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PubMed1989

Recent findings and future perspectives of digestive physiology in rabbits: a review.

The rabbit is one of the most common laboratory animals. Consequently, there is an enormous number of publications concerning its physiology. The present review is restricted to a special field and deals with the new findings of the rabbit's digestive physiology. For the sake of better intelligibility the most important antecedents are also given. First the particularities of feed intake regulation are demonstrated. The strong control mechanism can be disturbed by feed antinutritives, mycotoxins and high environmental temperature. Caecotrophy depends on three main factors: stimulation of rectal mechanoreceptors, perception of the specific odour of the soft faeces, and the inner motive determined by the blood level of metabolites and hormones. The species characteristics of proportions, pH conditions, microflora and -fauna of the rabbit's digestive tract are given. The digestion and absorption of dietary nutrients are discussed. Special sections deal with the sorption of electrolytes and VFAs in the gut, the caecal digestive process, the formation of hard and soft faeces and the role of the caecotrophy in stomachal carbohydrate degradation. A relatively new area, i.e. the development and maturation of the gastrointestinal tract, is also shown. The postnatal evolution of digestive enzyme activity is also summarized. The main endogenic factors (breed, sex, age, stress, caecotrophy, presence of hairball in the stomach) influencing the digestion of dietary nutrients are also described. The probable future trends are given, too.

Animals↗
PubMed1986

Digestion in horses after resection or ischemic insult of the large colon.

The effect of 60% resection of the large colon vs ischemic insult without resection on the ability of horses to digest grass hay was investigated. Digestion trials were performed on 9 horses before surgery (base line) and 3 weeks, 6 weeks, and 6 months after surgery. The percentage of apparent digestion of crude protein, crude fiber, nitrogen-free extract, calcium, phosphorus, magnesium, manganese, copper, and zinc was calculated. Horses that had resection (n = 5) had decreased apparent digestion of crude protein, crude fiber, and phosphorus 3 weeks after surgery, compared with those in horses with ischemic insults (n = 4) and with base-line values. Horses with ischemic insults also had a decrease in crude protein digestion 3 weeks after surgery, compared with base-line values. All horses returned to base-line values of digestion at the 6-month trials, although horses that had resection had higher fecal concentrations of phosphorus and nitrogen-free extract than did horses with ischemic insult. During the study, all horses had maintained good body condition.

Animals↗
PubMed1985

[Digestibility of nutrients in a feed mixture in certain swine helminthiases].

The average digestibility coefficients of feed mixture nutrients in pigs infected medium severely to severely by the helminths Ascaris suum and Oesophagostomum dentatum were lower in comparison with the post-dehelminthization condition (dry matter by 3.1%, crude protein by 6.7%, fat by 8.9%, nitrogen-free extracts and fibre by 2.2%, organic matter by 3.1%). The content of total digestible nutrients made 679 g in infected pigs and 708 g in dehelminthized pigs. In the period following the experimental infection of pigs by the helminths Ascaris suum, characterized by the formation of antibodies and adaptation after heavy injury of the organism, the digestibility coefficients of feed mixture nutrients were in comparison with the state prior to infection influenced positively. In two metabolism trials, on the 9th to 13th day after infection the digestibility coefficients increased as follows: of dry matter by 4.8% and 3.6%, crude protein by 8.2 and 4.2%, nitrogen-free extracts and fibre by 2.0 and 3.5% and organic matter by 3.0 and 3.3%. The decrease in fat digestibility coefficients was observed in both cases, by 12.4% and 9.9%. Prior to infection the content of total digestible nutrients was 712 g and 682 g, after infection 731 g and 707 g.

Animal Feed↗
PubMed1985

Chagas' disease: a model of denervation in the study of digestive tract motility.

The enteric nervous system (ENS) is an important neural network that integrates, modulates and coordinates various motor functions of the digestive tract. Chagas' disease, to a variable extent and in a nonsystematic way, causes destruction of ENS neurons throughout the digestive tract. The studies carried out on the pathophysiology of the digestive form of this disease have provided, as a corollary, a better understanding of the participation of the ENS in the regulation of the normal motor activities of the digestive tract and have led to the conclusion that the disease is a true model of intrinsic denervation of the human digestive tract. Among the motor alterations caused by impairment of the digestive tract in Chagas' disease are: absence of peristalsis in the esophagus, achalasia of the cardia, loss of the accommodation reflex in the proximal stomach, gastric emptying disorders, changes in the migrating motor complex (MMC), disappearance of postprandial motor phenomena in the colon and rectum, lack of relaxation of the internal sphincter of the anus, and anomalous responses of the gall bladder to cholekinetic stimuli.

