Seasonal and Ageing-Depending Changes of Aquaporins 1 and 9 Expression in the Genital Tract of Buffalo Bulls (Bubalus bubalis).

The presence of Aquaporins 1 (AQP1) and 9 (AQP9), integral membrane water channels that facilitate rapid passive movement of water and solutes, was immunohistochemically detected in the excurrent ducts collected from sexually mature buffalo bulls of proven fertility during the mating (late autumn-winter) and non-mating (late spring to the beginning of autumn) seasons. Furthermore, the research was performed also on the epididymal cauda of a senile buffalo bull with inactive testis. Aquaporins 1 and 9 were immunolocalized at distinct levels. In the efferent ducts, AQP1 immunoreactivity was strongly evidenced at the apical surface of the non-ciliated cells and weakly along the basal membrane of the epithelial cells. The latter reactivity disappeared during the non-mating season. No AQP1 immunoreactivity was detected in the epithelium of epididymis and vas deferens, whereas AQP1 was expressed in the smooth muscle layer of the vas deferens. Aquaporin 1 was present in the blood vessels and in small nerve bundles all along the genital tract. The supranuclear zone of the epididymal principal cells was AQP9 immunoreactive, limited to the corpus and cauda regions, and vas deferens. The samples collected in the two reproductive seasons showed a weaker AQP9 immunoreactivity during the non-mating season. A typical AQP9 immunoreactivity was noticed in the old buffalo examined. The tested AQP molecules showed a different expression pattern in comparison with laboratory mammals, primates, equine, dog and cat. In addition, seasonal differences were noticed which are possibly useful in regard to the comprehension of the morphophysiology of reproduction in the bubaline species, which are still a matter of debate.

Morphology and Aquaporin Immunohistochemistry of the Uterine Tube of Saanen Goats (Capra hircus): Comparison Throughout the Reproductive Cycle.

The expression of six different aquaporins (AQP1, 2, 3, 4, 5 and 9), integral membrane water channels that facilitate bi-directional passive movement of water, was investigated by immunohistochemistry in the uterine tube of pre-pubertal and adult Saanen goats (Capra hircus), comparing the different phases of the oestrous cycle. Regional morphology and secretory processes were markedly different during the goat oestrous cycle. The tested AQP molecules showed different expression patterns in comparison with already studied species. AQP1-immunoreactivity was evidenced at the endothelium of blood vessels and in nerve fibres, regardless of the tubal tract and cycle period. AQP4-immunoreactivity was shown on the lateral plasmalemma in the basal third of the epithelial cells at infundibulum and ampulla level in the cycling goats, more evidently during follicular than during luteal phase. No AQP4-immunoreactivity was noticed at the level of the isthmus region, regardless of the cycle phase. AQP5-immunoreactivity, localized at the apical surface of epithelial cells, increased from pre-puberty to adulthood. Thereafter, AQP5-immunoreactivity was prominent during the follicular phase, when it strongly decorated the apical plasmalemma of all epithelial cells at ampullary level. During luteal phase, immunoreactivity was discontinuous, being weak to strong at the apex of the secretory cells protruding into the lumen. In the isthmus region, the strongest AQP5-immunoreactivity was seen during follicular phase, with a clear localization in the apical plasmalemma of all the epithelial cells and also on the lateral plasmalemma. AQP2, 3 and 9 were undetectable all along the goat uterine tube. Likely, a collaboration of different AQP molecules sustains the fluid production in the goat uterine tube. AQP1-mediated transudation from the blood capillaries, together with permeation of the epithelium by AQP4 in the basal rim of the epithelial cells and final intervening of apical AQP5, could be involved in fluid production as well as in secretory processes.

Are the basal cells of the mammalian epididymis still an enigma?

