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Biomedical subjects

A Rerat

Publications and source records attributed to A Rerat.

At least 19 recordsLinked to original sources
PubMed1994

Intestinal absorption of medium chain fatty acids: in vivo studies in pigs devoid of exocrine pancreatic secretion.

In order to study the influence of pancreatic enzyme secretion on the intestinal absorption of medium-chain fatty acids (MCFA), three growing pigs (mean body-weight 61 kg) with ligated and severed pancreatic ducts were fitted with a permanent fistula in the duodenum and with two catheters in the portal vein and carotid artery respectively. An electromagnetic flow probe was also set up around the portal vein. A mixture of octanoic and decanoic acids, esterified as medium-chain triacylglycerols, together with maltose dextrine and nitrogenous fraction was continuously infused for 1 h into the duodenum. Samples of blood were withdrawn from the two vessels at regular intervals of time for 8 h and further analysed for their non-esterified octanoic and decanoic acid contents. The concentrations of non-esterified octanoic and decanoic acid in the portal blood increased slowly after the beginning of each infusion, reaching about 10 times higher values than the basal level. Only 26% of octanoic acid infused in the duodenum and 27% of decanoic acid were recovered in the portal flow throughout each experiment. The possible mechanisms underlying the appearance of MCFA in the portal blood in the absence of pancreatic enzyme secretions and the importance of duodenal absorption of MCT in such physiological conditions have been discussed.

Animals↗
PubMed1990

[Not Available].

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Biochemistry↗
PubMed1988

Intestinal absorption of bile acids in the pig. Role of distal bowel.

The role of distal bowel in intestinal recycling of total bile acids was investigated in five healthy, conscious, normally fed pigs. Total bile acids appearing in the portal blood of fistulated animals were measured when bile irrigated the whole bowel (control period) and again when it was diverted at 1 m proximal to the ileocecal valve so that enterohepatic circulation was limited to only the last meter of ileum plus large bowel. Measurements were taken just after the bile had been diverted and then four days later when a new steady state was reached. Under steady-state conditions bile acid reabsorption rate in distal bowel was 20% of the normal rate. This result has been discussed taking into account the high but transient ability of distal bowel to spare bile acids measured in the first hours after bile diversion. The present experiment, together with some other in vivo trials on small laboratory animals, indicate that the proximal bowel may take a large part in bile acid absorption and that we need to reevaluate the notion that bile acid absorption takes place mainly in distal bowel.

Animals↗
PubMed1988

Quantitative measurement of endogenous amino acid absorption in unanaesthetized pigs.

The present experiment was carried out with 11 pigs (mean body weight: 53.9 +/- 1.3 kg) fitted with permanent catheters in the portal vein and carotid artery and with an electromagnetic flow probe around the portal vein. They were each subjected to 2 or 3 trials at 3 to 4-day intervals. During each trial the animals received after a previous fasting of 20 h a given amount of a protein-free diet (200 to 1200 g). The blood was collected either continuously for a quantitative determination of amino nitrogen, reducing sugars, urea and ammonia (number of meals 12, mean intake: 727 +/- 60 g) or discontinuously every 30 min between 0 and 8 h after the meal for amino acid analysis (number of meals 8; mean intake 709 +/- 105 g). A rather constant appearance (2 g/h) of amino acids in the portal blood was observed throughout the postprandial period. The intestinal absorption of each amino acid was however variable and represented between 10 and 50% of the daily requirements of the animal during the measuring period (8 h). Glutamine and to a less extent glutamic acid were exceptions as they were taken up by the gut wall from the arterial blood. There was also a marked synthesis of ornithine and citrulline by the latter. Because of the low blood level of urea, there were no apparent exchanges of urea between the blood and the intestine; in contrast, the ammonia absorption represented about 70% of that observed after ingestion of normal protein diets. Most amino acids are largely taken up by the liver and peripheral tissues, but in the case of alanine the syntheses exceed the uptake.

Amino Acids↗
PubMed1987

[Influence of purified cellulose level in the diet of pigs on intestinal absorption of volatile fatty acids].

Nutrient and volatile fatty acid (VFA) absorption to portal blood was measured twice at 7 days interval in five pigs fed a semi-synthetic diet containing 6 (R6) or 16% (R16) purified cellulose for 21 or 7 days. The daily absorption (24 hrs.) of VFA in the large intestine which was larger (NS) when the cellulose level rose, increased significantly (P less than 0.05) with increasing length of adaptation (21 to 28 d.) to the diet whatever the cellulose level. The supplementary daily supply of energy in the form of VFA after increase of the cellulose level did not compensate for the corresponding deficit of absorption of reducing sugars and crude protein in the small intestine.

Animal Feed↗
PubMed1987

[Effect of the nature of carbohydrates in pig diets on the intestinal absorption of volatile fatty acids].

The appearance of nutrients (amino nitrogen and reducing sugars) and microbial metabolites (volatile fatty acids, VFA) was measured quantitatively in five pigs. After ingestion of a semi-synthetic diet (RFL) containing 22% lucerne meal (6% crude fibre), the absorption of reducing sugars (RS) in the small intestine was high (97.8%) and that of VFA low (880 +/- mmoles/24 hrs.). Ingestion of a semi-synthetic diet (RLa) containing 22% lactose and 6% purified cellulose led to lower absorption of RS (85.2%) and a higher absorption of VFA (1,180 +/- mmoles/24 hrs).

