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PubMed2006

Assessment of coenzyme Q10 absorption using an in vitro digestion-Caco-2 cell model.

The feasibility of using a coupled in vitro digestion-Caco-2 cell uptake as a model for examining the digestive stability and absorption of coenzyme Q10 (CoQ10) from a variety of commercially available CoQ10 products was examined. The products were first subjected to simulated digestion to mimic their passage through the GI tract to generate micelles containing CoQ10, and the micelle fractions added to monolayers of Caco-2 cells to determine CoQ10 uptake. The data demonstrate enhanced uptake of CoQ10 from formulations containing solubilized forms of CoQ10 and also from a CoQ10-gamma-cyclodextrin complex as compared with pure CoQ10 powder or tablets based on CoQ10 powder. The CoQ10 uptake by the cells was correlated with the extent of micellarization of CoQ10 during simulated digestion. Most of CoQ10 taken up by the cells was converted to ubiquinol either during or following uptake. The data also indicate a correlation between in vitro dissolution of CoQ10 products and uptake of CoQ10 by Caco-2 cells. Thus, this study demonstrates the utility of coupled in vitro digestion-Caco-2 cell model as a cost-effective screening tool that will provide useful information for the optimal design of human trials to assess the bioavailability of CoQ10 and also other bioactive compounds.

Biological Availability↗
PubMed1991

Assessments of lung digestion methods for recovery of fibers.

Evaluation of the pulmonary hazards associated with exposure to fibrous materials tends to be more complicated than assessments required for particulate materials. Fibers are defined by aspect ratios and it is generally considered that physical dimensions play an important role in the pathogenesis of fiber-related lung diseases. Several digestion techniques have been used to recover fibers from exposed lung tissue for clearance studies. Because many of the digestion fluids are corrosive (e.g., bleach, KOH), it is conceivable that the dimensions of recovered fibers are modified during the tissue digestion methods to assess whether the physical dimensions of bulk samples of fibers were altered following simulated digestion processing. Aliquots of crocidolite and chrysotile asbestos, Kevlar aramid, wollastonite, polyacrylonitrile (pan)-based carbon, and glass fibers were incubated with either saline, bleach, or KOH and then filtered. Scanning electron microscopy techniques were utilized to measure the physical dimensions (i.e., lengths and diameters) of at least 160 fibers per treatment group of each fiber type. Our results showed that the lengths and diameters of glass fibers and wollastonite were altered after treatment with KOH. In addition, treatment with bleach produced a small reduction in both asbestos fiber-type diameters, and greater changes in Kevlar and wollastonite diameters and carbon fiber lengths (P less than 0.05). These results indicate that lung digestion methods should be carefully assessed for each fiber type before initiating fiber clearance studies.

Asbestos↗
PubMed2003

Digestion of maize and sunflower pollen by the spotted maize beetle Astylus atromaculatus (Melyridae): is there a role for osmotic shock?

We investigated the mechanism and efficiency of digestion of two types of pollen, maize, Zea mays, and sunflower, Helianthus annuus, by the spotted maize beetle, Astylus atromaculatus (Melyridae). We found similar and high extraction efficiencies, but different mechanisms of digestion. Osmotic shock was apparently involved in digestion of the large and thin-walled maize pollen grains. In the anterior midgut most maize pollen grains were already ruptured, in contrast with the intact exines of sunflower pollen, which suggests another mechanism of digestion for the latter, such as enzymatic action. We investigated the effect of osmotic shock on maize pollen in vitro by looking at the behavior of pollen grains in varying osmotic concentrations. Maize pollen grains burst in both distilled water and sugar solutions of various concentrations, and the amount of rupturing decreased with an increase in sugar concentration. Digestion of maize pollen was much slower in honeybees than in spotted maize beetles. Maize pollen bursts early in the midgut of maize beetles, but remains intact in honeybees: this suggests that osmotic shock may not be as important for honeybees as previously suggested.

Animals↗
PubMed2003

The peritrophic matrix limits the rate of digestion in adult Anopheles stephensi and Aedes aegypti mosquitoes.

The peritrophic matrix (PM) is a chitin-containing acellular sheath that surrounds the blood meal and separates the food bolus from the midgut epithelium. Intense molecular traffic through the PM occurs during digestion. Digestive enzymes secreted by the midgut epithelium must traverse the PM to reach their substrates in the food bolus, and digestion products must cross the PM in the opposite direction to be absorbed by the epithelial cells. Here we report that the PM limits the rate of digestion. PM disruption by two independent means (chitinase and anti-PM antibodies) consistently increases the rate of blood digestion. The significance of these results in relation to PM function is discussed.