Basal cells are present in the columnar pseudostratified epithelium covering the epididymis of all mammalian species, which regulates the microenvironment where the functionally incompetent germ cells produced by the testis are matured and stored. Striking novelties have come from investigations on epididymal basal cells in the past 30-40 years. In addition to an earlier hypothesised scavenger role for basal cells, linked to their proven extratubular origin and the expression of macrophage antigens, basal cells have been shown to be involved in cell-cell cross-talk, as well as functioning as luminal sensors to regulate the activity of principal and clear cells. Involvement of basal cells in the regulation of electrolyte and water transport by principal cells was hypothesised. This control is suggested to be mediated by the local formation of prostaglandins. Members of the aquaporin (AQP) and/or aquaglyceroporin family (AQP3, AQP7 and AQP8) are also specifically expressed in the rat epididymal basal cells. Transport of glycerol and glycerylphosphorylcholine from the epithelium of the epididymis to the lumen in relation to sperm maturation may be mediated by AQP. Most probably basal cells collaborate to the building up of the blood-epididymis barrier through cell adhesion molecules, implying an involvement in immune control exerted towards sperm cells, which are foreigners in the environment in which they were produced.

Immunolocalization of aquaporin water channels in the domestic cat male genital tract.

Four different aquaporins (AQP1, 2, 5 and 9), integral membrane water channels that facilitate rapid passive movement of water, were immuno-localized in the excurrent ducts collected from sexually mature cats during orchiectomy. Aquaporins 1, 2 and 9, were immuno-localized at distinct levels, whereas AQP5 was undetectable all along the feline genital tract. No immunoreactivity was present at the level of the rete testis with any of the antibodies tested. In the efferent ducts, AQP1-immunoreactivity was strongly evidenced at the apical surface of the non-ciliated cells, and AQP9-immunoreactivity was shown at the periphery of both ciliated and non-ciliated cells. Aquaporins 2 was absent in the caput epididymidis, either in the efferent ducts or in the epididymal duct. Otherwise, AQP2 was increasingly localized at the adluminal surface of principal cells from the corpus to the cauda epididymidis and more weakly in the vas deferens epithelium. The supranuclear zone of the epididymal principal cells was AQP9-immunoreactive throughout the duct, with the exclusion of the vacuolated sub-region of the caput and with higher reaction intensity in the cauda region. AQP1 was present in the blood vessels all along the genital tract. AQP1 was expressed also in the smooth muscle layer of the vas deferens. The tested AQP molecules showed a different expression pattern in comparison with laboratory mammals, primates and the dog, unique other carnivore species studied to date. The present information is possibly useful in regard to the regional morphology of the feline epididymis and correlated functions, which are still a matter of debate.

An insight into testis and gubernaculum dynamics of INSL3-RXFP2 signalling during testicular descent in the dog.

Insulin-like 3 (INSL3) plays a prominent role in male development and is supposed to induce the growth of the gubernaculum testis (g.t.), thus being directly involved in testicular descent in humans and rodents. This happens through activation of the RXFP2 receptor (GREAT or LGR8). The INSL3-RXFP2 complex is reputed to play an additional paracrine role in the testis, possibly acting as part of an autocrine feedback loop. The present work provides evidence of the immunolocalisation of INSL3 in the Leydig cells of canine fetuses and of the expression of RXFP2 receptor in different tissues of the g.t. of the same specimens. RXFP2 was localised at the cell membrane of g.t. muscle and connective cells, as well as in the epithelial cells of the developing excurrent ducts. Notably, RXFP2 immunoreactivity of the g.t. was limited to fetuses at ~35-45 days of gestation, which is also the fetal period when the endocrine compartment of the dog testis is active endocrinologically, as confirmed by the anti-P450c17 and anti-INSL3 immunoreactivities of the fetal Leydig cells, and by anti-Müllerian hormone immunoreactivity of the Sertoli cells. The same immunoreactivities were also evaluated in the testes of cryptorchid dogs of different ages. RXFP2 immunoreactivity was absent from genital tracts of cryptorchid testes and g.t. remnants.

Time course of in vitro maturation of compact cumulus horse oocytes after roscovitine-induced meiotic inhibition: effects on the coordination between nuclear and cytoplasmic maturation.