Biliary Tract↗
PubMed1983

[Comparative study of gastric emptying of digestible and nondigestible solids in normal man and duodenal ulcer patients].

Few studies have compared the gastric emptying of digestible and non-digestible solids in man. In 9 normal subjects and 16 duodenal ulcer patients, we measured simultaneously and during 3 h, the gastric emptying of: (a) radioopaque pellets (n = 100; volume = 30 mm3) ingested with an ordinary meal (450 kcal, 500 ml) and counted on X-ray series; and (b) digestible solids of the meal (99mtechnetium tagged egg white) detected by an isotopic method. Gastric emptying of liquids (labelled with 113mindium DTPA) was also determined. In normal subjects, emptying rates of the pellets was 5 +/- 2 p. 100 per hour while that of digestible solids was 29 +/- 1 p. 100 per hour (P less than 0.01). No correlation was evidenced between the emptying rates of either kind of solids. Emptying of liquids was faster than that of both digestible solids and pellets. Similar results were obtained in duodenal ulcer patients; no significant difference was found between patients and normal subjects for the three meal phases tested. These results are consistent with the hypothesis that digestible solids are retained in stomach until they are ground, and show that inert particles do not always reflect the gastric emptying of natural solids of the meal.

Adult↗
PubMed1982

[Protein-carbohydrate ratio in the diet and its effect on digestive processes in sheep].

Four experimental periods were followed up with fistulated sheep. During each period the animals were offered rations of different protein and carbohydrate ration. Experiments were also carried out to elucidate the physiology of the digestive processes, and the resorption and metabolism of the various nutrients. It was established that digestive and metabolic processes ran a best course at the protein to carbohydrate ration of 1:5.8. At 1:10 and 1:14.5% a carbohydrate depression set in which led to a certain drop of the coefficients of digestibility. The body was forced to excrete higher amounts of digestive juices with a higher content of organic mineral matter in the duodenal chyme. The digestive apparatus was said to be subjected to substantial stress during the conversion of the various feeds and their components into nutrients that were characteristic of the organism, their ratio being thoroughly different in principle in the feeds and in the animals body. Conversion was shown to start not in the blood and tissues but in the digestive tract.

Animal Feed↗
PubMed1980

[Comparative digestive utilization and forms of fecal excretion in the rat of erucic and brassidic acids esterified in different glyceride structures].

The digestibility and fecal excretion patterns of erucic (cis n-9 docosenoic) and brassidic (trans n-9 docosenoic) acids, esterified in triglycerides of different structure, were compared in the rat. Synthetic triglycerides were prepared either by mixing or interesterifying trierucin or tribrassidin with an equal amount of corn oil. Rapeseed and peanut oils were used as references. The apparent digestibility of trierucin mixed or interesterified with corn oil was similar to that of peanut oil but higher than that of rapeseed oil. The high amount of 2-monoerucin resulting from diets containing trierucin explained the improved digestibility of erucic acid as compared to that of rapeseed oil which had a very small erucic acid content on the 2-position. It also seemed that 2-monoerucin enhanced the digestibility of saturated fatty acids. Tribrassidin mixed with corn oil had a poor digestibility because pancreatic lipase hydrolysis was delayed in the intestinal lumen. The high melting point of the homogeneous triglyceride was responsible for that phenomenon. The interesterification of tribrassidin with corn oil, which drastically lowered the melting point of the mixture from 52 to 37 degrees C, improved both the hydrolysis of the triglycerides and the digestibility of the C22: 1 trans fatty acid as well as that of the other fatty acids in the diets. Nevertheless, the unabsorbed brassidic acid in every case was principally excreted in the form of a compound insoluble in organic neutral solvent. In that respect, brassidic acid behaved like shorter chain saturated fatty acids such as palmitic and stearic acids.

Animals↗
PubMed1995

Eosinophilic gastroenteritis involving the entire digestive tract.

Eosinophilic gastroenteritis, an inflammatory disease of unknown etiology, commonly involves the stomach and small intestine with eosinophilic infiltration. Herein we describe an unusual case of eosinophilic gastroenteritis involving the entire digestive tract. A 24-yr-old woman came to our hospital presenting with diarrhea with marked peripheral eosinophilia. Stool specimens were negative for parasites, ova, bacteria, and fungi. Barium and endoscopic studies showed thickened edematous folds of the duodenum and small intestine. Biopsy specimens of the esophagus, stomach, duodenum, ileum, and colon showed eosinophilic infiltration. A diagnosis of eosinophilic gastroenteritis involving the entire digestive tract was made, and therapy with prednisone was started. Symptoms and peripheral eosinophilia rapidly resolved, and biopsies of the digestive tract demonstrated no eosinophilic infiltration. This case illustrates the expanded spectrum of the disease to the entire digestive tract and emphasizes the diagnostic usefulness of endoscopic biopsies. The initial presentation of patients with eosinophilia requires the evaluation of the entire digestive tract. It is worth noting that eosinophilic gastroenteritis can involve the entire digestive tract.

