Effect of increasing the proportion of dietary concentrate on gastrointestinal tract measurements and brush border enzyme activity in Holstein steers.

The aim of this study was to determine the time course for adaptation of the reticulo-rumen, omasum, abomasum, and small intestine in response to an abrupt increase in the proportion of grain in the diet. Adaptive responses include tissue and digesta mass, small intestinal length, and brush border enzyme activity in the duodenum, proximal jejunum, and ileum. Twenty-five Holstein steers (213 ± 23 kg; 5 to 7 mo of age) were blocked by body weight, and within block were randomly assigned to 1 of 5 treatments: the control diet (CTRL; 92% chopped grass hay and 8% mineral and vitamin supplement on a dry matter basis) or a moderate grain diet (MGD; 50% chopped grass hay, 42% rolled barley grain, and 8% mineral and vitamin supplement) that was fed for 3 (MGD3), 7 (MGD7), 14 (MGD14), or 21 d (MGD21). Dry matter intake was limited to 2.25% of body weight to ensure that changes in dry matter intake did not confound the results. On the last day of the dietary exposure, steers were slaughtered 2 h after feeding. Reticulo-rumen tissue mass and ruminal epithelium mass in the ventral sac of the rumen were not affected by the MGD. Wet reticulo-ruminal digesta mass decreased from CTRL to MGD7 and then increased, but reticulo-ruminal digesta dry matter mass did not differ between treatments. Omasal mass, omasal tissue mass, and omasum digesta mass decreased linearly with the number of days fed MGD, but abomasal tissue mass tended to increase linearly. Duodenal tissue mass tended to increase linearly, and ileal length increased linearly with the number of days fed MGD. Lactase activity in the proximal jejunum increased linearly and maltase activity in duodenum tended to increase linearly with days fed MGD. Aminopeptidase N activity in the proximal jejunum increased cubically with days fed MGD, and dipeptidylpeptidase IV activity in ileum tended to decrease from CTRL to MGD14 and then tended to increase. Adaptation to a diet with a greater proportion of concentrate involves changes in the mass and length of regions of the gastrointestinal tract and brush border enzyme activity. These changes take place gradually over at least 3 wk.

Computed tomography of the abdomen of calves during the first 105 days of life: I. Reticulum, rumen, omasum and abomasum.

Computed tomographic (CT) images of the reticulum, rumen, omasum and abomasum of five healthy Holstein-Friesian bull calves were compared with anatomical transverse cadaver sections of the same calves. The calves were scanned in the transverse plane from the 5th thoracic vertebra to the sacrum six times three weeks apart from birth to 105 days of age. Multiplanar reconstruction was used to create images in sagittal and dorsal planes. After subjective assessment of various anatomical structures, the rumen, omasum and abomasum as well as the ruminal strata (gas cap, fibre mat and fluid phase) were measured. After the last CT scan, all calves were euthanised, and four were kept at -18 °C in sternal position for 14 days. Transverse sections 1.0 to 1.5 cm thick were made from two calves and dorsal and sagittal sections were made from one calf each using a band saw. The CT images and anatomical slices were compared and the structures on the CT images identified. Very clear CT images were obtained from the reticulum, rumen, omasum and abomasum and there was excellent agreement between images and anatomical slices.