This study was carried out to evaluate the usefulness of a pre-maturation step in improving the coordination between cytoplasmic and nuclear maturation of horse compact cumulus oocytes by the addition of roscovitine (ROSC). Oocytes were collected by scraping and pre-cultured for 18 h in a maturation medium TCM199 supplemented with pyruvate, LH, FSH, insulin growth factor (IGF), epidermal growth factor (EGF), insulin, transferrin and selenium (IVM-ROSC) or in a simple medium (M199-ROSC). After pre-maturation, oocytes from both the groups were in part denuded and fixed-stained and in part in vitro matured to assess the kinetic of in vitro maturation (IVM). The nuclear progression and the cytoskeletal organization of microfilaments and cortical granules (CG) of treated and untreated oocytes were assessed by fluorescent probes. Oocytes immediately fixed after recovery and oocytes pre-cultured in M199-ROSC for 18 h did not show metaphase II (MII) plates, whereas in IVM-ROSC group, 6/69 oocytes (8.7%) showed MII plates. After inhibition, during maturation kinetics at 11, 18 and 29 h, maturation rate of M199-ROSC group progressively increased and at 29 h of IVM, reached the maturation rate of control group (13/66, 19.7% vs 31/125, 24.8%). No statistically significant differences in cytoplasmic maturation were found. The number of MII plates after 29 h of IVM, was significantly higher (p < 0.05) in IVM-ROSC group (34/90) compared with M199-ROSC (13/66) and control groups (31/125) as well as the number of oocytes with microfilaments and CG distributed in cortical region (25/34 vs 3/13 and 7/31 respectively). Our results showed that pre-culturing in the presence of Roscovitine in a fully supplemented maturation medium containing gonadotropins and growth factors partially suppressed the meiotic maturation, but established a more suitable environment for improving cytoplasmic maturation of horse compact cumulus oocytes as defined by microfilaments and CG configuration.

Immunohistochemical study of the pre- and postnatal innervation of the dog lower urinary tract: morphological aspects at the basis of the consolidation of the micturition reflex.

Immunohistochemical studies were performed on male and female bladder and urethra collected from 4 adults dogs and 10 foetal specimens with crown-rump length from 53 to 155 mm (medium-sized breeds, presumptive 38 days of gestation to term). A panel of antisera was tested, including PGP 9.5 to describe the general intramural innervation, ChAT and TH to depict the cholinergic and nor-adrenergic components and NOS1, CGRP, SP, NPY, VIP, SOM, GAL, 5-HT to investigate the possible nitrergic, peptidergic and aminergic ones. A rich cholinergic innervation was present in adult bladder and urethra, along with a lesser number of adrenergic nerves and a small number of nitrergic ones. Either bladder or urethra received numerous CGRP-, SP-, NPY-, VIP-containing nerve fibres which were distributed throughout the muscle layers. All over the lower urinary tract strong to weak ChAT-, CGRP-, SP- and NPY-immunoreactivity was detected in intramural ganglia, in peripheral nerve bundles and around blood vessels. 5-HT-immunoreactive endocrine cells were present in the urethral epithelium. Early foetal organs were supplied only by cholinergic nerve fibres. Few NOS-, CGRP- and SP-ergic components appeared at the end of pregnancy. It can be guessed that sensory mediators such as CGRP and SP increase in postnatal ages while other neuropeptides, such as NPY and VIP, appear only after birth, as the urinary reflex consolidates.

Response of the gut neuroendocrine system of Leuciscus cephalus (L.) to the presence of Pomphorhynchus laevis Müller, 1776 (Acanthocephala).

Immunohistochemical tests were applied to sections of intestine of uninfected and Pomphorhynchus laevis Muller-infected chub, Leuciscus cephalus (L.) using 15 different antisera. Nerve cell bodies and fibres immunoreactive (IR) to the anti-bombesin, -Cholecystokinin-8 (CCK-8), -galanin, -Gastrin-Releasing Peptide (-GRP), -Nitric Oxide Synthase (-NOS), -Substance P (-SP), and -Vasoactive Intestinal Peptide (-VIP) sera were observed in the myenteric plexus of uninfected chub. The density of nerve components immunoreactive to these antisera was high in the intestine of the infected fish, especially near the site of attachment. Moreover, numerous nerve fibres, immunoreactive to anti-bombesin, -GRP, -galanin, -SP, and -VIP sera, were encountered in the connective tissue capsule surrounding the bulb and proboscis of P. laevis. The occurrence of P. laevis in the chub gut significantly increased the number of endocrine cells per intestinal fold immunoreactive to galanin, met-enkephalin and leu-enkephalin antisera. CCK-8, Neuropeptide Y and glucagon-like immunoreactive cells were less numerous in the intestine of infected chub. A large number of cells in the tunica propria-submucosa of L. cephalus infected with P. laevis were immunoreactive to anti-serotonin and -leu-enkephalin sera.

