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PubMed2002

Excretion of bisphenol A-glucuronide into the small intestine and deconjugation in the cecum of the rat.

The environmental estrogen bisphenol A (BPA) is regarded as a modulator of endocrine systems and has been reported to have adverse effects on the reproductive organs of animals. In rats, BPA is metabolized to glucuronide by UDP-glucuronosyltransferase UGT2B1 in the liver and excreted into the bile. In the present study, we found that most of the bisphenol A-glucuronide (BPA-GA) excreted into the small intestine was deconjugated in the contents of the cecum. After BPA administration, BPA-GA was (immediately should be 15 min) found in the contents of the upper part of the small intestine, and then it moved to the lower part of the small intestine. However, only free BPA was found in the content of the cecum, and there was smaller amount of free BPA in the colon contents, indicating that BPA had been reabsorbed in the colon. BPA-GA was deconjugated by extract prepared from the cecum content which included highest beta-glucuronidase (beta-Gase) observed in Western blot analysis using antibodies against bacterial beta-Gase. These results indicate enterohepatic circulation of BPA and suggest that the adverse effects of BPA are enhanced by repeated exposure.

Animals↗
PubMed1997

Effect of L-lactic acid, short-chain fatty acids, and pH in cecal infusate on morphometric and cell kinetic parameters of rat cecum.

We studied the influences of cecal infusion of NaCl, short-chain fatty acids (SCFA), and L-lactic acid at pH 5.0 or 7.0 for seven days on morphometric and cell kinetic parameters of the rat cecum. SCFA increased relative weight of the mucosa and submucosa, crypt size, and mitotic index in the cecum. L-Lactic acid stimulated mitosis only at pH 5.0. Crypt size correlated positively to epithelial proliferative activity only when NaCl or L-lactic acid was infused. SCFA should have changed the balance between production and loss of the cecal epithelial cells. The infusate pH by itself had no effect, but modified the effects of SCFA and L-lactic acid in different ways. Crypt size correlated positively to the logarithm of daily proton load of infusates. The above results indicate that epithelial cell proliferation in the cecum is influenced by both SCFA and L-lactic acid, although differently, and by proton load.

Acetic Acid↗
PubMed1997

Morphological characteristics, epithelial cell proliferation, and crypt fission in cecum and colon of growing pigs.

Morphological characteristics and cellular proliferation were investigated in the hindgut tissue of 25 pigs ranging from 5 to 261 days of age; the three youngest pigs were unweaned. Tissue samples were taken from the cecum and from the proximal, middle, and distal part of the colon. In the young pigs a high incidence of branched crypts was observed. During the first three to four months there was an increase in crypt height and proliferative activity, as determined by the mitotic count, as well as an increase in the mucin secretion, especially the sulfomucins. Distinct regional differences were observed between the four intestinal sites. In general, the crypts were deeper and more closely spaced and the turnover time was higher in the distal part of the colon as compared to the cecum and the proximal colon. Furthermore, a greater proportion of the mucins in the middle and distal part of the colon are acidic or sulfated as compared to the cecum, where the mucins are more of the neutral type. These regional and age-related differences in morphological characteristics of the hindgut in pigs may have significance for the etiology of intestinal infections.

Age Factors↗
PubMed2000

Contribution of the cecum and colon to zinc absorption in rats.

