Leaky Gut as a Potential Culprit for the Paradoxical Dysglycemic Response to Gastric Bypass-Associated Ileal Microbiota

Altered host-intestinal microbiota interactions are increasingly implicated in the metabolic benefits of Roux-en-Y gastric bypass (RYGB) surgery. We previously found, however, that RYGB-associated ileal microbiota can paradoxically impair host glycemic control when transferred to germ-free mice. Here we present complementary evidence suggesting that this could be due to the heightened development of systemic endotoxemia. Consistently, application of ileal content from RYGB-treated compared with sham-operated rats onto Caco-2 cell monolayers compromised barrier function and decreased expression of the barrier-stabilizing proteins claudin-4 and desmoglein-2. Our findings raise the possibility that RYGB-associated ileal microbiota produce and release soluble metabolites which locally increase intestinal permeability to promote systemic endotoxemia-induced insulin resistance, with potential implications for the treatment of RYGB patients who eventually relapse onto type 2 diabetes.

Apparent total tract and ileal amino acids digestibility values of vegetal protein meals with dietary protease to broiler diet

This experiment was carried out to study the effect of dietary exogenous monocomponent protease on the coefficient apparent total tract (ATTD) and apparent ileal (AID) digestibility of amino acids of corn, soybean meal (SBM), and full fat soybean meal (FFSM) in broilers. A total of 400 males Cobb-500 (14 d of age) were equally allocated in 80 metabolic cages (50 cm × 50 cm × 45 cm) in a completely randomized design and a semi-controlled environment. Eight treatments (basal diet with or without a protease and three ingredients replacing the basal diets in 40% to corn and 30% to SBM and FFSM, with and without protease), with 10 replicates each were evaluated. The protease was added at 200 mg/kg resulting in 15,000 unit of PROT/kg. The total collection of excreta was held during 3 d, after 5 d for adaptation of broilers at the diets. The ileal content was collected on d 21, after slaughter of birds. The enzyme increased (P < 0.05) the ATTD and AID of most amino acids contained in SBM and FFSM. The digestibility of cysteine, glycine, proline, and threonine had higher (P < 0.05) ATTD and AID in all tested ingredients with the use of protease. On average, the dietary protease increased in 5.19% and 3.86% the total and ileal digestibility of amino acids, respectively. It was concluded that the dietary protease exerts major effects on toasted full-fat soybean, followed by soybean meal and corn to broilers.

A study protocol for a randomised crossover study evaluating the effect of diets differing in carbohydrate quality on ileal content and appetite regulation in healthy humans

Introduction: A major component of the digesta reaching the colon from the distal ileum is carbohydrate. This carbohydrate is subject to microbial fermentation and can radically change bacterial populations in the colon and the metabolites they produce, particularly short-chain fatty acids (SCFA). However, very little is currently known about the forms and levels of carbohydrate in the ileum and the composition of the ileal microbiota in humans. Most of our current understanding of carbohydrate that is not absorbed by the small intestine comes from ileostomy models, which may not reflect the physiology of an intact gastrointestinal tract. Methods: We will investigate how ileal content changes depending on diet using a randomised crossover study in healthy humans. Participants will be inpatients at the research facility for three separate 4-day visits. During each visit, participants will consume one of three diets, which differ in carbohydrate quality: 1) low-fibre refined diet; 2) high-fibre diet with intact cellular structures; 3) high-fibre diet where the cellular structures have been disrupted (e.g. milling, blending). On day 1, a nasoenteric tube will be placed into the distal ileum and its position confirmed under fluoroscopy. Ileal samples will be collected via the nasoenteric tube and metabolically profiled, which will determine the amount and type of carbohydrate present, and the composition of the ileal microbiota will be measured. Blood samples will be collected to assess circulating hormones and metabolites. Stool samples will be collected to assess faecal microbiota composition. Subjective appetite measures will be collected using visual analogue scales. Breath hydrogen will be measured in real-time as a marker of intestinal fermentation. Finally, an in vitro continuous fermentation model will be inoculated with ileal fluid in order to understand the shift in microbial composition and SCFA produced in the colon following the different diets. Registration: ISRCTN11327221.