Animals↗
PubMed1986

Enterohepatic circulation of bile acids in pigs: diurnal pattern and effect of a reentrant biliary fistula.

The present studies were undertaken 1) to assess the quantitative absorption of total bile acids in the portal vein of normally fed, unanesthetized pigs with an intact biliary tract and 2) to evaluate the effect of a chronic reentrant biliary fistula on absorption. In the intact biliary tract group (5 pigs), mean total bile acid concentration averaged 83.9 +/- 2.0 and 15.6 +/- 0.6 microM in portal and arterial blood, respectively, and 216.9 +/- 20.4 mmol of total bile acids were absorbed over 24 h. Time courses of blood concentration and absorption were described all along the light-dark cycle, and hepatic uptake averaged 79.3 +/- 0.5%. A reentrant choledocal fistula in the upper duodenum (5 pigs) did not affect mean daily blood concentrations (87.5 +/- 2.4 and 19.1 +/- 0.8 microM in portal and arterial blood, respectively), daily absorption (226.4 +/- 23.7 mmol, i.e., 93.5% of the daily secretion), or hepatic uptake (76.4 +/- 1.1%), but it did seem to influence the daily kinetics of blood concentration and absorption. These studies supply quantitative and kinetic data about the absorptive stage of the enterohepatic cycle in pigs and show that a bile fistula is suitable for the study of biliary dynamics.

Animals↗
PubMed1986

[Postprandial exchange of urea and ammonia nitrogen between the digestive tract and portal blood in the conscious pig after ingestion of a diet with or without urea].

The concentrations of urea and ammonia were measured in the portal and arterial blood simultaneously to the blood flow rate in the portal vein during the postprandial period (8 hrs.) after ingestion of a normal protein diet with 3% urea (10 meals) or without urea (12 meals) in conscious pigs (mean body weight: 55.5 +/- 2.3 kg). When no urea was present in the diet, there was a slight and permanent uptake of blood urea by the gut (570 mg/h, i.e. 9,5 mmoles/h) as well as a permanent appearance of ammonia in the portal vein (258 mg/h i.e. 15.2 mmoles/h), increasing with time (P less than 0.05). The absorbed ammonia nitrogen represented a maximum of 70% of urea nitrogen taken up. 2. Addition of urea to the diet brought about a large absorption of that substance (73% of the ingested amount) followed by a rather large excretion (960 mg/h, i.e. 16 mmoles/h), 5-6 hrs. after the meal and led to an increase (P less than 0.05) in the absorption of ammonia.

Ammonia↗
PubMed1985

[Comparative kinetics of appearance in the portal vein of alpha-aminated nitrogen from mixtures of small peptides of free amino acids of the same composition introduced in the duodenum of conscious pigs].

The quantitative kinetics of appearance of amino acids (a.a.) in the pig portal vein was studied in 6 animals for 5 hrs. after duodenal perfusion of an enzymatic hydrolysate of milk proteins or a solution of free a.a. of the same composition. Each product was given in two quantities (55 and 110 g). The quantities of a.a. appearing in the portal vein were higher after perfusion of the hydrolysate than after that of the free a.a., independently of the time after the perfusion. Thus, nitrogen present in the small intestine as small peptides is absorbed more quickly than when it is present as free amino acids.

Amino Acids↗
PubMed1985

[Measurement of the appearance of volatile fatty acids in the portal vein during digestion in conscious pigs].

A method used to measure the nutrient exchanges between the intestinal lumen and the portal blood was applied to 3 pigs receiving 800 g of a diet containing 6% of cellulose. During a postprandial period of 24 hrs., the mixture of volatile fatty acids (90 mM/h) appearing in the portal vein was composed of acetic acid (57%), propionic acid (30%), butyric acid (9%), isovaleric (2.5%) and valeric acid (1.5%). The composition of this mixture differed from that of the colic contents because of its acetic acid enrichment at the expense of butyric acid. The resulting energy supply to the animal represented about 600 to 700 kcal/24 hrs.

Animals↗
PubMed1980

[Enzymatic activities in the liver, and muscle nucleic acids, in swine receiving an unbalanced diet with an excess of methionine for 100 days].

Twelve growing Swine were fed an 18% protein diet (Maize and Soja bean) for one hundred days containing either 0,6% sulfur amino acids (basal diet) or 0,6% and 1% DL-methionine added to the control diet. Such an excess, reduced food intake and body weight gain mainly during the "finishing period" (60 to 100 kg). The RNA/DNA and protein/DNA ratios in the muscle did not show any difference. Hepatic activities of some enzymes involved in glycolysis, gluconeogenesis and amino acid metabolism, were unchanged, except that of methionine adenosyl transferase, the first step of transsulfuration, which was induced in proportion with the amount of the methionine ingested. Swine seemed to adapt to the excessive methionine intake, which did not show any toxicity in our experimental conditions.

Animals↗