Histochemistry of glycoconjugates in mucous cells of Salmo trutta uninfected and naturally parasitized with intestinal helminths.

Mucus secreted onto the surface of the intestine forms a physical barrier to invading parasites so that a possible attachment of helminths to the surface is prevented and their expulsion by peristalsis facilitated. In mammals, intestinal parasites induce hyperplasia and hypertrophy of intestine goblet cells and provoke changes in the mucus composition. In fish, this topic has received less attention. In the present investigation, histochemical methods were employed to compose intestinal mucous cell numbers and their glycoconjugate composition were compared by uninfected brown trout Salmo trutta and in S. trutta parasitized with Cyathocephalus truncatus or Pomphorhynchus laevis. When P. laevis was present in the intestine of the brown trout, the total mucous cell number, and the number of mucous cells containing acid or mixed glycoconjugates were significantly enhanced. No significant change in the total mucous cell number was detected in the intestine of fish parasitized with C. truncatus in comparison with uninfected brown trout. A significant increase was observed in the number of both acid (especially sulphated) and mixed glycoconjugates containing mucous cells as well as a significant decrease in the number of neutral glycoconjugates containing mucous cells. When intestinal helminths were present, the thickness of the adherent mucous gel increased. In a limited number of other fish species, the occurrence of gill and intestinal parasites has been reported to increase the mucosal glycoconjugate secretions. Our study is the first quantitative report on the effects of intestinal helminths on the density of mucous cells and mucus composition in a fish species.

The urothelium: anatomy, review of the literature, perspectives for veterinary medicine.

Over time, much knowledge has been accumulated about the active role of the urothelium, principally in rodents and human. Far from being a mere passive barrier, this specialized epithelium can alter the ion and protein composition of the urine, is able to sense and respond to mechanical stimuli such as pressure, and react to mechanical stimuli by epithelial cell communication with the nervous system. Most of the specialized functions of the urothelium are linked to a number of morpho-physiologic properties exhibited by the superficial umbrella cells, including specialized membrane lipids, asymmetric unit membrane particles and a plasmalemma with stiff plaques which function as a barrier to most substances found in urine, thus protecting the underlying tissues. Moreover, the entire mucosa lining the low urinary tract, composed of urothelium and sub-urothelium, forms a functional transduction unit, able to respond to eso- and endogenous physical and chemical stimuli in a manner assuring an adequate functional response. This review will summarize the available information on each area of inquiry from a morpho-functional point of view. Possible considerations pertaining to species of veterinary interest are reviewed as well. The review was prepared consulting the electronic databases PubMed and Cab Abstracts and retrieving all pertinent reports and the relative reference lists, in order to identify any potential additional studies that could be included. Full-length research articles and thematic reviews were considered. Information on the urothelium of some domestic animal species was also included.

Periovulatory time in the bitch: what's new to know?: Comparison between ovarian histology and clinical features.

