Prenatal histomorphological development of the reticulum in fallow deer (Dama dama).

The histomorphological changes occurring in the Dama dama reticulum during prenatal development have been investigated. Twenty-five Dama dama embryos were used, from the first stages of prenatal life until birth. Differentiation of the reticulum was observed at 23% gestation. By 25% gestation the reticular wall comprised three layers: an internal epithelial layer, a middle layer of pluripotential blastemic tissue and an external layer or serosa. Primary reticular crests were visible at 38% gestation. Secondary reticular crests were observed at 61% gestation. Neuroendocrine cells were detected by synaptophysin (SYP) at 35% gestation, in the lamina propria-submucosa, tunica muscularis, and serosa. Epithelial Cytokeratin-18 (CK-18) cells were observed at 35% gestation extended throughout the epithelial layers. The glial cells (vimentin -VIM- and glial fibrillary acidic protein-GFAP-markers) were discerned at 25% and 43% gestation, respectively, in myenteric and submucosal plexuses, lamina propria, muscularis mucosae, tunica muscularis, and perivascular connective tissue. The neuropeptide Y (NPY) and vasoactive intestinal polypeptide (VIP) markers were immunodetected at 75% and 80 gestation, respectively, in the lamina propria-submucosa, muscularis mucosae, tunica muscularis, serosa, and myenteric plexuses. The prenatal development of the fallow deer reticular mucosa evidenced a considerable precocity similar to that previously reported in goat and red deer.

Gross Measurements of the Digestive Tract and Visceral Organs of Addax Antelope (Addax nasomaculatus) Following a Concentrate or Forage Feeding Regime.

Differences in macroscopic measurements of the gastrointestinal tract have been hypothesized to correlate with the browser-grazer continuum in the natural diet of ruminants. However, to what extent these characteristics represent species-specific traits, or respond to the actually ingested diet, remains to be investigated. Twelve surplus addax antelope (Addax nasomaculatus) were divided into two groups and fed, for 3 months, either their usual diet, consisting of a concentrate feed with a limited amount of hay, or a diet of unlimited hay only. After culling, macroscopic measurements were compared between groups. The macroscopic anatomy of the addax showed many characteristics considered typical for grazing or 'cattle-type' ruminants. While both diet groups had mesenteric, pericardial and perirenal adipose tissue, these depots were subjectively more pronounced in concentrate-fed animals. Hay-fed animals had significantly heavier filled forestomach compartments, with corresponding significantly longer linear measurements. Masseter muscles and the surface of first-order omasal leaves were significantly more prominent in hay-fed animals, reflecting possible adaptations to overcome resistance of grass forage and to reabsorb fluid from increased rumination, but differences were not as distinct as reported between 'cattle-type' and 'moose-type' ruminants. Some measurements such as reticular crests and empty foregut mass remained stable between groups, indicating possibly genetically pre-defined characteristics less prone to change in adult life. The results emphasize the adaptability of ruminant digestive tract anatomy in adult animals even after a short period of time, but also suggest limits to this adaptability that reveals a species-specific anatomy regardless of the diet actually consumed.

Anatomical study of the gastrointestinal tract in free-living axis deer (Axis axis).

The macroscopic anatomy of the stomach and intestines of adult axis deer (Axis axis), a cervid species considered intermediate/mixed feeder, was observed and recorded. Nine adult wild axis deers of both sexes were used and studied by simple dissection. The ruminal papillae were distributed unevenly in the overall area of the inner surface of rumen and primarily were more large and abundant within the atrium. The ruminal pillars had no papillae. There was an additional ruminal pillar located between the right longitudinal and right coronary ventral pillars connected to the caudal pillar. No dorsal coronary pillars were found, and the ventral coronary pillars are connected. The reticulum was the third compartment in size, and the maximum height of the reticular crests was 1.0 mm. The Cellulae reticuli were not divided and rarely contained secondary crests. There were no Papillae unguiculiformes. The omasum was the smallest gastric compartment. The abomasum had about twelve spiral plicae, and a small pyloric torus was present. The intraruminal papillation was similar to those species that are characterized by a higher proportion of grass in their natural diet. The finding of the small reticular crests is typical for browser ruminants and was coincident with data reported for other deer. The comparative ratio of the small intestine to the large intestine was 1.69, in terms of length measurements in axis deer and appears below of the 'browser range'. We concluded that the gastrointestinal system of axis deer reflected similar morphological characteristics of the both types of ruminants: browser and grazer, and we consider it as an intermediate feeder.