Dans le présent travail, on décrit les constatations tomodensitométriques sur la panse, le bonnet, le feuillet et la caillette de 5 veaux mâles en bonne santé dans les 105 premiers jours de vie et on les compare avec les résultats des examens post-mortem. Les veaux ont été examinés au total 6 fois par tomodensitométrie à intervalle de 3 semaines. L'examen a été réalisé par coupes transversales de la 5ème vertèbre thoracale jusqu'au sacrum. On a également reconstitué les structures dans les plans sagittal et dorsal au moyen de reconstruction multi planaires. Après l'examen subjectif, on a défini diverses structures, comme l'extension de la panse, du feuillet et de la caillette et celle des phases gazeuses, liquides et solides de l'ingestat de la panse. Tous les veaux ont été euthanasiés après les examens tomodensitométriques. Quatre d'entre eux ont été congelés durant 14 jours en position sternale à -18 °C. Deux veaux ont ensuite été sciés transversalement en tranches de 1.0 à 1.5 cm d'épaisseur. Un veau a été scié en tranches dorsales et un en tranches sagittales. Les coupes ont été comparées aux images tomodensitométriques afin d'identifier les structures visualisées. Le bonnet, la panse, le feuillet et la caillette ont pu être visualisés de façon exacte par tomodensitométrie. La topographie des images tomodensitométriques et des coupes anatomiques correspondent très bien.

Histamine receptors mediate contraction of reticular groove smooth muscle of adult goats.

The present study was conducted to evaluate the effect of histamine and to characterise its receptor subtypes in reticular groove (RG) smooth muscle of adult goats. The studies were done using floor and lip regions of RG. We used tension experiments on smooth muscle of RG isolated from adult goat for functional characterisation of H1 and H2 receptors. Western blotting and immunohistochemistry experiments were conducted for molecular characterisation of these receptors. Histamine evoked concentration-dependent contraction of isolated RG circular and longitudinal smooth muscle preparation. Pyrilamine antagonised the action of histamine. Histamine did not induce any relaxant effect on RG preparations. Additionally, cimetidine did not produce any significant effect on histamine-induced response. Non-selective histaminic receptor antagonist cyproheptadine attenuated the contraction response to histamine in the smooth muscle. Molecular characterisation and localisation of H1 and H2 receptor proteins confirmed the presence of these receptors in RG. It is most likely that histamine-induced contractile effect in RG smooth muscle of goats is mediated by H1 histaminic receptors.

Anatomical subdivisions of the stomach of the Bactrian camel (Camelus bactrianus).

Twenty stomachs of Bactrian camels (Camelus bactrianus) were studied by gross dissection. Based on the configuration of the stomach and the structure of the mucous membrane, the stomach was divided into three ventricles that differ from the arrangement described for ox and sheep. The first and second ventricles of the proventriculus of camel form one stomach rather than two different stomachs. These ventricles of the proventriculus do not correspond to the rumen and reticulum of ox and sheep. The third ventricle appears to be the abomasum. One part of the abomasum has reticular mucosal folds that indicate it is not the reticulum. A second part of the abomasum has longitudinal mucosal folds suggesting it is not the omasum. Three glandular sac areas associated with the preventriculus and abomasum are also described.

Structural differences of the enteric nervous system in the cattle forestomach revealed by whole mount immunohistochemistry.

The specific motility patterns of the forestomach of ruminants, composed of three structurally distinct compartments (rumen, reticulum, omasum), require an elaborate intramural innervation. To demonstrate the complex structure of the enteric nervous system (ENS), whole mount preparations obtained from different sites of the bovine forestomach were submitted to immunohistochemical procedures in which neuronal (protein gene product 9.5, neurofilament 200) and glial (protein S-100, glial fibrillary acid protein) markers were applied. Immunohistochemistry performed on whole mounts allowed a detailed two-dimensional assessment of the architecture of the intramural nerve networks. Generally, the myenteric and submucosal plexus layers were composed of ganglia and interconnecting nerve fiber strands, whereas the mucosal plexus consisted of an aganglionated nerve network. However, the texture of the ENS showed considerable regional differences concerning the ganglionic size, shape and density and the arrangement of nerve fiber strands. The myenteric plexus of the ruminal wall, showing a low ganglionic density and wide polygonal meshes, contrasted with the nerve network within the ruminal pillar which consisted of ropeladder-like nerve fiber strands and parallel orientated ganglia. The highest ganglionic density was observed at the reticular groove, the most prominent ganglia were found within the omasal wall. Branches of the vagal nerve frequently ramified within the myenteric plexus layers. The submucosal plexus of the rumen was divided into an external and internal layer; the reticular submucosal plexus followed the cristae and cellulae reticuli, the omasal submucosal (sublaminar) plexus showed intra- and parafascicular ganglia apart from ganglia located at the junctions of the nerve network. The mucosal plexus of the rumen consisted of thin nerve fascicles ramifying between the ruminal papillae, and reticular mucosal nerve fibers passed throughout the base of the cellulae reticuli. The highly specialised nerve network of the intralaminar omasal plexus showed radial and transverse trajectories reflecting the spatial arrangement of the intralaminar musculature. The demonstrated structural complexity of the ENS reflects the functional complexity of the ruminant forestomach and indicates the relatively high degree of autonomy in coordinating the different motility patterns required for the processing of the ingesta.

