Scanning electron microscopic study of vascular and biliary casts in chicken and duck liver.

Avian liver is structurally different from that of mammal. There are only a few reports about the ultrastructure of the hepatic vessels and bile duct in birds. Casts of the hepatic vessels and bile ducts in chicken and duck were examined by a scanning electron microscope (SEM) to provide further detail. The sinusoidal vessels formed regular three-dimensional networks but the replicated bile ducts formed irregular ones. There was a dense plexiform network around each tubular cavity in biliary casts. This biliary plexus formed around a small branch of the portal vein. It was the transition between the bile capillaries and ductules. The present study shows that the liver of chicken and duck had the characteristic structure at the peripheral part of biliary system, i.e., biliary plexus.

Impact of transglutaminase on the textural, physicochemical, and structural properties of chicken skeletal, smooth, and cardiac muscles.

This study examined the effects of microbial transglutaminase (MTG; 3.1mg/ml) on chicken skeletal, smooth, and cardiac muscles; the meat containing the different muscle types was shaped into sausages and treated at 40°C and/or 78°C for 30min. Although the three muscle types were obtained from the same bird, the effects of MTG addition were not uniform. All the muscle types showed a significant increase in the breaking strength (P<0.01), but skeletal muscle exhibited the maximum increase. All samples showed a decrease in the fluorescence intensity and a significant reduction in the concentration of proteins that were extracted in a high ionic strength solution (P<0.05). Scanning electron microscopy images and histological studies revealed that different muscle types had different physical structures and frameworks after MTG treatment, which is a reflection of the differences in the reaction specificity of MTG with different muscle proteins. Histological studies revealed that the reactions of MTG with meat proteins are both exogenous and endogenous. Cooking loss data suggested that MTG did not have any negative effect on water retention during cooking. MTG appears to be a functional and contributive substance since the results suggest that MTG can function on all muscle types that are mechanically processed for different industrial applications. MTG aggregates muscle proteins in different ways that improve their organoleptic properties such as texture, appearance, and water retention.

Effect of microbial transglutaminase on the natural actomyosin cross-linking in chicken and beef.

The objective of this research was to investigate the difference between chicken and beef in the interaction of actomyosin (myosin B) with microbial transglutaminase (MTG). The gel strength of myosin B was improved in both species and was significantly greater in beef than in chicken (P<0.01). The degree of protein viscosity and the ε(γ-glutamyl)lysine (G-L) content were significantly higher in beef than in chicken (P<0.01). Myosin heavy chain (MHC) bands visualized by SDS-PAGE revealed that the same proteins in various meat species vary in their size and structure. Scanning electron microscope images (SEMI) revealed that myosin B in both species was polymerized, and formed multi-projection structures of G-L; surprisingly, more of these structures were found in beef than in chicken. It is possible that the proteins in chicken are folded into a strand shape that tightly encases a considerable number of glutamine and lysine residues, whereas MTG substrate cannot couple glutamine and lysine. This suggests that the reactivity of MTG is dependent on the residual amino acids present on the surface of myosin B in meat. Some protein components (peptides with long reiterated methylene groups attached) joined by disulfide bonds (cysteine) in chicken samples were inhibitory and reduced MTG activity. SEMI also suggested that all MTG-dependent mega-structures of protein molecules generated in chicken and beef may vary greatly in size, configuration and complexity after treatment with MTG. We concluded that the optimal cross-links in myosin B induced by MTG are heterogeneous in chicken and beef.

Secondary lymphoid areas in calf ileal Peyer's patch.

The secondary lymphoid tissues appear in sheep ileum after involution of ileal Peyer's patch (PP). However, the existence of the secondary lymphoid tissues before involution of ileal PP has not yet been studied. We examined morphological characteristics of the full length of calf ileal PP using gross and microscopic anatomical techniques. Most areas of ileal PP consisted of densely packed lymphatic follicles contained very few follicular T-cell and associated with only scant interfollicular areas. However, the proximal end of ileal PP consisted of widely dispersed lymphatic follicles contained many follicular T-cell and associated with large interfollicular areas. The histological architectures of the proximal end of ileal PP strongly resembled those of the secondary lymphoid tissue in calf.