Aedes↗
PubMed1998

The diet and digestive energetics of an Australian short-necked turtle, Emydura macquarii.

We described the diet of Emydura macquarii, an omnivorous turtle from south-eastern Australia, compared its digestive performance on diets of fish or plants at two temperatures, and related how both diet and temperature affect its food selection in nature. Filamentous algae constituted 61% of the stomach content of E. macquarii. The turtles rarely fed on motile prey, but selected carrion from the lagoon bottom and terrestrial insects (Diptera, Hymenoptera and Coleoptera) trapped on the surface of the water. Digestive efficiency of E. macquarii was affected little by body temperature, in contrast to consumption rates and rates of passage which were strongly influenced by both temperature and diet. In combination, these responses resulted in a slower rate of digestion at 20 degrees C than at 30 degrees C. Digestive efficiency of E. macquarii on a herbivorous diet at 30 degrees C (49%) was about half that of turtles on a carnivorous diet (91%), but they had longer transit times (118 h on the plant diet versus 70 h). Lower consumption rates and longer mean retention times in turtles fed plants compared those fed fish relate to slower digestive processing of the plant. Rapid processing and higher consumption rates of fish by E. macquarii resulted in higher energy gains compared to turtles consuming plants (almost 100 times more energy at 30 degrees C). The laboratory results suggest that fish carrion and aquatic and terrestrial invertebrates are probably essential dietary items of E. macquarii in the wild, because its metabolic requirements cannot be met from aquatic macrophytes alone.

Animals↗
PubMed2002

Inhibition of digestive enzyme release by neuropeptides in larvae of Opisina arenosella (Lepidoptera: Cryptophasidae).

Leucokinins are a group of structurally related neuropeptides stimulating gut motility and fluid secretion by Malpighian tubule in insects. For studying effect of neuropeptides on digestive enzyme release, empty midgut tubes of larvae of Opisina arenosella ligated at both ends with hair were incubated with Leucokinins (LK I-VIII), LK analogues and Leucopyrokinin (LPK) in a bioassay apparatus at 37 degrees C for 30 min. The lumen contents were subsequently analyzed for digestive enzyme levels. The neuropeptides LK III, FFSWG amide, 122 A[1] WP-2, LPK and 434 [phi2] WP-1 inhibited the release of digestive enzymes, protease and amylase while LK VIII, unique in having tyrosine residue, stimulated protease release. The minimum sequence of amino acids at the C-terminal required for activity of LK peptides was found to be FXSWGamide (X=Asn, His, Ser, or Trp). The N-terminal pyroglutamate residue and proline at the C-terminal may contribute to the inhibitory effect of LPK on digestive enzyme release. The present study reveals for the first time an inhibitory effect for leucokinins and pyrokinin on the release of digestive enzymes from the insect midgut.

Amylases↗
PubMed2001

Improvement of in-rumen digestibility of alfalfa forage by genetic manipulation of lignin O-methyltransferases.

Lignin inhibits forage digestibility by ruminant animals, and lignin levels and the proportion of dimethylated syringyl (S) lignin monomers increase with progressive maturity in stems of forage crops. We generated transgenic alfalfa (Medicago sativa L.) with reduced lignin content and altered lignin composition. Down-regulation of caffeic acid 3-O-methyltransferase (COMT) reduces lignin content, accompanied by near total loss of S lignin, whereas down-regulation of caffeoyl coenzyme A 3-O-methyltransferase (CCoAOMT) reduces lignin content without reduction in S lignin. These changes are not accompanied by altered ratios of cell wall polysaccharides. Analysis of rumen digestibility of alfalfa forage in fistulated steers revealed improved digestibility of forage from COMT down-regulated plants, but a greater improvement in digestibility following down-regulation of CCoAOMT. The results indicate that both lignin content and composition affect digestibility of alfalfa forage, and reveal a new strategy for forage quality improvement by genetic manipulation of CCoAOMT expression.

Animals↗
PubMed1998

Partial in vitro digestion of active gliadin-related peptides in celiac disease.

Peptides corresponding to residues 75-86 (RPQQPYPQPQPQ) and 75-85 of the A-gliadin structure, which were shown to be active in an animal model of celiac disease, were digested in vitro with small intestinal mucosa from children with celiac disease in remission and with mucosa from normal children. The products of digestion were separated into two fractions by gel permeation chromatography. Undigested residues (Mr > 400 fraction) from both peptides contained mainly glutamine, proline, and tyrosine, while the digested materials (Mr < 400 fraction) contained mainly proline, glutamine and arginine. Much larger amounts of undigested peptides were obtained from digestion with celiac mucosa than from normal mucosa. The results with peptide 75-86 indicated that the octapeptide 77-84 (QQPYPQPQ) was the main residual component and this peptide was shown to be active in the assay. Peptide 77-84 was also obtained as a residue from digestion of peptide 75-85, together with heptapeptide 77-83. The results lend further support for a primary mucosal defect in celiac disease and indicate that residual peptides in the small intestine of patients with the disease still retain appreciable toxicity.

