Gross Anatomy of the Intestine in the Giraffe (Giraffa camelopardalis)

We describe the macroscopic anatomy of the intestine of the giraffe (Giraffa camelopardalis). The small intestine was divided into duodenum, jejunum and ileum as usual. The caecum was attached to the ileum by a long ileocaecal fold, and to the proximal ansa of the ascending colon by a caecocolic fold. The ascending colon was the most developed portion of the gross intestine and had the most complex arrangement with three ansae: the proximal ansa, the spiral ansa and the distal ansa. The proximal ansa completely encircled the caecum, describing a 360° gyrus, and represented the widest portion of the intestine. The spiral ansa was formed by three and a half centripetal gyri, a central flexure and three centrifugal gyri. The last centrifugal gyrus left the spiral and described nine flexures of different form and direction over the left side of the mesentery. The two portions that formed each of these flexures ran parallel to each other. The last part of this gyrus ran parallel to the jejunum. When compared with domestic cattle, giraffe had a comparatively short small intestine and a comparatively long large intestine, with a resulting small ratio of small:large intestine. Reasons are presented why this should be considered a peculiarity of cattle‐like ruminants rather than a different representative of a browser–grazer dichotomy in general.     

Ultrasonographic examination of the small intestine, large intestine and greater omentum in 30 Saanen goats

The small and large intestine of 30 healthy Saanen goats were examined ultrasonographically using a 5.0 MHz-linear transducer. The goats were examined on the right side, from the eighth rib to the caudal aspect of the flank. The small and large intestine could be easily differentiated. The descending duodenum could be imaged in 19 goats, and the jejunum and ileum seen in all goats. The jejunum and ileum were most often seen in cross-section and rarely in longitudinal section in the ventral region of the right flank. The intestinal contents were usually homogenously echoic, and active motility was observed in all the goats. The diameter of the small intestine was 0.8–2.7 cm (1.6 [0.33] cm). The spiral ansa of the colon was imaged in all the goats, and in 21 the caecum was also seen. Both these sections of large intestine were most commonly seen in the dorsal region of the right flank. The spiral ansa of the colon was easily identified by its spiral arrangement of centripetal and centrifugal gyri, which had a garland-like appearance. Because of intraluminal gas, only the wall of the colon closest to the transducer could be imaged. The diameter of the spiral colon ranged from 0.8 to 2.0 cm (1.1 [0.24] cm). Usually only the wall of the caecum closest to the transducer could be imaged and it appeared as a thick, echoic, slightly undulating line. The greater omentum could be seen in all the goats.     

Obstruction of the Ascending Colon in Cattle: II. An Experimental Model of Partial Bypass of the Large Intestine

Four dairy calves were subjected to partial bypass of the large intestine by uniting the ileum to the distal centrifugal coil of the spiral loop of the ascending colon (spiral colon). Digesta bypassed the distal ileum, cecum, proximal loop of the ascending colon, and the centripetal coils of the spiral colon. The calves survived the surgical procedure and were healthy throughout the 4-week postoperative experimental period. Feces were loose immediately after bypass, but fecal dry matter (DM) gradually increased over the subsequent 2 weeks (P < 0.01), indicating adaptation of remaining bowel to absorb more water. There was no significant change in serum concentration of sodium or chloride. The calves continued to grow and gain weight at acceptable rates after bypass. Necropsy of 3 of the calves demonstrated a decrease in size of the bypassed bowel.     

Myoelectric activity in the intestine of cows with strangulating obstruction of the distal small intestine

Myoelectric activity in 2 cows instrumented with permanent electrodes in the ileum, cecum, proximal loop of the ascending colon (PLAC), and spiral colon was analyzed after an obstruction developed in the distal small intestine. Results were compared with patterns from a group of 7 normal cows. Myoelectric activity in the ileum immediately orad to the occlusion was characterized by abolition of the migrating myoelectric complex (MMC) and a constant pattern of strong spike bursts of long duration. Cyclic activity was present in all parts of the large intestine, and propagation of phase III activity was evident from proximal to distal. A slight degree of disorganization in phase III propagation was restricted to the spiral colon. Activity cycles tended to be shorter in the cecum and PLAC of both cows with colic than in normal cows, and the intensity of spiking activity was generally lower. Changes in duration of the MMC in the spiral colon (bovine colonic MMC, bcMMC) were inconsistent, but the intensity of spiking activity tended to be lower in phases I and II of both cows compared to controls. The organization of phase III in several spindles typical of the bovine spiral colon was not disrupted, but phase IV of the bcMMC occurred only infrequently. Organized cyclic activity occurred in the large intestine of both cows despite complete disruption of the small intestinal MMC, indicating the presence of mechanisms able to initiate and regulate coordinated myoelectric patterns in the large intestine independent of the small intestine.     

