Nutrient absorption

Antibiotics (qv) have been fed at subtherapeutic levels to promote mminant animal growth. Possible reasons for the observed growth include decreased activity of microbes having a pathogenic effect on the animal, decreased production of microbial toxins, decreased microbial destmction of essential nutrients, increased vitamin synthesis or synthesis of other growth factors, and increased nutrient absorption because of a thinner intestinal wall... 

Somatostatin acts on various organs, tissues and cells as neurotransmitter, paracrine/autocrine and endocrine regulator on cell secretion, smooth muscle contractility, nutrient absorption, cell growth and neurotransmission [1]. Some of its mainly inhibitory effects are listed in Table 1. Somatostatin mediates its function via a family of heptahelical G-protein-coupled receptors termed... 

The molecules in Olestra have been modified since it was first marketed, to avoid some of the more unpopular side effects, but some remain. Adding carotenoids and fat-soluble vitamins to the product has also been done, but this does not eliminate all of the problems with nutrient absorption. 

The lower rates of nutrient absorption associated with diets high in nonstarch polysaccharides are probably due to the increased viscosity of digesta (Vaugelade et al., 2000), which increases the thickness of the unstirred layer overlying the enterocytes and causes anon-specific decline in solute absorption. This explains why diets high in 3-glucans, which are structural carbohydrates and which increase viscosity of digesta, reduce absorption of nutrients and... 

Proteinaceous phytochemicals can contain toxic epitopes that elicit defense responses for example gliaden and glutein peptides which cause celiac disease and other mucosal disorders (Tighe and Ciclitira, 1995 Van de Wal et al, 1999). The mucosal inflammation caused by feeding carnivorous Atlantic salmon diets with soybean meal decreases rates of nutrient absorption (Nordrum et al, 2000), whereas the detrimental influence of such diets is much less pronounced when fed to omnivorous fish, such as catfish and tilapia. 

As stated earlier, mycorrhizae enhance nutrient absorption. Greater soil exploitation by mycorrhizal roots as a means of increasing phosphate uptake is well established. The normal phosphate depletion zone around non-mycorrhizal roots is 1-2 mm, but an endomycorrhizal root symbiont increased this zone to 7 cm (140). This ability to increase the nutritional level (particularly with regard to phosphorus), and subsequently the overall better growth dynamics of the mycorrhizal plant has been suggested as the reason for the salt (43) and drought (44-46) tolerance and increased nodulation (47) observed in mycorrhizal associations. Another interesting aspect of this enhanced nutrient uptake is the possible effect of mycorrhizae on competitive ability between two plant species. Under some conditions, mycorrhizal... 

Although there is no doubt as to the importance of mycorrhizae in nutrient absorption, reviews on ion uptake have generally not considered it. Hatling et al. (143) made this same point more than 10 years ago. In addition, although phenolic acids inhibit phosphate (144, 145) and potassium (146) uptake, no work has examined the effects of these compounds on nutrient absorption of mycorrhizal associations. Since soil microorganisms produce the bulk of the volatile compounds emitted from soil, which are known to inhibit or stimulate fungal development (147-148), this group of compounds from microbial sources should receive more attention. 

ML Halperin, SL Wolman, DR Greenberg. Paracellular recirculation of sodium is essential to support nutrient absorption in the GI tract. Clin Invest Med 9 209-211, 1986. 

Stephenson, L.S., Pond, W.G., Nesheim, M.C., Krook, L.P. and Crompton, D.W. (1980) Ascaris suum nutrient absorption, growth, and intestinal pathology... 

Miller, J. K., Perry, S. C., Chandler, P. T. and Craig, R. G. (1967). Evaluation of radiocerium as a nonabsorbed reference material for determining gastrointestinal sites of nutrient absorption and excretion in cattle, J. Dairy Sci. 50, 355. 

Interactions between foods and dietary supplements are complex and measurement of nutrient absorption presently lacks the precision of characterization generally achieved with drug bioavailability. 

The structure of the rice root is therefore apparently dominated by the need for internal gas transport. On the face of it, this structure may conflict with the needs for efficient nutrient absorption (Kirk and Bouldin, 1991). The development of gas-impermeable layers in the root wall seems likely to impair the ability of those parts of the root to absorb nutrients, and the disintegration of the cortex might impair transport from the apoplasm to the main solute transport vessels in the stele, though these points are uncertain (Drew and Saker, 1986 Kronzucker et al, 1998a). It seems likely that the short fine lateral roots are responsible for the bulk of the nutrient absorption by the root system and compensate for any impairment of nutrient absorption by the primary roots as a result of adaptations for internal aeration. 

MODEL OF ROOT AERATION VERSUS NUTRIENT ABSORPTION... 

NUTRIENT ABSORPTION PROPERTIES OF WETLAND PLANT ROOTS... 

Nutrient Absorption Properties of Wetland Plant Roots... 

Drug interactions Sandostatin has been associated with changes in nutrient absorption, so it may effect the absorption of orally administered drugs. Concomitant administration of Sandostatin with cyclosporine may decrease blood levels of cyclosporine and result in transplant rejection. Patients receiving insulin, oral hypoglycemic agents, beta blockers. 

Octreotide has been associated with alterations in nutrient absorption, and thus may have an effect on any orally administered drug... 

The tegument of the Neodermata is a living structure that can presumably react dynamically to changes in environmental conditions, engage in defence and provide a means by which nutrients can be absorbed (Halton, 1 997 Dalton et al., 2004). Tyler and Tyler (1997) reviewed the four criteria characterized by the neodermatan tegument assumed to be adaptations to parasitism, namely that it (i) shows features, which will promote nutrient absorption,... 

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