The ability to recognize specific events happening in the ovaries during periovulatory time allows optimal management of canine reproduction. The objective of this study was to assess the efficacy of vaginal cytology and blood progesterone (P4) assay to identify accurately the changes occurring at the ovarian structures, mainly during the fertile period. Tertiary follicles, corpora hemorrhagica (CHs) and corpora lutea (CLs) from forty healthy bitches undergoing ovariohysterectomy were evaluated by histo-morphometry based on their aspect, number and size. The tertiary follicles distribution (small, medium and large) was statistically different (P<0.002) among all the stages of the reproductive cycle, except for small follicles (<2mm), which were always observed from proestrus to anestrus. Very large follicles (>4mm) were predominant (P=0.008) around ovulation when P4 mean level was 6.1±1.7ng/mL. The early postovulatory estrous period was characterized by CHs (P<0.002) and P4 level of 16.7±5.9ng/mL. The end of the fertile period - start of diestrus - coincided with the development of CLs (P=0.001) associated with a P4 mean level of 73.9±9.9ng/mL. The small (P<0.001) and medium (P<0.05) follicle diameters were positively correlated with the bitch size. The number of follicles larger than 4mm was significantly lower in bitches younger than 4 years (P<0.02). This study provides insight into some critical steps in the canine reproductive processes in the periovulatory phase and the end of the fertile period, essential to plan breeding programs.

"In vitro" and in animal model studies on a double virus-inactivated factor VIII concentrate.

To improve the safety of plasma derived factor VIII (FVIII) concentrate, we introduced a final super heat treatment (100 degrees C for 30 min) as additional virus inactivation step applied to a lyophilized, highly purified FVIII concentrate (100 IU/mg of proteins) already virus inactivated using the solvent/detergent (S/D) method during the manufacturing process. The efficiency of the super heat treatment was demonstrated in inactivating two non-lipid enveloped viruses (Hepatitis A virus and Poliovirus 1). The loss of FVIII procoagulant activity during the super heat treatment was of about 15%, estimated both by clotting and chromogenic assays. No substantial changes were observed in physical, biochemical and immunological characteristics of the heat treated FVIII concentrate in comparison with those of the FVIII before heat treatment.

Transferrin treatment corrects aging-related immunologic and hormonal decay in old mice.

Experiments were conducted to study the effect of heterologous plasma transferrins separated and purified from human plasma pools on endocrine and immune functions of old, aging mice. Two similar experiments have shown that parenteral treatment with iron and zinc-free human transferrins produces a significant improvement of immunological and endocrine functions in the aging mice toward more juvenile values. Those changes occur in the thymus and its cell subsets, in peripheral blood lymphocytes, in the restoration of juvenile levels of thyroxine, in the increase of testis weight, and in the normalization of plasma zinc levels. These totally unsuspected effects of transferrin in aging mice suggest a most important role of endogenous transferrins in the maintenance of neuroendocrine and immune functions. The mechanism remains unexplained although the basic immunoenhancing and anti-apoptotic effect of transferrin-vehiculated zinc may be relevant.

Donor-derived plasma transferrin facilitates the engraftment of xenogeneic (rat) bone marrow in irradiated mice.

Endogenous factors originally found in the bone marrow (BM) and facilitating the engraftment of xenogeneic (rat) BM in lethally irradiated mice have been recently identified as transferrins (Tf). Tf have been separated and purified from plasma pools of inbred Rii/2 rats and injected in lethally irradiated BALB/c and C57BL/6 mice 1 h before the infusion of BM and for several days after BM transplantation. Other groups of irradiated mice have been similarly treated with human Tf, Tf from other strains of rats different from the BM donors and with human or rat serum albumin. A remarkable facilitation of BM engraftment and a durable graft-versus-host disease (GVHD)-free hemopoietic chimerism have been achieved in the irradiated mice when a combination of BM and Tf from the same donor rat (Rii/2) strain was used for transplantation. Durable survival and persistent chimerism were not observed in the control groups. It seems that donor Tf profoundly affects the outcome of BM transplantation when combined with donor BM. These results indicate that the mechanism by which Tf promotes engraftment of xenogeneic BM deserves investigation in order to improve this novel procedure and to extend it to other species and possibly to man.

Localization of regulatory peptides in the male urogenital apparatus of domestic equidae: a comparative immunohistochemical study in Equus caballus and Equus asinus.