Ultrasonographic examination of the caecum and the proximal and spiral ansa of the colon of cattle

The large intestine of 10 cows was examined from the right abdominal wall with a 3.5 MHz linear transducer. The cows were then slaughtered, and the organs were re-examined in a water bath. The caecum was visualised from the middle region of the abdominal wall. It ran caudo-cranially, varied in diameter from 5.2 to 18.0 cm and was situated immediately adjacent to the abdominal wall. The lateral wall of the caecum appeared as a thick, echogenic, crescent-shaped line. It could be visualised as far cranially as the 12th intercostal space. Although its junction could not be identified, the proximal ansa of the colon was recognised on the basis of its anatomical position and its diameter, which was smaller than that of the caecum. The spiral ansa of the colon and the descending colon were situated dorsal to the caecum and could be identified by moving the transducer horizontally along the abdominal wall to the last rib. The spiral ansa of the colon was situated ventral to the descending colon, and its walls appeared as thick echogenic lines. In a contracted state, the spiral colon had the appearance of a garland.     

Plasma lactate as a predictor of colonic viability and survival after 360 degrees volvulus of the ascending colon in horses

Objectives— To determine the relationship between plasma lactate concentration and colonic viability and survival in horses with ≥360° volvulus of the ascending colon.
Study Design— Retrospective study.
Animals— Horses (n=73) with ≥360° volvulus of the ascending colon.
Methods— Medical records (January 2000–November 2005) of all horses examined for colic at Michigan State University Veterinary Teaching Hospital were reviewed. Horses were included only if plasma lactate concentration was measured preoperatively and a diagnosis of ≥360° volvulus of the ascending colon was confirmed by surgery or necropsy. Non-survivors were only included if the ascending colon was evaluated histopathologically. Logistic regression analysis was used to model the relationship between lactate, colonic viability, and survival.
Results— Of 73 horses, 61 were discharged. Mean (±SD) plasma lactate concentration was significantly lower in survivors (2.98±2.53 mmol/L) compared with non-survivors (9.48±5.22 mmol/L; odds ratio [OR]=1.628, 95% confidence limit [CI]=1.259–2.105). Plasma lactate concentration was significantly lower in horses with a viable colon (3.30±2.85 mmol/L) compared with horses with a non-viable colon (9.1±6.09 mmol/L; OR=1.472, 95% CI=1.173–1.846). Plasma lactate concentration <6.0 mmol/L had a sensitivity of 84% and a specificity 83% for predicting horse survival.
Conclusions— Our results demonstrate a strong association between plasma lactate concentration at the time of hospital admission and outcome in horses with ≥360° volvulus of the ascending colon.
Clinical Relevance— Plasma lactate concentration may help predict colonic viability and horse survival after ascending colon volvulus in horses.     

Myoelectric activity of the spiral colon in dairy cows

OBJECTIVE: To describe myoelectric activity of the spiral colon in healthy cows. ANIMALS: 7 lactating Simmental X Red-Holstein crossbred cows. PROCEDURE: Cows were implanted with 7 pairs of bipolar silver electrodes (4 in the spiral colon and 1 each in the cecum, distal part of the ileum, and proximal loop of the ascending colon [PLAC]). Myo-electric activity was recorded during 4 days for each cow. Patterns were analyzed, using computer-based methods. RESULTS: Myoelectric activity of the spiral colon was closely associated with motility of the ileum and PLAC and showed the typical organization of migrating myoelectric complexes (MMC). The MMC in the bovine spiral colon (bcMMC) had a mean +/- SD duration of 188.6 +/- 30.8 minutes and was divided into 4 phases. Phases I and II lasted 11.3 +/- 1.4 and 159.4 +/- 33.3 minutes, respectively. Phase III (duration, 5.4 +/- 1.2 minutes) was characterized by 5.2 +/- 0.9 regular spindles (35.4 +/- 5.4 seconds) and 1 final elongated spindle (137.2 +/- 56.4 seconds). Phase III most commonly (73.8 +/- 16.1%) was followed by phase IV (duration, 173 +/- 3.6 minutes). Propagation velocity of phase III was 4.4 +/- 0.5 cm/min, and 13.6% of bcMMC were incompletely propagated through the spiral colon. CONCLUSIONS: Myoelectric activity of the bovine spiral colon is composed of a recurring cyclic pattern similar to MMC of the small intestine. Data of colonic myoelectric activity in healthy cows will serve as a basis for studies on cecal dilatation and dislocation in cattle.     

