Sleeve gastrectomy with duodenoileal bipartition using linear magnets: feasibility and safety at 1-year follow-up.

BACKGROUND: Single-anastomosis metabolic/bariatric surgery procedures may lessen the incidence of anastomotic complications. This study aimed to evaluate the feasibility and safety of performing side-to-side duodenoileal (DI) bipartition using magnetic compression anastomosis (MCA). In addition, preliminary efficacy, quality of life (QoL), and distribution of food through the DI bipartition were evaluated. METHODS: Patients with a body mass index (BMI) of ≥35.0 to 50.0 kg/m2 underwent side-to-side DI bipartition with the magnet anastomosis system (MS) with sleeve gastrectomy (SG). By endoscopic positioning, a distal magnet (250 cm proximal to the ileocecal valve) and a proximal magnet (first part of the duodenum) were aligned with laparoscopic assistance to inaugurate MCA. An isotopic study assessed transit through the bipartition. RESULTS: Between March 14, 2022 to June 1, 2022, 10 patients (BMI of 44.2 ± 1.3 kg/m2) underwent side-to-side MS DI. In 9 of 10 patients, an SG was performed concurrently. The median operative time was 161.0 minutes (IQR, 108.0-236.0), and the median hospital stay was 3 days (IQR, 2-40). Paired magnets were expelled at a median of 43 days (IQR, 21-87). There was no device-related serious advanced event within 1 year. All anastomoses were patent with satisfactory diameters after magnet expulsion and at 1 year. Respective BMI, BMI reduction, and total weight loss were 28.9 ± 1.8 kg/m2, 15.2 ± 1.8 kg/m2, and 34.2% ± 4.1%, respectively. Of note, 70.0% of patients reported that they were very satisfied. The isotopic study found a median of 19.0% of the meal transited through the ileal loop. CONCLUSION: Side-to-side MCA DI bipartition with SG in adults with class II to III obesity was feasible, safe, and efficient with good QoL at 1-year follow-up. Moreover, 19% of ingested food passed directly into the ileum.

ARE THERE ADVANTAGES IN DOUBLE TRANSIT RECONSTRUCTION AFTER TOTAL GASTRECTOMY IN PATIENTS WITH GASTRIC CANCER? A SYSTEMATIC REVIEW.

BACKGROUND: Curative treatment for gastric cancer involves tumor resection, followed by transit reconstruction, with Roux-en-Y being the main technique employed. To permit food transit to the duodenum, which is absent in Roux-en-Y, double transit reconstruction has been used, whose theoretical advantages seem to surpass the previous technique. AIMS: To compare the clinical evolution of gastric cancer patients who underwent total gastrectomy with Roux-en-Y and double tract reconstruction. METHODS: A systematic review was carried out on Web of Science, Scopus, EmbasE, SciELO, Virtual Health Library, PubMed, Cochrane, and Google Scholar databases. Data were collected until June 11, 2022. Observational studies or clinical trials evaluating patients submitted to double tract (DT) and Roux-en-Y (RY) reconstructions were included. There was no temporal or language restriction. Review articles, case reports, case series, and incomplete texts were excluded. The risk of bias was calculated using the Cochrane tool designed for randomized clinical trials. RESULTS: Four studies of good methodological quality were included, encompassing 209 participants. In the RY group, there was a greater reduction in food intake. In the DT group, the decrease in body mass index was less pronounced compared to preoperative values. CONCLUSIONS: The double tract reconstruction had better outcomes concerning body mass index and the time until starting a light diet; however, it did not present any advantages in relation to nutritional deficits, quality of life, and post-surgical complications.

Mechanism of Mulberry Leaves and Black Sesame in Alleviating Slow Transit Constipation Revealed by Multi-Omics Analysis.