Adult↗
PubMed1996

The effect of Helicobacter pylori infection on gastric emptying of digestible and indigestible solids in patients with nonulcer dyspepsia.

OBJECTIVE: There is no general agreement with regard to the effect of Helicobacter pylori infection on gastric emptying in patients with nonulcer dyspepsia. METHODS: We performed the 14C urea breath test as well as simultaneous recordings of scintigraphic gastic emptying and gastric clearance of radiopaque markers to determine the effect of Helicobacter pylori infection on gastric emptying of digestible and indigestible solids in nonulcer dyspepsia patients. RESULTS: Sixty patients, 30 males and 30 females, were enrolled in the study. There were 22 patients (36.7%) without and 38 patients (63.3%) with H. pylori infection. Twenty-four of the 60 patients (40%) showed normal and 36 patients (60%) showed delayed gastric emptying of digestible solids. In addition, 21 patients (35%) showed normal and 39 patients (63%) showed delayed gastric emptying of indigestible solids. There was no correlation between delayed gastric emptying of digestible and indigestible solids (p > 0.05, difference not significant). Although not statistically significant, the incidence of delayed indigestible solid emptying was higher than that of delayed digestible solid emptying (65% vs. 60%). Among different patterns of gastric emptying, no difference was noted between the patients with and without H. pylori infection. CONCLUSION: Delayed gastric emptying of indigestible solids is as common as delayed gastric emptying of digestible solids in nonulcer dyspepsia patients. The status of H. Pylori infection appeared not to influence the incidence of delayed gastric emptying of digestible and indigestible solids.

Adolescent↗
PubMed1977

Peculiarities of digestion in senescence.

It is established, that involutional changes of digestive tract limits digestion in old patients. In the age digestive capacities mostly are sufficient, but there is a great tendency to maldigestion. The decrease of functional capacity doesn't show the clinical features of a manifest digestive insufficiency in old healthy probands. But it was shown that the digestive efficiency is exhausted by hyper-alimentation more quickly in elderly. The pancreas of elderly is able to digest small meals taken frequently.

Adult↗
PubMed1976

[Digestion and absorption of dietary triglycerides].

This review is an attempt to put in order some facts obtained during twenty-five years of studying the digestion and absorption of dietary triglycerides. After a short history of this problem to show the progress of research, the active mechanism of pancreatic lipase on triglycerides is explained: this enzyme specifically hydrolyses fatty acids esterified with the primary hydroxyl groups of glycerol, forming 2-monoglycerides and free fatty acids. This fact is very important for the further process involving formation and composition of intraluminal micelles, along with absorption and de novo synthesis of triglycerides inside enterocytes. Several different points are disscussed: - Short or medium chain-length fatty acids are hydrolyzed more easily than long-chain ones; after their absorption, the former go to the liver by the portal circulation and the latter go to lymph. - An evaluation of the extent of digestive hydrolysis has been given by means of doubly-labelled triglycerides (glycerol and fatty acids), and by comparing isotope ratio values of lymph and dietary triglycerides. - The physico-chemical state that intraluminal fats are in is discussed; 2-monoglycerides and fatty acids released from triglyceride hydrolysis form macromolecular agregates with biliary salts and phospholipids, cholesterol, and dietary phospholipids (or their degradation products). These are termed mixed micelles and are absorbed by diffusion. - Many recent morphological studies carried out with the electron microscope are indicated. - Two metabolic pathways for triglyceride resynthesis in the mucosal cells have been established, one from free fatty acids and alpha-glycerophosphate, the other from 1 or 2-monoglycerides. Phosphatidic acids are involved in this resynthesis, but the role of other phospholipids is almost certainly not so narrowly limited. - The apparent digestibility of fats according to their fatty acid composition, and mainly according to the location of the fatty acids in the initial triglyceride molecule, is discussed. - The nature and importance of endogenous fatty acids in the digestive tract and lymph is discussed. - The lipid and fatty acid composition of lymph chylomicrons is given. - The importance of lymph lipid particles (average diameter 0,05 less than or equal mum) for transport of exogenous fatty acids is indicated. The biochemical mechanism involved in the digestion and absorption of dietary lipids are now well known, but some processes are still uncertain, particularly the physico-chemical state of intraluminal lipids, the role of enterocyte membranes, the synthesis and secretion of digestive enzymes, and the role of intestinal flora.