Amino Acids↗
PubMed2004

Cytochemical and histochemical aspects of the digestive gland cells of the mussel Mytilus galloprovincialis (L.) in relation to function.

The epithelium of the digestive tubules of the mussel Mytilus galloprovincialis is comprised of two cell types, namely digestive and basophilic cells. In basophilic cells, the secretory granules are beta-glucuronidase immunoreactive, a fact that enhances the hypothesis that beta-glucuronidase is synthesized in basophilic cells. A novel observation at the ultrastructural level is the pinocytic activity associated with the formation of coated pits. This observation constitutes direct evidence for endocytic processes taking place in basophilic cells. The use of cryostat sections from the same digestive tubules reveals, in many instances, a very pronounced neutral lipid accumulation in the same structures giving a positive reaction for N-acetyl-beta-hexosaminidase, indicating the association of those lipids with lysosomes. In some mussels, a high content of lipofuscin was observed in the lysosomes of the digestive cells. In these cases, the lysosomal structures show a limited neutral lipid content, and a weaker N-acetyl-beta-hexosaminidase reaction. In the digestive cells, the carbohydrate content of the lysosomes, and very well-developed canal system in the apical part of cells are discussed in relation to their function.

Animals↗
PubMed2005

[South American camelids in Switzerland. III. Digestibilities of different feedstuff].

Feces from 15 adult llamas were collected in 4 herds and the exact diet was determined, either of the group or of individual animals, to examine apparent digestibility. A questionnaire was submitted to the animal owners. The questionnaire included questions about the animals in the herd (number, age, gender, origin), management methods, pastures, watering and feeding facilities for the animals, hay supplementation, composition of the ration and fodder additives used. Analysis of the feed revealed an average apparent digestibility for dry matter of 81+/-4%, for the organic matter 77+/-7%, for crude protein 69+/-10%, for nitrogen-free extract 83+/-5%, for calcium 60+/-17%, for phosphorus 54+/-11% and 81+/-9% for crude fiber. All feed components seem to be digested similarly to domestic ruminants whereas the apparent digestibility of crude fiber was high, which indicates that the digesting system seems to be more effective.

Animal Feed↗
PubMed2000

Precaecal digestibility of niacin and pantothenic acid from different foods.

This study was conducted to investigate the apparent precaecal digestibilities of niacin and pantothenic acid from human nutrient related foods including wheat, coarse whole-meal bread, boiled potatoes and boiled pork and beef. Therefore, pigs were subjected to an end-to-end ileo-rectal anastomosis, so digesta passed straight from ileum to rectum, eliminating endogenous vitamin synthesis. Excreted chyme was collected over 5-days periods, and concentrations of niacin, and pantothenic acid in the food and chyme samples were determined microbiologically. The intestinal bioavailability of niacin and pantothenic acid was affected differently by the food administered. The digestibility values of niacin deriving from the wheat-, potato- and the meat-based meals ranged from 59 to 69%. Wholemeal bread exerted a nutritionally important negative effect on the apparent intestinal availability of dietary niacin relative to the other foods, which averaged by 40%. Food-related differences of the pantothenic acid digestibility values were greater than that observed with niacin. The digestibility values of pantothenic acid from wheat, potatoes and the meat meals ranged between 65 and 81% and were of the order wheat diet > pork diet > potato diet > beef diet, although differences were not statistically significant. The digestibility of pantothenic acid from the coarse wholemeal bread diet was lower than 30%.

Animals↗
PubMed2000

The lowering effect of dietary glucose versus starch on fat digestibility in rats is dependent on the type of fat in the diet.

The aim of the study was to determine whether the type of dietary fat influences the effect of dietary glucose on lipid digestibility. Earlier work had shown that glucose, when compared with starch, reduced fat digestibility in rats fed rations containing animal fat as fat source. Male rats (n = 6/group) were fed for two weeks on purified diets containing either 62% (w/w) starch or glucose and either 8% (w/w) palm oil, coconut fat, soybean oil or medium-chain triglycerides (MCT) as the main source of fat. The diets had no differential effect on growth. Glucose significantly depressed apparent lipid digestibility in rats fed the diets containing either palm oil or coconut fat, but not in rats given the diets containing either soybean oil or MCT. Thus, the inhibitory effect of glucose on lipid digestibility in rats is dependent on the dietary lipid source. This observation may contribute to understanding the mechanism by which dietary glucose inhibits fat digestion.