Traditional Chinese medicine (TCM) possesses the potential of providing good curative effects with no side effects for the effective management of slow transit constipation (STC), an intestinal disease characterized by colonic dyskinesia. Mulberry leaves (Morus alba L.) and black sesame (Sesamum indicum L.), referred to as SH, are processed and conditioned as per standardized protocols. SH has applications as food and medicine. Accordingly, we investigated the therapeutic potential of SH in alleviating STC. The analysis of SH composition identified a total of 504 compounds. The intervention with SH significantly improved intestinal motility, reduced the time for the first black stool, increased antioxidant activity, and enhanced water content, thereby effectively alleviating colon damage caused by STC. Transcriptome analysis revealed the SH in the treatment of STC related to SOD1, MUC2, and AQP1. The analysis of 16S rRNA gene sequences indicated notable differences in the abundance of 10 bacteria between the SH and model. Metabolomic analysis further revealed that SH supplementation increased the levels of nine metabolites associated with STC. Integrative analysis revealed that SH modulated amino acid metabolism, balanced intestinal flora, and targeted key genes (i.e., SOD1, MUC2, AQP1) to exert its effects. SH also inhibited the AQP1 expression and promoted SOD1 and MUC2 expression.

Does Ileus Represent the Forgotten End Organ Failure in Critical Illness?

PURPOSE OF REVIEW: This review evaluates the current literature on ileus, impaired gastrointestinal transit (IGT), and acute gastrointestinal injury (AGI) and its impact on multiple organ dysfunction syndrome. RECENT FINDINGS: Ileus is often under recognized in critically ill patients and is associated with significant morbidity and is potentially a marker of disease severity as seen in other organs like kidneys (ATN).

Robotic Heller Myotomy for Advancements in Surgical Management of Achalasia.

Achalasia is an esophageal motility disorder. It occurs due to the destruction of nerves in the lower esophageal sphincter (LES), which leads to the failure of the LES to relax. Patients typically complain of dysphagia, chest pain, and regurgitation. They often report drinking liquids with solids intake to help propel food boluses into the stomach. The diagnosis of achalasia is typically confirmed with an esophagogram and a motility study (esophageal manometry). An esophagogram classically shows the bird beak sign with tapering in the distal esophagus. The treatment for achalasia includes both surgical and non-surgical options. Surgical treatment is associated with a lower rate of recurrences, high clinical success rate, and durability of symptom relief. The current gold standard of surgical technique is myotomy, or the dividing of the muscle fibers of the distal esophagus. Surgical myotomy can be accomplished via a laparoscopic or robotic technique; per-oral endoscopic myotomy is a new alternative intervention. Due to the theoretical risk of gastroesophageal reflux following a myotomy, an antireflux procedure is sometimes performed. We reviewed the approach to a robotic heller myotomy for the treatment of achalasia.

Gastric Emptying Studies in Pediatrics: A Cincinnati Children's Hospital Experience.

Gastric emptying studies are routinely performed in many nuclear medicine departments; however, there are many different techniques used to perform the procedure across the country. Creating consistency in clinical practice will aid gastroenterologists in diagnosing and treating illnesses associated with abnormalities related to gastric emptying. In 2017, Cincinnati Children's Hospital adopted adult standards for pediatric gastric emptying studies that included a standard meal along with imaging over the course of 4 h. Gastric emptying studies are the second-highest-volume examination performed in the nuclear medicine section at Cincinnati Children's Hospital. Accommodating this volume required changes in the scheduling template, scheduling questionnaire, and epic order sets, as well as identification of specific days and locations for gastric emptying studies. Both protocol standardization and workflow optimization are critically important in creating consistency in patient care. Gastric emptying can be evaluated with solid food, liquid food, or solid and liquid food simultaneously. The methodology of the study is initially determined by the ordering provider but may require special accommodations based on what the patient will tolerate. In coordination with the ordering and interpreting physicians, the nuclear medicine technologists at Cincinnati Children's Hospital have the decision-making ability to deviate from the provider's request as necessary, which helps expedite workflow and eliminates wasted time. Any deviation from the standardized protocol is documented by the nuclear medicine technologist and incorporated into the final report by the interpreting physician, as dietary information is meaningful to the ordering provider. Reference values associated with the standardized or modified protocol are also included in the final report.