Effect of glucagon-like peptide-1 and -2 on regulation of food intake, body temperature and locomotor activity in the Japanese quail.

To investigate the physiological roles of glucagon-like peptide-1 (GLP-1) and glucagon-like peptide-2 (GLP-2) in avian species, we elucidated the effect of intraperitoneal (i.p.) and intracerebroventricular (i.c.v.) administration of GLP-1 and GLP-2 on food intake, body temperature and gross locomotor activity in adult Japanese quail. Both i.p. and i.c.v. administration of GLP-1 suppressed food intake at 2, 4 and 12h after administration. Moreover, both i.p. and i.c.v. administration of GLP-1 significantly decreased both body temperature and gross locomotor activity 2h after administration. On the other hand, both i.p. and i.c.v. administration of GLP-2 had no effect on food intake, body temperature or gross locomotor activity. These results suggest that GLP-1 may have an important role in the regulation of food intake, body temperature and locomotor activity while GLP-2 may have no apparent effect on feeding regulation in adult Japanese quail.

Guanylyl cyclase C and guanylin reduce fat droplet accumulation in cattle mesenteric adipose tissue.

Guanylyl cyclase C (GC-C) is a member of a family of enzymes that metabolize GTP to cGMP and was first identified as a receptor for heat-stable enterotoxin. Guanylin (GNY) has since been identified as an endogenous ligand for GC-C in the intestine of several mammalian species. The GNY/GC-C system regulates ion transportation and pH in the mucosa. Recently, it was reported that GC-C and GNY are involved in lipid metabolism in rat mesenteric adipose tissue macrophages. To examine the role of GC-C and GNY in lipid metabolism in cattle, we used a bovine mesenteric adipocyte primary culture system and a coculture system for bovine adipocytes and GNY-/GC-C-expressing macrophages. Fat droplets were observed to accumulate in bovine mesenteric adipocytes cultured alone, whereas few fat droplets accumulated in adipocytes indirectly cocultured with macrophages. We also observed that GC-C was present in bovine mesenteric adipose tissue, and that fat droplet accumulation decreased after in vitro GNY administration. Expressions of mRNAs encoding lipogenic factors decreased significantly in adipocytes after either coculture or GNY administration. These results suggest that the GNY/GC-C system is part of the control system for lipid accumulation in bovine mesenteric adipose tissue.

Histological studies on the ontogeny of bovine palatine and pharyngeal tonsil: germinal center formation, IgG, and IgA mRNA expression.

The development and distribution of lymphocyte subsets in calf palatine and pharyngeal tonsil were examined. During prenatal development, B cells were distributed in the subepithelial area, and T cells and MHC class II(+) cells were found in the deep layer of B-cell area, respectively, in both tonsils. At neonatal stage, lymphoid follicle containing a few CD4(+) cells have been formed in both tonsils. IgG(+) and IgA(+) cells were found in the parafollicular and epithelial area. At 3 months old, many germinal centers were recognized in both tonsils. CD4(+) cells and IgG mRNA expression were detected in light zone of germinal centers. Many IgG, and IgA mRNA expressions also could be detected in the parafollicular and subepithelial area of both tonsils. The data suggest that both tonsils have an important role of local immune defense against invading antigen after birth. The comparison of the histological characteristics of tonsil and Peyer's patch during ontogeny is also discussed.

Kinetics and distribution of bovine gammadelta T-lymphocyte in the intestine: gammadelta T cells accumulate in the dome region of Peyer's patch during prenatal development.

The kinetics and distribution of gammadelta T cells in bovine intestine including jejunal and ileal Peyer's patch were examined. The number of gammadelta T cells increased significantly in the dome region during prenatal development, but decreased notably after birth. The number of some gammadelta T cells, CD4+ cells, and CD8+ cells in the intestinal villi remained constant during prenatal development, but increased significantly after birth. The kinetics of the gammadelta T cells in the dome region during prenatal development were quite distinct from those of the gammadelta T cells, CD4+ cells, and CD8+ cells in the intestinal villi. In the fetal ileum at full-term gestation, the frequencies of expression of the T-cell receptor gamma variable region (TCR Vgamma) family were TCR Vgamma1 (48%), Vgamma2 (4%), and Vgamma5 (48%). However, in 2-month-old calf ileum, TCR Vgamma5 (90%) was dominant. We speculate that functional differences exist between gammadelta T cells in the dome region during prenatal development and in the intestinal villi after birth.

