Effect of drying method as a pretreatment on CUAZ preservative impregnation in Japanese cedar logs

Green Japanese cedar logs 2 m in length and 18 cm in diameter were dried to a mean moisture content of less than 30% by either air drying or kiln drying. Dried logs were impregnated with copper azole (CUAZ) solution according to Japanese Industrial Standard (JIS) A9002. Preservative absorption was calculated from the log weight before and after preservative impregnation. Impregnated logs were then dried in the air and cut at the center to determine preservative penetration. The penetration area was determined after visualizing the preservative with chrome azurol S. The visualized area indicated that the preservative solution penetrated into the sapwood portion of almost all the air-dried logs. However, the kiln-dried logs did not show full penetration into the sapwood portion. The visualized area of some kiln-dried sapwood showed a penetration value of less than 80%, which is the minimum requirement set by the Japanese Agricultural Standard (JAS) for sawn timber. Statistical analysis showed that penetration in the air-dried sapwood was significantly better than that in the kiln-dried sapwood. It was concluded that air drying is more favorable than kiln drying as the predrying method for CUAZ impregnation. On the other hand, preservative absorption was not affected by the drying method.     

Dimethoxypyrimidines as Novel Herbicides. Part 2. Synthesis and Herbicidal Activity of O-Pyrimidinylsalicylates and Analogues

A new series of the O-pyrimidinylsalicylates was synthesized and their herbicidal activity was examined. Some of these compounds showed very strong herbicidal activity under pre- and post-emergent treatment conditions against various kinds of grass and broadleaf weeds. Among these compounds, O-(4, 6-dimethoxypyrimidin-2-yl) salicylic acid and its methyl ester were found to exhibit the highest activity. The herbicidal symptoms observed after the treatments included early cessation of plant growth followed by chlorosis, necrosis and plant death. The symptoms were similar to those caused by sulfonylureas and imidazolinones, which inhibit branched-chain amino acid biosynthesis.     

Dietary 5‐aminolevulinic acid enhances adenosine triphosphate production,ecdysis and immune response in Pacific white shrimp,Litopenaeus vannamei (Boone)

Previous studies have shown that 5‐aminolevulinic acid (5‐ALA), a precursor of haem, can enhance haem synthesis and the activity of haemoproteins. Here, we investigated the effects of dietary 5‐ALA on Pacific white shrimp, Litopenaeus vannamei (Boone). Dietary groups included basal diet (BD, control) and BD plus 15, 30 and 60 ppm 5‐ALA (ALA15, ALA30 and ALA60 respectively). Hepatopancreas adenosine triphosphate (ATP) levels increased with increasing 5‐ALA concentration (ALA60 p < 0.05) after 2 weeks of feeding. 5‐aminolevulinic acid diets significantly increased the expression of ecdysis‐related genes: nuclear receptor E75 and chitinase 4 (ALA15, ALA30, ALA60), cytochrome P450 Shade (ALA60), chitinase 1 (ALA60) and chitinase 3 (ALA15, ALA60). Catalase (CAT) and prophenoloxidase gene expression levels were also significantly higher in ALA60 after 12 weeks of feeding. Six hours after L. vannamei were exposed to Vibrio parahaemolyticus, total haemocyte count (ALA60) and gene expression levels of CAT (ALA30, ALA60) were significantly higher in 5‐ALA groups compared to the control. 5‐aminolevulinic acid diets also increased survival of L. vannamei following V. parahaemolyticus immersion challenge. These results suggest that supplementing L. vannamei diets with 5‐ALA can enhance ATP production, immune response against V. parahaemolyticus, total haemocyte count and expression of some immune‐related genes. 5‐aminolevulinic acid can also induce ecdysis‐related gene expressions, without adversely affecting growth.     

Myxosporean and microsporidian infections in cultured Pacific bluefin tuna <Emphasis Type="Italic">Thunnus orientalis</Emphasis> in Japan

During the parasitological survey of cultured juvenile Pacific bluefin tuna (PBT) Thunnus orientalis in 2007 and 2008, two myxosporeans and one microsporidian were found. Morphological and molecular analysis showed that the heart-infecting and brain-infecting myxosporeans are identified as Kudoa shiomitsui and K. yasunagai, respectively. This is a new host record for both species. High prevalence of infection (77–100%) with K. shiomitsui was observed in October to December (1–2 months post-transfer to sea cages), whereas only a few fish were infected with K. yasunagai. A microsporidian observed as white “cysts” in the trunk muscle of PBT had a resemblance to Microsporidium seriolae, the causative parasite of beko disease in yellowtail. Phylogenetic analysis showed that the microsporidian from PBT is closely related to but distinct from several other muscle-infecting species such as M. seriolae, Microsporidium sp. RSB, and Microsporidium sp. SH. Additionally, the spore dimension (2.7 × 1.5 μm on average) was remarkably smaller than the others. These results suggest that the present microsporidian is an undescribed species and designated Microsporidium sp. PBT. Prevalence and intensity of infection with Microsporidium sp. PBT reached a maximum of 100% and 20 cysts/fish, respectively. Although pathogenic effects of the two Kudoa species on fish health remain unknown, the microsporidian could be of concern to PBT aquaculture due to unsightly cysts in the musculature, reducing the market value of the fish.     

