Usefulness of computed tomography for cryptorchidism in bulls

Cryptorchidism is defined as the failure of the testis to descend into the scrotal position. Bulls with cryptorchidism have problems in both meat quality and husbandry management; thus, it is greatly important to accurately identify the retained testis and remove it during the early stage. Abdominal computed tomography (CT) was performed under general anesthesia in 34 bulls aged 3–9 months with cryptorchidism. All bulls underwent laparoscopic or incision approach for cryptorchidectomy, and 40 testes were dissected. The detection rates of retained testes were 64.5% in the abdominal cavity and 100% in the subcutaneous inguinal region, and the total detection rate was 72.5%. Furthermore, all cases in this study were suspected to have intra-abdominal cryptorchidism in primary care, but CT revealed that 22.5% of cases had cryptorchidism in the subcutaneous inguinal region. The CT value (mean ± standard deviation) of the retained testes was 20.96 ± 7.54 Hounsfield Unit, and the CT value and size of the retained testes showed a positive weak correlation with bovine age. Therefore, there is the demerit that general anesthesia and a huge device are necessary; nevertheless, CT is suggested to be useful in identifying the location of retained testes and selecting an appropriate surgical approach in bulls with cryptorchidism. Moreover, CT findings suggested that the maturation of the retained testes might depend not on the descending process but on age.     

Improvement in recruitment of Japanese sardine with delays of the spring phytoplankton bloom in the Sea of Japan

To evaluate the impact of temporal variation of primary productivity on the recruitment of Japanese sardine (Sardinops melanostictus) in the Sea of Japan, the phenology of sea surface phytoplankton abundance was estimated from 8 day multiple satellite (SeaWiFS, MODIS‐Aqua, MERIS, and VIIRS) derived sea surface chlorophyll (SSChl) a concentrations from January 1998 to December 2015. Because relationships between SSChl a and in situ chlorophyll a concentrations were significantly different among periods based on the satellite combinations used, maximum and minimum SSChl a concentrations of 1 year were relativized as 1 and 0, respectively. Spatio‐temporal variation of relativized SSChl a concentrations was determined by using empirical orthogonal function (EOF) analysis. Scores in the first EOF mode denoted the basin‐scale variations of SSChl a concentrations in the Sea of Japan, and the major peak from the end of February to the end of May displayed the spring bloom. The logarithm of recruitment per spawner (LNRPS) for sardine was positively affected by delays in the start and end dates of the spring phytoplankton bloom. The delay of the date of the lowest sea surface temperature contributed to the delay of the end of the spring bloom during the period 1998–2015 and elevated the LNRPS during the period 1982–2015. Sardine spawns in the southern Sea of Japan from April to May, hence, delays of the spring bloom prolonged its overlap with sardine larval periods, and thus improved the recruitment of Japanese sardine in the Sea of Japan.     

Campylobacter spp. prevalence and fluoroquinolone resistance in chicken layer farms

Chicken is a major source of human campylobacteriosis. Chicken meat originates not only from broilers but also from spent layers; however, few reports have documented the prevalence and antimicrobial resistance of Campylobacter spp. in layers in Japan. Therefore, we investigated the prevalence and antimicrobial susceptibility of Campylobacter spp. in 47 layer farms in Japan. Fecal samples were collected from the youngest and oldest flocks on the farm, and Campylobacter spp. was isolated from 46/47 (97.9%) farms. Among the C. jejuni isolates, the resistance rates to ampicillin, tetracycline, and ciprofloxacin were 29.6%, 22.2%, and 19.8%, respectively. The ciprofloxacin resistance rate (7.3%) in C. jejuni isolated from old flocks was significantly (P<0.01) lower than that in young flocks (32.5%).     

Magnetic resonance imaging of alveolar echinococcosis experimentally induced in the rat lung

Pulmonary alveolar echinococcosis (AE) caused by the metacestode of Echinococcus multilocularis is a lethal zoonosis and is a lesion secondarily induced by hematogenous dissemination from hepatic AE lesions. In the present study, a hematogenous pulmonary AE model was experimentally induced in rats by the injection of echinococcal larval tissue homogenate to the tail vein, and then the pathological and diagnostic aspects of pulmonary AE were examined by magnetic resonance imaging (MRI). Histological primary, mature and degenerated AE lesions were observed 5, 18 and 50 weeks after injection, respectively. These lesions were discriminated as signal-void, hypointense and hyperintense regions in T1-weighted MRI (T1WI), respectively. The change in signal intensity in T1WI might reflect the content of proteinaceous fluid as a result of AE cyst degeneration. Western blot analysis of sera with antibodies of two epitopes (Em18 and Em16) of E. multilocularis provided evidence for AE infection in the early stage. T1WI in combination with Western blot analysis could possibility become definitive and early signs of hematogenous pulmonary AE infection.     