Morphological study on the stomach of the lesser mouse deer (Tragulus javanicus) with special reference to the internal surface.

The stomach of the lesser mouse deer (Tragulus javanicus) was observed macroscopically. It consisted of only three compartments, rumen, reticulum and abomasum without omasum. The rumen was S-shaped with large ventral and caudoventral blind sacs and the reticulum was larger than the abomasum. Internally, the rumen was covered with numerous ruminal papillae even on the pillars and the ruminoreticular fold. These papillae were leaf- or tongue-like shaped and varied in size and density. The reticulum had honey-combed crests and the secondary crests were found rarely. The lips of the reticular groove were prominent and more developed in the aboral part than in the oral one. A sac-like transition zone, which had more prominent mucosal folds than had the floor of the reticular groove, was observed between the caudal end of the reticular groove and the abomasum. Mucosal folds of the abomasum were spiral, low but rather thick. These findings were discussed in view of comparison with other ruminants and of possible functional implications.

Histogenesis of the reticular groove of the buffalo (Bubalus bubalis) stomach.

Histogenesis of the reticular groove (sulcus reticuli) of the buffalo (Bubalus bubalis) was observed from primordial stage to birth. The epithelium of the reticular groove was considered early embryonic until a crown-rump (CR) length of 2.2 cm, and was uniformly distributed at CR 2.2 cm; superficial and basal zones developed by CR 3.2. cm. At CR 10.5 cm, the basal zone in the floor evaginated and formed longitudinal folds. At CR 25.5 cm, the basal zone in the lipids evaginated and formed papillae. The core of the longitudinal folds and papillae was formed by the lamina propria, muscularis mucosae, and submucosa. Keratinization was seen at CR 50.5 cm, and the epithelium was stratified squamous epithelium with keratinization, similar to that of the adult buffalo. The floor and lip had a single layer of muscle. A small oblique muscle layer was also found in the concavity of the lip. The correlation between structure and function of the reticular groove is discussed.

Distribution of methionine-enkephalin-Arg6-Gly7-Leu8-immunoreactive nerves in the forestomach of cattle.

The distribution of methionine-enkephalin-Arg6-Gly7-Leu8-immunoreactive nerves in the forestomach of calves and cows was studied, using immunohistochemical methods. Methionine-enkephalin-Arg6-Gly7-Leu8-immunoreactive nerves were found in all regions of the bovine forestomach. Cell bodies were found mainly in myenteric ganglia, and nerve fibers were found principally in muscular layers. Nerve fibers and ganglia were concentrated in the lips of the reticular groove, but were least numerous in ruminal and omasal walls. The reduced number of immunoreactive nerves in cows, compared with the number of those in calves, was striking, especially in the lips of the reticular groove and the omasal leaves. Results may indicate that the importance of methionine-enkephalin-Arg6-Gly7-Leu8-containing nerves in the physiologic regulation of the forestomach of the calf is different from that of the cow.

Light microscopic studies of the stomach of the lesser mouse deer (Tragulus javanicus).

