scholarly journals Determination of digestible energy values and fermentabilities of dietary fibre supplements: a European interlaboratory study in vivo

1995 ◽  
Vol 74 (3) ◽  
pp. 289-302 ◽  
Author(s):  
G. Livesey ◽  
T. Smith ◽  
B. O. Eggum ◽  
I. H. Tetens ◽  
M. Nyman ◽  
...  
Keyword(s):  
Sugar Beet ◽  
Dietary Fibre ◽  
Direct Determination ◽  
Basal Diet ◽  
Metabolizable Energy ◽  
Digestible Energy ◽  
Maize Bran ◽  
Heats Of Combustion

The performance of methods to determine energy conversion factors for dietary fibre (DF) supplements and fermentability (D) values of their non-starch polysaccharides (NSP) was investigated. Heats of combustion, digestible energy (DE) and D values were determined on five DF supplements in five European laboratories on five separate occasions. In each instance the DF supplements were fed to juvenile male VVistar rats at two doses, 50 and 100 g/kg basal diet, for 3 weeks with food and faeces collected in the 3rd week. Among-laboratory variations in heats of combustion (DHC<) were <2%. DE values (kJ/g dry weight) at the upper and lower doses respectively were: 10·4 and 9·9 for a high-methoxyl apple pectin, 9·5 and 9·4 for a sugar-beet DF supplement, 12·2 and 12·7 for soyabean DF supplement, 38 and 4·0 for maize bran, and 0·3 and 0·3 for Solka-floc cellulose. Variations among laboratories, among occasions and among animals were <1, <2 and <2·5 kJ/g respectively. The among-occasion: among-laboratory variance ratio for DE was 0·5, suggesting the method performed equally well in all laboratories. There was no evidence of learning or fatigue in the performance of the method. D values were also independent of dose and at the high and lower doses were: pectin 0·92 and 0·95, sugar-beet NSP 0·68 and 0·68, soyabean NSP 0·86 and 0·88, maize bran 0·17 and 0·18, cellulose 0·07 and 0·06. Among-laboratory variance tended to increase with decreasing fermentability and ranged from 0·03 to 0·18. The DE and D data were not significantly different from a previously proposed relationship DE = 0·7 × DHc × D, where DHc is the heat of combustion of the supplement. We conclude that while the among-laboratory variation in the D of difficult-to-ferment NSP is too large for the reliable prediction of energy value the method for the direct determination of DE is both reproducible and repeatable, that DE is independent of dosage of DF supplement up to 100 g/kg diet, and that it is safe to discriminate between energy values with a precision of 3 kJ/g. The conversion of both DE and D to net metabolizable energy for the purpose of food labelling, tables and databases is described.

Determination of cerebral glucose transport and metabolic kinetics by dynamic MR spectroscopy

1997 ◽  
Vol 273 (6) ◽  
pp. E1216-E1227 ◽  
Author(s):  
P. C. M. Van Zijl ◽  
D. Davis ◽  
S. M. Eleff ◽  
C. T. W. Moonen ◽  
R. J. Parker ◽  
...  
Keyword(s):  
Glucose Transport ◽  
Kinetic Equations ◽  
Direct Determination ◽  
Life Time ◽  
Compartment Model ◽  
Brain Extract ◽  
Influx Rate ◽  
Positron Emission

A new in vivo nuclear magnetic resonance (NMR) spectroscopy method is introduced that dynamically measures cerebral utilization of magnetically labeled [1-13C]glucose from the change in total brain glucose signals on infusion. Kinetic equations are derived using a four-compartment model incorporating glucose transport and phosphorylation. Brain extract data show that the glucose 6-phosphate concentration is negligible relative to glucose, simplifying the kinetics to three compartments and allowing direct determination of the glucose-utilization half-life time [ t ½ = ln2/( k 2 + k 3)] from the time dependence of the NMR signal. Results on isofluorane ( n = 5)- and halothane ( n = 7)- anesthetized cats give a hyperglycemic t ½ = 5.10 ± 0.11 min−1 (SE). Using Michaelis-Menten kinetics and an assumed half-saturation constant Kt = 5 ± 1 mM, we determined a maximal transport rate T max = 0.83 ± 0.19 μmol ⋅ g−1 ⋅ min−1, a cerebral metabolic rate of glucose CMRGlc = 0.22 ± 0.03 μmol ⋅ g−1 ⋅ min−1, and a normoglycemic cerebral influx rate CIRGlc = 0.37 ± 0.05 μmol ⋅ g−1 ⋅ min−1. Possible extension of this approach to positron emission tomography and proton NMR is discussed.