A study protocol for a randomised crossover study evaluating the effect of diets differing in carbohydrate quality on ileal content and appetite regulation in healthy humans

Introduction:A major component of the digesta reaching the colon from the distal ileum is carbohydrate. This carbohydrate is subject to microbial fermentation and can radically change bacterial populations in the colon and the metabolites they produce, particularly short-chain fatty acids (SCFA). However, very little is currently known about the forms and levels of carbohydrate in the ileum and the composition of the ileal microbiota in humans. Most of our current understanding of carbohydrate that is not absorbed by the small intestine comes from ileostomy models, which may not reflect the physiology of an intact gastrointestinal tract.Methods:We will investigate how ileal content changes depending on diet using a randomised crossover study in healthy humans. Participants will be inpatients at the research facility for three separate 4-day visits. During each visit, participants will consume one of three diets, which differ in carbohydrate quality: 1) low-fibre refined diet; 2) high-fibre diet with intact cellular structures; 3) high-fibre diet where the cellular structures have been disrupted (e.g. milling, blending). On day 1, a nasoenteric tube will be placed into the distal ileum and its position confirmed under fluoroscopy. Ileal samples will be collected via the nasoenteric tube and metabolically profiled, which will determine the amount and type of carbohydrate present, and the composition of the ileal microbiota will be measured. Blood samples will be collected to assess circulating hormones and metabolites. Stool samples will be collected to assess faecal microbiota composition. Subjective appetite measures will be collected using visual analogue scales. Breath hydrogen will be measured in real-time as a marker of intestinal fermentation. Finally, anin vitrocontinuous fermentation model will be inoculated with ileal fluid in order to understand the shift in microbial composition and SCFA produced in the colon following the different diets.Registration:ISRCTN11327221.

Ileal digestibility of calcium and phosphorus in broilers fed diets with different phytases and Ca:available P ratios

The objective of this work was to determine the apparent ileal digestibility of calcium and phosphorus in broilers fed diets with different phytases and calcium:available phosphorus (Ca:aP) ratios. Two experiments were carried out: one with broilers with 22 to 33 days of age, and the other with broilers with 35 to 42 days. The Ca:aP ratios used were 4.5:1.0, 6.0:1.0, and 7.5:1.0 in the first period, and 3.5:1.0, 5.0:1.0, and 6.5:1.0 in the second. All diets were supplemented with 1,500 units of phytase activity per kilogram of six different sources of microbial phytase. At the end of each experiment, two broilers per replicate were slaughtered to collect the ileal content. In the samples of digested food, the Ca and P contents were determined for later calculation of the apparent ileal digestibility coefficients of these minerals. The Ca:aP ratio influenced the activity of phytases, and the highest digestibility was observed with lower ratios, in both experiments. The phytases that provided greater digestibility coefficients were A, D, and E. In both ages evaluated, the inclusion of phytases in the feed improved the digestibility of Ca and P, which was also affected by the content of calcium and by the phytase source used.

The effect of heat treatment on ileal amino acid digestibility of growing broilers given vetch and bitter vetch meals

Forty-eight 4-week-old White Rock growing chickens (mean live weight 500 (s.e. 9·3) g) were given, by crop intubation, four isoencrgetic (13·1 M] metabolizable energy (ME) per kg dry matter (DM)) and isonitrogenous (120 g crude protein (CP) per kg DM) semisynthetic diets based on vetch (V) or bitter vetch (B) seeds, untreated or antoclaved at 120°C for 30 ruin (diets V, AV, B and AB, respectively). Autoclaving of the seeds caused some changes in amino acid (AA) composition but did not reduce the availability of A As, especially of lysine.The average apparent AA digestibility values derived from ileal content were 0·75, 0·85, 0·59 and 0·85 for diets V, AV, B and AB, respectively, corresponding to true absorption values of 0·90, 1·00, 0·74 and 0·97, respectively. Although the apparent digestibility values of several AAs were relatively low (methionine, isoleucine, tyrosine and cystine), most were higher than 0·70. Heat treatment resulted in a significant increase (P < 0·05) in the AA apparent digestibility of both seeds. It is concluded that heat treatment is useful for improvement of vetch and bitter vetch seeds for inclusion in poultry diets.