Pasture quality and ruminant nutrition. 2. Carbohydrate and lignin composition of detergent extracted residues from pasture grasses and legumes.
TL;DR: In this article, neutral and acid detergent residues prepared from a range of grass and clover tissues have been analyzed for various cell wall carbohydrates and lignin, in agreement with the neutral detergent residue.
Abstract: Neutral and acid detergent residues prepared from a range of grass and clover tissues have been analysed for various cell wall carbohydrates and lignin. The neutral detergent residues, in agreement...
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TL;DR: In this paper, a total, soluble and insoluble non-starch polysaccharides (NSP) and lignin were analysed for low-molecular weight (LMW) sugars by high-performance liquid chromatography, starch, fructan and mixed linked β(1 → 3;1 → 4)-D-glucan by colorimetry, total, insoluble NSP by gas-liquid chromatography and Lignin by gravimetry.
1,449 citations
TL;DR: In early lactation, dietary CP and energy can profoundly affect milk yield, but current methods of assessing these nutrients are often inadequate to predict animal performance.
628 citations
TL;DR: Current production studies yield no clear evidence as to the benefits of postruminal digestion of starch to enhance milk yield or to change its composition, however, studies suggest that starch digested postruminally is used more efficiently for milk synthesis than that digested in the rumen.
606 citations
TL;DR: This chapter focuses on the hemicelluloses of the Gramineae (grasses and cereals), which refers to all of the types of polysaccharide in the Gramineaae, other than celluloses, starches, and fructans.
Abstract: Publisher Summary This chapter focuses on the hemicelluloses of the Gramineae (grasses and cereals). The term “hemicelluloses” is also often extended to include certain carbohydrates in cereal endosperms—namely, non-starch polysaccharides. Hemicellulose refers to all of the types of polysaccharide in the Gramineae, other than celluloses, starches, and fructans. Hemicellulose chemistry has a vocabulary lacking invariant definitions, and insight into the nature of hemicelluloses has been gained by the work not only of chemists and biochemists but of applied scientists having research interests in animal nutrition, brewing, cereals, paper manufacture, and starch production. The chapter also discusses species and various tribes of Gramineae, isolation of hemicellulosimca materials and of pure hemicelluloses, and structural feature in hemicelluloses. The importance of knowledge about the hemicelluloses may be gauged by looking at the abundance of photosynthetically renewable grasses and bearing in mind that, apart from the materials in the seed, one third of their composition is hemicellulose.
357 citations
01 Dec 1973
TL;DR: Because of the failure of the crude fibre method to recover indigestible substances, SI;E appears less digestible than crude fibre in significant numbers of cases (Cranipton & >‘laynard, 1938).
Abstract: Crude fibre determination is commonly used to estimate the quality of foods of plant origin on the premise that it constitutes their least digestible fraction. Therefore, a criterion for evaluating fibre methods is thc recovery of indigestible plant residues. ‘I’he so-called Weende method for fibre estimation was not developed at Weende, but at Moglin after 1806 by Heinrich Einhof, who assumed that the fibrous residue left after sequential extraction with solvent, dilute aqueous acid and dilute alkali, represented the indigestible matter. Binhof calculated estimates of nutritive value of vegetables and forages on this basis (von Thaer, 1809). The deficiencies of Einhof’s method became apparent in the nineteenth century (Henneberg, 1859). Over the years many systems of analysis have been proposed for the replacement of crude fibre, but none have been successful in dislodging it as the official method. The crude fibre method as an estimate of the amount of fibre or plant cell wall in foods has many defects. On average, SooX of the hemicellulose or pentosans and from 50 to 90y0 of the lignin are removed by the acid and alkaline sequential extraction, while cellulose rccovery is j0-800/,. Thus, much of the hemicelliilose and lignin appears in the nitrogen-free-extract (NFE) to be counted as available carbohydrate (Maynard, 1940). The XFE of straws and grasses may contain as milch as 90‘;(, of these substances (Nordfeldt, Svanberg & Claesson, 1949 ; Stallcup, Davis & Ward, 1964; Kim, Gillingharn & T,oadholt, 1967). Because of the failure of the crude fibre method to recover indigestible substances, SI;E appears less digestible than crude fibre in significant numbers of cases (Cranipton & >‘laynard, 1938). In the case of vegetables and cereals the error is lcss because of the relatively lower content of hemicelluloses and lignin. IIowever, it may be substantial. There have been various attempts to replace the crude fibre method with a system of analysis which gives a better characterization of the less nutritive fraction of food. Such attempts face several problems, not all of them necessarily analytical. The problems are ( I ) conflicting concepts o f what constitutes fibre; ( 2 ) the definition of lignin, cellulose and hemicellulose ; (3) achieving separation of lignin from interfering matter; (4) the isolation of indigestible fibre and its relation to the true fibre of the food; (j) the failure of hemicellulose, cellulose and lignin to be biologically or chemically similar in different plant materials.
278 citations
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TL;DR: In this paper, the reliability of the various Somogyi-Shaffer-Hartmann (SHH) copper reagents for glucose determination in biological material has been established, which can be accomplished by omission of the iodide and iodate in their preparation, since these interfere with the molybdate color reagents.
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TL;DR: The steps used in the initial purification of lignin, and particularly those concerned with the removal of nitrogenous impurities using proteolytic enzymes, have been investigated and a modified procedure is proposed and described in detail, suitable for routine work.
Abstract: 1. The methods for estimating lignin based on 72% sulphuric acid are lengthy and usually require large corrections for the residual nitrogenous impurities. The steps used in the initial purification of lignin, and particularly those concerned with the removal of nitrogenous impurities using proteolytic enzymes, have been investigated. 2. The conditions that remove the maximum amount of nitrogen were investigated. The nitrogenous material remaining in the lignin isolated by the adopted procedure was partly characterized, and it was shown that about half of the resistant N could be obtained in the form of amino acids which were presumably present in the lignin in the form of protein. The amino acid compositions of the resistant nitrogenous material in lignin derived from grass, and in lignin derived from faeces of sheep, when the same grass was given, were compared. They were found to be sufficiently similar to suggest a common origin. 3. A modified procedure is proposed and described in detail; it is suitable for routine work. 4. Comparisons were made between the results obtained by determining lignin in forage and faeces samples by the method now presented and those obtained by the method used previously.
258 citations