previously identified clusters and gene sets representing rumen epithelial, metabolic and muscular functions. In addition, the expression of the cell cycle genes as a group was consistently positively correlated with acetate and butyrate concentrations (p < 0.05, based on AUS and NZ data together). The expression of a group of metabolic genes showed positive correlations in both AUS and NZ datasets with CH4 production (p < 0.05) and yield (p < 0.01). These genes encode key enzymes in the ketone body synthesis pathway and included members of the poorly characterized aldo-keto reductase 1C (AKR1C) family. Several AKR1C family genes appear to have ruminant specific evolution patterns, supporting their specialized roles in the ruminants. Combining differential gene expression in the rumen wall muscle of the shortest and longest MRT AUS animals (no data available for the NZ animals) with correlation and network analysis, we identified a set of rumen muscle genes involved in cell junctions as potential regulators of MRT, presumably by influencing contraction rates of the smooth muscle component of the rumen wall. Higher rumen expression of these genes, including SYNPO (synaptopodin, p < 0.01) and NEXN (nexilin, p < 0.05), was associated with lower CH4 yield in both AUS and NZ datasets. Unlike the metabolic genes, the variations in the expression of which may reflect the availability of rumen metabolites, the muscle genes are currently our best candidates for causal genes that influence CH4 yield.
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Affiliation(s)
- Ruidong Xiang
- CSIRO Agriculture & Food, Queensland Bioscience Precinct, St Lucia, QLD, Australia.,Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, Parkville, VIC, Australia.,Agriculture Victoria, AgriBio, Centre for AgriBioscience, Bundoora, VIC, Australia
| | - Jody McNally
- F. D. McMaster Laboratory, CSIRO Agriculture & Food, Armidale, NSW, Australia
| | - Jude Bond
- NSW Department of Primary Industries, Extensive Livestock Industries Centre, University of New England, Armidale, NSW, Australia
| | - David Tucker
- NSW Department of Primary Industries, Extensive Livestock Industries Centre, University of New England, Armidale, NSW, Australia
| | - Margaret Cameron
- NSW Department of Primary Industries, Extensive Livestock Industries Centre, University of New England, Armidale, NSW, Australia
| | - Alistair J Donaldson
- NSW Department of Primary Industries, Extensive Livestock Industries Centre, University of New England, Armidale, NSW, Australia
| | - Katie L Austin
- NSW Department of Primary Industries, Extensive Livestock Industries Centre, University of New England, Armidale, NSW, Australia
| | - Suzanne Rowe
- Invermay Agricultural Centre, AgResearch Limited, Mosgiel, New Zealand
| | - Arjan Jonker
- Grasslands Research Centre, AgResearch Limited, Palmerston North, New Zealand
| | - Cesar S Pinares-Patino
- Grasslands Research Centre, AgResearch Limited, Palmerston North, New Zealand.,New Zealand-Peru Dairy Support Project, MINAGRI, Lima, Peru
| | - John C McEwan
- Invermay Agricultural Centre, AgResearch Limited, Mosgiel, New Zealand
| | - Phil E Vercoe
- School of Animal Biology, The University of Western Australia, Crawley, WA, Australia.,Institute of Agriculture, The University of Western Australia, Crawley, WA, Australia
| | - V H Oddy
- NSW Department of Primary Industries, Extensive Livestock Industries Centre, University of New England, Armidale, NSW, Australia
| | - Brian P Dalrymple
- CSIRO Agriculture & Food, Queensland Bioscience Precinct, St Lucia, QLD, Australia.,Institute of Agriculture, The University of Western Australia, Crawley, WA, Australia
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Hussein HS, Merchen NR, Fahey GC. Effects of chemical treatment of whole canola seed on digestion of long-chain fatty acids by steers fed high or low forage diets. J Dairy Sci 1996; 79:87-97. [PMID: 8675787 DOI: 10.3168/jds.s0022-0302(96)76338-5] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
The objective was to evaluate the effectiveness of alkaline H2O2 treatment of whole canola seed as a means of weakening the seed coat while simultaneously protecting long-chain unsaturated fatty acids from ruminal biohydrogenation without hindering their digestion in the lower gut. Six ruminally and duodenally cannulated beef steers were offered six isonitrogenous diets for ad libitum intake twice daily in a 6 x 6 Latin square design. Treatments were arranged as a 2 x 3 factorial with two forage percentages (70 vs. 30% of dietary DM as corn silage) and three forms of canola seed supplementation, including no canola seed or canola seed added at 10% of dietary DM as treated whole seed or as crushed seed. Canola seed contributed 5% added fat to the total diet. Treated whole canola seed was superior to crushed seed in increasing the amounts of C18:1, C18:2, and C18:3 flowing to the duodenum and the amounts digested postruminally. However, digestibilities of these long-chain fatty acids (as percentages of the amounts entering the small intestine) did not differ between diets containing canola seed as treated whole seed or crushed seed. Results suggest that chemically treated whole canola seed can be used as a means of postruminal delivery of digestible long-chain unsaturated fatty acids, especially C18:1, which contributes 62% of the total fatty acids in canola seed. Results also suggest that treated whole canola seed may be more beneficial when fed with low than with high forage diets.
