Nuclear Magnetic Resonance to Detect Rumen Metabolites Associated with Enteric Methane Emissions from Beef Cattle

Abstract

this study presents the application of metabolomics to evaluate changes in the rumen metabolites of beef cattle fed with three different diet types: forage-rich, mixed and concentrate-rich. Rumen fluid samples were analysed by 1 H-nMR spectroscopy and the resulting spectra were used to characterise and compare metabolomic profiles between diet types and assess the potential for NMR metabolite signals to be used as proxies of methane emissions (CH 4 in g/kg DMi). the dataset available consisted of 128 measurements taken from 4 experiments with CH 4 measurements taken in respiration chambers. predictive modelling of cH 4 was conducted by partial least squares (PLS) regression, fitting calibration models either using metabolite signals only as predictors or using metabolite signals as well as other diet and animal covariates (DMI, ME, weight, BW 0.75 , DMI/BW 0.75). cross-validated R 2 were 0.57 and 0.70 for the two models respectively. The cattle offered the concentrate-rich diet showed increases in alanine, valerate, propionate, glucose, tyrosine, proline and isoleucine. Lower methane yield was associated with the concentrate-rich diet (p < 0.001). The results provided new insight into the relationship between rumen metabolites, CH 4 production and diets, as well as showing that metabolites alone have an acceptable association with the variation in cH 4 production from beef cattle. Livestock production is the largest anthropogenic contributor to the global CH 4 budget (103 [95-109] Tg CH 4 yr−1 during 2000-2009) 1 , with enteric CH 4 emissions being the largest contributors to this (87-97 Tg CH 4 yr−1 during 2000-2009) 1-3. Methane is a potent greenhouse gas (GHG) with a global warming potential (GWP) 28 times higher than carbon dioxide (CO 2), with a 12-year atmospheric lifetime 4 and it contributes significantly to stratospheric ozone depletion 5. Methane production is also associated with a net loss of energy to the animal, ranging from 2-12% of energy intake 6. Methane production is mainly associated with fermentation of feed and occurs primarily in the rumen, with the rest (11% in one study) occurring in the lower hindgut 7. Rumen methanogens principally utilise H 2 and CO 2 to produce CH 4 in the hydrogenotrophic pathway. Acetate and butyrate production results in more H 2 being produced and available for CH 4 production, whilst propionate results in less, as propionate production uses up H 2 , leaving less available for CH 4 production 8,9. Until recently, this was thought to be the sole pathway for CH 4 production. However, another group of methanogens uses methyl-containing metabolites such as methanol and methylamine to produce CH 4 , utilising the methylotrophic methanogenic pathway 10. This pathway is found in the Thermoplasmata genus of archaea showing enhanced growth when given methylamine supplements. The contribution of these substrates to CH 4 production has not been assessed as yet, although it is known that these archaea can be stimulated by increasing dietary pectin concentrations, as well as i...

The Rumen Microbiome Inhibits Methane Formation Through Dietary Choline Supplementation

“…The concentration of VFA was analysed using HPLC (System Hitachi Lachrom; Merck, Tokyo, Japan) following the procedure of Ehrlich et al 51 . Various metabolites were identi ed and quanti ed by NMR ( 52 . If necessary, additional data from DQF-COSY, TOCSY, HSQC and HMBC spectra recorded for speci c samples were used for this purpose.…”

Comparison of HPLC and NMR for Quantification of The Main Volatile Fatty Acids in Rumen Digesta

“…The details of the performed 1 H-NMR experiment can be found in Bica et al [23]. Chenomx NMR suite tool (v6.1; Chenomx, Canada) was used to identify and quantify rumen metabolites based on 1H-NMR spectra, as reported by Ametaj et al [43] and Jung et al [44].…”

Metabolomics Comparison of Hanwoo (Bos taurus coreanae) Biofluids Using Proton Nuclear Magnetic Resonance Spectroscopy

“…-acetylglycine, (10) trimethylamine, (11) alanine, (12) 3-hydroxyphenylacetate, (13) cadaverine, (14) methylamine, (15) choline, (16) dimethylamine, (17) ethanol, (18) adenine, (19) anserine, (20) isoleucine, (21) phenylalanine, (22) uridine, (23) tyrosine, (24) galacarate, (25) threonine, (26) leucine, (27) methionine, (28) xanthine, (29) uracil, (30) ô-methylhistidine, (31) sucrose, (32) p-Cresol, (33) mannose, (34) O-acetylcholine, (35) creatine phosphate, (36) choline, (37) hypoxanthine, (38) gentisate, (39) thymidine, (40) malonate, (41) benzoate, (42) acetoacetate, (43) isopropanol, (44) 1,7-dimethylxanthine, (45)…”

“…-acetylglycine, (10) trimethylamine, (11) alanine, (12) 3-hydroxyphenylacetate, (13) cadaverine, (14) methylamine, (15) choline, (16) dimethylamine, (17) ethanol, (18) adenine, (19) anserine, (20) isoleucine, (21) phenylalanine, (22) uridine, (23) tyrosine, (24) galacarate, (25) threonine, (26) leucine, (27) methionine, (28) xanthine, (29)…”

“…Since then, similar studies of ruminant biofluids have been conducted [10]. Representative metabolomics data on various ruminant biofluids (rumen fluid, serum, plasma, milk, urine, and feces) have been applied to increase global productivity [11,12], identify metabolic changes due to heat stress [13,14], reduce methane emissions to prevent global warming [15,16], and explore biomarkers to aid on metabolic disease prevention [17][18][19].…”