Morphological and histochemical features of the duodenal glands in six marsupial species

The duodenal glands of four marsupial species, the kangaroo, native cat, marsupial mouse, and bandicoot, form a narrow lobular collar immediately distal to the gastrointestinal junction. In two species, the koala and wombat, the duodenal glands are diffuse and scattered along the intestinal tract distal to the gastrointestinal junction for considerable distances. The glands of all species examined empty independently into the intestinal lumen. Histochemical studies indicate that the latter two species, the koala and wombat, elaborate an acid mucin whereas the former species produce a neutral mucosubstance. Ultrastructural examination shows that generally the duodenal glands are comprised of large pyramidal cells that show a definite polarity, with basally-placed nuclei and apically-situated secretory granules. Species differences, with regard both to the morphology and nature of the secretory granules and to the proportions of cell organelles, exist. The diversity of diet between species is discussed.     

Morphological and histochemical observations on the duodenal glands of eight wild ungulate species native to North America

The duodenal glands of the species examined (Alces alces, Ovis canadensis, Cervus canadensis, Oreamnos americanus, Bison bison, Antilocapra americana, Odocoileus virginianas, Odocoileus heminous) are confined primarily to the submucosa of the small intestine. In one species, the moose, a significant population of secretory tubules also is observed in the mucosa. The ducts of the duodenal glands pierce the overlying muscularis mucosae to empty most often independently into the intestinal lumen. Those of the bison, unlike the other species examined, drain into intestinal glands. The duodenal glands consist primarily of a simple columnar epithelium, the cells of which contain basally positioned round or oval nuclei. The lumina of scattered duodenal glands in the pronghorn and to some extent those of the moose, white-tailed deer, and mule deer may be extremely dilated, and the surrounding epithelium thin and attenuated. Component cells of the duodenal glands of all the species examined show remarkably similar ultrastructural features. They exhibit scattered profiles of rough endoplasmic reticulum, dilated cisternae of which contain an electron-dense, amorphous material. Numerous well-developed Golgi complexes occupy the supranuclear region together with transport vesicles and forming secretory granules. Electron-dense, membrane-bound secretory granules generally are concentrated in the apical cytoplasm immediately subjacent to the cell membrane. The apical cell membrane exhibits short, scattered microvilli; and the basal cell membrane is smooth without apparent specialization. Histochemically, the duodenal glands of most species examined in this study consist of a heterogeneous population. The majority of the glands of the moose, elk, mountain goat, bison, pronghorn, and white-tailed deer elaborate a neutral mucin, whereas scattered individual glands, tubules or cells also produce acid mucins. Cells near the terminations of the ducts of the bighorn sheep are the only elements to produce acid mucins in the duodenal glands of this species. The duodenal glands of the bison are unusual in that only the peripheral portions of individual glands produce acid mucins. The remainder of the glands elaborate neutral mucins. Morphological differences between the two regions were not observed. The duodenal glands of the mule deer secrete both acid and neutral mucins. The structural and histochemical observations appear unrelated to the diet of individual species.     

Quantitative characteristics of the endocrine cells of the duodenal glands of Carnivora

In the duodenal glands of the Carnivora investigated endocrine elements have been revealed, a part of them is presented as serotonin-producing EC-cells. Endocrine cells are situated in terminal parts and in glandular ducts, among them elements of open and close types are distinguished. Distribution of these cells in the glandular lobules is subjected to the distal gradient regularity, specific for the gastrointestinal tract mucosal membrane. Amount of endocrinocytes in the glands is much less than in the gut crypts. There is no correlation between distribution of the endocrine cells in the glands and in the crypts. The results of unifactor analysis of variance demonstrate a slight effect of the taxonomic position of the species on the number of endocrine cells in the duodenal glands. The proper endocrine apparatus of the duodenal glands is supposed to produce a local regulatory influence on the secretory activity of exogenic glandulocytes, as well as ensure humoral connections of the duodenal glands with other parts of the gastrointestinal tract.     

