The Cornell Net Carbohydrate and Protein System (CNCPS) has a submodel that predicts rates of feedstuff degradation in the rumen, the passage of undegraded feed to the lower gut, and the amount of ME and protein that is available to the animal. In the CNCPS, structural carbohydrate (SC) and nonstructural carbohydrate (NSC) are estimated from sequential NDF analyses of the feed. Data from the literature are used to predict fractional rates of SC and NSC degradation. Crude protein is partitioned into five fractions. Fraction A is NPN, which is trichloroacetic (TCA) acid-soluble N. Unavailable or protein bound to cell wall (Fraction C) is derived from acid detergent insoluble nitrogen (ADIP), and slowly degraded true protein (Fraction B3) is neutral detergent insoluble nitrogen (NDIP) minus Fraction C. Rapidly degraded true protein (Fraction B1) is TCA-precipitable protein from the buffer-soluble protein minus NPN. True protein with an intermediate degradation rate (Fraction B2) is the remaining N. Protein degradation rates are estimated by an in vitro procedure that uses Streptomyces griseus protease, and a curve-peeling technique is used to identify rates for each fraction. The amount of carbohydrate or N that is digested in the rumen is determined by the relative rates of degradation and passage. Ruminal passage rates are a function of DMI, particle size, bulk density, and the type of feed that is consumed (e.g., forage vs cereal grain).

A net carbohydrate and protein system for evaluating cattle diets: II. Carbohydrate and protein availability.

Resistant starch (RS) is starch and products of its small intestinal digestion that enter the large bowel. It occurs for various reasons including chemical structure, cooking of food, chemical modification, and food mastication. Human colonic bacteria ferment RS and nonstarch polysaccharides (NSP; major components of dietary fiber) to short-chain fatty acids (SCFA), mainly acetate, propionate, and butyrate. SCFA stimulate colonic blood flow and fluid and electrolyte uptake. Butyrate is a preferred substrate for colonocytes and appears to promote a normal phenotype in these cells. Fermentation of some RS types favors butyrate production. Measurement of colonic fermentation in humans is difficult, and indirect measures (e.g., fecal samples) or animal models have been used. Of the latter, rodents appear to be of limited value, and pigs or dogs are preferable. RS is less effective than NSP in stool bulking, but epidemiological data suggest that it is more protective against colorectal cancer, possibly via butyrate. RS is a prebiotic, but knowledge of its other interactions with the microflora is limited. The contribution of RS to fermentation and colonic physiology seems to be greater than that of NSP. However, the lack of a generally accepted analytical procedure that accommodates the major influences on RS means this is yet to be established.

Short-Chain Fatty Acids and Human Colonic Function: Roles of Resistant Starch and Nonstarch Polysaccharides

Antioxidant activity and phenolic compounds of 112 traditional Chinese medicinal plants associated with anticancer.

Standardization of procedures for nitrogen fractionation of ruminant feeds

The control and consequences of bacterial fermentation in the human colon.

Methods for dietary fiber, neutral detergent fiber, and nonstarch polysaccharides in relation to animal nutrition.

There is a need to standardize the NDF procedure. Procedures have varied because of the use of different amylases in attempts to remove starch interference. 'Ihe original Bacillus subtilis enzyme Type IIIA (XIA) no longer is available and has been replaced by a less effective enzyme. For fiber work, a new enzyme' has received AOAC approval and is rapidly displacing other amylases in analytical work. This enzyme is available from Sigma (Number A3306, Sigma Chemical Co., St. Louis, MO). The original publications for NDF and ADF (43, 53) and the Agricultural Handbook 379 (14) are obsolete and of historical interest only. Up to date procedures should be followed. Tnethylene glycol has replaced 2-ethoxyethanol because of reported toxicity. Considerable development in regard to fiber methods has occurred over the past 5 yr because of a redefinition of dietary fiber for man and monogastric animals that includes lignin and all polysaccharides resistant to mammalian digestive enzymes. In addition to NDF, new improved methods for total dietary fiber and nonstarch polysaccharides including pectin and B-glucans now are available. The latter are also of interest in rumen fermentation. Unlike starch.