An immunohistochemical study was carried out on specimens of testis, excurrent duct including the male accessory glands and urethra in its various tracts in the horse and the donkey, in order to localize nine regulatory peptides. Immunoreactivities were tested by means of Labelled Strept Avidin-Biotin (LSAB) method. The study has shown that Equine male genitalia are supplied by many peptide immunoreactive nerves containing NPY-, VIP-, leu- and met-Enkephalin-, Substance P-, CGRP- and Bombesin/GRP-like peptides, each of them having a characteristic distribution pattern. These neurotransmitters were localized in nerve fibers running in the connective tissue or in contact with the smooth muscle cells, as well as in sub- and intraepithelial nerve terminals, and in perivascular nerve fibers. In addition, leu- and met-Enkephalin-like-immunoreactive endocrine cells were shown in the bulbourethral gland of the horse. In both species it was evident that an extensive utilization of NPY and VIP exists. A contingent of NPY- and VIP-ir nerve fibers may have an intrinsic origin. The other regulatory peptides tested show a characteristic distribution pattern, limited to some organs and peculiar to each of the two species of Equidae. Differences observed comparing E. caballus and E. asinus might be related to the species-specific balance of the accessory neurotransmitters which in turn accompany adrenergic innervation. In both species it is noteworthy the complete absence of any regulatory peptide in the testis, with the exception of the perivascular localization of NPY-ir nerve fibers.

Immunolocalization of regulatory peptides and 5-HT in bovine male urogenital apparatus.

Specimens of testis, excurrent duct including the accessory genital glands and urethra throughout its extension were investigated in adult bovines, in order to immunohistochemically localize both the peptidergic innervation and the epithelial cell types belonging to the diffuse endocrine system (DES). Immunoreactivities to GRP, met- and leu-enkephalins, CGRP, NPY, substance P, VIP, somatostatin, beta-endorphin and 5-HT antisera were tested by means of a labelled streptavidin-biotin (LSAB) method. Such regulatory substances were found in components of the peripheral nervous system (nerve fibers in the connective and muscular tissues, sub- and intrapithelial nerve terminals, nerve cells bodies and fibers in intramural ganglia), and in epithelial endocrine/paracrine cells. Bovine urogenital apparatus is supplied by many peptide-containing nerves, which contain in many localizations GRP and enkephalins, and to a lesser extent substance P, CGRP, NPY and VIP. A thin network of peptidergic nerves distributes to the musculature of the canalicular organs and accessory glands. The prostatic complex was especially rich in peptidergic innervation, and also contained somatostatin- and 5-HT-secreting endocrine cells. In addition, 5-HT-immunoreactive endocrine cells were found in the bulbourethral gland and urethral epithelium. CGRP-ir nerves were present contacting striated muscle fibers of urethra (motor end plates). The testis was devoid of any immunoreactivity. These data are compared with those obtained in a companion study carried out the same organs in two species of Equidae (Equus caballus and Equus asinus). Different patterns of immunoreactivities can be outlined in these domestic ungulates.

Morphological examination of epididymal epithelium in the mule (E. hinnus) in comparison with parental species (E. asinus and E. caballus).

Following previous studies about the ultrastructure of male genital tract in parental species, a comparative study of epididymis of one of the possible hybrids, the mule, has been undertaken. Apart from small differences, general features of epididymal epithelium in the mule are similar to those of parental species. However, extension of our studies from the donkey to the horse to the hybrid permits a deeper insight into the morphology of this tract of excurrent duct. In the meantime, it is possible to evidence some features, sometimes shared with other species if taken separately, which in the whole characterize the epididymis in Equidae: the presence in principal cells of intranuclear inclusions and peculiar small granules in the basal cytoplasmic edge; the organization of groups of cells, likely to be principal ones, in such a way as to constitute intraepithelial crypts; a cumbersome presence of lipofuscinic matter all along the epithelium. Another interesting observation in the presence in the mule epididymis of well recognizable macrophages. All these data are discussed in comparison with parental species and with other species described in literature. Beyond any other consideration, it can be outlined that the complex morphology of the epithelium lining ductus epididymis in the mule is unaffected by the absence of spermatozoa, which are normally the target of the manifold functions of the epithelium itself.

Cholinergic, nitrergic and peptidergic (Substance P- and CGRP-utilizing) innervation of the horse intestine. A histochemical and immunohistochemical study.

