Effects of Sampling Time, Cultivar, and Methodology on Water- and Ethanol-Soluble Carbohydrate Profiles of Three Cool-Season Grasses in Central Kentucky

Kagan, Isabelle A.; Lawrence, L.M.; Seman, Dwight H.; Prince, Kelly; Fowler, A.L.; Smith, S. Ray

doi:10.1016/j.jevs.2017.11.011

Cited by 17 publications

(9 citation statements)

References 43 publications

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“…We have adapted this technique to fingerprint the AX contained in the vegetative tissue of cool-season forages. This method, which targets the water-insoluble hemicellulosic fraction of cool-season forages, complements the use of HPAEC-PAD to profile the water-soluble and ethanol-soluble carbohydrate fractions of various cool-season forages ( Kagan et al., 2011 ; Kagan et al., 2018 ).…”

Section: Resultsmentioning

confidence: 99%

Profiling of cool-season forage arabinoxylans via a validated HPAEC-PAD method

Joyce

Kagan²,

Flythe³

et al. 2023

Front. Plant Sci.

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Cool-season pasture grasses contain arabinoxylans (AX) as their major cell wall hemicellulosic polysaccharide. AX structural differences may influence enzymatic degradability, but this relationship has not been fully explored in the AX from the vegetative tissues of cool-season forages, primarily because only limited AX structural characterization has been performed in pasture grasses. Structural profiling of forage AX is a necessary foundation for future work assessing enzymatic degradability and may also be useful for assessing forage quality and suitability for ruminant feed. The main objective of this study was to optimize and validate a high-performance anion-exchange chromatography with pulsed amperometric detection (HPAEC-PAD) method for the simultaneous quantification of 10 endoxylanase-released xylooligosaccharides (XOS) and arabinoxylan oligosaccharides (AXOS) in cool-season forage cell wall material. The following analytical parameters were determined or optimized: chromatographic separation and retention time (RT), internal standard suitability, working concentration range (CR), limit of detection (LOD), limit of quantification (LOQ), relative response factor (RRF), and quadratic calibration curves. The developed method was used to profile the AX structure of four cool-season grasses commonly grown in pastures (timothy, Phleum pratense L.; perennial ryegrass, Lolium perenne L.; tall fescue, Schedonorus arundinaceus (Schreb.) Dumort.; and Kentucky bluegrass, Poa pratensis L.). In addition, the cell wall monosaccharide and ester-linked hydroxycinnamic acid contents were determined for each grass. The developed method revealed unique structural aspects of the AX structure of these forage grass samples that complemented the results of the cell wall monosaccharide analysis. For example, xylotriose, representing an unsubstituted portion of the AX polysaccharide backbone, was the most abundantly-released oligosaccharide in all the species. Perennial rye samples tended to have greater amounts of released oligosaccharides compared to the other species. This method is ideally suited to monitor structural changes of AX in forages as a result of plant breeding, pasture management, and fermentation of plant material.

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Section: Resultsmentioning

confidence: 99%

Profiling of cool-season forage arabinoxylans via a validated HPAEC-PAD method

Joyce

Kagan²,

Flythe³

et al. 2023

Front. Plant Sci.

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“…Samples were replicated by plot (four plots per timepoint, except for two missing timothy samples in 2020 and two missing timothy samples in 2021, as mentioned in Section 2.1). Samples (100 mg) were extracted by shaking in water at ambient temperature for 1 h, as described by Kagan et al (2018). Extracts were filtered through #4 filter paper (Whatman, GE Healthcare, Buckinghamshire, England) and brought to 25 mL with water.…”

Section: Methodsmentioning

confidence: 99%

“…Grasses were harvested between noon and 4:00 PM, and duration of harvesting varied with the amount of field assistance. Afternoon harvesting was chosen to minimize diurnal variation in WSC concentrations (Kagan et al, 2018).…”

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confidence: 99%

Seasonal and species variation in raffinose, short‐chain fructan, and long‐chain fructan accumulation in tall fescue (Festuca arundinacea Schreb.) and timothy (Phleum pratense L.) grown in Central Kentucky