We examined the role of the large intestine in zinc absorption in rats in three separate experiments. In the first experiment, we examined apparent zinc absorption in rats fed diets containing graded levels of zinc carbonate (0.015-0.535 mmol Zn/kg diet) and evaluated zinc status on the basis of the zinc concentrations in serum and several tissues. The zinc absorption and the serum zinc concentration increased with the zinc content of the diet up to 0. 153 mmol Zn/kg diet. Femoral and pancreatic zinc levels increased linearly up to 0.229 mmol Zn/kg diet. In the second experiment, a zinc carbonate suspension was administered into the cecum via an implanted cannula or into the stomach via an orogastric tube, and the rats were fed diets with or without a highly fermentable fiber, guar gum hydrolysate (GGH, 50 g/kg diet), with coprophagy prevention. The amount of instilled zinc corresponded to the amount of zinc ingested as a component of the diet by the rats of a control group, 0.229 mmol Zn/kg diet. Apparent absorption of cecally instilled zinc was approximately half that observed when zinc was administered into the stomach in both diet groups. Serum and femur zinc concentrations in the cecum-administered groups were approximately 50 and 25% lower, respectively, than those in rats administered zinc into the stomach. The results demonstrate that, in vivo, the absorptive efficiency in the large intestine is not sufficient to satisfy the rat's zinc requirement and does not change when the luminal environment is substantially altered by feeding GGH. In Experiment 3, the effects of cecocolonectomy on zinc absorption were examined in rats with gastric acid suppression. In the cecocolonectomized groups, serum zinc concentration was lower as a result of treatment with a proton pump inhibitor, omeprazole, than in vehicle-treated rats, but not in sham-operated groups. These findings suggest that the cecum and colon contribute to zinc absorption when absorption in the small intestine is impaired.

Analysis of Variance↗
PubMed2001

Mutations induced by 2-amino-1-methyl-6-phenylimidazo [4,5-b]pyridine (PhIP) in cecum and proximal and distal colon of lacI transgenic rats.

2-Amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) is a food-borne mutagen and carcinogen that induces tumors of the colon and the prostate gland in male rats and of the mammary gland in female rats. In this study we describe the frequency and specificity of PhIP-induced mutations in the cecum, proximal colon and distal colon of male and female lacI transgenic rats. This is the first report of mutational data from discrete regions of the colon. After 61 days of treatment with 200 p.p.m. PhIP mixed into the diet, PhIP-induced mutant frequencies were elevated 7-fold in the cecum and 14- to 21-fold in the colon of male and female rats compared with untreated controls. PhIP-induced mutant frequencies increased significantly (overall trend, P < 10(-4)) along the length of the colon of both males and females, with cecum < proximal colon < distal colon. A total of 754 PhIP mutants (363 male, 391 female) were sequenced to provide the mutational spectra for each of the three tissue sections from males and females. These mutational spectra consisted predominantly of G:C-->T:A and G:C-->C:G transversions and deletions of G:C base pairs. There were no significant differences between the mutational spectra with respect to sex or position in the colon. Therefore, we surmise that following induction of mutations by PhIP in male and female colons, non-mutagenic factors, possibly hormonal, preferentially influence the formation of tumors in the colon of male rats.

Animals↗
PubMed2006

Microbial community composition of the ileum and cecum of broiler chickens as revealed by molecular and culture-based techniques.

The microbial communities of the ileum and cecum of broiler chickens from a conventional and an organic farm were investigated using conventional culture techniques as well as cloning and sequencing of 16S rRNA genes. Eighty-five percent of the 557 cloned sequences were <97% related to known cultured species. The chicken ileum was dominated by lactobacilli, whereas the cecum harbored a more diverse microbial community. The cecum was dominated by a large group of bacteria with hitherto no close cultured relatives but most closely related to Faecalibacterium prausnitzii. Approximately 49 and 20% of the cecal clones belonged to this cluster in conventional and organic broiler chickens, respectively. We were, however, able to recover a number of these phylotypes by cultivation, and the isolates were shown to be butyric acid producers. The investigation was a descriptive rather than a comparative study of 2 different rearing systems; however, several differences were observed. For instance, Clostridium perfringens was found in significantly higher numbers in the birds from the organic farm compared with the conventional broilers, probably due to the addition of salinomycin to the conventional feed. In the ileum, the abundance of the different Lactobacillus species differed between the 2 broiler types. The culture-based and culture-independent techniques complemented each other well. Strengths and limitations of the different methods are discussed.

Animal Feed↗
PubMed1997

[Variation of the position of the cecum and ascending colon of the 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.