The small and large intestine of adult horses were histochemically and immunohistochemically investigated in order to evidence components of the intramural nervous system. The general structural organization of the intramural nervous system was examined by using Nissl-thionin staining as well as the anti-neurofilament 200 (NF200) immunoreaction, which demonstrated the presence of neurons in the submucous as well as myenteric plexuses. The additional presence of subserosal ganglia was shown in the large intestine. Acetylcholinesterase (AChEase) activity was observed in both the submucous and myenteric plexuses. Localization of acetylcholine-utilizing neurons was also evidenced by immunohistochemical reactions for choline acetyltransferase (ChAT) and vesicular acetylcholine transporter (VAChT). With both histochemistry and immunohistochemistry possible cholinergic nerve fibres were detected in the inner musculature. The two possible cholinergic co-mediators Calcitonin Gene-Related Peptide (CGRP) and Substance P (SP) have been investigated by an immunohistochemical approach. CGRP immunoreactivity was detected in roundish nerve cell bodies as well as in nerve fibres of the submucous plexus, whereas SP immunoreactivity was evidenced in nerve fibres of the tunica mucosa, in nerve cell bodies and fibres of the submucous plexus and in nerve fibres of the myenteric plexus. NADPH-diaphorase reactivity, which is linked to the synthesis and release of nitric oxide, was detected in nerve cell bodies and nerve fibres of both the submucous and myenteric plexuses as well as in a subserosal localization of the large intestine. The nitrergic components were confirmed by the anti-NOS (nitric oxide synthase) immunoreaction. Results are compared with those of other mammals and related to the complex intestinal horse physiology and pathophysiology.

The influence of different fibrous supplements in the diet on ruminal histology and histometry in veal calves.

The aim of this study was to determine whether the administration of four different solid feeds would influence selected morphological and morpho-functional aspects of the rumen mucosa in veal calves. The fibrous supplementation of the liquid diet of veal calves has been provided by recent EU formulation (EC Council Directive 91/629/1991; EC Council Directive 97/2/1997). Twenty-five Holstein calves were assigned to either exclusively liquid diet (milk replacer, control), or pelleted feed, corn silage, extruded feed, dried corn silage. The morpho-functional effects of the fibre-containing diets were examined evaluating histological and histometrical characteristics of ruminal mucosa after the slaughter of calves. There were slight to severe histological abnormalities in the rumens of all animals examined. The severe histological abnormalities were present in calves given pelleted feed, corn silage, and extruded feed. Dried corn silage caused less ruminal damage. We found that the length and epithelial thickness of ruminal papillae were higher in control veal calves than in dietary fibre-supplemented animals. The results of the present study, even if partially, support the EU prescription in the use of fibre diets in veal calves as integration of the traditional milk replacer diet.

Ultrastructural features of the gut in the white sturgeon, Acipenser transmontanus.

Electron-microscopic examinations of the sturgeon gut were performed. Oesophageal goblet cells were abundant in the stratified epithelium. The ultrastructural features of the secretory granules of the oesophageal and intestinal goblet cells were quite similar to those of other vertebrates. Lobules of multilocular adipose tissue were observed in the deep tunica propriasubmucosa of the oesophagus, in close association with vasculature and large fibre bundles of myelinated and unmyelinated axons. Similarly composed nerve fibre bundles were observed in the cardiac stomach, too. The presence of myelinated axons is an unusual feature in the vertebrate enteric nervous system. Cardiac and fundic zones of the stomach showed an epithelium with columnar ciliated and non-ciliated cells, the latter equipped with fuzzy microvilli. Cells lining the tubular gastric proper glands were markedly granulated. Intestinal superficial epithelium was columnar and contained ciliated, as well as non-ciliated and goblet cells. In the tunica propria all over the intestine, the presence and ultrastructure of granulated cells was in addition described. Intraepithelial granulated leukocytes were seen throughout the alimentary canal. Various types of endocrine cells were seen both in the stomach and in the intestine, the size of their granules was measured and their ultrastructure described and compared to that of mammalian cell types.