scholarly journals Experimental model for in vivo determination of dietary fibre and its effect on the absorption of nutrients in the small intestine

1981 ◽  
Vol 45 (2) ◽  
pp. 283-294 ◽  
Author(s):  
Ann-Sofie Sandberg ◽  
H. Andersson ◽  
B. Hallgren ◽  
Kristina Hasselblad ◽  
B. Isaksson ◽  
...  
Keyword(s):  
Small Intestine ◽  
Wheat Bran ◽  
Dietary Fibre ◽  
Dry Weight ◽  
Direct Analysis ◽  
Fresh Weight ◽  
Wet Weight ◽  
Definition Of

1. An experimental model for the determination of dietary fibre according to the definition of Trowell et al. (1976) is described. Food was subjected to in vivo digestion in ileostomy patients, and the ileostomy contents were collected quantitatively, the polysaccharide components of which were analysed by gas–liquid chromatography and the Klason lignin by gravimetric determination. The model was used for the determination of dietary fibre in AACC (American Association of Cereal Chemists), wheat bran and for studies on the extent of hydrolysis of wheat-bran fibre in the stomach and small intestine. The effect of wheat bran on ileostomy losses of nitrogen, starch and electrolytes was also investigated.2. Nine patients with established ileostomies were studied during two periods while on a constant low-fibre diet. In the second period 16 g AACC wheat bran/d was added to the diet. The ileostomy contents and duplicate portions of the diet were subjected to determinations of wet weight, dry weight, water content, fibre components, starch, N, sodium and potassium.3. The wet weight of ileostomy contents increased by 94 g/24 h and dry weight by 10 g/24 h after consumption of bran. The dietary fibre of AACC bran, determined as the increase in polysaccharides and lignin of ileostomy contents after consumption of bran, was 280 g/kg fresh weight (310 g/kg dry matter). Direct analysis of polysaccharides and lignin in bran gave a value of 306 g/kg fresh weight. Of the added bran hemicellulose and cellulose 80–100% and 75–100% respectively were recovered in ileostomy contents. There was no significant difference between the two periods in amount of N, starch and K found in the ileostomy contents. The Na excretion increased during the ‘bran’ period and correlated well with the wet weight of ileostomy contents.4. In conclusion, it seems probable that determination of dietary fibre by in vivo digestion in ileostomy patients comes very close to the theoretical definition of dietary fibre, as the influence of bacteria in the ileum seems small. Bacterial growth should be avoided by using a technique involving the change of ileostomy bags every 2 h and immediate deep-freezing of the ileostomy contents. True dietary fibre can be determined by direct analysis of polysaccharides and lignin in the food, at least in bran. Very little digestion of hemicellulose and cellulose from bran occurs in the stomach and small bowel. The 10–20% loss in some patients may be due to digestion by the gastric juice or to bacterial fermentation in the ileum, or both. The extra amount of faecal N after consumption of bran, reported by others, is probably produced in the large bowel.

PSIV-B-25 Digestible energy and metabolizable energy of high-fiber ingredients in growing pig diets

2021 ◽  
Vol 99 (Supplement_3) ◽  
pp. 394-395
Author(s):  
Jongkeon Kim ◽  
Yun Yeong Jo ◽  
Beob Gyun G Kim
Keyword(s):  
Latin Square ◽  
Basal Diet ◽  
Growing Pigs ◽  
Metabolizable Energy ◽  
Adaptation Period ◽  
Digestible Energy ◽  
High Fiber ◽  
Cashew Nut ◽  
Growing Pig ◽  
Gluten Feed

