• Animal Bioscience
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• v.34 no.2
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• pp.213-222
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• 2021

Objective: The metabolites that constitute the rumen fluid and milk in dairy cattle were analyzed using proton nuclear magnetic resonance (1H-NMR) spectroscopy and compared with the results obtain for other dairy cattle herds worldwide. The aim was to provide basic dataset for facilitating research on metabolites in rumen fluid and milk. Methods: Six dairy cattle were used in this study. Rumen fluid was collected using a stomach tube, and milk was collected using a pipeline milking system. The metabolites were determined by 1H-NMR spectroscopy, and the obtained data were statistically analyzed by principal component analysis, partial least squares discriminant analysis, variable importance in projection scores, and metabolic pathway data using Metaboanalyst 4.0. Results: The total numbers of metabolites in rumen fluid and milk were measured to be 186 and 184, and quantified as 72 and 109, respectively. Organic acid and carbohydrate metabolites exhibited the highest concentrations in rumen fluid and milk, respectively. Some metabolites that have been associated with metabolic diseases (acidosis and ketosis) in cows were identified in rumen fluid, and metabolites associated with ketosis, somatic cell production, and coagulation properties were identified in milk. Conclusion: The metabolites measured in rumen fluid and milk could potentially be used to detect metabolic diseases and evaluate milk quality. The results could also be useful for metabolomic research on the biofluids of ruminants in Korea, while facilitating their metabolic research.

• Animal Bioscience
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• v.36 no.1
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• pp.53-62
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• 2023

Objective: In this study, metabolites that changed in the rumen fluid, urine and feces of dairy cows fed different feed ratios were investigated. Methods: Eight Holstein cows were used in this study. Rumen fluid, urine, and feces were collected from the normal concentrate diet (NCD) (Italian ryegrass 80%: concentrate 20% in the total feed) and high concentrate diet (HCD) groups (20%: 80%) of dairy cows. Metabolite analysis was performed using proton nuclear magnetic resonance (NMR) identification, and statistical analysis was performed using Chenomx NMR software 8.4 and Metaboanalyst 4.0. Results: The two groups of rumen fluid and urine samples were separated, and samples from the same group were aggregated together. On the other hand, the feces samples were not separated and showed similar tendencies between the two groups. In total, 160, 177, and 188 metabolites were identified in the rumen fluid, urine, and feces, respectively. The differential metabolites with low and high concentrations were 15 and 49, 14 and 16, and 2 and 2 in the rumen fluid, urine, and feces samples, in the NCD group. Conclusion: As HCD is related to rumen microbial changes, research on different metabolites such as glucuronate, acetylsalicylate, histidine, and O-Acetylcarnitine, which are related to bacterial degradation and metabolism, will need to be carried out in future studies along with microbial analysis. In urine, the identified metabolites, such as gallate, syringate, and vanillate can provide insight into microbial, metabolic, and feed parameters that cause changes depending on the feed rate. Additionally, it is thought that they can be used as potential biomarkers for further research on subacute ruminal acidosis.

• Animal Bioscience
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• v.35 no.10
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• pp.1535-1544
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• 2022

Objective: The objective of this study was to investigate the effects of decreasing dietary crude protein content on rumen fermentation, mictobiota, and metabolites in goats. Methods: In an 84-day feeding trial, a total of twelve male Anhui white goat kids with initial body weight 15.9±1.13 kg were selected and randomly classified into two groups, feeding a normal crude protein diet (14.8% CP, NCP) or a low crude protein diet (12.0% CP, LCP). At the end of the experimental trial (on day 84), six animals were randomly selected from each group and were slaughtered to collect rumen fluid samples for the analysis of rumen fermentation parameters, microbiome, and metabolome. Results: The concentrations of ammonia-nitrogen, total volatile fatty acid, acetate, and propionate were decreased (p<0.05) in the LCP group in comparison with those in the NCP group. The abundances of genera Prevotella, Campylobacter, Synergistetes, and TG5, which were associated with nitrogen metabolism, were lower (p<0.05) in the LCP group compared with those in the NCP group. The levels of 78 metabolites (74 decreased, 4 increased) in the rumen fluid were altered (p<0.05) by the treatment. Most of the ruminal metabolites that showed decreased levels in the LCP group were substrates for microbial protein synthesis. Metabolic pathway analysis showed that vitamin B6 metabolism was significantly different (p<0.05) in rumen fluid between the two treatments. Conclusion: Decreased dietary protein level inhibited rumen fermentation through microbiome and metabolome shifts in goat kids. These results enhance our understanding of ruminal bacteria and metabolites of goat fed a low protein diet.