Efficiency of stagnant water larviculture using disinfected amictic eggs of the rotifer <Emphasis Type="Italic">Brachionus plicatilis</Emphasis> in Japanese flounder <Emphasis Type="Italic">Paralichthys olivaceus</Emphasis>

There is a need to develop low-cost methods for larviculture that emphasize disease prevention. We evaluated stagnant water larviculture in flounder Paralichthys olivaceus using rotifer amictic eggs treated with glutaraldehyde. Growth and survival of the larvae were similar to in larvae reared by standard running water larviculture with daily feeding of rotifers (control). In the experimental group, the n-3 highly unsaturated fatty acid content of rotifers in the rearing water was higher than in the enriched rotifers fed to the control group. We also observed a similar pattern for the fatty acid composition of flounder larvae. The viable bacterial counts associated with rotifers in stagnant water were lower than those associated with enriched rotifers, and there were fewer bacterial genera. However, the viable bacterial count was the same or higher in the experimental rearing water compared with that in the control group. The α-Proteobacteria and Cytophaga–Flavobacterium–Bacteroidetes group dominated the bacterial community structure after larval hatching. To our knowledge, this is the first time that stagnant water larviculture, using only disinfected amictic eggs, has been successfully demonstrated on a mass production scale. This method appears to offer benefits including improved nutrition, more favorable bacterial communities, and lower cost.     

Toxoplasma gondii antibody prevalence and isolation in free-ranging cats in Okinawa,Japan

Cats are an important host of Toxoplasma gondii from an epidemiological perspective because they are the only definitive hosts that excrete oocysts in their feces. In this study, 201 free-ranging cats in Okinawa were examined for T. gondii infection. Using the latex agglutination test, we detected antibodies against T. gondii in 26.9% (54/201) of the cats. Oocysts of T. gondii were not detected upon microscopic examination of the feces of 128 cats. T. gondii was isolated from the tissues of 9 out of 24 seropositive or pseudo-seropositive cats with a bioassay using laboratory mice. Genotyping for the GRA6 gene revealed that five and four of the isolates were type I and II, respectively.     

The distribution and early growth of juvenile Pacific bluefin tuna Thunnus orientalis around Sado Island in the eastern Sea of Japan

Fisheries Science - The distribution and early growth of juvenile Pacific bluefin tuna (PBF) Thunnus orientalis were studied based on trawl surveys conducted around Sado Island, eastern Sea of...     

Virulence characteristics of Yersinia pseudotuberculosis isolated from breeding monkeys in Japan

Between April 2001 and 2007, 18 Yersinia pseudotuberculosis outbreaks occurred in breeding monkeys at 12 zoological gardens in Japan, and 28 monkeys of 8 species died. A total of 18 Y. pseudotuberculosis strains from the dead monkeys, comprising one strain per outbreak, were examined for serotype and the presence of the virulence genes virF, inv, ypm (ypmA, ypmB and ypmC) and irp2. Of the 18 Y. pseudotuberculosis strains, 7 (38.9%) were serotype 4b, 7 (38.9%) were serotype 1b, and there was one each of serotypes 2b, 3, 6 and 7. All the 18 strains examined harbored virF and inv. Sixteen (88.9%) strains, including the strain of serotype 7, harbored ypmA. However, no strain harbored ypmB, ypmC and irp2.

This study demonstrated that among other pathogenic factors, almost all the Y. pseudotuberculosis isolated from the outbreaks had the ypm gene encoding the superantigenic toxin, YPM. As most of the monkeys who died in those outbreaks originated from South America and other regions, where the presence of the ypm gene have not been reported, YPM might be the cause, or at least the most important factor for, the high mortality of the breeding monkeys infected by Y. pseudotuberculosis in Japan. This is also the first report of a fatal case due to Y. pseudotuberculosis serotype 7 infection in the world.     

Phylogenetic study on a bacterial community in the floodwater of a Japanese paddy field estimated by sequencing 16S rDNA fragments after denaturing gradient gel electrophoresis

Phylogenetic positions of characteristic bands of 16S rDNA that were obtained from the floodwater of a Japanese paddy field by denaturing gradient gel electrophoresis (DGGE) analysis in a previous work (Biol Fertil Soils 36:306–312, 2002) were determined to identify dominant bacterial members in the floodwater. Sequences of DGGE bands were affiliated with the Cytophaga–Flavobacterium–Bacteroides group, β-Proteobacteria, and Actinobacteria and showed phylogenetically close relationships with species inhabiting other aquatic environments, although most of their closest relatives were uncultured bacterial clones.     

Absorption and urinary excretion of quercetin,rutin, and alphaG-rutin,a water soluble flavonoid,in rats

Quercetin, rutin, alphaG-rutin (a water soluble flavonoid), and a mixture of rutin and alphaG-rutin were administered to rats by a single gastric intubation, and their absorption and urinary excretion were examined. The plasma and 24 h urinary levels of aglycons (quercetin and tamarixetin/isorhamnetin) were measured by HPLC after deconjugation with beta-glucuronidase/sulfatase treatment. alphaG-rutin was absorbed more rapidly than quercetin or rutin, and the plasma concentrations of quercetin and tamarixetin/isorhamnetin reached the highest peak level 30 min after dosing. Quercetin, rutin, and the mixture of rutin and alphaG-rutin showed the first peak level 8 h, 8 h, and 30 min after dosing, respectively. The area under the concentration-time curve (AUC) for quercetin in rats administered alphaG-rutin was approximately 4.5- and 2-fold higher than those in rats administered quercetin and rutin, respectively, and was almost the same as that in rats administered a mixture of rutin and alphaG-rutin. The highest 24 h urinary excretion was observed in alphaG-rutin-administered rats. These results suggest that alphaG-rutin is absorbed more efficiently than either quercetin or rutin and that a high plasma concentration can be maintained by supplying rutin and alphaG-rutin in combination.