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Affiliation(s)
- H S Hussein
- Department of Animal Sciences, University of Illinois, Urbana 61801, USA
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Bauchart D, Doreau M, Kindler A. Effect of fat and lactose supplementation on digestion in dairy cows. 2. Long-chain fatty acids. J Dairy Sci 1987; 70:71-80. [PMID: 3571628 DOI: 10.3168/jds.s0022-0302(87)79981-0] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Dairy cows fitted with rumen and proximal duodenal cannulae were given diets of 60% hay, 7% soybean and rapeseed meal, and either 33% concentrate (control diet) or 33% milk (lipid-supplemented diet: "milk" diet). Amounts of total long-chain fatty acids consumed, entering the duodenum and excreted in the feces were examined. Long-chain fatty acid intake was 192 and 764 g/d with the control and milk diets, respectively. The duodenal flow of long-chain fatty acids was greater (17.3%) than the amount consumed when the control diet was fed; with the milk diet, there was a net loss (-22.2%), mainly due to a decrease in total C16 and C18 acids. The extent of C18:2 hydrogenation in the rumen was reduced by the high fat ration, but for C18:3, hydrogenation was very high and unchanged. Apparent intestinal digestibility of fatty acids was high, especially on the milk diet (86.1%), although the amount of fatty acids absorbed (60.6 g/kg dry matter intake/d) was three times greater than with the control.
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Taylor JA, Jackson HD. Formation of ketone bodies from [14C]palmitate and [14C]glycerol by tissues from ketotic sheep. Biochem J 1968; 106:289-92. [PMID: 5721464 PMCID: PMC1198497 DOI: 10.1042/bj1060289] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
Labelled ketone bodies were produced readily from [U-(14)C]palmitate, [2-(14)C]palmitate and [1-(14)C]glycerol by sheep rumen-epithelial and liver tissues in vitro. On a tissue-nitrogen basis, both tissues had similar capacities for ketogenesis. Palmitate was a ketogenic substrate in both rumen-epithelial tissue and liver, and more of its (14)C appeared in ketone bodies than in the (14)CO(2) liberated. Glycerol was actively metabolized to ketone bodies, but more readily underwent complete oxidation to carbon dioxide; this complete oxidation was most pronounced in rumen-epithelial tissue from ketotic ewes. These experiments with labelled compounds confirm earlier observations that rumen-epithelial tissue, like liver, actively forms ketone bodies from long-chain fatty acids and show further that normal rumen-epithelial tissue can convert palmitate into ketone bodies as readily as into carbon dioxide. Free glycerol, which is metabolized only by liver tissue in non-ruminants, is also metabolized by rumen epithelium. The rumen epithelium thus has unique metabolic capacity among extrahepatic tissues.
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Hird FJ, Jackson RB, Weidemann MJ. Transport and metabolism of fatty acids by isolated rumen epithelium. Biochem J 1966; 98:394-400. [PMID: 5941335 PMCID: PMC1264857 DOI: 10.1042/bj0980394] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
1. The metabolism of even-numbered saturated (acetic acid to stearic acid) and unsaturated (oleic acid and linolenic acid) fatty acids by diaphragms of isolated rumen epithelium has been investigated. 2. When fatty acids are presented to the papillae surface, ketone bodies are released from the opposite (muscle) side of the tissue. 3. When the concentration of octanoate or decanoate is increased to a critical value, which varies inversely with the chain length of the fatty acid, the respiration of the tissue is inhibited and ketone body synthesis is diminished. Under these conditions unmetabolized fatty acid crosses the tissue down a concentration gradient. 4. The inhibitions by octanoate and decanoate are more marked when the fatty acid is presented to both surfaces of the rumen epithelium. 5. During the oxidation of octanoate and decanoate at non-inhibitory concentrations, small quantities of shorter chain fatty acids, including acetate, are produced.
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