Animals↗
PubMed1978

Bacteria isolated from the duodenum, ileum, and cecum of young chicks.

Facultatively anaerobic and strictly anaerobic bacteria colonizing the intestinal tracts of 14-day-old chicks fed a corn-based diet were enumerated, isolated, and identified. Colony counts from anaerobic roll tubes (rumen fluid medium) or aerobic plates (brain heart infusion agar) recovered from homogenates of the duodenum, upper and lower ileum, and cecum varied appreciably among samples from individual birds. Anaerobic and aerobic counts from the duodenum and ileum were similar. Anaerobic counts were highest from the cecum (0.7 X 10(11) to 1.6 X 10(11)/g of dry tissue) and exceeded aerobic plate counts by a factor of at least 10(2). Facultatively anaerobic groups (Streptococcus, Staphylococcus, Lactobacillus, and Escherichia coli) comprised the predominant flora of the duodenum and ileum, although large numbers of anaerobes (9 to 39% of the small intestine isolates), represented by species of Eubacterium, Propionibacterium, Clostridium, Gemmiger, and Fusobacterium, were also recovered. Strict anaerobes (anaerobic gram-positive cocci, Eubacterium, Clostridium Gemmiger, Fusobacterium, and Bacteriodes) made up nearly the entire microbial population of the cecum. Scanning electron microscopy of the intestinal epithelia of chicks revealed populations of microbes on the duodenal, ileal, and cecal mucosal surfaces.

Anaerobiosis↗
PubMed1979

Comparison of bacterial populations of the pig cecum and colon based upon enumeration with specific energy sources.

Concentrations of bacteria in the ceca and colons of pigs were measured by determinations of colony counts on rumen fluid-based media in anaerobic roll tubes. With our most complete medium (medium CCA), the mean colony count of cecal samples from 20 pigs was 2.37 X 10(10) +/- 1.0 X 10(10) (+/- standard deviation)/g (wet weight). The mean number of bacteria attached to or associated with cecal epithelial tissues from three pigs on medium CCA was 2.67 X 10(7) +/- 0.81 X 10(7)/cm2 of tissue. The proportions of gut bacterial populations able to use various energy substrates were estimated on the basis of relative colony counts. The following substrates are listed in descending order of their capacity to support growth of cecal bacteria: glucose, starch, cellobiose, xylose, Trypticase, gastric mucin from swine, mannitol, glycerol, and lactate. The effect of diet upon this distribution was not examined. The relative proportions of bacteria from a given population that were able to grow on various selective media were used as population profiles. Comparisons of populations in this way indicated that differences could be detected between (i) populations from the cecum of littermate pigs, (ii) populations from the cecum and colon of the same pig, and (iii) populations in the lumen of the cecum as compared with populations associated with cecal mucosa.

Animals↗
PubMed1989

Influence of diet and monensin on development of anaerobic fungi in the rumen, duodenum, cecum, and feces of cows.

Three cows with fistulated rumens, duodenums, and ceca were fed five different diets: lucerne hay, lucerne hay plus whey (40:60), lucerne hay plus beets (50:50), corn silage plus monensin (40 ppm [40 g/kg] of dry matter intake), and lucerne hay plus monensin (80 ppm of dry matter intake). The fungal population was observed in the rumen, duodenum, cecum, and rectum and varied with diet; it was most abundant with lucerne hay alone and with corn silage plus monensin. The proportion of particles colonized by fungi in the duodenum, the cecum, and feces was measured by microscopic observation and varied from 5 to 50%, depending on the diet. The further sporangia attached to the plant particles were from the rumen, the more likely they were to be devoid of spores. Results confirmed the influence of diet on the development of the ruminal fungal population and showed that monensin does not eliminate these microorganisms. They also confirmed the presence of anaerobic fungi in the ruminant intestine. It is likely that anaerobic fungi leave the rumen attached to plant particles. However, large colonies of nonrhizoidal-type fungi were observed in cecum samples and in feces; at these sites, environmental conditions are perhaps more favorable for this type of fungus than they are in the rumen.