Animal Nutritional Physiological Phenomena↗
PubMed1991

Morphologic analysis of digestive cancers from the registry of Vaud, Switzerland.

Detailed data and statistics per each morphological site of various digestive neoplasms were obtained for the period 1976-87 from the Vaud Cancer Registry datafile, a population-based cancer registration scheme covering about 530,000 inhabitants from the French-speaking part of Switzerland. Tabulations presented include absolute number of cases (1,041 oral and pharyngeal, 545 oesophageal, 1,131 gastric, 83 small intestine, 1,980 colon, 1,267 rectal, 357 liver, 328 gallbladder and 725 pancreatic cancers), percent distributions, age-standardised rates, sex ratios and 5-year survival. The report has essentially a descriptive value, and should be viewed as a contribution towards quantification, in a well surveilled population of the West-central part of Europe, of the proportional distribution of digestive neoplasms by morphological type, and corresponding incidence and survival rates. Among the points deserving specific attention, there are the elevated frequency of upper digestive tract cancers, the very high male-to-female ratios for squamous cell carcinomas, adenocarcinomas of the oesophagus and hepatocellular carcinomas of the liver, the female excesses in infiltrating carcinoids of the colon, transitional and squamous cell carcinomas of the rectum and adenocarcinomas of the gallbladder, and the crossover in male-to-female ratio in squamous cell carcinoma along the digestive tract (i.e. from 6.0 at the level of the mouth/pharynx to 0.5 in the rectum). As concerns survival, rates were higher for lymphomas and sarcomas than for carcinomas in oral cavity and stomach, similar for carcinoids and carcinomas in the small bowel (about 35% at 5 years), as well as for colon (34%) and rectal (37%) cancers. Some of the findings, such as the higher survival of carcinomas arising from polyps in the colon and rectum, or the higher proportion of cholangiocellular and combined cholangio- and hepatocellular carcinomas in females than in males find plausible prognostic or aetiologic correlates, but others, such as the large proportions of squamous and transitional cell cancers of the rectum in females are more difficult to explain. These and several other indications emerging from careful examination of the data herein presented underline the interest of morphological analyses of digestive tract cancers.

Adult↗
PubMed1996

Stability of food allergens to digestion in vitro.

An integral part of the safety assessment of genetically modified plants is consideration of possible human health effects, especially food allergy. Prospective testing for allergenicity of proteins obtained from sources with no prior history of causing allergy has been difficult because of the absence of valid methods and models. Food allergens may share physicochemical properties that distinguish them from nonallergens, properties that may be used as a tool to predict the inherent allergenicity of proteins newly introduced into the food supply by genetic engineering. One candidate property is stability to digestion. We have systematically evaluated the stability of food allergens that are active via the gastrointestinal tract in a simple model of gastric digestion, emphasizing the major allergens of plant-derived foods such as legumes (peanuts and soybean). Important food allergens were stable to digestion in the gastric model (simulated gastric fluid). For example, soybean beta-conglycinin was stable for 60 min. In contrast, nonallergenic food proteins, such as spinach ribulose bis-phosphate carboxylase/oxygenase, were digested in simulated gastric fluid within 15 sec. The data are consistent with the hypothesis that food allergens must exhibit sufficient gastric stability to reach the intestinal mucosa where absorption and sensitization (development of atopy) can occur. Thus, the stability to digestion is a significant and valid parameter that distinguishes food allergens from nonallergens.

Allergens↗
PubMed2000

Digestibility of cocoa butter from chocolate in humans: a comparison with corn-oil.

OBJECTIVE: To compare, in humans, the digestibility of moderate amounts of cocoa butter (30.7 g/d) consumed in the form of chocolate as part of a normal western diet with that of a well-absorbed fat (corn oil); and hence determine whether, by virtue of its apparent low absorption, cocoa butter can be considered to be a low calorie fat. DESIGN: Randomised, two-period crossover metabolic study, conducted under free-living conditions, but with strict control over food intake. SETTING: Metabolic Unit, Nestlé Research Center Lausanne. SUBJECTS: Twelve healthy men were selected from volunteers at the Nestlé Research Center and all subjects completed the study. INTERVENTION: Two treatment periods of two weeks each: cocoa butter and control periods, with strict dietary control separated by a two week wash out period. RESULTS: No differences (P>0.05) were observed in faecal weight (wet or dry), faecal fat nor in defecation frequency between treatments (cocoa butter and corn oil). Cocoa butter at a dose of 30.7 g/d in the form of black chocolate, consumed between two meals, was found to have a similar digestibility to that of corn oil (99 % of corn oil digestibility). CONCLUSION: Cocoa butter, consumed as back chocolate within a normal mixed diet, has a high digestibility, similar to that of corn oil, and a digestible energy value of 37 kJ/g in man. Thus, cocoa butter cannot be considered to be a low-calorie fat. SPONSORSHIP: Nestec Ltd, Switzerland. European Journal of Clinical Nutrition (2000) 54, 120-125