Kagan,

Davis,

Schendel

2023

Grass and Forage Science

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Fructans in cool‐season grasses may have some negative effects on equine health. However, they may have positive effects on ruminant performance, and fructans of different lengths appear to be metabolized differently in the rumen. Hence, seasonal variation in fructan concentrations may impact equine and ruminant performance. Long‐chain fructan with degree of polymerization (DP) > 8, short‐chain fructan (DP 4 to 8), raffinose, and three fructan trisaccharides were profiled and quantified in timothy (Phleum pratense L.) cultivar ‘Clair’ and tall fescue (Festuca arundinacea Schreb.) cultivar ‘Cajun II’ harvested in April, June, August, and October of two consecutive years in central Kentucky. Harvest year influenced concentrations of long‐chain fructan (p = .0017). Harvest date influenced species differences in raffinose (p = .0035), which was most abundant in timothy in June, and in 1‐kestose and neokestose (p < .0001), which were most abundant in tall fescue in April. Harvest date influenced species differences in short‐ and long‐chain fructan (p < .0001). Tall fescue had two‐ to three‐fold more short‐chain fructan than timothy in April, August, and October. Timothy had two‐ to five‐fold more long‐chain fructan than tall fescue in April, June, and October. Species choice and weather patterns may have contributed to relatively low concentrations of all the carbohydrates measured in this study. Fermentation or feeding studies could help to determine if the concentrations present could affect equine health or ruminant performance.

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“…19 Column and detector temperatures were 28 C, and the autosampler was at ambient temperature (23-24 C). The gradient described by Kagan et al 20 was used for separation.…”

Section: Sample Preparation and Hpaec Analysismentioning

confidence: 99%

A chromatographic method to monitor fructan catabolism in two cool‐season grasses fermented by mixed bovine ruminal microbiota

2022

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BACKGROUND: Cool-season grasses contain fructans (fructose-based polymers), whose monomers are linked by β-2,6 or β-1,2 bonds. Fructans in the rumen are hydrolysed to fructose by bacterial enzymes, but little is known about the kinetics of fructan catabolism in the rumen. A chromatographic method, using high-performance anion-exchange chromatography (HPAEC) with pulsed amperometric detection, was developed to monitor changes in fructan profiles during the in vitro fermentation of timothy (Phleum pratense L.) and cocksfoot (Dactylis glomerata L.) by mixed rumen microbes. Sterile suspensions of freeze-dried and milled tissue in minimal media were inoculated with washed rumen microbial cells under anaerobic conditions, and aliquots of the incubations were profiled 0, 2, and 5 h post-inoculation.RESULTS: Timothy and cocksfoot differed in initial concentrations of glucose and sucrose, and in the amounts remaining 2 h post-inoculation (p < 0.01). The grasses also differed in initial concentrations of short-chain fructan, and in concentrations present 2 h post-inoculation (p = 0.01). Timothy and cocksfoot also differed in amounts of longchain fructans remaining 2 and 5 h post-inoculation (p = 0.03), and in the maximum degree of polymerisation after 2 h (p < 0.01).CONCLUSIONS: Over the first 2 h, long-chain fructans in cocksfoot decreased while short-chain fructans increased. In timothy, concentrations of short-chain fructans doubled, and the degree of polymerisation decreased by 15%. The results support a model of degradation of the longest fructan chains and conversion into shorter ones.

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Effects of Sampling Time, Cultivar, and Methodology on Water- and Ethanol-Soluble Carbohydrate Profiles of Three Cool-Season Grasses in Central Kentucky

Cited by 17 publications

References 43 publications

Profiling of cool-season forage arabinoxylans via a validated HPAEC-PAD method

Profiling of cool-season forage arabinoxylans via a validated HPAEC-PAD method

Seasonal and species variation in raffinose, short‐chain fructan, and long‐chain fructan accumulation in tall fescue (Festuca arundinacea Schreb.) and timothy (Phleum pratense L.) grown in Central Kentucky

A chromatographic method to monitor fructan catabolism in two cool‐season grasses fermented by mixed bovine ruminal microbiota

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