Histomorphometric characterization of forestomach of yak (Bos grunniens) in the Qinghai-Tibetan Plateau / Caracterización histomorfométrica del preestómago del yak (Bos grunniens) en la Meseta Qinghai-Tíbet

Six forestomachs of yaks (Bos grunniens) were studied with gross dissection and histological methods. It was found that the forestomach of yak consisted of the following three parts, rumen, reticulum and omasum, which were composed of the mucosa, submucosa, muscularis and serosa. In addition, the mucosal epithelium was covered with stratified squamous epithelium, with part of keratinized the shallow cells. Rumen, the mucosa of which formed ligulate papillae varying in size and shape, was no muscularis mucosa. Reticulum, consisted of a surface epithelium that invaginated to various extent into the lamina propria, formed various folds in shape, namely, grid-like small rooms. Furthermore, there are many secondary folds densely covered with keratinized papillae. The most striking feature of the omasum was to be formed the laminae omasi varying in length, with short and rough papillae distributing on both sides. Taken together, there was no glands within the mucosa and lamina propria of forestomach of yak, where diffuse lymphoid tissues can be observed clearly. It is, therefore, believed that the yak forestomach may have evolved those specific structural characteristics in response to the unique living environment and dietary habits impose on the Qinghai-Tibetan Plateau.

Seis preestómagos de yaks (Bos grunniens) fueron estudiados mediante disección macroscópica y métodos histológicos. Se encontró que el preestómago del yak constaba de tres partes: rumen, retículo y omaso, compuestas de mucosa, submucosa, muscular y serosa. Además, el epitelio de la mucosa se conformó con epitelio escamoso estratificado, con parte de células cornificadas superficiales. En el rumen, la mucosa formó papilas linguladas que variaron en tamaño y forma. El retículo, consistió en una superficie epitelial que se invaginó en distinta medida en la lámina propia, conformando varias formas de pliegues, es decir, cuadrículas como pequeños cubículos. Además, existían muchos pliegues secundarios densamente cubiertos con papilas cornificadas. La característica más llamativa del omaso, fue formar láminas que variaron en longitud, con papilas cortas y ásperas distribuidas en ambos lados. Tomados en conjunto, no hubo glándulas dentro de la mucosa y la lámina propia del preestómago del yak, donde los tejidos linfoides difusos se pueden observar claramente. Por lo tanto, creemos que esas características estructurales específicas del preestómago del yak pudieron haber evolucionado en respuesta a las condiciones de vida únicas y hábitos dietéticos que se presentan en la meseta de Qinghai-Tíbet.

[Reduction of plant fibers in the digestive tract of the moose and the red deer].

A comparative study of the reduction of plant fibers moving in the digestive tract of nine red deer (Cervus elaphus) and six moose (Alces alces) was made. In the winter season, the character of fiber reduction in the moose and the red deer was similar. In the deer obtained in the early autumn, the relative concentration of small-sized fractions was significantly higher. A sharp decrease in the share oflarge-sized fibers was observed in the omasum as compared to the rumen and the reticulum. It was especially pronounced in the deer obtained in September. Deceleration of fibers of large-sized fractions in the rumen and the reticulum and the structure of the reticulo-omasal opening and its functions were considered.

Reticular groove of the domestic ruminants: histochemical and immunocytochemical study.

The reticular groove mucosa of adult cattle, buffalo and sheep was investigated by histochemical and immunocytochemical techniques. Intense NADPH-d staining was observed in the folds of the epithelium mucosa and at the bottom of the reticular groove in all domestic ruminants studied. The NADPH-d staining showed that the innervations of the tunica muscularis of the reticular groove lip were composed of nerve corpuscles, nerve fibres and nerve cells of the mucosa epithelium. SEM analysis showed an intense nitric oxide synthase (NOS) I immunoreactivity in deep and medium cellular layers. It is interesting to note that the same morphologies were observed in samples of the mucosa epithelium, and of the tunica muscularis processed by NADPH-d and in those processed by immunogold techniques. This study has demonstrated that nitric oxide (NO) is involved in the rumination activity and that it plays a double role in this activity in the reticular groove of all domestic ruminants studied: (1) NO plays a role similar to the one it has in the mucosa epithelium of all the other compartments of the ruminant forestomach, (2) The lip sections of the reticular groove has shown abundant innervations that may indirectly coordinate and control the forestomach motility through the direct activation of the nitrergic (nitroxidergic) nerve cells and nerve fibres.