Scanning electron microscopic study on the microarchitecture of the vascular system in the pigeon lung.

The resin casts of the respiratory and vascular systems in pigeon lung were examined using a scanning electron microscope. The primary bronchi branched to form many secondary bronchi that anastomosed with each other via the parabronchi. Numerous infundibula protruded from the parabronchi via the atria and ramified into the air capillaries. The pulmonary artery entered into the lung and branched into three vessels that coursed the interparabronchial parts. The intraparabronchial arterioles penetrated the gas-exchange tissue to form the anastomosing networks of blood capillaries. The observation of the double casts of the respiratory and vascular systems revealed three-dimensional complicated networks of air capillaries and blood capillaries.

Detection and quantification of bovine signal joint T-cell receptor excision circles.

A signal joint (sj) T-cell receptor excision circle (TREC) is produced by T-cell receptor (TCR) gene rearrangements during αß T-cell maturation in the thymus. sjTREC have been studied as a marker of thymic function in several spices. We designed specific primers for δrec-ψJα sj region to identify the location of the bovine sjTREC region and determined the nucleotide sequence of the PCR product. The obtained sequences were subjected to a BLAST search, which identified a matching region. This matching region contained TCR δ genes and was identified on bovine chromosome 10. We also confirmed the polymorphism of the sj region by sequencing of 10 PCR products, and observed irregular insertion of bases in the δrec-ψJα recombination signal sequence. We then developed a quantitative PCR (QPCR) assay for evaluation of sjTRECs level in order to evaluate bovine thymic function for application in the veterinary clinic. This QPCR assay specifically amplified the sj region of bovine sjTREC and could detected 10(1)-10(7) copy numbers of sjTRECs. Using this assay we found that the number of sjTRECs in peripheral blood mononuclear cells was less than 10% that of the thymus.

Histological studies on the ontogeny of bovine gut-associated lymphoid tissue: appearance of T cells and development of IgG+ and IgA+ cells in lymphoid follicles.

The development and distribution of lymphocyte subsets in bovine gut-associated lymphoid tissues (ileal and jejunal Peyer's patches (PP)) were examined. Before birth, the composition of lymphocyte subsets in both PP follicles did not differ except for the dimensions of the interfollicular area and the dome region. Many IgM+ cells were observed in these follicles, but very few CD3+, IgG+, and IgA+ cells could be found. At neonatal period, the IgG+ cells, which did not produce IgG mRNA, were dominant within both PP follicles. From 1 month after birth, many CD3+ cells, IgG mRNA expression, and IgA mRNA expression were detected within the jejunal PP follicles, but very few were in the ileal PP follicles. These data suggest that the characteristics of the jejunal PP follicles metamorphose into secondary lymphoid tissue such as germinal centers at around 1 month after birth, whereas the characteristics of ileal PP follicles were distinct from those of germinal centers.

Scanning electron microscopic study of third-instar warbles in yak in China.

Scanning electron microscopic observations were performed to compare the structures of third-instar of three species of warbles (Hypoderma bovis, H. lineatum and H. sinense) that infest yak in China. The heads of the warbles consisted of mouths and opercular sutures with spinal bands between them. We could not detect any morphological differences in the shape of the warble's heads among these three species. The spiracular plate of H. bovis was strongly concaved and had numerous spines at the spiracular opening rims. The H. lineatum had flat spiracular plates and no spines on the spiracular plates. In the case of H. sinense the spiracular plate was as flat as that of H. lineatum but had small sized and fewer spines on the spiracular plates. At the ventral side on the tenth segment of the warble body of H. bovis the spinal band was absent. Although H. lineatum had only one band at the posterior border on the tenth ventral segment, H. sinense had two bands of spines at the anterior and posterior border on the tenth segment.