Butterfly Wings Effect on High Resolution Manometry in A Patient with Esophageal Achalasia.

A 57-year-old man presented with dysphagia in solids and liquids deteriorating in the last months and weight loss of 3 kg. A thoracic CT revealed a limit dilatation of the lower esophagus with food residue. An upper endoscopy was performed revealing bubble content and a contraction of the Lower Esophageal Sphincter (LES). A barium esophagogram demonstrated deceleration of esophageal emptying and a bird beak sign indicative of esophageal achalasia (Figure A). High resolution esophageal manometry was performed to evaluate the subtype of achalasia. The catheter could not be intubated into the stomach because of LES spasticity, it folded back cephalad at this level, producing a mirror image, the characteristic "butterfly wings" appearance of a folded manometry catheter (Figure B).

Radiopaque marker colonic transit study in the pediatric population BSPGHAN Motility Working Group consensus statement.

Functional constipation (FC) is a common condition in childhood in the United Kingdom and worldwide. Various radiological approaches have been established for diagnostic purposes. The radiopaque marker study (ROMS) is universally accepted and used to assess colonic transit time (CTT) in children with FC. Despite being widely used, there is a lack of standardization with various technical protocols, reproducibility of different populations, the purpose for using investigation, variance in the number of markers used, the amount of study days and calculations, the need to empty the colon before performing the test, and whether to perform on medication or off, or the use of specific diets. As part of the British Society of Paediatric Gastroenterology, Hepatology and Nutrition (BSPGHAN) motility working group (MWG), we decided to explore further into the evidence, in order to provide guidance regarding the use of ROMS in dealing with FC in the pediatric population.

Association between fecal short-chain fatty acid levels and constipation severity in subjects with slow transit constipation.

OBJECTIVE: We measured the fecal levels of short-chain fatty acids (SCFAs) in subjects with slow transit constipation (STC) and assessed the correlation between SCFA levels and disease severity as well as quality of life. METHODS: We isolated the supernatant from fecal samples of healthy and STC subjects and measured the SCFA levels. To assess the correlation between fecal SCFA levels and disease severity as well as quality of life, we used the Constipation Scoring System, Patient Assessment of Constipation Symptoms, and Patient Assessment of Constipation Quality of Life questionnaires. RESULTS: 16 STC subjects and 16 healthy controls were enrolled. STC subjects had lower SCFA levels, but the difference was not statistically significant (475.85 ±â€…251.68 vs. 639.77 ±â€…213.97 µg/ml, P = 0.056). Additionally, STC subjects had lower acetic and propionic acid levels (149.06 ±â€…88.54 vs. 261.33 ±â€…109.75 µg/ml and 100.60 ±â€…60.62 vs. 157.34 ±â€…66.37 µg/ml, respectively, P < 0.05) and higher isobutyric and isovaleric acid levels (27.21 ±â€…15.06 vs. 18.16 ±â€…8.65 µg/ml and 31.78 ±â€…18.81 vs. 16.90 ±â€…10.05 µg/ml, respectively, P < 0.05). At 252.21 µg/ml acetic acid, the specificity and sensitivity to distinguish healthy from STC subjects were 93.7% and 56.3%, respectively. In STC subjects, there were significant negative correlations between acetic and propionic acid levels and Constipation Scoring System scores. CONCLUSION: Fecal SCFA, acetic acid, and propionic acid levels decreased in STC subjects. There were significant negative correlations between the levels of the two acids and constipation severity.

Nobiletin, an active component of Wenyang Yiqi formula, alleviates constipation associated depression through targeting MAPT to inhibit the MAPK signaling pathway.