Lagevariationen von Caecum und Colon ascendens beim Degu (Octodon degus, Molina 1782)

Twenty formalin fixed animals, nine male and eleven female, belonging to the genus Octodon degus (Molina 1782) were examined as to the topography of the cecum and ascending colon (Colon ascendens). The cecum shows differing forms and positions. The position of the Caput ceci is normally on the left side, directed cranially or caudally. Besides its topography on the left side, it can extend over the median level to the right side or remain with caput and corpus on the right, while the apex appears on the left side in front of the entry to the pelvis. Further findings were that the ascending colon (Colon ascendens) is arranged in two superimposed, often spiral folds, which may differ as to their form and extension, depending on the position of the cecum.     

Obstruction of the Ascending Colon in Cattle: I. Clinical Presentation and Surgical Management

Obstruction of the spiral loop of the ascending colon (spiral colon) due to adhesions causing extraluminal constriction was diagnosed in 8 cows during a 2-year period. The adhesions resulted from intraperitoneal injections in 7 cows and from previous intra-abdominal surgery in the 8th. Surgical correction was performed in 4 of the cows by uniting the bowel proximal and distal to the obstruction, thus creating an intestinal bypass. Approximately half of the large intestine was bypassed in this manner in 3 cows; all but a portion of the descending colon and rectum was bypassed in the 4th. Each of the cows survived surgery, although 1 died 30 days later, possibly as a result of a second obstruction caused by further adhesions. Appetite, general physical condition, and milk production returned after celiotomy and intestinal bypass. Feces were loose after operation but gradually firmed to near-normal consistency in 3 of the cows.     

Uptake of ferritin by follicle-associated epithelium in the colon of calves.

Uptake of macromolecules (e.g., ferritin) by M cells in follicle-associated epithelium in small and large intestine was investigated in three healthy, conventionally raised, 2- to 3-week-old, female Holstein Frisian calves. A 2.5% solution of ferritin was injected into the ligated loops in mid-jejunum, in terminal ileum, in the ascending colon adjacent to the ileocecal junction, and in the proximal loop of the ascending colon containing gut-associated lymphoid tissue. After exposure times that ranged from 82 to 165 minutes, ferritin was detected in M cells of domes in the small intestine, as well as in cells in follicle-associated epithelium of proprial lymphoid nodules and lymphoglandular complexes of colon that morphologically resembled M cells of small intestine. Ferritin was found in apical invaginations, apical vesicles, multivesicular bodies, basal vesicles, and adjacent intercellular spaces. In addition to ferritin, apical vesicles, multivesicular bodies, and intercellular spaces contained 50-nm membrane-bound particles. More ferritin was endocytosed by M cells of the small intestine than by M cells of the large intestine. In the large intestine, higher amounts of ferritin were found in M cells of follicle-associated epithelium overlying proprial lymphoid nodules than in M cells of follicle-associated epithelium in the depth of lymphoglandular complexes. Based on these results, we concluded that M cells of follicle-associated epithelium in the colon of calves provide a route for antigen uptake into the intestinal lymphoid system.     