• Asian-Australasian Journal of Animal Sciences
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• v.33 no.1
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• pp.79-90
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• 2020

Objective: In the present study, an liquid chromatography/mass spectrometry (LC/MS) metabolomics approach was performed to investigate potential biomarkers of milk production in high- and low-milk-yield dairy cows and to establish correlations among rumen fluid metabolites. Methods: Sixteen lactating dairy cows with similar parity and days in milk were divided into high-yield (HY) and low-yield (LY) groups based on milk yield. On day 21, rumen fluid metabolites were quantified applying LC/MS. Results: The principal component analysis and orthogonal correction partial least squares discriminant analysis showed significantly separated clusters of the ruminal metabolite profiles of HY and LY groups. Compared with HY group, a total of 24 ruminal metabolites were significantly greater in LY group, such as 3-hydroxyanthranilic acid, carboxylic acids, carboxylic acid derivatives (L-isoleucine, L-valine, L-tyrosine, etc.), diazines (uracil, thymine, cytosine), and palmitic acid, while the concentrations of 30 metabolites were dramatically decreased in LY group compared to HY group, included gentisic acid, caprylic acid, and myristic acid. The metabolite enrichment analysis indicated that protein digestion and absorption, ABC transporters and unsaturated fatty acid biosynthesis were significantly different between the two groups. Correlation analysis between the ruminal microbiome and metabolites revealed that certain typical metabolites were exceedingly associated with definite ruminal bacteria; Firmicutes, Actinobacteria, and Synergistetes phyla were highly correlated with most metabolites. Conclusion: These findings revealed that the ruminal metabolite profiles were significantly different between HY and LY groups, and these results may provide novel insights to evaluate biomarkers for a better feed digestion and may reveal the potential mechanism underlying the difference in milk yield in dairy cows.

• Asian-Australasian Journal of Animal Sciences
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• v.31 no.8
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• pp.1230-1237
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• 2018

Objective: The present study was undertaken to determine an optimal balance between the amount of physically effective neutral detergent fiber (peNDF) to metabolizable glucose (MG) on rumen fermentation, blood metabolites and growth performance of 8 to 10-month-old heifers. Methods: A total of 15 healthy Holstein heifers weighing an average of 256 kg (8 month of age) were randomly assigned to three groups of five. Treatment diets consisted of the following three $peNDF_{8.0}/MG$ levels: 1.46 (Treatment A), 1.74 (Treatment B), and 2.08 (Treatment C). Results: The results showed that the ratio of $peNDF_{8.0}/MG$ affected rumen fermentation, blood metabolites and growth performance of heifers. The average daily gain of heifers tended to decrease as the ratio of $peNDF_{8.0}/MG$ increased (p = 0.07). The concentrations of blood urea nitrogen, triglyceride, and cholesterol increased significantly (p<0.05), while the high-density lipoprotein concentration decreased (p<0.05). After feeding 2 h and 4 h, insulin concentration in Treatment A was greater than Treatment C (p<0.05). Propionate concentration had decreasing trend (p = 0.07); acetate to propionate ratio and non-glucogenic to glucogenic volatile fatty acid (NGR) increased significantly (p<0.05). In addition, the digestibility of dry matter, crude protein, neutral detergent fiber, and acid detergent fiber decreased significantly (p<0.05). Conclusion: The present investigation indicated that dietary $peNDF_{8.0}/MG$ ratio can affect the growth and development, blood metabolites, rumen fermentation and apparent digestibility of heifers, and the optimal dietary $peNDF_{8.0}/MG$ ratio for 8 to 10-month-old heifers in the present study was 1.46.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.12
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• pp.814-824
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• 2018