BACKGROUND: Slow transit constipation (STC) is a common gastrointestinal disorder that is often accompanied by depression. Nobiletin is a natural compound that has been shown to have anti-inflammatory and anti-depressant effects. PURPOSE: To study the effects of nobiletin extracted from Wenyang Yiqi Formula 19 (WYF) on STC accompanied by depression and the related mechanism in STC mouse models. METHODS: In this study, the effects of nobiletin on STC accompanied by depression were investigated in both an STC animal model and an in vitro study. The animal model was induced by loperamide, and the in vitro study used Interstitial cells of Cajal (ICCs) isolated from STC mice. The efficacy of nobiletin was assessed by comparing various parameters, including stool particle counts, moisture content, intestinal propulsive rate, colon histopathology, microtubule-associated protein-tau (MAPT) expression in colon tissue, serum levels of TNF-α, IL-1ß, IL-6, IFN-γ, and the levels of MAPK pathway-related proteins among three experimental groups. RESULTS: Nobiletin treatment significantly improved stool particle counts, moisture content, intestinal propulsive rate, and colon histopathology in the STC animal model. Nobiletin also decreased MAPT expression in colon tissue and serum levels of TNF-α, IL-1ß, IL-6, IFN-γ, and the levels of MAPK pathway-related proteins. In the in vitro study, nobiletin treatment reversed the increased cell proliferation and cell apoptosis observed in ICC isolated from the STC model. CONCLUSION: The findings of this study indicate that nobiletin exhibits promising therapeutic potential in addressing STC accompanied by depression. This potential may be attributed to its ability to regulate the function of ICC by targeting MAPT.

Comparing the short-term clinical outcomes and therapeutic effects of different colectomies in patients with refractory slow-transit constipation in eastern countries: a network meta-analysis.

Surgical treatment has been widely used in patients with refractory slow transit constipation (RSTC). The aim of this network meta-analysis (NMA) was to compare the effects of different colectomies on short-term postoperative complications and quality of life in patients with RSTC. Electronic literature searches were performed in the PubMed, Web of Science, EMBASE, WANFANG DATA, and Cochrane Central Register of controlled trials databases and were searched up to December 2022. Selected to compare the short-term clinical outcomes and quality of life of the treatment of RSTC. A random-effects Bayesian NMA was conducted to assess and rank the effectiveness of different surgical modalities. This study included a total of six non-randomized controlled trials involving 336 subjects. It was found that subtotal colectomy with cecorectal anastomosis (CRA) demonstrated superior effectiveness in several aspects, including reduced hospital stay (MD 0.06; 95% CI [0.02, 1.96]), shorter operative time (MD 4.75; 95% CI [0.28, 14.07]), lower constipation index (MD 0.61; 95% CI [0.04, 1.71]), improved quality of life (MD 4.42; 95% CI [0.48, 4.42]). Additionally, in terms of short-term clinical outcomes, subtotal colectomy with ileosigmoidal anastomosis (SC-ISA) procedure ranked the highest in reducing small bowel obstruction (OR 0.24; 95% CI [0.02, 0.49]), alleviating abdominal pain (OR 0.53; 95% CI [0.05, 1.14]), minimizing abdominal distension (OR 0.33; 95% CI [0.02, 0.65]), and reducing incision infection rates (OR 0.17; 95% CI [0.01, 0.33]). Furthermore, SC-ISA ranked as the best approach in terms of patient satisfaction (OR 0.66; 95% CI [0.02, 1.46]). Based on our research findings, we recommend that CRA be considered as the preferred treatment approach for patients diagnosed with RSTC.

Mechanisms underlying the laxative effect of lactulose: A randomized placebo-controlled trial showing increased small bowel water and motility unaltered by the 5-HT3 receptor antagonist, ondansetron.