Ultrasonographic findings in cows with dilatation, torsion and retroflexion of the caecum

Thirty cows with caecal dilatation underwent clinical and ultrasonographic examinations, followed by a right flank laparotomy and surgical correction. The intraoperative findings were compared with the results of the ultrasonographic examination. The appearance, position, dimensions, diameter and nature of the contents of the caecum and proximal and spiral ansa of the colon were determined with a 3.5 MHz linear transducer. The wall of the proximal ansa of the colon and of the dilated caecum closest to the abdominal wall was visible in all the cows and appeared as an echogenic semicircular line immediately adjacent to the peritoneum. The contents of the caecum and of the proximal and spiral ansa of the colon were not visible in 21, 25 and 25 cows, respectively, owing to gas. In the remaining cows, the contents were hypoechogenic to echogenic in appearance. In all of the cows, the dilated caecum was imaged from the right abdominal wall at the level of the tuber coxae. The caecum was imaged from the 12th, 11th and 10th intercostal spaces in 11, five and three cows, respectively. The caecum and proximal ansa of the colon were situated immediately adjacent to the right abdominal wall in 28 cows, but in the other two cows parts of these structures were pushed away from the abdominal wall by the liver or gall bladder. The diameter of the caecum, measured at various sites varied from 7.0 to 25.0 cm. Caecal dilatation was diagnosed on the basis of the results of rectal examinations in 28 of the cows, but in all 30 cows on the basis of the results of the ultrasonographic examinations. Dilatation and caudal displacement of the caecum were diagnosed in 18 cows; dilatation and cranioventral retroflexion of the caecum were diagnosed in six cows, and dilatation and craniodorsal retroflexion of the caecum were diagnosed in two cows. In the four other cows, the direction of the retroflexed caecum could not be determined. The diagnosis of caecal dilatation based on the ultrasonographic findings was confirmed in all the cows during exploratory laparotomy. The results of ultrasonography and exploratory surgery with regard to the position of the dilated and sometimes retroflexed or twisted caecum were in complete agreement in 18 cases, in partial agreement in eight cases, but in four cases did not agree.     

Microbial activity in the gut of piglets: I. Effect of prebiotic and probiotic supplementation

Four groups of six 21 days-old piglets were used to evaluate the effect of a prebiotic or probiotic on the intestinal fermentative activity. In each group, piglets received one of the following diets: basal diet (C); basal diet supplemented with xylo-oligosaccharide (C-XOS); basal diet supplemented with Saccharomyces cerevisiae (C-SC); and basal diet supplemented with xylo-oligosaccharide and S. cerevisiae (C-XOS + SC).

The short chain fatty acids in the colon of piglets were decreased with the inclusion of S. cerevisiae in the diet (P < 0.01). The xylanolytic activity was higher (P < 0.05) in the small intestine of piglets fed C-XOS + SC diet, but no significant differences were found in the caecum and colon. In the caecum contents, the cellulolytic activity was increased (P < 0.05) by the C-XOS and C-SC diets, but remained similar when the diet was supplemented with the two additives combined.     

Arterial Vascularization of the Gastrointestinal Tract of the Pampas Deer (Ozotoceros bezoarticus,Linnaeus, 1758)

Based on gross dissection of fifteen adult animals (11 females, 4 males), we described the arterial supply of the stomach and intestines of the pampas deer (Ozotoceros bezoarticus), a South American endangered species. The coeliac artery emitted the splenic, left gastric and hepatic arteries. The splenic artery directed towards the spleen, and the right ruminal artery, which is its only collateral directed towards the stomach, being the main artery of the rumen. The left gastric artery gave origin to the left ruminal, the reticular and the left gastroepiploic arteries. The left gastroepiploic artery originated the reticular accessory artery. Both arteries, gastric and left gastroepiploic, anastomosed their right counterparts derived from the hepatic artery on the curvatures of the abomasum. The cranial mesenteric artery irrigated the second half of the duodenum until the beginning of the descending colon. The thickest branch emitted by the cranial mesenteric artery was the ileocolic artery, which was destined to the ascending colon, caecum and ileum. The colic branches and the right colic arteries were irradiated on the right surface of the spiral loop of the ascending colon and distributed to both centripetal and centrifugal coils of the ascending colon; the colic branches were also anastomosed with the last jejunals and ileals and with the right colic arteries. There were no variations in the origin of any of the main branches derived from the coeliac and cranial mesenteric arteries. This species had a basic pattern of arterial distribution similar to small domestic ruminants.     

Effect of exposure to dietary nivalenol on activity of enzymes involved in glutamine catabolism in the epithelium along the gastrointestinal tract of growing pigs.