Extent and method of grinding of sorghum prior to inclusion in complete pelleted broiler chicken diets affects broiler gut development and performance

A broiler experiment was conducted to examine the effects of sorghum particle size and milling type on the performance, nitrogen corrected apparent metabolisable energy (AME_n), digestive tract development, digesta pH, duodenal digesta particle size and digesta passage rate. Complete pelleted diets with identical botanical and chemical composition containing 750 g/kg whole sorghum (WS), sorghum ground through hammer mill with 1 mm and 3 mm screen (HM1 and HM3) and sorghum ground on a roller mill with 0.15 mm spacing (RM0.15), were made. Sorghum for diets HM3 and RM0.15 were milled to approximately the same mean particle size. Diet WS resulted in poorer (P<0.05) weight gain and feed conversion ratio (FCR) than the other diets from 11 to 21 days of age, while diet RM0.15 resulted in improved FCR. Apparent ME_n determined between 25 and 28 days of age, however, was higher (P<0.05) for diet WS than for the other diets. This was possibly due to a longer adaptation time to a larger feed particle size, as indicated by a lower (P<0.05) pH in the gizzard and smaller duodenal digesta particle size for this diet. Diet HM1 gave similar performance as diet HM3, but resulted in a significantly smaller gizzard, a higher pH of the gizzard content, a lower pH of the duodenal content and larger particles in the duodenal contents, thus indicating that gizzard development and activity were compromised by this diet. Total tract passage rate of the liquid phase marker was slower (P<0.05) in the WS fed birds, but there were no differences in solid phase marker excretion rates.     

小鼠胚胎附植前后瘦素长型受体在下丘脑及消化器官的表达

目的对长型瘦素受体在雌性昆明鼠生殖周期中的表达情况进行研究。方法采用蛋白免疫印迹实验方法对下丘脑、胃、十二指肠组织中的瘦素受体进行了分析,并用免疫组织化学染色法对雌性KM鼠生殖周期不同阶段的下丘脑、胃、十二指肠组织中表达的瘦素长型受体进行定位分析。结果与结论瘦素受体六个亚型的分子量大约分别为(120、90、77、66.2、54、47)×103;下丘脑神经元胞质中有棕褐色阳性颗粒,且数目随妊娠日龄增加而增加;胃底腺中下部分胞质和细胞核有棕褐色阳性颗粒,且阳性率随妊娠日龄的增加而增加;十二指肠腺中胞质和细胞核有棕褐色阳性颗粒,且阳性率随妊娠日龄的增加而增加。     

Endocrine cells of the duodenal glands in various representatives of Primates]

The duodenum of four species of monkeys, belonging to the genera Macaca and Papio, has been investigated. In order to reveal argyrophil and argentaffin Ec-cells, Grimelius and Masson-Hamperl methods have been used, respectively. In all the species studied in the terminal parts and in the ducts of the duodenal glands presence of endocrine cells is noted; their amount, however, is considerably less than in crypts. Open and close types of endocrine cells++ have been revealed in the glands. A part of the endocrine cells population is argentaffin Ec-cells (about 40% in Papio and 80% in Macaca). This demonstrates participation of serotonin they produce in regulation of the duodenal glands functional activity. Dependence between taxonomic position of the species and degree of endocrine cells++ development in the duodenal glands has been followed. In particular, in representatives of Macaca amount of argyrophil and argentaffin in the glands is greater than in Papio. Possible reasons of the differences are discussed. Comparing the results on investigation of the glands in the primates with those previously obtained for representatives of Carnivora, a suggestion is made concerning some general principles in organization of the proper endocrinic apparatus of the mammalian duodenal glands.     

Experimental substantiation of differences in the extent of development of the duodenal glands in mammals

The glandulo-duodenal index was lower in carnivorous animals than in herbivores. The character of the distribution of the duodenal glands in the intestinal wall of animals with different types of nutrition differed. The given indices also varied within the range for each group of animals; this could be associated with fine differences in nutritional specialization. A diet rich in cellulose led to an increase in the glandulo-duodenal index and to changes in gland topography in the rat duodenum.     