The stomach of the lesser mouse deer was studied at the light microscopic level using histological and immunohistochemical methods. The stomach was clearly differentiated into rumen, reticulum including reticular groove, a small transition zone and abomasum. The mucosal surface of the rumen, reticulum and transition zone was lined with a stratified squamous epithelium and that of the abomasum with a simple columnar type. The epithelial keratinization was weak in the rumen, floor of the reticular groove and transition zone, while it was strong in the reticulum, especially on the tip of the reticulum papillae. Large sinusoidal capillaries were often present in the ruminal papillae. In the ruminal mucosa, a thin layer of alpha-smooth muscle actin immunoreactive cells was demonstrated by immunohistochemistry. The muscularis mucosae of the reticulum was continuous and well-developed. The transition zone appeared as a nonglandular area having many low mucosal folds and two layers of tunica muscularis. The abomasal mucosa consisted of cardiac, proper gastric and pyloric glands. Cells immunoreactive for bovine pepsinogen and bovine prochymosin antisera were demonstrated in the abomasum. It is suggested that the characteristic features observed might be adaptations to a relatively rapid passage and rapid absorption of the fermentation products. There is some evidence that the transition zone is not a part of either the floor of the reticular groove or the abomasum, suggesting a possible reevaluation of the term used for the reticulo-abomasal orifice in the mouse deer.

Third compartment ulcers in the llama.

The diagnosis of third compartment ulcers in the llama and alpaca is largely one of exclusion. Clinical signs may include mild to severe colic, inappetence, decreased fecal output, bruxism, and depression. Abdominocentesis results are usually unremarkable if C3 perforation has not occurred but reflective of a generalized peritonitis if full thickness ulceration has occurred. The H-2 receptor antagonists cimetidine and ranitidine do not suppress C3 acid production for a significant period of time and are of questionable efficacy in the management of C3 ulcers.

Forestomach motility in llamas and camels.

Major aspects of forestomach anatomy in llamas and camels are described. The pattern of forestomach motility is a succession of motoric cycles, consisting of A- and B-contraction sequences and a pause. Respective differences between llamas and camels are discussed. Observations on regulation of motility are mentioned. Occurrences and courses of rumination and eructation within the motility cycles are emphasized. Motility of the forestomach achieves a selective retention of feed particles in the forestomach; a long retention time is a prerequisite for an effective microbial digestion, especially of poor quality feed.

Transabdominal ultrasonographic appearance of the gastrointestinal viscera of healthy camels (Camelus dromedaries).

The purpose of this study was to describe the ultrasonographic picture of the gastrointestinal tract in healthy camels (Camelus dromedarius). For this purpose, 22 camels were examined. The rumen and its glandular sacs were filling most of the left side of the abdomen. The rumen wall was smooth and echogenic. The ventral part of the reticulum could be best imaged in 17 (77%) camels from the left and right paramedian region just behind to the sternal pad. The reticulum in these animals had a thick wall (1.17±0.27 cm) that appeared as a half-moon-shaped structure with a biphasic contraction. The omasum was best viewed through the right 8th to 6th intercostal spaces in 18 (82%) camels. In the remaining 4 (18%), it was visualized through four consecutive intercostal spaces (right 9th to 6th). It had a wall thickness of 1.1±0.7 cm and a transverse diameter of 8.74±3.4 cm. The abomasum could be best visualized from the right 9th and 8th intercostal spaces in 14 (64%) camels, while it was observed in the 9th intercostal space in 3 (14%) animals and in the 8th and 7th intercostal space in 5 (22%) camels. Small intestinal structures were best seen low in the right paralumbar fossa. It was thin-walled (0.43±0.14 cm) and had a diameter of 2.62±0.47 cm. The cecum was imaged chiefly in the caudal right flank. It was thin-walled (0.37±0.05 cm), had a diameter of 13.8±1.6 cm. The proximal loop of the large colon appeared as thick, echogenic, continuous and slightly curved lines. It was thin-walled (0.51±0.08 cm) and had a diameter of 3.5±0.8 cm. The spiral colon was confined in all camels to the caudal ventral half of the abdomen. It appeared as structures with thick echoic lateral walls with a number of echogenic arched lines next to each other. Free peritoneal fluid pockets were imaged in two locations in 19 (86%) camels. Ultrasound-guided abdominocentesis was successful in 15 (68%) of the examined camels. This study provides the ultrasonographic appearance of the normal gastrointestinal tract in healthy camels that could be used as a reference for the interpretation of suspected digestive abnormalities.