This study was conducted to investigate VFA, monosaccharides and metabolites in rumen fluid according to feeding methods. Three castrated Hanwoo steers were used to the $3{\times}3$ Latin square design, 10 day for the diet adaptation period. VFA and monosaccharides which were not detected by HPLC and HPAEC however, those were detected by $^1H-NMR$. Among the metabolites measured by $^1H-NMR$ carbohydrate metabolites, pyruvate was detected only in the rumen fluid before feeding and succinate was detected before and after feeding rumen fluid. In amino acid total 9 metabolites were detected. In lipid metabolites, ethylene glycol was significantly higher (P<0.05) in before feeding Con group. In aliphatic acylic metabolite, trimethylamine N-oxide was no significant difference observed compare to Con group. In this study, many metabolites were observed in the rumen fluid by $^1H-NMR$, and it confirmed that rumen metabolic products were changed by feeding methods.

• Asian-Australasian Journal of Animal Sciences
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• v.30 no.3
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• pp.370-378
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• 2017

Objective: An experiment was conducted to investigate the effects of a specific mixture of essential oils (MEO), containing thyme, clove and cinnamon EO, on rumen microbial fermentation, nutrient apparent digestibility and blood metabolites in fistulated sheep. Methods: Six sheep fitted with ruminal fistulas were used in a repeated measurement design with two 24-d periods to investigate the effect of adding MEO at 0 (control), 0.8, and 1.6 mL/d on apparent nutrient digestibility, rumen fermentation characteristics, rumen microbial population and blood chemical metabolites. Animals were fed with a 50:50 alfalfa hay:concentrate diet. Results: Ruminal pH, total volatile fatty acids (VFA) concentration, molar proportion of individual VFA, acetate: propionate ratio and methane production were not affected with MEO. Relative to the control, Small peptides plus amino acid nitrogen and large peptides nitrogen concentration in rumen fluid were not affected with MEO supplementation; while, rumen fluid ammonia nitrogen concentration at 0 and 6 h after morning feeding in sheep fed with 1.6 mL/d of MEO was lower (p<0.05) compared to the control and 0.8 mL/d of MEO. At 0 h after morning feeding, ammonia nitrogen concentration was higher (p<0.05) in sheep fed 0.8 mL/d of MEO relative to 1.6 mL/d and control diet. Ruminal protozoa and hyper ammonia producing (HAP) bacteria counts were not affected by addition of MEO in the diet. Relative to the control, no changes were observed in the red and white blood cells, hemoglobin, hematocrit, glucose, beta-hydroxybutyric acid, cholesterol, total protein, albumin, blood urea nitrogen and aspartate aminotransferase and alanine aminotransferase concentration. Apparent total tract digestibility of dry matter, crude proten, organic matter, and neutral detergent fiber were not influenced by MEO supplementation. Conclusion:The results of the present study suggested that supplementation of MEO may have limited effects on apparent nutrient digestibility, ruminal fermentation and protozoa and HAP bacteria count, blood cells and metabolites.

• Asian-Australasian Journal of Animal Sciences
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• v.18 no.1
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• pp.38-41
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• 2005