Ontogenesis of the reticulum with special reference to neuroendocrine and glial cells: a comparative analysis of the Merino sheep and Iberian red deer.

The present study was designed to compare the differences in the ontogenesis of the reticulum in sheep (domestic ruminant) and deer (wild ruminant). A total of 50 embryos and foetuses Merino sheep and 50 Iberian deer were used, from the first pre-natal life until birth. The appearance of the reticulum from the primitive gastric tube was earlier in the sheep (22% gestation, 33 days) than in the deer (25% gestation, 66 days). In both cases, it displayed a primitive epithelium of a stratified, cylindrical, non-ciliary type. At around 48% gestation in the sheep (72 days) and 36% (97 days) in the deer, the reticulum was configured of four clearly differentiated layers: mucosa (with epithelial layer and lamina propria), submucosa, tunica muscularis and serosa. The stratification of the epithelial layer was accompanied by modifications in its structure with the appearance of the primitive reticular ribs. The primary ribs began to be formed first in the deer, at 117 days of pre-natal life (40% gestation) and later in the sheep (79 days, 53% gestation). The differentiation of the corneum papillae in the primary ribs coincided with the appearance of secondary reticular ribs. These structures began to be formed first in the deer, at 142 days of pre-natal life (51% gestation) and later in the sheep (83 days, 55% gestation). The presence of neuroendocrine cells (non-neuronal enolase-positive cells) in the reticular mucosa was not detected until 97 days (36% gestation) in deer and 81 days (54% gestation) in sheep. The presence of glial cells (GFAP-positive cells) occurred at around 142 days (51% gestation) in deer and at 112 days (75% gestation) in sheep. In conclusion, the presence of neuroendocrine and glial cells was detected in deer at earlier stages than sheep.

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.

Immunohistochemical evaluation of the muscularis mucosae in the ruminant forestomach.

The muscularis mucosae and condensed fibrous layer of the ruminant forestomach were studied by immunohistochemistry using specific antibodies against alpha-smooth muscle actin (alphaSMA) and gamma-smooth muscle actin (gammaSMA). The specimens were collected from the rumen, reticulum and omasum of cattle, water buffalo, sheep, goat, Barbary sheep, Japanese serow, sika deer and mouse deer. The muscularis mucosae showed immunoreactivity for both alphaSMA and gammaSMA. On the other hand, the condensed fibrous layer appearing between the propria mucosa and tela submucosa was immunoreactive only for alphaSMA except for that in the goat and Barbary sheep reticulum which is intermingled with gammaSMA immunoreactivity. The distribution of muscularis mucosae and/or condensed fibrous layer varied among the compartments of forestomach and ruminant species. In the rumen, only the condensed fibrous layer was detected. On the other hand, the omasum contained only the muscularis mucosae. In the reticulum, both were detected. The amount of the condensed fibrous layer in the reticulum varied among different species in the following order of abundance: goat > Barbary sheep > sika deer> sheep > water buffalo > cattle and Japanese serow. Smooth muscle cells of external muscle layer were immunoreactive for alphaSMA and gammaSMA whereas those of blood vessels and pericytes were immunoreactive only for alphaSMA. The present findings on the actin immunoreactivity and distribution profile of muscularis mucosae and the condensed fibrous layer provide additional knowledge to further understand the histophysiological specialization of the different compartments of the ruminant forestomach.

Effect of short-term underfeeding on weight of splanchnic organs in ewes.