Autoradiographic demonstration of specific binding sites for E. coli enterotoxin in various epithelia of the North American opossum

Summary In the North American opossum, heat-stable specific binding sites for E. coli enterotoxin are observed (i) in epithelial cells lining the small intestine, colon, gall bladder, cystic duct, common bile duct and trachea, and (ii) in epithelial cells forming the duodenal (Brunner's) glands, liver, kidneys (metanephros, mesonephros) and testis, as demonstrated by autoradiography. Enterotoxin-specific binding sites in the intestinal tract are only found in intestinal epithelial cells with the highest concentration in the microvillus border. Enterotoxin-specific binding sites also occur in epithelial cells comprising the secretory tubules and ducts of the duodenal glands. In the kidneys (metanephros and mesonephros), enterotoxin-specific binding sites are confirmed primarily to the proximal tubules, whereas in the testis they are localized in seminiferous tubules. In the liver, enterotoxin-specific binding sites are confined primarily to hepatocytes. E. coli enterotoxin caused a 7-fold increase of cGMP in the liver and a 30-fold increase in the duodenal glands. The liver responded in about half of the animals studied, whereas the duodenal glands gave a consistent response in each case. Likewise, the duodenal glands consistently showed strong labelling for ¹²⁵I-enterotoxin, whereas receptor labelling of hepatocytes was inconsistent in nearly half the incubations and corresponds to the observed cGMP measurements.Supported by a Weldon Springs Grant, University of Missouri and by funds from the Medical Research Service, Department of Veteran's Affairs     

Comparative lectin histochemical analysis of the duodenal glands in various mammals

Composition and histotopography of lectin receptors have been studied in 12 species of mammals with various nutritional specialization: carnivorous, phytophagous and omnivorous. In cells of the duodenal glands of the carnivorous and omnivorous receptors to concanavalin A and lentil lectin (D-mannosoglycans ) are absent and they are present in the glands of the phytophagous animals. In cells of some parts of the glands presence of receptors to soya bean lectin (N-acetyl-D-galactosamine++) is the most characteristic sign of the duodenal glands in the carnivorous and phytophagous animals. Together with certain differences, depending on the nutritional way of the animals, specific peculiarities of lectins binding with glandulocytes of the duodenal glands are demonstrated. The data on rearrangement of the lectin receptors are obtained during the process of cellular differentiation. Presence of N-acetyl-D-galactosamine++ remnants-biding soya bean lectin in composition of oligosaccharide++ chains of glycoconjugates is a sign of low differential degree of the glandular cells. In more differentiated cells concealment in oligosaccharide chains of D-galactose remnants (peanut and castor-oil lectins receptors) by L-fucose, N-acetil-D-glucosamin remnants and sialic acid can have place; this is demonstrated as accumulation of receptors to wheat germ and Laburnum anagyroides lectins in the glandular cells.     

The trypsin activity in the chyme and parietal layer of the mucus in experimental exclusion of the Brunner's gland section of the duodenum in rats]

The duodenal glands secretion into intestine was excluded by surgical ablation or ligation of Brunner's glands region. The trypsin activity in chyme and adherent mucous layer was reduced following these manipulations. Possible reasons for changes established are discussed.     

Meal-related stimuli differentially induce c-Fos activation in the nucleus of the solitary tract

Feedback signals arising from the oral cavity and upper gastrointestinal tract contribute to the control of meal size. To assess how these signals are integrated at central sites involved in ingestive control, we compared levels of c-Fos activation in the nucleus of the solitary tract (NTS) and area postrema (AP) in response to meal ingestion or gastric and duodenal infusions in the rat. Ingestion of a liquid diet to satiety induced significant fos-like immunoreactivity (FLI) at multiple levels of the NTS and within the AP. The restriction of intake to one-half the normal ingestion of a rat did not result in significant FLI, although gastric infusion of this liquid diet volume did. Fast bolus infusion resulted in greater FLI than did the same volume infused at a rate to mimic that of normal ingestion. Prior experience with gastric infusions did not affect the amounts of FLI within the NTS or AP. In rats with pyloric cuffs blocking flow from the stomach to the intestine, combined gastric load and duodenal nutrient elicited significantly greater FLI than either gastric or duodenal infusions alone. These data demonstrate that neural activation arising from meal-related stimuli are integrated at the level of the NTS.     

Histochemistry of the duodenal glands of the cat and horse.