An experiment was conducted on 3 male rumen fistulated adult buffaloes fed on wheaten straw and concentrate mixture in a Latin square design to study the impact of niacin supplementation on rumen metabolites. Three animals were fed wheaten straw+concentrate mixture (group I, control), wheaten straw+concentrate mixture+100 ppm niacin (group II), and wheaten straw +concentrate mixture+200 ppm niacin (group III). After 21 days feeding, rumen liquor was drawn for 3 consecutive days at different time intervals (0, 2, 4, 6 and 8 h) to study the various rumen metabolites i.e., rumen pH, ammonia-N, total-N, trichloroacetic acid precipitable-N, non-protein nitrogen, total volatile fatty acids, their fractions and number of protozoa. Mean pH values in strained rumen liquor (SRL) of animals in 3 groups were 6.64, 6.71 and 6.67, indicating no statistically significant difference. Results revealed a significant (p<0.01) increase in TVFA concentration among the supplemented groups (group II and III) in comparison to control group. Mean TVFA concentration (meq/dl) was 9.75, 10.97 and 11.44 in 3 groups respectively. The highest concentration of TVFA was observed at 4 h and minimum at 0 h in all the 3 groups. The percentage of acetic, propionic, butyric and isobutyric acid was statistically similar among the three groups. The mean ammonia-N concentration (mg/dl SRL) was significantly (p<0.01) lower in group II (16.38) and group III (15.42) than group I (18.14). Ammonia-N concentration was higher (p<0.01) at 4 h as compared to all the time intervals. The mean total-N concentration (mg/dl SRL) was higher (p<0.01) in group II (74.16) and group III (75.47) as compared to group I (62.04). Total-N concentration was higher (p<0.01) at 4 h as compared to other time intervals and lowest value was recorded at 0 h.Concentration of TCA-ppt-N (mg/dl SRL) was significantly (p<0.01) lower in control group as compared to niacin supplemented groups. Mean value of NPN (mg/dl SRL) was significantly (p<0.01) lower in group III (23.21) as compared to group I (25.71), whereas groups I and II, and groups II and III were similar to each other. Total protozoa number (${\times}10^4$/ml SRL) ranged from 18.06 to 27.41 in group I, 20.89 to 38.44 in group II and 27.61 to 39.45 in group III. The mean protozoa number was significantly (p<0.01) higher in SRL of group II (27.60) and III (30.59) as compared to group I (22.48). It can be concluded from the study that supplementation of niacin in the diet of buffaloes had improved the rumen fermentation by decreasing the concentration of ammonia-N and increasing protein synthesis.

• Asian-Australasian Journal of Animal Sciences
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• v.23 no.12
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• pp.1608-1613
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• 2010

This study was designed to investigate the effects of supplementation of spent mushroom substrates (SMS) on rumen fermentation and blood metabolites in Hanwoo steers. The experiment was conducted as a duplicated Latin square design with six Hanwoo steers ($600{\pm}47\;kg$), each permanently fitted with a ruminal cannula. There were three treatments; i) control (concentrates 4.8 kg +rice straw 1.2 kg/d), ii) Pleurotus eryngiia (PE) treatment (concentrates 4.8 kg+rice straw 0.73 kg+Pleurotus eryngiia 1.20 kg/d) and iii) Pleurotus osteratus (PO) treatment (concentrates 4.8 kg+rice straw 0.73 kg+Pleurotus osteratus 1.20 kg/d). There were no major effects of different dietary treatments on rumen parameters such as pH, ammonia-N, individual and total VFA production. Parameters of N utilization, including blood urea nitrogen (BUN), total protein and albumin levels, were not significantly different among the treatments, except for creatinine. Thus, the present results indicated that protein utilization was mostly unaffected by SMS treatments such as PE and PO, even though creatinine concentration was lower in PE compared with control and PO treatments (p<0.05). The present results indicate that Pleurotus eryngii and Pleurotus osteratus could be used as a forage source to replace 40% of rice straw without any negative effects on rumen fermentation and blood metabolites in Hanwoo steers.

• Asian-Australasian Journal of Animal Sciences
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• v.13 no.4
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• pp.451-456
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• 2000

Fifty mid-lactation Holstein cows were used in a six-week feeding trial to study effects of high-forage, and high-fat diets on blood constituents, rumen fermentation and dry matter digestibility. Cows were divided into 10 replicates, each consisting of five cows. Each cow was assigned to a control (diet 1) or one of the four experimental diets (high-forage (75%), high-fat (7.5%) (diet 2); high-forage. medium-fat (5.0%) (diet 3); medium forage (65%), high-fat (diet 4); medium-forage, medium-fat (diet 5)), or a control diet containing about 50% forage and 2% fat. All diets were isonitrogenous (17.7% crude protein). The forage mixture consisted of 20% alfalfa hay, 40% alfalfa haylage, and 40% corn silage. Supplemental fat included 80% rumen-protected fat and 20% yellow grease. A non-significant difference was observed in concentrations of blood glucose for cows on different experimental and control diets. Plasma nonesterified fatty acids (NEFA) were higher in cows consuming experimental diets than those consuming the control diet. However, differences in NEFA concentrations in the plasma of cows consuming diets with different forage and fat levels were not significant. Rumen pH, concentration of volatile fatty acids (VFA) in rumen contents, and dry matter digestibility of control and experimental diets, and diets with different levels of forage and supplemental fat did not differ significantly.