Animals↗
PubMed1995

Studies on the morphological changes in the midguts of two ixodid tick species Boophilus microplus and Rhipicephalus appendiculatus during digestion of the blood meal.

Light and electron microscopy were used to study the morphological changes which accompanied feeding and digestion of the blood meal in the midgut epithelium of two ixodid tick species Boophilus microplus and Rhipicephalus appendiculatus. In unfed ticks of both species, the midgut epithelium was lined by stem cells and empty digest cells in which haematin accumulated with starvation. On attachment to its hosts, differentiation of the stem cells and the loss of haematin from the midgut epithelium, seemed to be synchronous. Digestive activity with the appearance of the digest cell series started in the anterior end of the midgut when it came in contact with the blood meal. Although various stages can be distinguished, it would appear that these are in reality phases of activity of a single cell type--the digest cell. No additional evidence was obtained on other cell types.

Animals↗
PubMed2002

The digestive tract of Nautilus pompilius (Cephalopoda, Tetrabranchiata): an X-ray analytical and computational tomography study on the living animal.

Using X-ray analytical studies and computational tomography, the position of the digestive tract of the tetrabranchiate cephalopod Nautilus pompilius L. was demonstrated in a living animal. For the first time, a detailed analysis of the rate of digestion and the duration of the different phases of a digestive cycle has been made using these in vivo methods. At 20 min after food intake, the food has entered the stomach, where it is reduced to small pieces; most is stored in the crop, which is enlarged to approximately four times its original size. The chyme reaches the midgut gland 3 h and the rectal loop 5 h after food intake. The time between food intake and elimination is 12 h. Thus, in Nautilus pompilius, digestion takes approximately the same time as described for nectobenthic sepioids and benthic octopods but is approximately 6 h longer than in loliginids, which have a pelagic mode of life. Furthermore, the three-dimensional structure of the digestive tract of a living Nautilus pompilius L. was demonstrated using computational tomography.

Animals↗
PubMed1993

Influence of gastrointestinal microflora on digestibility and biological value of protein in rats.

The influence of the gastrointestinal microflora on the digestibility and biological value of casein was investigated in germ-free (GF) and conventionalized (Cvd) Fischer 344/Yit rats fed an 8% casein diet. There was no significant difference in the true digestibility of casein between GF and Cvd rats, but the apparent digestibility was higher in Cvd than in GF rats. The biological value of casein was significantly higher in GF than in Cvd rats. In the casein diet period, body weight gain was almost the same in GF and Cvd rats, but food intake was significantly greater in Cvd than in GF rats. The excretion of fecal N was similar in GF and in Cvd rats whereas more urinary N was excreted in Cvd than in GF rats. In the protein-free diet period, metabolic fecal N per 100 g of food intake was significantly higher in GF than in Cvd rats, but there was no difference in the excretion of endogenous urinary N per 100 grams of body weight between the GF and Cvd rats. The results indicate that the presence of a gastrointestinal microflora does not influence the true digestibility, but increases the apparent digestibility and decreases the biological value of casein at an 8% level in the diet.

Animals↗
PubMedDate not supplied

[Effect of the digestive process on the survival of the plague agent in Xenopsylla gerbilli Minax fleas].

Hystological investigations of experimentally infected X. gerbilli minax have shown that at the early stages of the digestion, while in the intestine compact clots of non-digested blood, are preserved, proceeds the reproduction of the plague agent. With the decay of the alimentary clot it changes into the dying off of the microbe population and after the ceasing of digestion the accumulation of bacteria renews again. Simultaneously with the changes in the number of microbes their morphology varies. At the initial stage of blood digestion bacilli typical for the agent are dominant. With the decay of the alimentary clot they are replaced by ovoid and spheroid forms. After the ceasing of the digestion cycle the microbe mass is represented by small coccobacteria. During the decrease in the plague agent abundance bacteria are absent mostly often from the midgut and posterior parts of the alimentary canal. Most favourable conditions for their preservation exist in this period in the proventriculus and in adjoining to it oesophagus part.

Animals↗
PubMed1999

Efficient and economical recovery of poly(3-hydroxybutyrate) from recombinant Escherichia coli by simple digestion with chemicals.