Anaerobiosis↗
PubMed1981

Transepithelial calcium transport by rat cecum: high-efficiency absorptive site.

Transepithelial calcium transport has been investigated in rat cecum under in vitro voltage-clamp conditions. Under short-circuit conditions, the cecum behaves as a relatively tight epithelium for calcium fluxes, where mucosal-to-serosal (JCam leads to s) flux exceeds the reverse flux by at least 15-fold. JCanet is abolished in the presence of 1 mM N-ethylmaleimide, is inhibited by 40% with 1 mM ouabain, and is decreased by at least 60% when medium sodium is replaced by choline. Voltage-clamping experiments suggest that both electroneutral- and electrogenic-mediated calcium fluxes traverse the cell in the mucosal-to-serosal direction. Serosal-to-mucosal flux is purely diffusional and probably constrained to the paracellular pathway. In rats weighing less than 175 g, a low-calcium diet has no significant stimulatory effect on JCam leads to s, but a high-calcium diet markedly reduces this flux. These results suggest that the cecum possesses the highest density of calcium transport sites in the rat intestine and is ideally suited for bulk calcium absorption, which may be "down regulated" in response to an increased calcium load in growing animals.

Animals↗
PubMed1993

Characterization of an apical sodium conductance in rabbit cecum.

Rabbit cecum in vitro exhibits electrogenic Na+ absorption not blocked by amiloride but inhibited by the amiloride analogue phenamil, suggesting transport mediated by modified Na+ channels in the apical membrane. To further characterize the mechanism(s) of Na+ absorption, microelectrode impalements of single epithelial cells were performed to measure intracellular potential difference (psi mc) and fractional resistance of the apical membrane, to characterize ionic conductances of the apical and basolateral membranes, and to determine the response to phenamil. The electrical potential profile of cecum (psi mc = -31 +/- 2 mV, fractional resistance = 0.71 +/- 0.03) was qualitatively similar to distal colon. The apical membrane exhibited responses suggesting both Na+ and K+ conductances, whereas the basolateral membrane appeared to have a predominant K+ conductance. Phenamil elicited a depolarization of psi mc and a decrease in fractional resistance; neither response is consistent with inhibition of an apical Na+ conductance. Studies were performed in apical membrane vesicles to characterize ionic conductances by a second independent methodology. These additional studies confirmed the presence of an apical Na+ conductance not inhibited by either amiloride or phenamil. Thus both microelectrode impalement and vesicle studies demonstrated an apical membrane Na+ conductance in rabbit cecum; this is the likely mechanism of electrogenic Na+ absorption in this epithelium. However, the anomalous response to phenamil suggests that the inhibitory effect of this agent is not directly on the conductance. The cecal transporter may be one of a family of cation channels related to, but significantly different from, the classic Na+ channel found in distal colon and other tight epithelia.

Amiloride↗
PubMed2001

Modulation of 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine-induced mutation in the cecum and colon of big blue rats by conjugated linoleic acid and 1,2-dithiole-3-thione.

2-Amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) is a potent mutagen and suspected human carcinogen present in cooked protein-rich food. It preferentially induced colon tumors in male rats and mammary tumors in female rats. In the present study, the in vivo antimutagenic efficacy of two dietary compounds, conjugated linoleic acid (CLA) and 1,2-dithiole-3-thione (DTT), against PhIP was explored using 1acI transgenic Big Blue rats. Five- or six-week-old male Big Blue rats were fed a diet containing CLA (0.5%, wt/wt) or DTT (0.005%, wt/wt) starting one week before exposure to 200 ppm PhIP for 61 days. PhIP treatment induced a approximately 8- to 16-fold increase in the mutation frequency (MF) in the colon. The induced MF was significantly lower in the cecum than in the proximal and distal colon (approximately 52 x 10(-5) vs. 100 x 10(-5), p < 0.008). CLA and DTT significantly reduced the PhIP-induced MF in the distal colon (p < 0.05) by 14% and 24%, respectively. The frequency of -1 frameshift mutations was lower in the distal colon of CLA- or DTT-treated rats. This protective effect was not observed in the cecum or in the proximal colon. In contrast, the PhIP-induced MF in the cecum (specifically, the frequency of -1 frameshifts and GC-->TA transversions) was elevated by 43% after treatment with CLA. In conclusion, CLA and DTT modulate PhIP-induced mutagenesis in a tissue-specific manner, and different modulation pathways are employed by CLA and DTT.

