Correlation between villous height and the disaccharidase activity in the small intestine of piglets from nursing to growing

Early weaning induces villous atrophy in the small intestine. Reduction in villous height in the small intestine after weaning is associated with reductions in brush‐border enzyme activity. Body weight gain after weaning is, therefore, correlated with villous height. This evidence suggested that the maintenance of small intestinal structure and function after weaning is important for the growth of young pigs. On the other hand, the relationship between villous height and the activity of the digestive enzymes in the small intestine has not been studied with piglets from the suckling to the growing period. Five suckling piglets, four piglets in the proximal stage of weaning, four pigs in the distal stage of weaning and four growing pigs were used. The activities of lactase (LA), sucrase (SA) and maltase (MA) were determined. LA showed a positive correlation with villous height in weaning. SA and MA were positively correlated with villous height from suckling to growing. In a previous study, non‐infectious dyspeptic diarrhea was frequently observed in growing piglets on Japanese swine farms. The maintenance of villous height to retain disaccharidase activity may prevent dyspepsic diarrhea in this stage.     

Examining the Optimal Method to Extract Logging Residues from Small-Scale Forestry in the Nasunogahara Area,Tochigi Prefecture,Japan

This study examines the optimal method to extract logging residues from small, fragmented and scattered forests separately from the mechanized operational systems used on aggregated forestry operation sites. First, small-scale logging systems operated by a private logging contractor and an individual forest owner were investigated. Regression equations for estimating felling and processing cycle times were established as a function of stem and log volumes, respectively. Equations to estimate the forwarding and transporting cycle times were established as a function of the forwarding and transporting distances using the forwarding and transporting velocities, respectively. Then, equations to estimate productivities and costs were established with the cycle times, volumes and hourly operational expenses consisting of labour and machinery expenses. Finally, costs of the small-scale systems—mini-forwarder and 4 t truck operated by a private logging contractor, and manual logging and light truck operated by an individual forest owner—were estimated and compared with the mechanized operation system operated by the Forest Owners’ Association. The mechanized operation system was found to have the highest cost and could not compete for small forestry operational sites and small stem volumes. The small-scale systems could be effective for harvesting small areas. This was especially true when conducting extracting operations without machines, as done by the individual forest owner, and transporting operations by a private logging contractor, in which the hourly income of the individual forest owner was higher than the hourly labour expenses.     

<Emphasis Type="Italic">In silico</Emphasis> genomic subtraction guides development of highly accurate,DNA-based diagnostics for <Emphasis Type="Italic">Ralstonia solanacearum</Emphasis> race 3 biovar 2 and blood disease bacterium

New rapid diagnostic methods are urgently needed to discriminate the quarantine pathogen Ralstonia solanacearum (Rs) race 3 biovar 2 (R3B2) from other populations of Rs that lack the adaptation to cause bacterial wilt disease in temperate regions. We used an in silico bioinformatic approach to identify several genome sequences potentially specific to R3B2 strains. Primer sets were designed to PCR-amplify sequences in these regions, and four sets were ultimately shown to be >99% accurate for detection of R3B2 strains. On the basis of these results, several primers were designed to enable development of a loop-mediated isothermal amplification assay that was rapid, technologically simple, and essentially 100% accurate for identification of R3B2 when applied to a comprehensive collection of geographically diverse Rs strains. We fortuitously found that a sequence in one of the “R3B2-specific” regions has ~90% identity to a sequence present in strains of the blood disease bacterium (BDB), a member of the Rs species complex that infects banana. Alignments of these sequences allowed design of a second PCR primer set that proved 100% accurate for identification of BDB strains when tested on the 22 BDB strains available to us. These results demonstrate the power of in silico genomic subtraction for rapid identification of population-specific DNA sequences and for the development of simple, reliable detection methods for Rs subpopulations.     

Histopathological changes in the pancreas due to decreased pancreatic blood flow in a canine tachycardia-induced cardiomyopathy model

In dogs, pancreatic acinar cell injury is thought to be caused by decreased pancreatic blood flow due to heart failure. In previous our report, it demonstrated that decreased heart function causes a significant decrease in pancreatic blood flow in heart failure dog model caused by rapid ventricular pacing (RVP). However, the types of histopathological changes remain unclear. We aimed to verify the types of histopathological changes occurring in the pancreatic tissue due to decreased heart function. After RVP for 4 weeks, atrophy of pancreatic acinar cells, characterized by a decrease in zymogen granules, was observed in all areas of the pancreas. In conclusion, the result of this study suggests that attention should be paid to ischemia/hypoperfusion injury in the pancreas.     

Density and sound-speed contrasts,and target strength of Japanese sandeel <Emphasis Type="Italic">Ammodytes personatus</Emphasis>

Sound-speed and density contrasts (h and g, respectively), important acoustic material properties, of Japanese sandeel Ammodytes personatus were measured to estimate theoretical target strength (TS). The measured sound-speed contrast of adult fish varied between 1.016 and 1.023 (mean 1.020), and showed temperature dependence. The measured density contrast differed significantly between juvenile and adult. The density contrast of juvenile varied between 1.017 and 1.024 (1.021), and that of adult varied between 1.026 and 1.038 (1.032). Using these results, TS at 38 and 120 kHz in the fishing season were estimated by an empirical sound scattering model. TS of an individual fish varied significantly with change of tilt angle. TS of near-dorsal aspect (TS_max) and tilt-averaged TS (TS_ave) differed by up to 7 dB. At both frequencies, two different TS_ave−length relationships (TS_ave = a log L + b) were obtained for adult and juvenile. The coefficients of log L of adult were close to 20, suggesting that backscattering strength was proportional to square of body length. These values were larger in juvenile (34.0 at 120 kHz, 56.5 at 38 kHz), suggesting that backscattering strength varied drastically with the cube or fifth power of body length.     