A simple method for the recovery of microbial poly(3-hydroxybutyrate) [P(3HB)] from recombinant Escherichia coli harboring the Ralstonia eutropha PHA biosynthesis genes was developed. Various acids (HCl, H2SO4), alkalies (NaOH, KOH, and NH4OH), and surfactants (dioctylsulfosuccinate sodium salt [AOT], hexadecyltrimethylammonium bromide [CTAB], sodium dodecylsulfate [SDS], polyoxyethylene-p-tert-octylphenol [Triton X-100], and polyoxyethylene(20)sorbitan monolaurate [Tween 20]) were examined for their ability to digest non-P(3HB) cellular materials (NPCM). Even though SDS was an efficient chemical for P(3HB) recovery from recombinant E. coli, it is expensive and has waste disposal problem. NaOH and KOH were also efficient and economical for the recovery of P(3HB), and therefore, were used to optimize digestion condition. When 50 g DCW/L of recombinant E. coli cells having the P(3HB) content of 77% was treated with 0.2 N NaOH at 30 degrees C for 1 h, P(3HB) was recovered with purity of 98.5%. Using this simple recovery method, the effect of recovery method on the final production cost of P(3HB) was examined. Processes for the production of P(3HB) by recombinant E. coli from glucose with two different recovery methods, surfactant-hypochlorite digestion and simple digestion with NaOH, were designed and analyzed. By employing the fermentation process that resulted in P(3HB) concentration, P(3HB) content and P(3HB) productivity of 157 g/L, 77%, and 3.2 P(3HB) g/L-h, respectively, coupled with the recovery method of NaOH digestion, the production cost of P(3HB) was US$ 3.66/kg P(3HB), which was 25% less than that obtained by employing the surfactant-hypochlorite digestion method.

Alkalies↗
PubMed2002

Membrane-mediated ultrafast restriction digestion and subsequent rapid gel microchip electrophoresis of DNA.

Ultrafast, membrane-mediated restriction digestion of DNA molecules followed by rapid gel microchip electrophoresis of the resulting fragments is described. Combination of restriction endonuclease digestion on small pore-size microfibrous membranes with sample loading and electrophoresis analysis in a multilane (up to 96) format resulted in very fast restriction digest based microscale DNA analysis. Complete digestion of several nanogram target DNA was accomplished on the microporous membrane at room temperature just in a few minutes with a single or a combination of various restriction enzymes, using only submicroliter quantities of samples and reagents. The reaction mixture containing membrane also served as sample loading device for the subsequent gel microchip electrophoresis based analysis. This work establishes methods for high-speed, high-throughput DNA analysis, featuring extremely low sample and reagent consumption, and fast restriction digestion in combination with sample loading and rapid gel microchip analysis of the resulting fragments. The entire restriction digestion, sample loading and electrophoresis analysis process required less than 20 min.

Bacteriophage phi X 174↗
PubMed2001

Simplified sample preparation method for protein identification by matrix-assisted laser desorption/ionization mass spectrometry: in-gel digestion on the probe surface.

Identification and detailed characterization of complex mixtures of proteins separated by polyacrylamide gel electrophoresis (PAGE) require optimized and robust methods for interfacing electrophoretic techniques to mass spectrometry. Peptide mapping by matrix-assisted laser desorption/ionization-time of flight mass spectrometry (MALDI-TOF-MS) is used as the first protein screening method in many laboratories because of its inherent simplicity, mass accuracy, sensitivity and relatively high sample throughput. We present a simplified sample preparation method for MALDI-MS that enables in-gel digestion of protein samples directly on the MALDI-MS metal probe. Removal of detergent and reagents as well as protein reduction and S-alkylation were performed prior to cutting of protein samples from the polyacrylamide gel slab. The general utility of this approach was demonstrated by on-probe digestion and MALDI-MS peptide mapping of femtomole amounts of standard proteins isolated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. A representative set of 47 human proteins obtained from a silver stained two-dimensional electrophoretic gel was analyzed by the new method and resulted in a success rate for protein identification similar to that obtained by the traditional protocols for in-gel digestion and MALDI peptide mass mapping of human proteins, i.e. approximately 60%. The overall performance of the novel on-probe digestion method is comparable with that of the standard in-gel sample preparation protocol while being less labour intensive and more cost-effective due to minimal consumption of reagents, enzymes and consumables. Preliminary data obtained on a MALDI quadrupole-TOF tandem mass spectrometer demonstrated the utility of the on-probe digestion protocol for peptide mass mapping and peptide sequencing on this instrument. Automation of the on-probe protein digestion procedure and its combination with automated MALDI tandem mass spectrometry should be advantageous in proteomics research aimed at the systematic identification and analysis of large sets of proteins from electrophoretic gels.

Amino Acid Sequence↗