Animals↗
PubMed1997

Wheat bran- but not oat bran-enriched diets increase the mucosal height of the cecum and colon of newly weaned and aged rats.

The effect of diets enriched with oat or wheat bran (prepared by the addition of 300 g of each fiber to 1000 g of the regular diet), given for 8 weeks, on the mucosal height of the colon and cecum was investigated. Newly weaned (21 days old) and aged (12 months old) male Wistar rats were used in this study. As compared to controls, diets enriched with wheat bran provoked a significant increase in the mucosal height, whereas oat bran did not cause any effect. In newly weaned rats (21 days old), wheat bran increased the mucosal height (microns) in the cecum by 20% (mean +/- SEM for 8 rats; 169.1 +/- 5.2 and 202.9 +/- 8.0 for control and wheat bran, respectively) and in the colon (218.8 +/- 7.2 and 264.5 +/- 18.8 for control and wheat bran, respectively). A similar effect was observed in aged rats (12 months old), with an increase of 15% in the mucosal height (microns) of the cecum (mean +/- SEM of 8 rats; 193.2 +/- 8.6 and 223.7 +/- 8.3 for control and wheat bran, respectively) and of 17% in the colon (300.4 +/- 9.2 and 352.2 +/- 15.9 for control and wheat bran, respectively).

Aging↗
PubMed2003

Effects of monoamines formed in the cecum of horses on equine digital blood vessels and platelets.

OBJECTIVE: To determine in vitro vasoactive potency of monoamines formed in the cecum and found in the systemic circulation of horses. SAMPLE POPULATION: Segments of digital blood vessels obtained from 6 healthy mixed-breed horses and ponies euthanatized at an abattoir and platelets isolated from 4 healthy ponies. PROCEDURE: Paired rings of digital artery and vein from the same horse were examined, and isometric tension was recorded. Concentration-response curves for tryptamine (TRP), tyramine (TYR), phenylethylamine (PEA), isoamylamine (IAA), and isobutylamine (IBA) were obtained. Vasoconstrictor mechanisms were investigated for TRP and TYR by the use of antagonists. Washed platelets loaded with [3H]-5-hydroxytryptamine (5-HT) were incubated with monoamines; the amount of radioactivity displaced after 30 minutes was estimated. RESULTS: TRP, TYR, and PEA were potent constrictors of arteries and veins, with TRP and TYR being more potent in veins than arteries. Constrictions induced by TYR were inhibited by benextramine (alpha-antagonist) and nisoxetine (neuronal-uptake blocker), whereas TRP responses were inhibited by ketanserin (5-HT receptor antagonist). All 5 amines displaced 5-HT from platelets with the order of potency being TYR > TRP > PEA > IAA > IBA. CONCLUSIONS AND CLINICAL RELEVANCE: Amines from the equine cecum cause digital vasoconstriction. The most potent (TRP and TYR) cause selective venoconstriction. Tyrosine activates predominantly alpha-adrenoceptors through the release of neuronal norepinephrine, whereas TRP activates 5-HT receptors. All amines tested released 5-HT from platelets. Amines formed in the cecum and released into the systemic circulation warrant additional investigation as trigger factors for digital ischemia and subsequent laminitis.

Adrenergic alpha-Agonists↗
PubMed2003

Seasonal changes in plasma concentrations of cecum-derived amines in clinically normal ponies and ponies predisposed to laminitis.