Suitability of genetically modified soybean meal in a dietary ingredient for common carp Cyprinus carpio

The effect of genetically modified (GM) soybean meal (SBM) in a feed ingredient on growth performance of common carp was investigated in comparison to nonGM SBM. GM SBM was included at 34 and 48% in two experimental diets that were formulated with fish meal (FM) to obtain approximately 38% protein in diet. Two other experimental diets were formulated to contain the same levels of nonGM SBM. The diets were fed to juvenile common carp (22 g initial mean weight) for 12 weeks. The cauliflower mosaic virus (CaMV) 35S promoter fragment (205 base pairs) of the GM SBM was examined in fish muscle and blood samples at the twelfth week. From the twelfth week, the GM groups were fed with nonGM diets to determine the residual span of the transferred promoter fragment. There was no significant difference in growth and feed performance between GM and nonGM groups at two inclusion levels after 12 weeks. The CaMV 35S promoter fragment was not detected in fish muscles or blood receiving either level of GM SBM diet. The results demonstrated that the availability of GM SBM was similar to that of nonGM SBM and the GM SBM would be a suitable and safe ingredient in feed for common carp.     

Patchiness structure and mortality of Pacific saury Cololabis saira larvae in the northwestern Pacific

Patchiness structure and mortality rates of Pacific saury Cololabis saira larvae were estimated in the frontal area of the Kuroshio Extension in spring 2000 and 2001. Drogued GPS buoys, which were used as Lagrangian reference points, were deployed to mark dense patches of saury larvae and a series of samplings was conducted using a neuston net around the buoys during the night over a period of several days. A total of 225 tows were conducted and 11 690 specimens were sampled during four buoy tracking. Despite the occurrence of water diffusion, patchiness density, distance between adjacent patches and patch size estimated by geostatistical analysis did not drastically change during the buoy tracking and these parameters were robust for the difference of variogram models and the threshold larval density defining patchiness. Such a stability of the patchiness allowed the estimation of larval mortality from the decrease of larval density for different size classes with respect to individual growth based on the samples taken repeatedly during the buoy tracking. Although low or negative values were obtained for the larvae right after hatching, probably due to continuous hatching, the estimates of mortality then increased and became stable in the range of 23–37% day⁻¹ with a small standard deviation until their knob length reached to 36 mm. In situ information on the patchiness structure and larval mortality provides crucial parameters for simulating the recruitment process of small pelagic fishes in high-resolution hydrodynamic models.     

Convenient Method to Determine Free Fatty Acid of Rice Using Thin‐Layer Chromatography and Flame‐Ionization Detection System

A convenient method which possessed simplicity and high sensitivity was designed to investigate the changes in free fatty acid (FFA) of rice during storage using a thin‐layer chromatography and flame‐ionization detection (TLC/FID) system. In this method, two different solvent systems for TLC were used according to the purpose of experiments. Solvent system A (hexane and diethyl ether and acetic acid 80:20:1) was suitable to obtain a chromatogram showing the overall state of rice lipid degradation. Using solvent system A, the degradation of triglyceride or the increase in FFA during storage was clearly visualized as changes in the chromatogram. Solvent system B (hexane and acetic acid 100:1) was used to improve the low reproducibility of the TLC/FID method. When methyl stearate was used as an internal standard with solvent system B, high reproducibility of the FFA value was obtained, and very small changes were detectable in stored white milled rice. This method has small sample size and simple operation and is more sensitive than the standard titration method. Therefore, this seems to be an especially convenient method for small‐scale storage tests or for experiments using many samples.     

Studies on the pathogenesis of streptococcal infection in cultured yellowtails Seriola spp.: the fate of Streptococcus sp. bacteria after inoculation

Abstract. The causative agent of streptococcal infection of yellowtails has been isolated but no information is presently available with respect to the mechanism of infection. The present study deals with the growth of the bacteria in the fish body at various periods after either per-oral or per-cutaneous challenge with Streptococcus sp. YT-3 strain at different passage levels. After percutaneous challenge with bacteria of high virulence, the kidneys retained the bacteria with the relatively high count of 10⁷ cells per gram of tissue while in other organs, although high concentrations of 10⁵-10⁶ cells were detected in 10 min, this was followed by a progressive decrease up to 24 h post-inoculation with a subsequent rapid increase during the later stages of the disease process. The highest rate of growth was obtained in the intestine, where 10⁷ cells were detected at 72 h after inoculation. After oral challenge, the bacteria were detected at high levels from organs and blood within 10 min but they were completely removed from all organs except the intestine within 24 h.     

Distribution of adipocyte-related cells in skeletal muscle of rainbow trout Oncorhynchus mykiss

Adiponectin is one of the adipokines secreted mainly from adipocytes in mammals. In rainbow trout, however, adiponectin is highly expressed in skeletal muscle. Although it has been suggested that fish skeletal muscle contains adipocytes, their endocrine function and distribution are poorly understood. Recently, an EST analysis of rainbow trout found that heart-type fatty acid binding protein (H-FABP), a member of the intracellular fatty acid binding protein family, encodes an adipose-specific gene. In this study, we produced anti-adiponectin and H-FABP antibodies and investigated the distribution of adipocytes and related cells in skeletal muscle of rainbow trout. The adiponectin signal was detected at around 75 kDa in muscle in Western blotting. Since the molecular mass of rainbow trout adiponectin is around 25 kDa, this 75 kDa band would be a trimer. For H-FABP, the signal band was detected at around 15 kDa. Immunohistochemistry of skeletal muscle sections indicated that adiponectin and H-FABP signals were present outside of muscle cells and throughout the muscle tissues, suggesting the existence of adipocyte-related cells in these regions. These results will contribute to our understanding of energy metabolism in fish skeletal muscle.