Journal of Veterinary Medical Science最新文献

Beta-nicotinamide mononucleotide (beta-NMN) is a direct precursor of nicotinamide adenine dinucleotide (NAD⁺), a coenzyme essential for maintaining homeostasis in living organisms. NMN administration has attracted attention as a potential treatment for aging and age-related conditions, including diabetes, Alzheimer's disease, and chronic kidney disease. Duchenne muscular dystrophy (DMD) is a progressive, degenerative muscle disease caused by X-linked frameshift mutations in the Dmd gene. NAD⁺ levels in skeletal muscle decline in DMD pathology. In this study, we explored the therapeutic potential of NMN as an NAD⁺ booster for muscular dystrophy by administering NMN to DMD rats, which exhibit severe phenotypes comparable to those of human DMD patients, for 2 months. Although NMN administration did not improve muscle function in DMD rats, it did reduce the release of creatine kinase in their blood. RNA-seq analysis revealed that NMN administration could reverse DMD-related gene expression changes associated with skeletal muscle homeostasis. These results suggest that NMN can protect skeletal muscle against degeneration in DMD and may hold therapeutic potential for DMD patients.

Neonicotinoid pesticides (NNs) are widely used for their selective toxicity to insects via an agonistic action on nicotinic acetylcholine receptors. However, growing evidence suggests that NNs may have adverse health effects in mammals. In parallel, recent studies have shown that trace environmental chemicals such as antibiotics, endocrine disruptors, and pesticide residues can alter the gut microbiota, a key regulator of host health. Thus, NNs may also disrupt gut microbial homeostasis and impact host physiology. In this study, we investigated the effect of the neonicotinoid pesticide clothianidin (CLO) on the rat gut microbiota. Male rats were orally administered CLO at 0, 30, and 300 mg/kg/day (designated as the CLO-0, 30, and 300 groups) for 28 days; doses were selected based on the no-observed-adverse-effect level (NOAEL; 27.9 mg/kg/day). Cecal contents were collected after euthanasia and subjected to 16S rRNA sequencing. Our results showed that even at approximately the NOAEL dose, CLO exposure altered gut microbiota composition and tended to reduce microbial diversity, especially in the CLO-300 group. Notably, several CLO-affected taxa are known producers of short-chain fatty acids, and changes were particularly prominent in two individuals from the high-dose group. Moreover, CLO exposure resulted in distinct alterations in butyrate-producing bacteria, with increases observed in the CLO-30 group and decreases in the CLO-300 group. These results suggest that CLO has various effects on the gut microbiota and that even exposure at the NOAEL may affect host health.

This study aimed to determine the effect of the timing of human chorionic gonadotropin (hCG) administration to embryo transfer (ET) recipients on the reproductive outcome of ET in crossbred beef heifers. Heifers (n=1,887) were randomly assigned to the non-treatment group (n=1,160), and hCG was administered on day 5 (n=201), 6 (n=210), 7 (n=213), or 8 (n=103) after estrus. The χ² test showed that the conception rates in the hCG administration on day 5 (79.6%, P=0.0001) and day 6 (75.2%, P=0.0047) were higher than those in the non-treatment group (65.2%). However, the conception rates with hCG administration on day 7 (70.9%, P=0.1103) and day 8 (70.9%, P=0.2499) were comparable to the non-treatment. A multiple logistic regression analysis, furthermore, showed that early treatment (hCG on day 5 or 6 after estrus) positively affected the conception rates compared to non-treatment (odds ratios (OR)=1.723 [95% confidence intervals (CI)=1.316-2.257]), but not late treatment (hCG on day 7 or 8 after estrus) (OR=1.299 [95% CI=0.981-1.719]). None of the confounding variables, including years, season at the time of ET, age in months, and number of ET, significantly affected the conception rate. In conclusion, hCG administration on day 5 or 6 after estrus for ET recipients improved the conception rate, but not on day 7 or 8, in beef heifers.