Standardized data and relationship between bone growth and bone metabolism in female Göttingen minipigs.

Minipigs have been studied as a model of osteoporosis. However, little information is available regarding their bone physiology. We established standardized bone data and investigated the relationship between bone growth and bone metabolism in female minipigs. Blood and urine samples were obtained from 53 female Göttingen minipigs, 3-76 months of age, for measurement of bone biomarkers (i.e., BAP, OC, NTX, and DPD). The lumbar vertebra and femur were excised to determine the growth plate condition, bone length, bone mineral content (BMC), and bone mineral density (BMD). High levels of bone biomarkers were observed during the initial period after birth, decreasing thereafter with age. Bone biomarkers were confirmed to be highly correlated with age (R(2) > 0.7). The growth plates of the lumbar vertebra and the femur began to close at 21 and 25 months of age, respectively, and closed completely at 42 months of age. Bone length increased rapidly before growth plate closure, and reached a peak at 21 and 28 months of age in the lumbar vertebra and the femur, respectively. The levels of BMC and BMD increased rapidly before growth plate closure, and continued to increase slowly until 76 months of age. A high negative correlation (-0.855 < r < -0.711, p<0.001) was confirmed between the bone biomarkers and the bone measurement data. These results indicate that the bone turnover velocity is consistent with the bone growth velocity in female Göttingen minipigs.

Migration of warble fly larvae in the yak and optimum timing of ivermectin treatment.

Sixty yaks were autopsied to determine the migration pattern of warble fly larvae. In August, first instars were observed in the body of yak for the first time. These larvae peaked in number in October. From November to February, second instars were detected and their number peaked in January. Third instars appeared in January and peaked in March. Forty-five yaks were administered with ivermectin: 15 animals in September, 15 in October and 15 in November. Between December and June, the number of warbles was checked by palpation. Although some warbles were observed in the September- and November-treated groups, no warbles were detected in the October-treated group. Treatment of yaks with ivermectin was most effective for warble fly in October.

Clindamycin in the treatment of Babesia gibsoni infections in dogs.

This report examines the effectiveness of clindamycin for the treatment of babesiosis in dogs (n=10) experimentally infected with Babesia gibsoni (B. gibsoni). Clindamycin (25 mg/kg body weight, per os, q 12 hours for 14 days) gradually reduced parasitemia levels and induced morphological changes that indicated degeneration of parasites (e.g., segmentation; size reduction; localization in the cell limbic and/or torn state of the nucleus; and swelling, decrease, or disappearance of the cytoplasm) in the majority of dogs. Clindamycin treatment reduced the clinical symptoms characteristic of Babesia infection, including anemia, anorexia, and listlessness. Clindamycin might be useful as a medicine for treatment of B. gibsoni infection.

Development of the ductus venosus in the SD rat.

We used scanning electron microscopy to observe the development of the ductus venosus in the fetal rat liver. At day 13 of gestation, the vascular system in the liver was already formed and the umbilical vein had branched many capillaries to the parenchyma of the liver and was connected to the posterior vena cava directly by one small ductus venosus. At day 14 of gestation, the umbilical vein bulged at its terminal part and bifurcated into the ductus venosus, which joined the posterior vena cava, and a branch that anastomosed with the vitelline vein. The ductus venosus had no branches and subsequently enlarged and then degenerated just before birth. The bulging part of the umbilical vein and its branches degenerated in the later stages of gestation. The vitelline vein developed to form the capillaries of the liver and the intestinal venous system. In the SD rat liver, the ductus venosus was therefore established by development of the terminal part of the umbilical vein, which anastomosed directly with the posterior vena cava.

Neuropeptide distribution in the stellate ganglia of the domestic animal.