We assessed the effect of short-term underfeeding on weight and protein mass of splanchnic tissues in adult ewes submitted to a factorial experimental design. In a pre-experimental period, 18 ewes divided into 2 groups of 9 were fed a second cut of natural grassland hay during 4 weeks at 112 or 38% of their energy maintenance requirements. Three ewes of each group were then fed the same hay during 4 weeks at either low (group L), moderate (group M) or high intake (group H), corresponding to 38, 75 or 112% of their energy maintenance requirements, respectively, then slaughtered. Fresh weight and protein mass of splanchnic organs were measured. No carry-over effect of the pre-experimental level of intake on weight and protein mass was observed for any splanchnic organs. Splanchnic tissues contributed at 10.7 and 8.6% to the decrease in live weight for groups M and L, respectively. The decrease in weight of splanchnic tissues (-15%) was mainly attributed to reticulorumen (-23%), liver (-21%), and at a lesser extent small intestine (-11%). No large change in the mass ratio between mucosa and muscular-serosa in both dorsal and ventral sacs occurred in the rumen wall. These results are discussed together with previous published results on long-term underfed ewes, and suggest that the decrease in energy expenditure in whole animal induced by underfeeding is mainly related to the decrease in splanchnic weight at short-term, and to the decrease in other tissues at long-term, splanchnic weight being stabilized.

The stomach of the sambar deer (Cervus unicolor unicolor).

In New Zealand, the sambar deer is reported to feed on a variety of grasses and browse material. In the specimens studied, the average volume of the sambar rumen was about 151. Thick, non-papillated pillars divided the rumen into a saccus dorsalis and a saccus ventralis. The lining of the rumen was covered with papillae; those in the roof area were short and poorly developed. The omasum was a well-developed organ with 47-71 (mean 57) laminae. These were covered with short and poorly developed papillae. It is concluded that these sambar deer stomachs were typical of a grass-roughage feeder. This contrasts with the previous classification of the sambar deer as an intermediate feeder.

Ultrasonography of the reticulum in cows.

The reticulum and adjacent organs were examined ultrasonographically in 51 cows by use of a 3.5-MHz linear transducer applied to the ventral aspect of the thorax over the sixth and seventh intercostal spaces. Examination included assessment of the contour of the reticulum, of reticular contractions, and of the organs adjacent to the reticulum. The normal reticulum appeared as a half-moon-shaped structure with a smooth contour; it contracted at regular intervals and was situated immediately adjacent to the diaphragm and ventral portion of the abdominal wall when relaxed. Contents of the reticulum could not normally be imaged because of its partly gaseous composition. The ruminoreticular groove, craniodorsal blind sac of the rumen, and the ventral sac of the rumen were observed caudally. The distal aspect of the spleen and parts of the omasum, abomasum, and liver could be imaged. Reticular motility was characterized by a biphasic contraction pattern. Four biphasic reticular contractions usually were observed during a 4-minute period. During the first (incomplete) contraction, the reticulum contracted by a mean of 7.2 +/- 2.30 cm. There was then low-grade, incomplete relaxation of the reticulum, followed immediately by the second reticular contraction, during which the reticulum usually disappeared from the 17.5-cm-deep screen. The reticulum then reappeared in its normal position. The first reticular contraction lasted a mean of 2.6 +/- 0.33 seconds and the second contraction lasted 3.9 +/- 0.55 seconds. The mean interval between 2 biphasic contractions was 44.9 +/- 10.53 seconds. The speed of the first reticular contraction was 5.4 +/- 1.32 cm/s.(ABSTRACT TRUNCATED AT 250 WORDS)

Forage and splanchnic tissue mass in growing lambs: effects of dietary forage levels and source on splanchnic tissue mass in growing lambs.