The duodenal glands of cat and horse were studied using PAS, Alcian blue, dialysed iron, aldehyde fuchsin-Alcian blue and high iron diamine stains. It was found that the duodenal glands of the horse reacted positively to Alcian blue, dialysed iron stains and also took the Alcian blue stain in the combined aldehyde fuchsin-Alcian blue and high iron diamine-Alcian blue stains. Those of the cat gave negative results. These results suggest the presence of acidic groups in the mucosubstances secreted by the horse's duodenal glands. A suggestion is put forward on the strength of the high iron diamine-Alcian blue combined stains that the acidity is due to the presence of carboxyl groups. It is suggested that the acidity may be significant in either cellulose metabolism or the digestion of the bacterial microflora from the stomach of herbivores.     

Heterogeneity of the ABH antigenic determinants expressed in human pyloric and duodenal mucosae

We defined the chemical structure and the genetic control of the various A or B determinants expressed by pyloric and duodenal epithelial cells by indirect immunofluorescent staining using monoclonal anti-A or anti-B reagents that recognize only certain variants of A or B antigenic determinants.Some mucous cells in pyloric and Brünner's glands express AY or BY antigens whereas other mucous cells in the same glands express only the Y antigen. Absorptive and goblet cells of the duodenal villi and Lieberkühn glands express mono- and difucosylated A or B structures, mainly of type 1. The pyloric surface epithelium expresses mono- and difucosylated, type 1 and type 2, A or B structures. In addition, A or B antigens, with a so far undefined structure are found in the pyloric surface mucosae of non-secretor individuals.     

Observations on the anatomy of the stomach and duodenum of the bowhead whale, Balaena mysticetus

Gastric and cranial duodenal structure of the bowhead whale (Balaena mysticetus) was examined grossly and microscopically. The stomach was arranged in a series of four compartments. The first chamber, or forestomach, was a large nonglandular sac lined by a keratinized stratified squamous epithelium. It was followed by the fundic chamber, a large, somewhat globular and entirely glandular compartment. At the entrance of the fundic chamber, a narrow cardiac gland region could be defined. The remaining mucosa of the chamber contained the proper gastric glands. A narrow, tubular connecting channel, the third distinct gastric division, was lined by mucous glands and joined the fundic chamber with the final stomach compartment, or pyloric chamber. This fourth chamber was also tubular and lined by mucous glands but was of a diameter considerably larger than the connecting channel. The stomach terminated at the pyloric sphincter which consisted of a well-developed band of circular smooth-muscle bundles effecting a division between the pyloric chamber and small intestine. The small intestine began with the duodenal ampulla, a dilated sac considerably smaller than the fundic chamber of the stomach. The mucosa of this sac contained mucous glands throughout. The ampulla led without a separating sphincter into the duodenum proper which continued the intestine in a much more narrow tubular fashion. The mucosal lining of the duodenum was composed of villi and intestinal crypts. Although their occurrence varied among whales, enteroendocrine cells were identified within the mucous glands of the cardiac region, connecting channel, pyloric chamber, and cranial duodenum. The hepatopancreatic duct entered the wall of the duodenum shortly after the termination of the duodenal ampulla and continued intramurally along the intestine before finally joining the duodenal lumen.     

Mucosubstance histochemistry of Brunner's glands, pyloric glands and duodenal goblet cells in the ferret

The mucosubstance of Brunner's glands, pyloric glands and duodenal goblet cells were studied using the various histochemical methods. The secretions of both Brunner's and pyloric glands were similar in their histochemical reactions. They contained neutral mucosubstances as in these glands in man. The duodenal goblet cells showed variations in their histochemical characters. (i) The secretions of most of the deep cells and the majority of superficial cells contained sialidase-labile and sialidase-resistant sialomucins. (ii) There were a few superficial and occasional deep cells, the secretions of which contained sulphated mucosubstances. (iii) There were some goblet cells, more in the villi than in the crypts, the secretions of which contained a mixture of sialomucins and a sulphated mucin. The sialomucin was mostly sialidase-labile and partly sialidase-resistant.     