Evaluation of the low dose level of a heat-killed and dried cell preparation of Enterococcus faecalis to prevent porcine edema disease using experimental infection model with enterotoxcemic Escherichia coli in weaning pigs

Porcine edema disease (ED) is caused by Shiga toxin 2e-producing Escherichia coli (STEC). ED has become frequent in pig farms, and the use of antimicrobials has resulted in the development of antimicrobial-resistant STEC. Accordingly, the use of materials other than antimicrobials is requested for the prevention of ED. Oral administration of a heat-killed and dried cell preparation of Enterococcus faecalis strain EC-12 (EC-12) to weaning pigs was previously demonstrated to decrease animal mortality in a STEC-contaminated farm at 0.05% (w/w) dose level. In this study, pigs experimentally infected with STEC were used as a model for ED to evaluate the low dose level of EC-12 to prevent ED. Fifteen 21-day-old pigs were divided into 5 groups: STEC challenge with the basal diet, STEC challenge with EC-12 supplemented at 0.005, 0.01, or 0.05% (w/w) to the basal diet, and no STEC challenge with the basal diet. The challenge was carried out when the animals were 25, 26, and 27 days old using STEC contained in capsules resistant against gastric digestion. All pigs were euthanized at 32 days of age. The daily weight gain, feed conversion ratio, and palpebral edema were improved by supplementation with 0.05% EC-12, but not by the low dose levels. Accordingly, 0.05% level of supplementation was needed for EC-12 to improve clinical symptoms in weaning piglets infected by STEC.     

Spatial and temporal variation in the distribution of juvenile southern bluefin tuna Thunnus maccoyii: implication for precise estimation of recruitment abundance indices

Acoustic tags were used to examine the spatial and temporal distribution of southern bluefin tuna (SBT) in southern Western Australia, which is in a region where fishery-independent acoustic surveys of the recruitment abundance index of SBT have been historically undertaken. We investigated patterns of SBT distribution within and inshore of the acoustic survey area during three summer seasons. Annual differences in distribution patterns were characterized by two distinctive migration pathways. An inshore-migrating pathway was observed in two seasons (2004/2005 and 2006/2007), with a relatively high proportion of tagged SBT (84.5, 65.0%) migrating inshore of the acoustic survey area. The other pathway was concentrated along the shelf (2005/2006 season), with an estimated 63.3% of tagged SBT moving within the survey area. These variable migration patterns may bias the interannual fluctuations in abundance indices. Current survey methods can be modified to include both inshore and continental shelf areas. This contribution shows that the accuracy of acoustic surveys can be improved by including ecological patterns.     

Age, growth, and reproductive characteristics of dolphinfish Coryphaena hippurus in the waters off west Kyushu, northern East China Sea

The growth and reproductive characteristics of dolphinfish Coryphaena hippurus collected in the waters off western Kyushu from May 2008 to April 2011 were determined based on scale and otolith readings and gonad histological examinations, respectively. Based on annual increments in scales and daily increments in sagittal otoliths, the von Bertalanffy growth curves in male and females were determined as $ FL_{t} = 1049[1 - \exp \{ - 0.835(t + 6.975 \times 10^{ - 14} )\} ] $ and $ FL_{t} = 938[1 - \exp \{ - 1.029(t + 6.975 \times 10^{ - 14} )\} ] $ , respectively, where FL _t is the mean fork length (mm) at age t. The spawning period was found to last from June to August for dolphinfish, based on an examination of the monthly changes in the gonadosomatic index and histological observations. Therefore, based on the relationship between the fork length and the developmental stage of the testes or ovaries, male and female dolphinfish were found to reach sexual maturity by the following spawning season after hatching in the northern East China Sea.     

Enhanced expression of stress protein 70 in the brains of goldfish, Carassius auratus, reared with bluegills, Lepomis macrochirus

Induction of stress protein (HSP70) was studied in goldfish (Carassius auratus) reared with bluegills (Lepomis macrochirus), a predator of small fish. HSP70 was identified by Western blotting and quantified by optical density after SDS-PAGE. The expression of HSP70 was significantly enhanced in the brains of goldfish reared with bluegills for 6 and 12 h in a single tank. The hepatopancreas and the kidney were not affected by the treatment. When goldfish were separated from bluegills with a partition net (1×1 cm mesh size), this protein also increased in the brains after 6 h but then returned to the control level after 12 h. When the goldfish and bluegills were kept in separate tanks and were not able to see each other but were connected by circulating water, HSP70 levels in the goldfish were unaffected. Immunohistochemical observations indicated that an anti-HSP70 antibody was found to react predominantly with the optic and vagal lobes of the brains. These results suggest that visual perception plays a primary role in enhancement of HSP70 expression in the goldfish reared with bluegills.     

拖拉机沿曲线路径的跟踪控制

近年关于农业用车轮型移动机器人的研究很多,但主要集中在直线行走方面。该研究进行了沿给定的曲线路径跟踪控制的研究。首先由给定的曲线路径生成四元状态空间,其次在利用预见控制求得车辆的未来值和目标值的基础上,利用最优控制理论设计跟踪控制器。最后在牧草地上对正弦路径和圆形路径进行了跟踪实验。试验结果为：车辆以1.5 m/s的速度行驶时,在很小转弯半径时最大误差可控制在35 cm以内。