Structure and Function of Bovine Whey Derived Oligosaccharides Showing Synbiotic Epithelial Barrier Protective Properties.

Commensal gut microbiota and probiotics have numerous effects on the host's metabolic and protective systems, which occur primarily through the intestinal epithelial cell interface. Prebiotics, like galacto-oligosaccharides (GOS) are widely used to modulate their function and abundance. However, important structure-function relations may exist, requiring a detailed structural characterization.

Specific amino acids increase mucin synthesis and microbiota in dextran sulfate sodium-treated rats.

During the anabolic response associated with inflammation, mucin synthesis and colonic protection may be compromised by the limited availability of specific amino acids. We therefore determined the effect of dietary amino acid supplementation on the microbiota, mucin status, and mucosal damage in dextran sulfate sodium (DSS)-treated rats. From 8 d before to 28 d after colitis induction, male Sprague-Dawley rats (10 mo old, n = 8/group) were fed a control diet supplemented or not with 2 different doses of an amino acid cocktail containing L-threonine, L-serine, L-proline, and L-cysteine.

Dietary threonine restriction specifically reduces intestinal mucin synthesis in rats.

We determined whether the steady-state levels of intestinal mucins are more sensitive than total proteins to dietary threonine intake. For 14 d, male Sprague-Dawley rats (158 +/- 1 g, n = 32) were fed isonitrogenous diets (12.5% protein) containing 30% (group 30), 60% (group 60), 100% (control group), or 150% (group 150) of the theoretical threonine requirement for growth.

The chronic colitis developed by HLA-B27 transgenic rats is associated with altered in vivo mucin synthesis.

HLA-B27 transgenic rats spontaneously developing a chronic inflammation mainly involving the colon are recognized as a powerful animal model for IBD. We investigated the mucin production in 6-month-old HLA-B27 rats by measuring in vivo fractional synthesis rate (FSR) and expression of mucins. In the inflamed colon of HLA-B27 rats, the mucin FSR was stimulated by 75% compared to F-344 controls, while MUC2,3 mRNA expression was unchanged.

Mucin production and composition is altered in dextran sulfate sodium-induced colitis in rats.

We evaluated the small and large intestinal mucin production in a rat model of human ulcerative colitis by measuring the in vivo fractional synthesis rate (FSR) and the expression of mucins. A chronic colitis was induced by oral administration of 5% dextran sulfate sodium (DSS) for 9 days followed by 2% DSS for 18 days. DSS-treated rats showed increased colonic MUC2,3 mRNA levels compared pair-fed controls.

Short-term dietary conjugated linoleic acid supplementation does not enhance the recovery of immunodepleted dexamethasone-treated rats.

Background: Conjugated linoleic acid (CLA) has been reported to decrease fat deposition, and increase lean body mass. This has been broadly inferred to mean that CLA alters protein turnover. However, data to test the effects of CLA on protein turnover are lacking.

Development of a rapid and convenient method to purify mucins and determine their in vivo synthesis rate in rats.

The intestinal mucoprotein synthesis rate was measured in vivo for the first time. For this, a rapid, reproducible, and convenient method to purify mucoproteins from large numbers of intestinal samples at the same time was developed. The method takes advantage of both the high mucin resistance to protease activities due to their extensive glycosylations and the high mucin molecular size.

Free and protein-bound glutamine have identical splanchnic extraction in healthy human volunteers.

The objectives of the present study were to determine the splanchnic extraction of glutamine after ingestion of glutamine-rich protein ((15)N-labeled oat proteins) and to compare it with that of free glutamine and to determine de novo glutamine synthesis before and after glutamine consumption. Eight healthy adults were infused intravenously in the postabsorptive state with L-[1-(13)C]glutamine (3 micromol x kg(-1) x h(-1)) and L-[1-(13)C]lysine (1.5 micromol x kg(-1) x h(-1)) for 8 h.

Protein hydrolysate vs free amino acid-based diets on the nutritional recovery of the starved rat.

Background And Aims: To test the hypothesis that a peptide-based enteral product was equivalent to a low-fat, free amino acid-based formula in the nutritional and functional recovery of the starved rat.

Methods: Sixteen male Wistar rats were starved for 3 days. Then, rats were randomised to a whey protein hydrolysate-based diet or a free amino acid-based diet and refed for 3 days.

Effect of glutamine supplementation of the diet on tissue protein synthesis rate of glucocorticoid-treated rats.

Although glutamine status in the critically ill patient can be improved by nutritional means, the most effective way of effecting such supplementation has received little attention. We evaluated two different ways of supplementing clinical nutrition products with glutamine, either with free glutamine or by providing a glutamine-rich protein source, in acute glucocorticoid-treated (intraperitoneal dexamethasone, 120 mg/kg) rats. During the recovery period, the animals received isonitrogenous and isoenergetic diets containing either casein, mixed whey proteins with or without glutamine, or carob protein plus essential amino acids.

Neither glutamine nor arginine supplementation of diets increase glutamine body stores in healthy growing rats.

The aim of the work was to resolve whether glutamine and arginine supplemented diets affect plasma and tissue (muscle, liver and intestinal mucosa) glutamine concentrations, as well as glutaminase and glutamine synthetase specific activities. The trial was performed in growing rats fed 10% protein diets for 3 weeks. Protein sources were: whey proteins (W); whey proteins+free glutamine (WG); whey proteins+arginine (WA); and casein+wheat protein hydrolysate+acid whey (39:39:22), as source containing protein-bound glutamine (CGW).

Role of glutamine on the de novo purine nucleotide synthesis in Caco-2 cells.

Background: The body's nucleotide pool derives from three potential sources: de novo synthesis, salvage of preformed-nucleosides/bases or the diet. The relative contributions of these pathways of assimilation are poorly understood in vivo. Dietary nucleotides have been suggested to have beneficial effects an the development and repair of the gastrointestinal tract.

Food deprivation and refeeding influence growth, nutrient retention and functional recovery of rats.

The objective of this work was to determine the effects of starvation and refeeding on growth, nutritional recovery and intestinal repair in starved rats. Male Wistar rats, weighing 200 g, were starved for 3 d, then refed a soy-based diet for another 3 d. Normally fed rats were given the same diet and used as controls.

Effect of threonine on the behavioural development of the rat.

Rats received different levels of threonine (Thr), one, 1.7 and four times the normal dietary intake, from conception to adulthood. The mothers were fed the experimental diets before and during pregnancy.

Effects of diet-induced hyperthreoninemia. I). Amino acid levels in the central nervous system and peripheral tissues.

Rats were fed four levels of threonine (Thr, 0.4, 0.6, 0.

Plasma amino acid responses in humans to evening meals of differing nutritional composition.

The effect of a carbohydrate or a 20% protein (HP) or a carbohydrate + 0.4% tryptophan (TRP) evening meal on plasma amino acids and on plasma neutral amino acid (NAA) ratios was studied in eight healthy men. After consumption of the protein meal, plasma amino acids rose after 1 h and remained at the same level at 2 h.