Changes in the activity of enzymes involved in oxidative metabolism of glutamine, and in protein content, in the epithelial tissue along the gastrointestinal (GI) tract of growing pigs exposed to nivalenol (NIV) in the diet were investigated. The epithelial tissue was taken from the stomach, small intestine and colon of three groups of animals fed diets without NIV (control), with inclusion of 2.5 mg NIV/kg diet (low dose) and with inclusion of 5.0 mg NIV/kg diet (high dose). The activities of glutaminase, glutamate dehydrogenase, oxoglutarate dehydrogenase, isocitrate dehydrogenase and alanine aminotransferase were determined. In the control pigs the activities of oxoglutarate dehydrogenase and alanine aminotransferase were higher (P < 0.05) in the epithelium of the small intestine as compared with the stomach and colon, while there were no differences in the activities of glutaminase, glutamate dehydrogenase and isocitrate dehydrogenase. With increasing inclusion of NIV in the diet the activity of oxoglutarate dehydrogenase decreased (P < 0.05) in the epithelium of the small intestine and colon, and the activity of alanine aminotransferase tended (P = 0.07) to increase in the epithelium of the small intestine. The activities of glutaminase, glutamate dehydrogenase and isocitrate dehydrogenase remained unaffected by the inclusion of NIV in the diet. In the control pigs the protein content in the epithelium of the small intestine was higher (P < 0.05) than in the stomach and colon, while there were no effects of NIV inclusion in the diet on the protein content. It can be concluded from the present study that the epithelial tissue of the small intestine and colon of pigs exposed to a diet containing NIV will have a reduced enzymatic capacity to utilise alpha-ketoglutarate in the tricarboxylic acid cycle (TCA-cycle), suggesting an impaired energy supply to these organs.     

Gut-associated lymphoid tissue in the large intestine of calves. I. Distribution and histology

Gut-associated lymphoid tissue (GALT) in the large intestine was characterized in 12 calves (10 to 84 days old) obtained at necropsy (7, group A) or healthy animals (5, group B). Patches of mucosal lymphoid follicles were in all calves at ileocecal entrances (ICE), 23-42 cm distal to the ICE in the proximal loop of the ascending colon (proximal colon [PC] patch), and in the terminal rectum. PC patches varied from 8 to 30 cm in length. Solitary lymphoid follicles were found in the cecum of three calves, between the ileocecal entrances and the PC patch in four calves, adjacent to the PC patch in all calves, and in the ampulla recti. GALT occupied 7.8% of the large intestinal wall in animals of group A: 0.6% at the ileocecal entrance, 4.8% in the proximal colon, and 2.4% in the rectum. There were two different types of mucosal lymphoid follicles in group B: propria nodules with lymphoid follicles predominantly in the lamina propria, and lymphoglandular complexes with lymphoid follicles in the submucosa. In three 3-, 6-, and 7-day-old, germfree calves, distinct follicle-associated epithelium covered propria nodules and covering folds in depths of the lymphoglandular complexes; it was characterized by numerous intraepithelial cells and lack of goblet cells.     

Effects of an abrupt increase of starch-rich concentrates in the diet of dairy cows on concentrations of volatile fatty acids in the rumen and large intestine and on myoelectric activity of the spiral colon

OBJECTIVES: To describe the effects of an abrupt increase of concentrates in the diet of dairy cows on myoelectric activity of the spiral colon and on fermentation patterns in the rumen and large intestine. ANIMALS: 6 healthy lactating Simmental x Red-Holstein cows. PROCEDURES: The diet of 6 cows implanted with bipolar electrodes in the spiral colon was changed from hay only to a ration of 50% hay:50% starch-rich concentrates during a period of 60 hours. Myoelectric activity of the spiral colon, concentrations of absolute and undissociated volatile fatty acids (VFA), and pH of ruminal and large intestinal contents were monitored before, during, and after the dietary change. RESULTS: Significant changes in patterns of myoelectric activity of the spiral colon were restricted to phases III and IV of the bovine migrating myoelectric complex and to propagation velocity. Significant alterations were not observed in pH or VFA concentrations in ruminal fluid, but pH decreased and VFA concentrations increased significantly in fecal specimens after the change of diet. CONCLUSIONS AND CLINICAL RELEVANCE: Although rumen fluid is of limited value for measurement of certain indicators of fermentation, fecal samples can be used for measurement of pH and VFA concentrations, which serve as indicators of fermentation patterns in the large intestine. Increased concentrations of VFA and low pH in large intestinal digesta have a minimal influence on myoelectric activity of the spiral colon. Increased luminal VFA concentrations are unlikely to play an important role in the etiopathogenesis of motility disorders of the large intestine in cattle.     