BACKGROUND: Lactulose is a laxative which accelerates transit and softens stool. Our aim was to investigate its mechanism of action and use this model of diarrhea to investigate the anti-diarrheal actions of ondansetron. METHODS: A double-blind, randomized, placebo-controlled crossover study of the effect of ondansetron 8 mg in 16 healthy volunteers. Serial MRI scans were performed fasted and 6 h after a meal. Participants then received lactulose 13.6 g twice daily and study drug for a further 36 h. On Day 3, they had further serial MRI scans for 4 h. Measurements included small bowel water content (SBWC), colonic volume, colonic gas, small bowel motility, whole gut transit, and ascending colon relaxation time (T1AC), a measure of colonic water content. KEY RESULTS: Lactulose increased area under the curve (AUC) of SBWC from 0 to 240 min, mean difference 14.2 L · min (95% CI 4.1, 24.3), p = 0.009, and substantially increased small bowel motility after 4 h (mean (95% CI) 523 (457-646) a.u. to 852 (771-1178) a.u., p = 0.007). There were no changes in T1AC after 36 h treatment. Ondansetron did not significantly alter SBWC, small bowel motility, transit, colonic volumes, colonic gas nor T1AC, with or without lactulose. CONCLUSION & INFERENCES: Lactulose increases SBWC and stimulates small bowel motility; however, unexpectedly it did not significantly alter colonic water content, suggesting its laxative effect is not osmotic but due to stimulation of motility. Ondansetron's lack of effect on intestinal water suggests its anti-diarrheal effect is not due to inhibition of secretion but more likely altered colonic motility.

Understanding the gastrointestinal tract in obesity: From gut motility patterns to enzyme secretion.

BACKGROUND AND PURPOSE: The pathophysiology of obesity has been the product of extensive research, revealing multiple interconnected mechanisms contributing to body weight regulation. The regulation of energy balance involves an intricate network, including the gut-neuroendocrine interplay. As a consequence, research on the gut-brain-microbiota axis in obesity has grown extensively. The physiology of the gastrointestinal tract, far from being underexplored, has significant implications for the development of specific complications in people living with obesity across the fields of gastroenterology, nutrition, and pharmacology. Clinical research indicates higher fasting bile acids serum levels, and blunted postprandial increases in bilious secretions in people living with obesity. Findings are less straightforward for the impact of obesity on gastric emptying with various studies reporting accelerated, normal, or delayed gastric emptying rates. Conversely, the effect of obesity on gastrointestinal pH, gastrointestinal transit, and gastric and pancreatic enzyme secretion is largely unknown. In this review, we explore the current evidence on the gastrointestinal physiology of obesity.

Circadian rhythm and whole gut transit in mice.

BACKGROUND: In preclinical studies whole gut transit (WGT) in mice is a gold-standard "leading-edge" approach that measures the time between orogastric gavage of carmine red and defecation of the first carmine red pellet. Transit studies in humans are performed during the active day because GI motility and transit are suppressed during the night. Since mice are nocturnal, WGT studies traditionally done during the day occur during their rest phase. How circadian rhythm affects WGT in mice is not known. METHODS: We used an automated approach for high temporal resolution uninterrupted testing of mouse WGT and activity. We housed wild-type Bl6/C57 mice under the standard 12 h light-dark cycles. At 8 weeks, we performed carmine red orogastric gavage and assessed WGT during Light (rest) conditions. Then, we exposed mice to a reverse 12 h light-dark cycle for 2 weeks and tested them in the Dark (active) under red light conditions. Timelapse videos were analyzed to quantify activity and to timestamp all pellets, and multiple parameters were analyzed. KEY RESULT: When complementary light cycle reversal experiments were performed, we found a significant increase in mouse activity when mice were tested during their Dark (active) phase, compared to their Light (rest) phase. In mice tested in the Active phase compared to the Rest phase, we found a significant acceleration in WGT, increased rate and total number of pellets produced, and more pellet clustering. These data show that the mice tested in the Active phase have important differences in activity that correlate with multiple alterations in gastrointestinal transit. CONCLUSION & INFERENCES: During the Active phase mice have faster WGT, produce more pellets, and cluster their output compared to testing in the Rest phase. Like in humans, circadian rhythm is an important consideration for transit studies in mice, and a simple reverse light cycle approach facilitates further studies on the role of circadian rhythm in GI motility.