Adult↗
PubMed1989

Application of high-performance liquid chromatography--inductively coupled plasma mass spectrometry to the investigation of cadmium speciation in pig kidney following cooking and in vitro gastro-intestinal digestion.

The speciation of cadmium in retail pig kidney has been examined by size-exclusion chromatography (SEC) coupled directly to inductively coupled plasma mass spectrometry (ICP-MS). Approximately 35% of the cadmium from uncooked kidney was soluble after aqueous extraction at pH 8 and SEC - ICP-MS revealed three discrete peaks whose retention times corresponded to estimated relative molecular masses of 1.2 x 10(6), 7.0 x 10(4) and 6 x 10(3)-9 x 10(3). In the cooked kidney, 35% of the Cd was soluble and was all associated with a peak of a relative molecular mass (Mr) of 6 x 10(3)-9 x 10(3). After simulated gastric digestion of cooked pig kidney at pH 2.5, 60% of the cadmium was solubilised and associated with a species of Mr less than 1 x 10(3). When the digest was also subjected to simulated intestinal digestion at pH 6.8, a single peak, which corresponded to 20% of the original cadmium, was eluted. This peak co-eluted with the single peak extracted at pH 8.0 from the cooked kidney. It was also of similar estimated Mr to the single broad peak observed after simulated gastro-intestinal digestion of equine renal metallothionein (Mr = 1.1 x 10(4]. The results suggest that the majority of soluble cadmium in retail pig kidney is associated with a metallothionein-like protein that survives both cooking and simulated in vitro gastro-intestinal digestion.

Animals↗
PubMed2001

Prediction of protein digestibility in dog food by a multi-enzymatic method: a useful technique to develop.

The multi-enzymatic method with constant pH described by Dufour-Etienne et al. (Rec. Méd. Vét. 168, 789-796, 1992) was tested using 17 industrial dry dog foods and two ingredients, sodium caseinate and beef meat, which were used as references. The quantity of sodium hydroxide added to the enzymatic solution was measured after incubation times of 2, 5 and 10 min and the best prediction of the apparent protein digestibility was obtained with an incubation time fixed at 2 min. The volume of sodium hydroxide 0.1 N constantly added to maintain the pH of the solution at 8 was correlated to the value of in vivo digestibility of the protein measured in the dog. The correlation coefficient obtained was 0.90 with a standard error of the regression of 1.9 for all samples. The correlation coefficients calculated for incubation times of 5 and 10 min were lower than that at 2 min; thus an incubation period of 2 min provided the highest correlation coefficient for this multi-enzymatic method at constant pH. However, considering the lack of samples with an apparent protein digestibility ranging between 85 and 95%, the slope of the regression line and the correlation coefficient were strongly influenced by the ingredients, such that when the correlation coefficient was calculated for 17 dog foods without the reference ingredients, a coefficient of 0.71 (+/- 1.9) was obtained. These tests of in vitro digestibility are valuable to predict the apparent digestibility of the protein in the dog, but, it is essential to confirm the results by an in vivo test.

Animal Feed↗
PubMed2003

Studies on feed digestibilities in captive Asian elephants (Elephas maximus).

In order to test the suitability of the horse as a nutritional model for elephants, digestibility studies were performed with six captive Asian elephants on six different dietary regimes, using the double marker method with acid detergent lignin as an internal and chromium oxide as an external digestibility marker. Elephants resembled horses in the way dietary supplements and dietary crude fibre content influenced digestibility, in calcium absorption parameters and in faecal volatile fatty acid composition. However, the absolute digestibility coefficients achieved for all nutrients are distinctively lower in elephants. This is because of much faster ingesta passage rates reported for elephants. No answer is given to why elephants do not make use of their high digestive potential theoretically provided by their immense body weight. Differences in volatile fatty acid concentrations between these captive elephants and those reported from elephants from the wild are in accord with a reported high dependence of free-ranging elephants on browse forage.

Animal Feed↗