Apparent digestibility of crude fibre in ponies fed either a low or high-protein diet

The question addressed was whether apparent crude fibre digestibility in ponies would change after lowering protein intake from adequate to borderline deficient. Four adult ponies were fed a low- and high-protein diet according to a cross-over design. The diets consisted of grass hay and concentrates and provided either 1.5 or 3.6 g digestible crude protein/kg^0.75 per day. The two whole rations provided 2.4 g crude fibre/kg body weight per day. Apparent crude fibre digestibility was not affected by protein intake (low-protein diet: 42.9 ± 4.03%; high-protein diet: 38.1 ± 1.14%, means ± SE, n =4). The low-protein diet caused a significant increase in the ratio of faecal: urinary nitrogen. It is suggested that, when the low-protein diet was fed, sufficient urea flew from the blood into the intestine and ammonia released in the hindgut was conserved so that microbial growth, and thus fibre fermentation, was maintained.     

The topography and gross anatomy of the gastrointestinal tract of the Cape dune mole-rat (Bathyergus suillus)

The Cape dune mole-rat, Bathyergus suillus, is the largest truly subterranean rodent in the world and is restricted to sandy soil areas of the southern and South-western Cape Province. These animals are herbivorous, feeding mostly on the below ground portions of grass and geophytes. The present study was undertaken to explore whether there are any gross anatomical gastrointestinal adaptations associated with the herbivorous diet of the Cape dune mole-rat and to provide a basis for further investigations into the nutrition and ecology of this animal. The stomach was unilocular (simple) and the entire internal aspect displayed macroscopically visible glandular epithelium. The caecum was voluminous and arranged into a spiral of approximately one and a half turns. The tip of the caecum resembled a vermiform appendix and lay against the left lateral abdominal wall. The ascending colon consisted of proximal and distal portions, arranged in a large double loop and attached to each other by a fat-filled mesenteric fold. The looped, folded ascending colon filled the right side of the abdominal cavity, lying against the right dorsal, lateral and ventral abdominal wall. The internal structure of the ascending colon revealed a shallow groove, lined on either side by a row of papillae. The simple, glandular stomach in conjunction with a prominent caecum and a greatly enlarged ascending colon suggests that this animal is a hindgut fermenting herbivore, rather than a caecal fermenter, as is the case in most rodent species.     

Influence of dietary fiber on luminal environment and morphology in the small and large intestine of sows

In this study, the effect of feeding different types and amounts of dietary fiber (DF) on luminal environment and morphology in the small and large intestine of sows was studied. Three diets, a low-fiber diet (LF) and 2 high-fiber diets (high fiber 1, HF1, and high fiber 2, HF2) were used. Diet LF (DF, 17%; soluble DF 4.6%) was based on wheat and barley, whereas the 2 high-fiber diets (HF1: DF, 43%; soluble DF, 11.0%; and HF2: DF, 45%; soluble DF, 7.6%) were based on wheat and barley supplemented with different coproducts from the vegetable food and agroindustry (HF1 and HF2: sugar beet pulp, potato pulp, and pectin residue; HF2: brewers spent grain, seed residue, and pea hull). The diets were fed for a 4-wk period to 12 sows (4 receiving each diet). Thereafter, the sows were killed 4 h postfeeding, and digesta and tissue samples were collected from various parts of the small and large intestine. The carbohydrates in the LF diet were well digested in the small intestine, resulting in less digesta in all segments of the intestinal tract. The fermentation of nonstarch polysaccharides in the large intestine was affected by the chemical composition and physicochemical properties. The digesta from pigs fed the LF diet provided low levels of fermentable carbohydrates that were depleted in proximal colon, whereas for pigs fed the 2 high-DF diets, the digesta was depleted of fermentable carbohydrates at more distal locations of the colon. The consequence was an increased retention time, greater DM percentage, decreased amount of material, and a decreased tissue weight after feeding the LF diet compared with the HF diets. The concentration of short-chain fatty acids was consistent with the fermentability of carbohydrates in the large intestine, but there was no effect of the dietary composition on the molar short-chain fatty acid proportions. It was further shown that feeding the diet providing the greatest amount of fermentable carbohydrates (diet HF1, which was high in soluble DF) resulted in significant morphological changes in the colon compared with the LF diet.