OBJECTIVE: To measure concentrations of amines formed in the cecum of clinically normal ponies, determine amine concentrations in plasma samples collected in spring and winter, and compare concentrations of amines and serotonin in plasma samples obtained from clinically normal ponies and ponies predisposed to laminitis. SAMPLE POPULATION: Cecal contents obtained from 10 ponies euthanatized at an abattoir and blood samples obtained from 42 adult ponies. PROCEDURE: Cecal contents were assayed for amines by high-performance liquid chromatography (HPLC). Blood samples were collected at various times of the year from 20 ponies predisposed to acute laminitis and 22 clinically normal ponies. Plasma serotonin concentration was measured by HPLC, and tryptamine (TRP), tyramine (TYR), phenylethylamine (PEA), and isoamylamine (IAA) were measured by liquid chromatography-mass spectrometry. RESULTS: 15 amines were identified in cecal contents. Plasma TRP, TYR, PEA, and IAA concentrations ranged from 10pM to 100nM in both groups of ponies. Plasma concentrations of serotonin or other amines did not differ between clinically normal ponies and those predisposed to laminitis; however, significantly higher concentrations of TRP, PEA, and IAA were found in samples obtained in the spring, compared with winter samples. CONCLUSIONS AND CLINICAL RELEVANCE: Various amines are found in the cecum of ponies, several of which can be detected in the plasma. Concentrations increase significantly in the spring and may reach concentrations close to the threshold for causing vasoconstriction. Release of amines from the cecum into the systemic circulation may contribute to hemodynamic disturbances in horses and ponies with acute laminitis.

Amines↗
PubMed2001

Beneficial effect of dietary wheat glycolipids on cecum short-chain fatty acid and secondary bile acid profiles in mice.

In the present study, to explore the beneficial effect of dietary galactoglycerolipids on the lower digestive tract environment, male BALB/c mice were fed a 5% wheat glycolipid, fiber-free diet, or the standard AIN diet for 3 wk. The wheat glycolipid composition was digalactosyldiacylglycerol 51.6%, ceramide monohexoside 6.6%, acylated sterylglucoside 3.4%, and other lipids 22.2%, (mostly phospholipids). Cecum and colon weights and colonic crypt depth were significantly greater in the glycolipid-diet mice relative to groups fed the other two diets. Furthermore, in the cecum, propionate. butyrate, and total short-chain fatty acids, concentrations were significantly greater in the glycolipid-diet mice than others were, and correlated with the observed increased lower digestive tract (cecum and colon) weights and colonic crypt depth. The cecal lithocholic acid/deoxycholic acid ratio, a risk index for colorectal cancer, was significantly lower in the glycolipid-diet mice than in the other two dietary groups. These results suggest that the dietary supplementation of plant-source galactoglycerolipids may contribute to improving the lower digestive tract environment.

Animals↗
PubMed2002

An improved technique for the histological evaluation of the mucus-secreting status in rat cecum.

Mucin secreted into the alimentary tract often forms a mucus layer on the mucosa and is believed to protect the underlying epithelium against various factors in the lumen. We developed an improved histological technique for the evaluation of the mucus layer in the rat cecum. We used this technique to compare the effect of three nonstarch poly- and oligosaccharides on the status of mucus layer. Rats were divided into four groups (fiber-free [FF], cellulose [CEL], fructooligosaccharide [FOS], or guar gum [GG]). The frozen cecum with its contents was cut into cross-sections (5 mm thick) and fixed overnight in half-strength Bouin's solution. The sections were then transferred to 80% ethanol for 24 h. After being stained with alcian green, the mucus layers were clearly visualized in thin sections of the rat cecum, except for those that received FOS where the mucus layer had disappeared; the strong signal of mucus was seen in the cecal digesta of FOS-fed rats. Our histological method successfully provided information about the status of mucus layer that is important for an assessment of the epithelial state in the intestine.

Acetic Acid↗