http://webpages.icav.up.pt/ptdc/cvt/098487/2008/van soest, 1991.pdf

SYMPOSIUM: CARBOHYDRATE METHODOLOGY, METABOLISM, AND NUTRITIONAL IMPLICATIONS IN DAIRY CAlTLE Methods for Dietary Fiber, Neutral Detergent Fiber, and Nonstarch Polysaccharides in Relation to Animal Nutrition

The structure-activity relationships of synthetic caffeic acid amide and ester analogues as potential antioxidants and free radical scavengers have been investigated. The 2,2-diphenyl-1-picrylhydrazyl radical (DPPH.) scavenging activity of the test compounds was N-trans-caffeoyl-L-cysteine methyl ester (5) > N-trans-caffeoyldopamine (4) > N-trans-caffeoyltyramine (3) > N-trans-caffeoyl-beta-phenethylamine (2) > Trolox C (8) > caffeic acid phenethyl ester (1) > caffeic acid (6) > ferulic acid (7). This established that the radical scavenging activity of the compounds increased with increasing numbers of hydroxyl groups or catechol moieties and also with the presence of other hydrogen-donating groups (-NH, -SH). The antioxidative activity of the compounds was also investigated in an emulsified linoleic acid oxidation system accelerated by 2,2'-azobis(2-amidinopropane) dihydrochloride. The order was 1 > 2 > 4 > 3 > or = 5 > 6 > 8 > 7. Therefore, in the emulsion system, the antioxidative activity of the test compounds depends not only on the hydroxyl groups or catechol rings but also on the partition coefficient (log P) or hydrophobicity of the compounds. This supports the concept that hydrophobic antioxidants tend to exhibit better antioxidative activity in an emulsion system.

Free radical scavenging and antioxidative activity of caffeic acid amide and ester analogues: structure-activity relationship.

The composition of common buckwheat (Fagopyrum esculentum Moench) seed milling fractions depends upon the relative abundance of various seed tissues in each. Fancy (light) flour contains mainly central endosperm, while the bran milling fraction has seed coat and some embryo tissues. Phytate, found in protein bodies of embryo and aleurone cells, is the major storage form of phosphorus, potassium, magnesium and some microelements in seeds. Phytic acid (35-38 g kg(-1)) and minerals are concentrated in bran, a milling fraction with high concentrations of phytate-rich tissues. Polyphenolics, including condensed tannins (proanthocyanidins), are also concentrated in bran (11-15 g kg(-1)). Rutin is concentrated in the hull of common buckwheat (0.8-4.4 g kg(-1)). Rutin concentration is low (0.2-0.3 g kg(-1)) in groats of common buckwheat but higher (0.7-0.8 g kg(-1)) in bran containing hull fragments. Rutin is 300-fold more concentrated (81 g kg(-1)) in groats of tartary buckwheat (Fagopyrum tataricum (L) Gaertn) than in groats of common buckwheat. Only small amounts of quercetin were detected. Bran is a concentrated source of phytic acid and tannins, a consideration in consumption of large amounts of buckwheat bran for nutritional or medicinal purposes. (C) 2001 Society of Chemical Industry.

Betty A. Lewis

Papers

Methods for dietary fiber, neutral detergent fiber, and nonstarch polysaccharides in relation to animal nutrition.

SYMPOSIUM: CARBOHYDRATE METHODOLOGY, METABOLISM, AND NUTRITIONAL IMPLICATIONS IN DAIRY CAlTLE Methods for Dietary Fiber, Neutral Detergent Fiber, and Nonstarch Polysaccharides in Relation to Animal Nutrition

Free radical scavenging and antioxidative activity of caffeic acid amide and ester analogues: structure-activity relationship.

Minerals, phytic acid, tannin and rutin in buckwheat seed milling fractions

Buckwheat seed milling fractions: Description, macronutrient composition and dietary fibre