Forty-two crossbred lambs (33.4 kg initial body weight; twenty-four wethers and eighteen ewes) were used in a 42 d experiment with a 2 x 3 factorial treatment arrangement to determine effects of forage level and source on splanchnic tissue mass. Diets were 250 and 750 g/kg of chopped lucerne (Medicago sativa) (A), ryegrass (Lolium multiflorum)-wheat (Triticum aestivum) (RW) or bermudagrass (Cynodon dactylon) (B) hay, with the remainder being maize-based concentrate. Five lambs per treatment were slaughtered at the end of the experiment and measurements made of internal organs and contents of the gastrointestinal tract (GIT). Digestible organic matter intake (DOMI) on the 7 d preceding slaughter was 0.89, 0.83, 0.90, 0.83, 0.77 and 0.61 (SE 0.05) kg/d, and live-weight gain was 0.20, 0.17, 0.18, 0.10, 0.10 and 0.07 (SE 0.02) kg/d for diets A-25, RW-25, B-25, A-75, RW-75 and B-75 respectively. Total GIT mass (fresh) was higher (P < 0.05) for 750 than 250 g forage/kg and for B than RW (4.80, 4.57, 5.55, 5.84, 5.99 and 6.91 kg for diets A-25, RW-25, B-25, A-75, RW-75 and B-75 respectively). Non-fat organic matter was 259, 295, 292, 303, 277 and 264 g for the total GIT; 93, 102, 103, 106, 95 and 97 g for the reticulo-rumen (forage level x type (diet A v. diets RW and B) interaction; P < 0.05); and 204, 196, 202, 177, 156 and 127 g for the liver (SE 10) with diets A-25, RW-25, B-25, A-75, RW-75 and B-75 respectively. In summary, differences in properties of forage A and the grasses at 250 g/kg diet may have influenced GIT mass independent of energy intake and digesta mass. Conversely, with 750 g dietary forage/kg, higher digesta mass for diet B than diet RW appeared responsible for high reticulo-rumen mass relative to DOMI. Greater digesta mass for 750 than 250 g forage/kg may have elevated intestinal tissue mass/DOMI with diets A and B but not with diet RW, for which NDF digestibility was highest.

Histomorphometric analysis of the reticulum of the sheep during development.

Histomorphometric and scanning electron microscopic analysis were performed on 74 embryos and foetuses and on 20 sheep (early post-natal to adult age). Histodifferentiation of the reticulum took place at 33 days of foetal life. Reticular ribs were observed as evaginations of the epithelial stratum germinativum at 64 days. Neutral mucopolysaccharides first appeared in epithelial cells at 46 foetal days, thereafter to decrease gradually in number, subsequently stabilising in postnatal life. Acid mucopolysaccharides, mucins and mucoid compounds were not detected. Growth curves and formulae were constructed for each tissue layer. Initial test involved multiplicative (y = axb), linear (y = a+bx) and polynomial model (y = a+b+cx2+dx3).

The stomach of the Kafue lechwe (Kobus leche kafuensis).

The Kafue lechwe is endemic to the Kafue Flats area of Zambia. It is semi-aquatic in habit, feeding upon grasses above and below the waterline. The volume of the lechwe rumen is 17 L in the male and 14 L in the female. It has strong and definite pillars. The interior of the rumen is papillated except in the roof area and on the pillars. The omasum has more than 70 laminae which are papillated on the reticular end. The anatomy of the lechwe stomach is similar to the stomachs of other water dependent grazers such as Bohor Reedbuck, Waterbuck, Uganda Kob and Puku.

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.

Observations on the alimentary tract of gnotobiotic lambs.

Seventeen gnotobiotic lambs were reared up to 21 weeks of age on cows' milk followed by sterile solid diets similar to diets fed to conventional lambs. Seven were inoculated with limited defined populations of rumen bacteria, seven were left uninoculated and three were dosed with rumen contents from conventional sheep ('conventionalised'). Seven naturally-born lambs were reared for purposes of comparison. As with other species of gnotobiotic animals, both the inoculated and the uninoculated gnotobiotic lambs had small, poorly developed lymph nodes, soft colon contents and thin intestinal walls. Unlike other species the caeca of gnotobiotic lambs were of normal size. The overall size of the reticulo-rumen including contents relative to body weight was similar in gnotobiotic and conventional lambs. However, macroscopically, the musculature of the rumen seemed to be poorly developed and histological studies showed hypoplasia of the muscle tissue of both the rumen and reticulum. Rumination was noted only infrequently in gnotobiotic lambs. The epithelium of the rumen and reticulum of the uninoculated gnotobiotic lambs was similar to that of neonatal lambs, but there was normal development of papillae in gnotobiotic lambs inoculated with limited defined populations of rumen bacteria and in conventionalised lambs. Degenerative changes were observed histologically in some of the organs of gnotobiotic lambs which were consistent with nutritional deficiencies.