Dietary components composition

A DIFF relates a specified body component isotopic composition to the various compositions of a specified and complete set of dietary components. The complete diet must be accounted for in the DIFF, but it can be partitioned in any way that seems sensible for example, into individual amino acids or into protein, carbohydrate and lipid, etc. 

Other factors that can influence fat digestibility include the level of fat inclusion in the diet and presence of other dietary components (Wiseman, 1984). Fat composition can influence overall fat digestion because different components can be digested and/or absorbed with varying efficiency. 

The bioavailablllty of a mineral nutrient is Influenced by a plethora of factors. Composition of the diet can influence the interaction between specific dietary components and metals. The physical characteristics of these interactions will determine how much mineral is available for absorption. These interactions are undoubtedly Influenced by the acid conditions of the gastric secretions and the hydrolytic activity of the Intestine. In order to understand how these factors might influence the absorption of a nutrient metal such as zinc, it is first necessary to understand the mechanism of zinc absorption and the systemic factors which regulate it. 

The adsorption of salivary components on enamel during pellicle formation has been shown to be a specific process that might be influenced by dietary components [13, 44, 65, 135, 136], Some in vivo studies have suggested that differences in pellicle formation and composition are correlated with the dietary habits of the individual [44, 135]. The chemical composition of a... 

In addition to seasonal factors, significant changes in the FA composition of milk fat can be achieved by manipulating the cow s diet. Milk fat composition is influenced more by dietary fat than by any other dietary component. The effects of fat supplementation on FA composition are dependent on the type and amount of dietary fat. In most cases, fat supplements decrease the proportions of 6 0 to 14 0 acids (de novo synthesized) and increase the proportion of long-chain (dietary) FA. Diets containing supplemental fat do not affect the proportion of C4 0 in milk fat. 

Where there is no evidence of malnutrition, the dietary components that affect blood lipids and lipoproteins most profoundly are fats and carbohydrates. In the fat component the nature of the fatty acid composition has attracted most attention. Thus where conventional diets are modified so as to increase the proportion of fat containing vegetable (unsaturated) oils significant reductions in total plasma cholesterol concentrations are seen with the major reduction being in the LDL fraction. When low-fat diets are eaten with the calorie intake kept constant by an additional carbohydrate content VLDL levels increase without affecting LDL concentrations significantly. 

Formulating diets to meet the requirement for 10 or 11 essential amino acids is likely to be difficult, as in theory there is almost unlimited scope for adjusting dietary components (including synthetic amino acids) to ensure that the essential amino acid supply matches the requirement. However, in practice the relative proportions of different amino acids supplied by the diet often fail to match the requirements, and they are inefficiently utihsed because one or two amino acids are very markedly deficient. By comparing the amino acid requirements with the amino acid composition of typical diets, it has been shown that the first-limiting amino acid for pigs is... 

Empirical and experimental data have indicated that different bone tissues reflect different components of the diet (27-22). In general, bone collagen is produced primarily from the protein portion of the diet, while bone apatite and tooth enamel are produced from a mixture of dietary protein, carbohydrates and fats. Stable isotope analysis of both bone collagen and apatite thus permits quantitative estimates of several dietary components. Both bone collagen and apatite are constantly being resorbed and replenished, so that their isotopic composition reflects dietary averages over at least the last several years of an individual s life. The apatite in tooth enamel, however, is not turned over, and represents diet at the time of tooth formation, often from a pre-weaning age. 

The first animal production study aimed at identifying factors that affect RA concentrations in ruminant products (milk) was conducted by Jiang et al. (1996). Since then, the research on dietary factors that modulate the BH process and thus fatty acid composition of milk and meat has greatly increased. The exploration of plants secondary metabolites as dietary components capable to manipulate ruminal BH is very recent and will be reviewed here. 

In view of the practical importance of these grains, for example in dietary fibers, it is useful to study the cell wall polymers of their tissues during differentiation. In the present work, we used rice grains (brown rice without husk) as a starting material. They were fractionated into several distinct histological components, and the composition and detailed structure of cell wall polymers was compared. 

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