We used immunohistochemical techniques to analyze the localization and distribution of the catecholamine-synthesizing enzyme tyrosine hydroxylase (TH) and the neuropeptides methionine-endephalin (M-Enk), neuropeptide Y (NPY), vasoactive intestinal polypeptide (VIP), calretinin (Cal), calcitonin gene-related peptide (CGRP), substance P (SP), and galanin (Gal) in the stellate ganglia of two species of domestic animal (cattle and horses). NPY, VIP and Gal immunoreactive neurons (both cell body and nerve fiber) were observed in the stellate ganglia of both animals. M-Enk and CGRP immunoreactive nerve fibers were detected in the stellate ganglia of both animals, but positive cell bodies were found only in the stellate ganglia of the horse. In contrast, Cal- and SP-positive cell bodies existed in the stellate ganglia of cattle but not in the horse. SP-immunoreactive cells were observed only in young cattle. In both cattle and horses, almost all ganglion cell bodies exhibited TH immunoreactivity, but no positive nerve fibers were found.

An epidemiological study of Hypoderma infection and control using ivermectin in yaks in Qinghai Province, China.

The prevalence of Hypoderma spp. in yaks grazed in the east of Qinghai province was investigated in 2008. In this area, the prevalence in young yaks (1- to 3-year-old) was very high at 82.2-98.7%, whilst in adult yaks (4-year-old and older), the prevalence was 42.4-50.6%. The seasonal development and migration pattern of Hypoderma larvae in yak bodies was found to be similar for different locations in this area. The numbers of first, second and third instar larvae detected in yak bodies peaked in October, December and March, respectively. Different doses of ivermectin (125 to 500 µg/kg body weight) almost completely dewormed the larvae from yaks, suggesting that using a quarter of the prescribed dose (500 µg/kg body weight) was effective. In October of each year between 2009 and 2012, ivermectin (125 µg/kg body weight) was administered to a total of 562,995 yaks grazed in four counties in Qinghai province, and the pevalence of Hypoderma larval infection in yaks was reduced to 0.5-1.0%.

Epidemiological study and control trial of taeniid cestode infection in farm dogs in Qinghai Province, China.

An epidemiological study and control trial were conducted to assess taeniid infection in farm dogs in Qinghai Province, China. To improve egg detection by fecal examination, a deworming step with praziquantel was incorporated into the sampling methodology. As a result, a marked increase in the number of egg-positive samples was observed in samples collected at 24 hr after deworming. Then, the fecal examination and barcoding of egg DNA were performed to assess the prevalence of taeniid species in dogs from Xinghai, Haiyan, Gangcha and Chengduo counties. Analysis of 277 dog feces revealed that taeniid cestodes, including Taenia spp. and Echinococcus granulosus, were highly prevalent in Xinghai (34.4%), but eggs were not found in Haiyan where a control trial on canine echinococcosis had been conducted 20 years previously. A control trial involving the administration of 5-10 mg/kg praziquantel to 90 farm dogs at 45-day intervals was conducted in Xinghai. The prevalence of taeniid cestodes in the dogs was reduced to 9.6% and 4.9% after one and two years, respectively, indicating that some dogs were not administered praziquantel properly. A questionnaire survey of farmers in Xinghai and Haiyan revealed that most farmers in Xinghai were not familiar with echinococcosis or the transmission route of the disease, while most farmers in Haiyan had a more thorough understanding of the disease. The findings implied that a program for educating local farmers would be important for efficiently controlling canine taeniid infection in the region.

A mechanism for selective lymphocyte homing in bovine hemal nodes.

The distribution and abundance of MECA-79(+) cells in bovine hemal nodes (HNs) was analyzed. In addition, T cell subsets which expressed the homing receptor l-selectin were analyzed by flow cytometry. The frequency of MECA-79(+) HNs varied depending on the location. There were 61, 33, and 17% MECA-79(+) HN in the subcutaneous region, along the abdominal aorta and in the mesenteric region, respectively. MECA-79(+) cells in mesenteric lymph nodes were mainly distributed in the paracortex. Many MECA-79(+) cells were distributed in the perifollicular area of HNs and a few positive cells were also located in the paracortical and interfollicular areas. CD4(+) and CD8(+)l-selectin(+) cells were significantly higher in MECA-79(+) HNs compared to MECA-79(-) HNs. The data suggest that a selective lymphocyte homing mechanism exists in bovine HNs, which could be related to functional differences between locations.