Faster Gastrointestinal Transit, Reduced Small Intestinal Smooth Muscle Tone and Dysmotility in the Nlgn3R451C Mouse Model of Autism.

Individuals with autism often experience gastrointestinal issues but the cause is unknown. Many gene mutations that modify neuronal synapse function are associated with autism and therefore may impact the enteric nervous system that regulates gastrointestinal function. A missense mutation in the Nlgn3 gene encoding the cell adhesion protein Neuroligin-3 was identified in two brothers with autism who both experienced severe gastrointestinal dysfunction. Mice expressing this mutation (Nlgn3R451C mice) are a well-studied preclinical model of autism and show autism-relevant characteristics, including impaired social interaction and communication, as well as repetitive behaviour. We previously showed colonic dysmotility in response to GABAergic inhibition and increased myenteric neuronal numbers in the small intestine in Nlgn3R451C mice bred on a mixed genetic background. Here, we show that gut dysfunction is a persistent phenotype of the Nlgn3 R451C mutation in mice backcrossed onto a C57BL/6 background. We report that Nlgn3R451C mice show a 30.9% faster gastrointestinal transit (p = 0.0004) in vivo and have 6% longer small intestines (p = 0.04) compared to wild-types due to a reduction in smooth muscle tone. In Nlgn3R451C mice, we observed a decrease in resting jejunal diameter (proximal jejunum: 10.6% decrease, p = 0.02; mid: 9.8%, p = 0.04; distal: 11.5%, p = 0.009) and neurally regulated dysmotility as well as shorter durations of contractile complexes (mid: 25.6% reduction in duration, p = 0.009; distal: 30.5%, p = 0.004) in the ileum. In Nlgn3R451C mouse colons, short contractions were inhibited to a greater extent (57.2% by the GABAA antagonist, gabazine, compared to 40.6% in wild-type mice (p = 0.007). The inhibition of nitric oxide synthesis decreased the frequency of contractile complexes in the jejunum (WT p = 0.0006, Nlgn3R451C p = 0.002), but not the ileum, in both wild-type and Nlgn3R451C mice. These findings demonstrate that changes in enteric nervous system function contribute to gastrointestinal dysmotility in mice expressing the autism-associated R451C missense mutation in the Neuroligin-3 protein.

Associations Between Physical Activity and Gastrointestinal Transit Times in People with Normal Weight, Overweight, and Obesity.

BACKGROUND: Rapid gastric emptying is associated with obesity and overeating, whereas delayed gastric emptying is associated with anorexia. Acute effects of exercise on gastric emptying have been investigated extensively, but the influence of habitual physical activity on gastric emptying and transit time in other regions of the gastrointestinal tract is poorly understood. OBJECTIVE: The objective was to investigate associations between objectively measured habitual physical activity and gastrointestinal transit times in adults with varying degrees of adiposity. METHODS: 50 adults (58% women) were included in this cross-sectional study. Physical activity was measured by an accelerometer placed on the lower back for 7 d. Gastric emptying time, small bowel transit time, colonic transit time, and whole gut transit time were simultaneously evaluated by a wireless motility capsule, which was ingested together with a standardized mixed meal. Linear regression models were applied to assess the associations of total activity counts and time spent at different intensities-sedentary activity (0-100 counts/min), low light activity (101-759 counts/min), high light activity (760-1951 counts/min); moderate and vigorous activity (≥1952 counts/min)) with gastrointestinal transit times. RESULTS: Median [Q1; Q3] age was 56.5 [46.6-65.5] y, and body mass index (BMI) was 32.1 [28.5-35.1] kg/m2. For every additional hour spent performing high light intensity physical activity, colonic transit time was 25.5 % [95% CI: 3.10, 42.7] more rapid (P = 0.028), and whole gut transit time was 16.2 % [95% CI: 1.84, 28.4] more rapid (P = 0.028) when adjusted for sex, age, and body fat. No other associations were observed. CONCLUSIONS: More time spent on physical activity at high light intensity was associated with more rapid colonic and whole gut transit time, independent of age, sex, and body fat, whereas other intensities of physical activity and gastrointestinal transit times were not associated. TRIAL REGISTRATION: Clinicaltrials.gov IDs (NCT03894670, NCT03854656).