We evaluated two human diagnostic agarose gel electrophoresis (AGE) kits (J711 and J718) for bovine serum protein fractionation using 79 bovine samples, comparing the results with a biochemistry analyzer (BA). While six protein fractions were commonly observed, β₂- and γ-globulin (Glb) fusion (β₂γ-Glb) occurred in some inflammatory and neonatal cases. The results using both AGE kits correlated with those of the BA for total albumin and Glb, with J711 showing superior agreement. However, inter-kit variability was observed for individual protein fractions, particularly α₁-, α₂-, and β₁-Glb, which showed proportional or constant errors and moderate-to-poor reliability, despite good agreement for β₂γ-Glb. These findings necessitate caution in interpreting fraction-specific results and underscore the importance of stating the AGE kit in veterinary diagnostics.

Melissococcus plutonius, the bacterium causing European foulbrood in honey bees, includes two distinct types: typical strains, which are fastidious and not easy to culture, and atypical strains, which grow more robustly and tolerate higher sodium levels. Several culture media have been used to isolate this pathogen, and growth dynamics and survival vary according to strain type and medium. The most commonly used media differs across countries, as does the ratio of typical to atypical strains isolated, implying that the choice of medium influences the type of M. plutonius that is more likely to be recovered. This study examined how two commonly used media, Basal and KSBHI, affect the isolation of typical and atypical strains from larval samples co-infected with both types. Both media supported the growth of both strains, and no isolation preference was observed, although KSBHI tended to yield more non-M. plutonius bacteria. Applying a drying treatment to larval smears reduced these secondary invaders but it shifted the isolation balance toward atypical strains. Drying resistance tests revealed that atypical strains survived longer under dry conditions than typical strains, which likely explains their increased recovery after drying. These results indicate that while both media can isolate either strain type, using both media in parallel is better for ensuring isolation of both types. Additionally, although drying reduces secondary invaders, it may bias the results toward atypical strains. These insights contribute to a more accurate diagnosis and epidemiological understanding of European foulbrood.

The oxygen reserve index (ORi) is a non-invasive parameter recently introduced in human medicine that detects impending hypoxemia earlier than peripheral oxygen saturation (SpO₂). This study evaluated the utility of ORi as an early warning indicator of hypoxemia in anesthetized dogs. Six beagle dogs were subjected to planned apnea under two oxygen conditions (FiO₂ 1.0 and 0.4). Changes in ORi, SpO₂, and arterial oxygen partial pressure (PaO₂) were monitored. Warning times (WT) were calculated as the time difference between each timepoint and SpO₂ reaching 90%. We defined Added warning times (AWT) as the time between an ORi warning point and the moment SpO₂ fell to 96%. When ORi decreased to half of its baseline value or reached 0.4, it provided early warnings of 43.2 ± 24.6 sec and 44.7 ± 37.0 sec, under FiO₂ 1.0, and 29.5 ± 21.9 sec and 37.0 ± 22.5 sec under FiO₂ 0.4, before SpO₂ began to decrease. A significant positive correlation was observed between ORi and PaO₂ when SpO₂ was ≥97% (r=0.74, P<0.0001). Receiver operating characteristic (ROC) analysis showed high diagnostic accuracy of ORi for predicting PaO₂ ≥150 mmHg (area under the curve [AUC]=0.92), with an optimal cutoff value of 0.48 (sensitivity 92%, specificity 78.8%). Unlike in humans, ORi continued to change at PaO₂ levels above 200 mmHg in dogs, suggesting species-specific differences. In conclusion, ORi can detect deterioration in oxygenation earlier than SpO₂ in anesthetized dogs and provides valuable non-invasive real-time monitoring of oxygen reserves during controlled apnea under anesthesia.