Structural, histochemical and immunocytochemical study of the forestomach mucosa in domestic ruminants.

The forestomach plays an important role in the digestion physiology of ruminants. The aim of this study is to clarify the morpho-functional role of the mucosa in each of the three compartments of the forestomach in three domestic ruminants species, viz cattle, buffalo and sheep, by means of structural, histochemical and immunocytochemical methods, including transmission electron microscopy, light microscopy and scanning electron microscopy. These methods were chosen to demonstrate the indirect evidence for the presence of nitric oxide (NO) employing NADPHd and nitric oxide synthase I (NOS I). The various cell layers of the forestomach epithelium are described and illustrated in detail. An intense NADPHd staining was observed in the granulosa, spinosa and basal layers of the epithelium, in particular in the cytoplasm over the nucleus. NOS I immunoreactivity was found in all specimens of the forestomach mucosa. The results of this study might reflect a possible role of NO in delaying the onset of cellular apoptosis in the forestomach mucosa of the domestic ruminants, by playing a role in the production of cell energy.

Gross anatomy of the stomach of the dorcas gazelle (Gazella Dorcas, Linnaeus, 1758) / Anatomía macroscópica del estómago de la gacela dorcas (Gazella Dorcas, Linnaeus, 1758)

The macroscopic anatomy of the stomach in four adult dorcas gazelle was described. Four adult, two male and two female dorcas gazelle (Gazella dorcas) of the Frigya Zoological Park, Enfidha, Tunisie, were used in this study. The ruminal papillae were distributed unequally in the rumen, and were larger and more abundant within the atrium and in the two saccus cecus. The papillae were absent in dorsal part of the dorsal sac. The ruminal pillars had no papillae. The cellulae reticuli were divided and contained secondary and tertiary crests. The curvatura omasi measured 12.1±0.1 cm. A comparison with literature data for sand gazelles (Gazella subgutturosa marica) emphasises that differences between closely related species that fill similar niches cannot be expected to follow a clear pattern, but yield an inhomogenous picture, with some measurements more tending towards a specific feeding type in the one, and some other measurements tending more towards that feeding type in the other species.We concluded that the stomach morphology of the dorcas gazelle indicates the'cattle-type' morphophysiology representative for intermediate feeders.

En este estudio se describe la anatomía macroscópica del estómago de cuatro gacelas dorcas adultas. Se utilizaron cuatro animales adultos, dos machos y dos hembras (Gazella dorcas) del Parque Zoológico Frigya, Enfidha, Túnez. Las papilas ruminales estaban distribuidas de manera desigual en el rumen, y se observaron de mayor tamaño y abundantes dentro de la aurícula, y en ambos saccus cecus. No se observaron papilas en la parte dorsal del saco dorsal. Los reticuli cellulae se dividieron y contenían crestas secundarias y terciarias. La curvatura omasi media 12,1±0,1 cm. Una comparación con los datos de la literatura en gacelas de arena (Gazella subgutturosa marica) indica que no se puede esperar un patrón exacto en las especies estrechamente relacionadas que llenan nichos similares, pero no cuentan con una imagen homogénea. En algunas de las mediciones se observa la tendencia hacia un tipo específico de alimentación en una especie, mientras que otras medidas tienden a asociar este tipo de alimentación a otras especies. La morfología del estómago de la gacela dorcas indica que la morfofisiologia de este tipo de ganado es representativa de alimentadores intermedios.