Functional study of the central nervous system for farm animal husbandry

The purpose of this mini-review is to describe the recent approaches for revealing the function of the central nervous system in farm animals. The sensory organs are the first sites to gain environmental information. The behavior of the animals is outputted as a result of changes in the integrated neuronal systems, and is largely influenced by the external environment. Therefore, it is necessary to know how farm animals catch and recognize environmental changes. To understand the mechanisms of sensing and behavioral output, approaches for analyzing the brain function are required. Neuroscientific approaches are able to give cues for resolving abnormal behaviors such as stereotypy, and may lead to the improved housing and management of farm animals.     

Conversion of pectenotoxin-2 to pectenotoxin-2 seco acid in the New Zealand scallop, Pecten novaezelandiae

SUMMARY: Comparison of pectenotoxin (PTX) profiles between the toxic dinoflagellate Dinophysis acuta and scallops Pecten novaezelandiae collected at Wedge Point, Queen Charlotte Sound, New Zealand was carried out by liquid chromatography–mass spectrometry (LC-MS) with turbo-ionspray ionization. Although the major PTX homolog in D. acuta was pectenotoxin-2 (PTX2), the scallops contained pectenotoxin-2 seco acid (PTX2SA) as the predominant toxin. Pectenotoxin-2 isolated from D. acuta was rapidly converted to PTX2SA and its epimer 7- epi -pectenotoxin-2 seco acid (7- epi -PTX2SA) in the scallop extracts. These results indicate that PTX2SA and 7- epi -PTX2SA arose from the conversion of PTX2 by scallop tissue. The results indicate that New Zealand scallops have an ability to reduce the cytotoxicity of PTX2 by conversion to PTX2SA.     

Clinico-pathological findings in peripartum dairy cows fed anion salts lowering the dietary cation-anion difference: involvement of serum inorganic phosphorus, chloride and plasma estrogen concentrations in milk fever

In our previous study, it was demonstrated that the administration of anion salts, which slightly lower the dietary cation-anion difference (DCAD), in the prepartum period is safe and effective for preventing milk fever in multiparous cows. In the present study, several clinico-pathological constituents in serum and urine, which might be related to milk fever, were analyzed using stored samples from the previous study to identify clinico-pathological parameters for easily evaluating the efficacy of lowering DCAD and to further investigate the mechanism by which lowering DCAD prevents milk fever. Among the parameters analyzed in the present study, inorganic phosphorus (iP) was involved in milk fever because the serum concentration and urinary excretion of iP were significantly higher in the group of primiparous cows (heifer group), which did not develop hypocalcemia, than those in other groups of multiparous cows. Serum chloride concentrations in the heifer group and the group of multiparous cows fed anion salts (anion group) tended to remain higher than those in other control groups of multiparous cows suggesting that serum chloride concentration may be utilized for evaluating the status of metabolic acidosis and the efficacy of lowerng DCAD in dairy cows fed anion salts. In addition, plasma estradiol-17beta concentration in the heifer group tended to be lower at parturition compared with that in other multiparous groups suggesting that estrogen known as a potent inhibitor of bone resorption may be involved in developing milk fever.     

Current status of leptospirosis in Japan and Philippines

Leptospirosis is an acute febrile illness with a wide variety of clinical manifestations and is encountered throughout the world, prominently in tropical areas with high rainfall. In this paper, we review the current status of leptospirosis in two Asian countries, Japan and Philippines, which have quite different situations in terms of economy, environment, infrastructures and prevailing infectious diseases. In Japan, until 1960, more than 200 deaths due to leptospirosis had been reported yearly. After 1960, the number of reported cases had rapidly decreased. Now, leptospirosis cases notified every year were less than 20. After the early 1960s, modernization of agriculture was introduced, at the same time, inactivated vaccine against Leptospira was applied for humans and there was good maintenance of infrastructures such as water works and sewage systems.

In Philippines, on the other hand, leptospirosis patients tend to be frequently found in flood-prone areas of urban setting such as Metro Manila, which was found to be the endemic foci of leptospirosis. Morbidity in a rural area (Cabatuan, Iloilo) was 147 cases per 100,000 populations. From 1998 to 2001, about 70% of 1200 suspected leptospirosis patients in Philippines were serologically positive. The average age of patients was 32 years old where 87% of the cases were males and 70% were outdoor workers. Case fatality rate was found to be 12–14%. The estimated major serovars in Metro Manila and neighboring provinces were Manilae, Losbanos, Tarassovi, Poi and an unknown serovar. Outbreaks of leptospirosis in the Philippines are thought to be associated with heavy rainfall, rapid urbanization (dramatic increase in populations), deforestation, increasing number of flood-prone areas, poor infrastructures and many others.     

Characterization of Escherichia coli strains obtained from layer chickens affected with colibacillosis in a commercial egg-producing farm

The present study reports colibacillosis of layer chickens in a commercial egg-producing farm in western Japan. Three flocks of chicken at 18-21 weeks of age were affected during the initiation of egg lay. Postmortem examination revealed pericarditis, perihepatitis, airsacculitis, subcutaneous inguinal lesion, and injured cloaca. Escherichia coli was isolated from the lesions of the affected birds. Twenty-two of 26 E. coli isolates (84.6%) obtained from 18 birds in the 3 flocks showed pulsed-field gel electrophoresis (PFGE) patterns that were considered to be closely associated to each other and arbitrarily designated as pattern A. All the 22 isolates with the PFGE pattern A harbored the putative virulence genes, astA, iss, iucD, tsh, and cva/cvi. Additional 2 PFGE patterns (B and C) were also found in E. coli isolates obtained from the affected flocks and had the putative virulence genes in combinations different from those in the pattern A strains. The results suggested that certain E. coli virulence genes and host factors, such as initiation of egg lay may be associated with occurrence of colibacillosis.     