High Prevalence of Anorectal Dysfunction in Ambulatory Patients with Chronic Constipation, Regardless of Colon Transit Time.

BACKGROUND: Classification of chronic constipation (CC) into its three subtypes of slow transit constipation, defecation disorder and normal transit constipation, may improve its multifaceted management. We assessed the merits of the London classification in patients with CC, who were studied by both wireless motility capsule (WMC) and high-resolution anorectal manometry (HR-ARM), examining their relative utilities in decision-making.s PATIENTS AND METHODS: Retrospective, community-based study of prospectively collected data on patients with CC by Rome IV criteria, who underwent WMC and HR-ARM, Balloon Expulsion Test, and Rectal Sensory Testing. Clinical assessment was made by standard questionnaires. On WMC, standard criteria for colonic transit time (CTT) were used (normal CTT < 59 h). The hierarchical London classification was used for HR-ARM analyses. RESULTS: Of 1261 patients with CC, 166 (91 M; ages 22-86) received technically satisfactory WMC and HR-ARM, formed the analyzed study cohort, of whom 84 had normal CTT and 82 had prolonged CTT (> 59 h). Patients with slow CTT were significantly older and had longer duration and more severe disease. Using the London classification criteria for disorders of anorectal function, we noted a high prevalence of anorectal dysfunction, regardless of CTT. Except for lower rate of anal hypertonicity in patients with slow CTT, disorders of recto-anal coordination, and rectal sensation were seen at a comparable rate in patients with CC, regardless of CTT. CONCLUSION: There is a significant overlap of anorectal disorders in patients with slow CTT. There is questionable specificity and utility of WMC and HR-ARM in assessing patients with CC. More work is needed to demonstrate the value of these studies as surrogate markers of the disease and its response to multifaceted therapy.

Guava fibre characterization and effects on digestibility, fermentation products, gastrointestinal transit time and palatability of dry diets for dogs.

The use of fruit fibres as a way of reusing industrial waste is attractive and necessary, increasing the efficiency and reducing the environmental impact of the industry. This study characterized guava fibre as a fibrous ingredient and evaluated its effects when included in extruded diets for dogs on nutrient digestibility, faecal traits, fermentation products, gastrointestinal transit time and palatability. Four diets were formulated: CO (control diet, no fibrous ingredients added), GF3 (3% guava fibre), GF6 (6% guava fibre) and GF12 (12% guava fibre). The guava fibre was added to diets in replacement of maize, with small adjustments in the other ingredients to ensure similar contents of protein and fat. The diets were fed to 24 adult Beagle dogs (6 per diet) during 15 days for adaptation followed by 15 days for assessment of digestibility, fermentation end products and gastrointestinal transit time. The palatability of G6 and G12 treatments was evaluated against the CO by the two-pan test. Results were compared by analysis of variance and polynomial contrasts according to the guava fibre inclusion level (p < 0.05). The addition of guava fibre did not change nutrient intake except for the increase on dietary fibre (p < 0.001). Fibre inclusion resulted in a quadratic reduction in total tract apparent digestibility for dry matter, organic matter, crude protein and crude energy (p < 0.001), and on the metabolizable energy content of the foods (p < 0.001). Guava fibre addition did not change the faecal concentration of ammonia, lactic acid, faecal pH and branched chain fatty acids but it decreased acetic and propionic acids concentration (p < 0.01). The inclusion of 12% guava fibre did result in a faster transit time (p = 0.046) compared to the control diet. Guava fibre can be characterized as a novel insoluble non-fermentable fibre source that could be safely used in levels up to 12% in canine extruded diets.