Abstract The objective of this study was to determine the digestible energy (DE) and metabolizable energy (ME) concentrations in high-fiber ingredients fed to growing pigs. Twelve barrows with an initial body weight of 57.5 kg (SD = 5.7) were individually housed in metabolism crates. A replicated 6 × 3 incomplete Latin square design with 12 animals, 6 experimental diets and 3 periods was employed. A basal diet was composed of 75.0% corn and 22.7% soybean meal (SBM) as the sole energy sources. Four experimental diets were prepared by replacing 40% of corn and SBM with soybean hulls (SH), corn gluten feed (CGF), wheat bran (WB), or rice bran (RB). An additional diet was prepared by replacing 10% of corn and SBM with cashew nut hulls (CNH). Each period consisted of a 4-d adaptation period and a 4-d collection period, and the marker-to-marker procedure was used for total collection of feces and urine. The DE and ME values in RB (3,969 and 3,936 kcal/kg DM) were greater (P &lt; 0.05) than those in CGF (2,654 and 2,520 kcal/kg DM) and SH (2,492 and 2,541 kcal/kg DM) and the energy values in WB (3,162 and 3,118 kcal/kg DM) were not different from those in RB, CGF, or SH. The DE and ME values in CNH (350 and 572 kcal/kg DM) were less (P &lt; 0.05) than those in all other test ingredients. In conclusion, energy concentrations in RB were greatest among the high-fiber test ingredients, whereas CNH had the lowest values.

scholarly journals Direct Determination of Ascorbic Acid in a Grapefruit: Paving the Way for In Vivo Spectroelectrochemistry

2017 ◽  
Vol 89 (3) ◽  
pp. 1815-1822 ◽  
Author(s):  
Jesus Garoz-Ruiz ◽  
Aranzazu Heras ◽  
Alvaro Colina
Keyword(s):  
Ascorbic Acid ◽  
Direct Determination ◽  
The Way

Direct determination of the contractility of the guinea pig gallbladder: a new in vivo model

1985 ◽  
Vol 63 (9) ◽  
pp. 1038-1042 ◽  
Author(s):  
I. S. Pomeranz ◽  
J. S. Davison ◽  
E. A. Shaffer
Keyword(s):  
Guinea Pig ◽  
Nerve Stimulation ◽  
Direct Determination ◽  
Displacement Transducer ◽  
In Vivo Model ◽  
Gallbladder Emptying ◽  
Gallbladder Contraction ◽  
Force Displacement

In vivo methods to study gallbladder contractility either equate gallbladder emptying with contraction or have relied on changes in gallbladder intravesicular pressure to reflect active transmural tension. We therefore devised an animal model in which the contractile force of the intact gallbladder is measured directly while the blood and neural supply remains uncompromised. Under general anesthesia one pole of the guinea pig gallbladder is anchored to the sternum and the other connected to a force displacement transducer. Any contraction–relaxation between these two points is recorded. This model was validated by measuring gallbladder response to both neuronal and humoral stimulation. Nerve stimulation was accomplished by means of two silver collar electrodes placed in contact with the cystic duct. With nerve stimulation, a frequency (0.5–10 Hz) or amplitude (1–10 V) dependent contraction occurred. Intravenous bethanechol (10 × 104 ng∙kg−1∙h−1) and cholecystokinin (3 × 104 ng∙kg−1∙h−1) both induced dose-dependent gallbladder contraction. This model should prove useful in assessing the physiologic control of gallbladder contraction.

scholarly journals Gastrointestinal morphology and absorption of monosaccharides in fowls conditioned to different types and levels of dietary fibre

1992 ◽  
Vol 67 (1) ◽  
pp. 77-89 ◽  
Author(s):  
C. J. Savory
Keyword(s):  
Dietary Fibre ◽  
Dietary Treatment ◽  
Basal Diet ◽  
Sugar Uptake ◽  
Fluid Loss ◽  
Standard Diet ◽  
Sugar Absorption ◽  
Body Tissues ◽  
Intestine Length