Amyloidosis is a disease caused by amyloid deposition and has been reported in various animal species; however, reports on Afrotherian species, including Cape hyraxes, are extremely limited. In this report, we describe the case of a 4-year-old captive Cape hyrax affected by amyloidosis. Histological examination revealed amyloid deposits in the liver, spleen, kidneys, and heart, which stained orange-red with Congo red and exhibited typical birefringence under polarized light. Mass spectrometry-based proteomic analysis and immunohistochemistry identified serum amyloid A in the amyloid deposits. Based on these findings, the case was diagnosed as amyloid A amyloidosis. This is a first case of amyloid A amyloidosis in Cape hyrax and, to our knowledge, the first documented case in any Afrotherian species.

The objectives of this study were (1) to confirm the expression of diamine oxidase (DAO) in the intestines of healthy calves immune-histologically and to clarify whether the expression of DAO in the intestines of calves with diarrhea differs from that of healthy animals, and (2) to clarify the relationship between DAO and intestinal inflammation using haptoglobin (HPT), a biomarker commonly used to evaluate inflammation. The abomasum, duodenum, jejunum and ileum, cecum, colon, and rectum of each animal were sampled at necropsy for immunohistochemical staining targeting DAO. DAO was diffusely expressed in all areas from the abomasum to the rectum in healthy calves, whereas its expression was reduced in calves with diarrhea. Four Japanese black calves with mild dehydration caused by diarrhea were included in the study to investigate the potential relationship between DAO and HPT. DAO activity was extremely low in diarrhea cases, whereas HPT levels were high. When an oral rehydration solution (ORS) was administered to these cases for three consecutive days, HPT significantly decreased logarithmically and fecal properties returned to normal on the fourth day of treatment. In contrast, DAO activities were significantly increased by oral rehydration therapy (ORT), and DAO activities were significantly negatively correlated with HPT concentrations. The present results confirmed that DAO is expressed in the epithelial cells of the intestinal mucosa in cattle, and that both the small and large intestines significantly contribute to blood DAO levels. Furthermore, DAO expression was reduced by enteritis.

An 11-month-old female kitten was evaluated for lameness and an inability to close her mouth. The kitten had marked hypocalcemia with elevated intact parathyroid hormone and 1,25(OH)₂D₃ levels. Radiographic imaging indicated generalized osteopenia and dysplasia of temporomandibular joints. Since a nutritionally complete diet was being fed, dysfunction of vitamin D receptors (VDR) was suspected. Genetic tests revealed three variants (c.439A >G, c.509C >T, and c.529_530insGCA) in the VDR gene, and c.509C >T, replacing proline 170 with leucine (p.Pro170Leu), was predicted to be damaging by in silico analysis. VDR-deficient feline kidney epithelial cells were transfected with wild-type or p.Pro170Leu VDR expression vectors, revealing impaired responsiveness to 1,25(OH)₂D₃ in mutants. Based on these findings, the cat was diagnosed with vitamin D-dependent rickets type 2.

The wall of eyeball limits the penetration of the common fixatives, raising inadequate fixation or degeneration of internal tissue and posing challenges for preparing thin sections of the whole eyeball. In addition, many formaldehyde-containing fixatives exhibit the strong cross-linking effect that can excessively mask antigenic epitopes, thereby hampering immunological analyses. This study tried to develop an available fixative that exerts high permeability to mouse whole eyeballs and applicability to immunostaining. Glyoxal is known to have milder cross-linking capacity compared to formaldehyde, bringing better preservation of epitopes. We substituted the formaldehyde component in Davidson's solution with glyoxal and supplemented 1-butanol, methanol, 2-mercaptoethanol, and tris (2-carboxyethyl) phosphine hydrochloride (TCEP-HCl). Using modified fixatives and the GBMT solution, which was named by the initial letters of each component listed above, mouse eyeballs were immersion-fixed with the modified fixatives, and both tissue morphology and immunostaining quality were evaluated. The results showed that the GBMT solution prepared with glyoxal and specific combinations of additives improved morphological preservation of the eyeball tissues and enhanced immunofluorescence signals for certain cytoplasmic antigens, compared to the standard Davidson's solution. Our findings demonstrated that the successful development of a novel fixative enables both high-quality whole eyeball sectioning and improved immunostaining performance through immersion fixation alone.