Abnormal distribution of chromosomes in the first division of nuclear transferred mouse embryos

The majority of somatic cell nuclear transferred (SCNT) embryos die before or after implantation. Many studies have focused on morphological remodeling of the donor nucleus and its associated cytoskeletal structures in the early events of nuclear transfer. However, little is known about the 2-cell stage of SCNT embryos after the first division. In this study, we compared the morphological status of chromosomal division during the 1-cell stage to the 2-cell stage in SCNT embryos with that in intracytoplasmic sperm injection (ICSI) embryos. The microtubules and cytoplasmic asters, which are related to chromatin segregation, disappeared at the pronuclear stage, although formation of the first mitotic spindle was normal in both the SCNT and ICSI embryos. However, nuclear fragmentation was observed in 30% of the 2-cell SCNT embryos and 12% of the 2-cell ICSI embryos. Nuclear fragmentation was present in both blastomeres of these embryos. No apoptotic DNA fragmentation was observed in TdT-mediated dUTP-biotin Nick End Labeling (TUNEL) assays for either the SCNT or ICSI embryos. In both the SCNT and ICSI embryos, the distribution of chromosomes in the first mitotic spindle was disturbed during the process of division from the 1-cell stage to the 2-cell stage. These results suggest that loss of SCNT embryos just before or after implantation may be due to an abnormal chromosome distribution at the 2-cell stage.     

Evaluation of the transmission risk of foot-and-mouth disease in Japan

The transmission risk of foot-and-mouth disease (FMD) in Japan was evaluated using a mathematical FMD transmission model. The distance-based transmission rate between farms, which was parameterized using the FMD epidemic data in 2010 in Japan, was used to calculate the local-level reproduction numbers—expected numbers of secondary infections caused by one infected farm—for all cattle and pig farms in the country, which were then visualized as a risk map. The risk map demonstrated the spatial heterogeneity of transmission risk in the country and identified risk areas with higher possibility of disease spread. This result suggests that, particularly in high-risk areas, it is important to prepare for the smooth and efficient implementation of control measures against FMD outbreaks.     

Comparative study of dermal components and plasma TGF-β1 levels in Slc39a13/Zip13-KO mice

Ehlers-Danlos syndrome (EDS) is a group of disorders caused by abnormalities that are identified in the extracellular matrix. Transforming growth factor-β1 (TGF-β1) plays a crucial role in formation of the extracellular matrix. It has been reported that the loss of function of zinc transporter ZRT/IRT-like protein 13 (ZIP13) causes the spondylocheiro dysplastic form of EDS (SCD-EDS: OMIM 612350), in which dysregulation of the TGF-β1 signaling pathway is observed, although the relationship between the dermis abnormalities and peripheral TGF-β1 level has been unclear. We investigated the characteristics of the dermis of the Zip13-knockout (KO) mouse, an animal model for SCD-EDS. Both the ratio of dermatan sulfate (DS) in glycosaminoglycan (GAG) components and the amount of collagen were decreased, and there were very few collagen fibrils with diameters of more than 150 nm in Zip13-KO mice dermis. We also found that the TGF-β1 level was significantly higher in Zip13-KO mice serum. These results suggest that collagen synthesis and collagen fibril fusion might be impaired in Zip13-KO mice and that the possible decrease of decorin level by reduction of the DS ratio probably caused an increase of free TGF-β1 in Zip13-KO mice. In conclusion, skin fragility due to defective ZIP13 protein may be attributable to impaired extracellular matrix synthesis accompanied by abnormal peripheral TGF-β homeostasis.     

Preparation of calibration standards of N1-H paralytic shellfish toxin analogues by large-scale culture of cyanobacterium Anabaena circinalis (TA04)

Mouse bioassay is the official testing method to quantify paralytic shellfish toxins (PSTs) in bivalves. A number of alternative analytical methods have been reported. Some methods have been evaluated by a single laboratory validation. Among the different types of methods, chemical analyses are capable of identifying and quantifying the toxins, however a shortage of the necessary calibration standards hampers implementation of the chemical analyses in routine monitoring of PSTs in bivalves. In our present study, we studied preparation of major PST analogues as calibrants by large-scale cultivation of toxic freshwater cyanobacteria Anabaena circinalis TA04. The cells were steadily grown in 10 L bottle for 28 days. The primary N1-H toxins, C1/C2, were produced at a concentration of 1.3 ± 0.1 μmol/L. The intracellular and extracellular toxins occupied 80% and 20%, respectively. Over 220 μmol of the toxins was obtained from approximately 200 L of the culture over six months, demonstrating that it is sufficient to prepare saxitoxin analogues. The toxins were chemically converted to six N1-H analogues. Preparation of the analogues was carried out at relatively high yields (50-90%). The results indicate that our preparation method is useful to produce N1-H toxins. In our present study, detailed conditions for preparation of one of the rare N1-H analogues, gonyautoxin-5, were investigated.