To test a possible influence of dietary fibre on intestinal sugar uptake, rates of absorption of 10 mm-d[U-14C] glucose and 10 mm-d-[U-14C] xylose were measured in either jejunum or (distal) caecum, by in vivo lumen perfusion, in immature female fowls preconditioned to a standard diet containing (g/kg) either 0, 100, 200 or 400 added dried grass, 200 powdered cellulose, or 200 grass with a polysaccharidase enzyme supplement. When birds were killed after perfusion, dimensions of (unperfused) parts of their alimentary tracts were determined, and recoveries of 14C radioactivity in some body tissues were compared with measured activities absorbed. On average, absorption of glucose was 1·9 and 1·2 times faster than xylose in jejunum and caecum respectively, although these differences varied with dietary treatment and order of perfusion. Increasing grass in the diet caused significant changes in xylose absorption rate in both jejunum and caecum, but only when it was perfused before glucose. With any one sugar and intestinal segment, mean rates of absorption were correlated positively with corresponding mean rates of fluid loss from perfusate. Although their influence on sugar absorption was not well defined, the dietary fibre treatments had more pronounced effects on gross dimensions of parts of the alimentary tract and, hence, potentially on total rates of absorption. Compared with the basal diet, addition of 100, 200 or 400 g grass/kg or 200 g cellulose/kg caused significant increases in small intestine length while 200 g grass/kg with supplementary enzyme did not, and combined caecal length increased with the 400 g grass/kg and the supplementary enzyme treatments. Absorbed 14C activity was recovered in plasma after jejunal perfusions but not caecal ones, whereas it was recovered in liver and in the flushed perfused segment after both types of perfusion. Since there was overlap in absorption rates between jejunum and caecum, this result suggests that the liver may be able to distinguish and treat differently compounds absorbed in the two regions.

The bioavailability of magnesium from different types of calcined magnesites of Greek origin

1993 ◽  
Vol 56 (3) ◽  
pp. 351-358 ◽  
Author(s):  
G. Zervas ◽  
G. Papadopoulos
Keyword(s):  
Ammonium Nitrate ◽  
Nitrate Solution ◽  
Latin Square ◽  
Basal Diet ◽  
Particle Size Fractions ◽  
Ammonium Nitrate Solution ◽  
Different Types ◽  
Apparent Bioavailability

AbstractThe objective of this work was to determine the apparent bioavailability of magnesium from four different types of calcined magnesites of Greek origin. These four types (A, B, C, D) were different in particle size fractions and production process. The solubility of the above four magnesium samples and their fractions were determined: (a) in the laboratory using ammonium nitrate solution after 24-h shaking and (b) in vivo using a nylon bag technique after 24-h incubation.Solubility was correlated with apparent bioavailability as determined in a balance experiment with five wether sheep in a 5×5 Latin-square design.Sheep were kept in metabolism cages and were given daily a basal diet (500 g hay + 700 g concentrate) plus 2 g magnesium supplements from types A to D. The magnesium bioavailability of the basal diet was used as a base for the determination of the bioavailability of magnesium in A, B, C and D supplements.Magnesium apparent bioavailability of the basal diet was found to be 0·203 and, for the supplements A, B, C and D, 0·381, 0·339, 0·315 and 0·292 respectively. The solubility of supplements A, B, C and D in ammonium nitrate solution and in vivo (using the nylon-bag technique) was found to be 0·812, 0·805, 0·784 and 0·773 or 0·294, 0·152, 0·102 and 0·200 respectively.The solubilities of the magnesium supplements in ammonium nitrate solution and in vivo both reflected dietary bioavailability differences up to a point, but neither was well enough correlated with the apparent bioavailability as determined by the balance experiment, this being judged to be the most precise method for bioavailability determination.

scholarly journals Optimized photochemistry enables efficient analysis of dynamic RNA structuromes and interactomes in genetic and infectious diseases

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Minjie Zhang ◽  
Kongpan Li ◽  
Jianhui Bai ◽  
Willem A. Velema ◽  
Chengqing Yu ◽  
...  
Keyword(s):  
Binding Sites ◽  
Rna Virus ◽  
Genome Structure ◽  
Direct Determination ◽  
Rna Structures ◽  
Disease States ◽  
Ribosome Binding Sites ◽  
Enterovirus D68

AbstractDirect determination of RNA structures and interactions in living cells is critical for understanding their functions in normal physiology and disease states. Here, we present PARIS2, a dramatically improved method for RNA duplex determination in vivo with >4000-fold higher efficiency than previous methods. PARIS2 captures ribosome binding sites on mRNAs, reporting translation status on a transcriptome scale. Applying PARIS2 to the U8 snoRNA mutated in the neurological disorder LCC, we discover a network of dynamic RNA structures and interactions which are destabilized by patient mutations. We report the first whole genome structure of enterovirus D68, an RNA virus that causes polio-like symptoms, revealing highly dynamic conformations altered by antiviral drugs and different pathogenic strains. We also discover a replication-associated asymmetry on the (+) and (−) strands of the viral genome. This study establishes a powerful technology for efficient interrogation of the RNA structurome and interactome in human diseases.

Sign in / Sign up

Export Citation Format

Share Document