No distinct difference in the excretion of large particles of varying size in a wild ruminant,the banteng (<Emphasis Type="Italic">Bos javanicus</Emphasis>)

The forestomach of ruminants and camelids does not only allow a differential excretion of fluids and small particles but also a differential excretion of small and large particles. The question whether larger particles of different size classes are also retained for different time periods, or whether simply a particle-size threshold exists above which all particles of a size higher than this threshold are retained in an undifferentiated manner, has not been addressed so far. We determined the mean retention time (MRT) of different-sized large particles (10 and 20 mm) in three banteng (Bos javanicus) on two forage only diets, grass and grass hay. We used cerium-mordanted fibre (10 mm) and lanthanum-mordanted fibre (20 mm) as particle markers, mixed in the food. Average total tract MRT for large and very large particles at the grass diet was 58 and 56 h and at the grass hay diet 66 and 64 h, respectively. Very large particles moved slightly faster than large particles through the gut of the banteng. Three interpretations are possible: Very large particles are resubmitted to rumination sooner than large particles; ingestive mastication of the particle markers could have reduced the difference in the size of the particle markers; alternatively, particle retention may be governed by a threshold, above which all particles of a size higher than this threshold are retained in an undifferentiated manner. In order to test these possibilities, experiments with fistulated animals would have to be performed.     

Mucosubstance histochemistry of Brunner's glands,pyloric glands and duodenal goblet cells in the ferret

Summary The mucosubstance of Brunner's glands, pyloric glands and duodenal goblet cells were studied using the various histochemical methods.The secretions of both Brunner's and pyloric glands were similar in their histochemical reactions. They contained neutral mucosubstances as in these glands in man.The duodenal goblet cells showed variations in their histochemical characters. (i) The secretions of most of the deep cells and the majority of superficial cells contained sialidase-labile and sialidase-resistant sialomucins. (ii) There were a few superficial and occasional deep cells, the secretions of which contained sulphated mucosubstances. (iii) There were some goblet cells, more in the villi than in the crypts, the secretions of which contained a mixture of sialomycins and a sulphated mucin. The sialomucin was mostly sialidase-labile and partly sialidase-resistant.     

A freeze-fracture study of the digestive tract of the parasitic nematode Trichinella

Freeze-fracture preparations of the esophagus and intestine of larvae and adults of the nematode Trichinella spiralis illustrate the distribution of intramembranous particles in membranes of a number of cell types, and several specializations were found. Esophageal glands are prominently linked by gap junctions, but gap junctions were not found between intestinal cells. Muscle cells of the esophagus have rectilinear arrays of particles, thought to be points of adherence of the muscles to the esophageal epithelium. Clusters of particles are associated with these arrays and particle-free areas (probably Z bodies) also occur. Intestinal cells have small particles in their microvilli, large particles in the cells' apical membranes, and intermediate size particles, similar to membranes of other cells, in the lateral and basal membranes. Apical smooth septate junctions and tricellular junctions occur between intestinal cells.     

马铁菊头蝠消化系统的组织学观察

应用石蜡常规切片、HE染色,对马铁菊头蝠消化系统各器官的组织结构进行了观察.结果 表明:食管粘膜上皮为复层扁平上皮,轻微角质化,前、中、后段的上皮结构没有显著差异,食管腺在前段较多,中、后段较少.胃固有层含有大量的管状腺.小肠粘膜表面有许多环形皱襞,在十二指肠上段粘膜下层分布有十二指肠腺.大肠粘膜表面光滑,无绒毛,在粘膜下层的结缔组织中有小动脉、静脉和淋巴管.肝内结缔组织多,肝小叶分界较明显,肝血窦发达.胰的小叶间分界不明显.     

The food and feeding ecology of Mugilidae in the St. Lucia lake system

The diet and feeding interrelationships of ten species of Mugilidae were studied over a two-year period in the St. Lucia lake system of South Africa. Qualitative stomach analyses were performed on over 1000 fish of more than 5 cm (standard length). All are soft bottom substrate feeders ingesting inorganic particles mixed with food items. The food of most species is the same and consists of Assiminea bifasciata , foraminifera, the large centric diatom Aptinoptychus splendens , small centric and pennate diatoms, and filamentous algae. Individual species of mullet however, differ, in the size of inorganic particles ingested and exhibit marked sand grain size preferences. The consumption of the various food items may depend upon their occurrence on substrates of the preferred particle size. There is no apparent change in diet and particle size preference according to age in any of the species and no seasonal variation was recorded in the diet. It is suggested that interspecific competition for food is reduced by substrate particle size selection and perhaps by differences in feeding periodicity. Where there is an apparent overlap in diet, as in the case of Assiminea bifasciata , on substrates of the same size then there is a superabundance of the food organism which serves to minimize competitive interactions.