Morphological identity of a taxonomically unassigned cytochrome c oxidase subunit I sequence from stomach contents of juvenile chum salmon determined using polymerase chain reaction

In a previous report, we analyzed the stomach contents of juvenile chum salmon Oncorhynchus keta by morphological observation and also by molecular identification using the mitochondrial cytochrome c oxidase subunit I (COI) region. However, one of the most frequently detected COI sequences could not be assigned to any specific taxon, even at the phylum level. In the present study, we conducted in situ hybridization (ISH) on the stomach contents of juvenile chum salmon using the COI sequence and polymerase chain reaction amplification of a 18S ribosomal RNA gene from the tissue sections where ISH signals were detected. As a result, the organism that was enigmatic at the phylum level was found to be an appendicularian. Moreover, Oikopleura longicauda collected from the bay where the juvenile chum salmon samples were obtained was shown to have the same COI sequences as this taxonomic “orphan” COI sequence from the stomach contents. The present results suggest that the COI sequences previously deposited in public databases for “Oikopleura” are actually derived from taxonomic groups other than appendicularians, and that this may have hampered our understanding of prey richness in the stomach or gut of certain marine animals based on DNA barcoding.     

Growth performance and physiological responses in striped knifejaw, Oplegnathus fasciatus, held under different photoperiods

The growth performance and stress response in striped knifejaw, Oplegnathus fasciatus (body weight 100–300 g) reared under four photoperiods (6L:6D, 12L:12D, 16L:8D and 24L:0D) were investigated. Fish were fed a commercial diet to apparent satiation, two times a day for 8 weeks. A trial of acute handling and confinement stress was also carried out to investigate the stress-induced levels of different stress indicators in O. fasciatus. Blood was also collected from undisturbed fish which was considered as control. Although there were no significant differences in weight gain, specific growth rate (SGR) and feed conversion efficiency (FCE) in fish exposed to 6L:6D, 16L:8D and 24L:0D photoperiods, all parameters in these photoperiods were significantly higher than those of 12L:12D photoperiod (P < 0.05). There was no significant difference in protein retention efficiency (PRE) between fish exposed to 16L:8D and 24L:0D photoperiods, but PRE in both photoperiods was significantly higher than that of 12L:12D photoperiod.Acute stress significantly increased the plasma levels of cortisol (110.3 ng ml^− 1) and glucose (195.4 mg dl^− 1), and decreased plasma levels of total protein (0.8 g dl^− 1); however, all parameters were returned back to the levels indistinguishable from those of control, undisturbed fish within 24 h. The levels of cortisol, glucose and total protein in fish exposed to different photoperiods during the study were far from the stress-induced levels (P < 0.05). The results demonstrated that the growth performance of O. fasciatus reared from 100 to 300 g can be stimulated significantly by using the manipulated photoperiods where feeding time may be playing an important role to increase food intake and feed conversion efficiency. It also revealed that the artificial photoperiods did not cause significant stress response in fish.     

Performance of Sugi lamina impregnated with low-molecular weight phenolic resin

This study was conducted to evaluate the performance of Sugi lamina impregnated with low-molecular weight phenolic (LMWP) resin using the full cell process followed by curing at high temperature. In this study, penetration of LMWP resin into finger-jointed lamina was examined. Physical and mechanical properties, such as surface hardness, dimensional stability, bending and shear strength of LMWP-resin-treated and untreated lamina were investigated. In addition, the bonding quality and nail-withdrawal resistance of 3-ply assembly specimen made from LMWP-resin-treated and untreated lamina bonded using resorcinol–phenol formaldehyde resin adhesive were also investigated. The main results were as follows: LMWP resin was found to have penetrated sufficiently into finger-jointed lamina. The physical properties of LMWP-resin-treated lamina were found to have improved significantly in comparison with untreated lamina. However, no significant difference was found between LMWP-resin-treated and untreated lamina in terms of their mechanical properties. There was an improvement in bonding quality of the assembly made from LMWP-resin-treated lamina when compared with that made from untreated lamina. In the assembly made from untreated lamina, a significant decrease in nail-withdrawal resistance was observed between dry conditions test and after humidity conditioning test. However, the same tendency was not found in the assembly made from LMWP-resin-treated lamina.     

Genetic diversity and pathogenicity of cucurbit-associated <Emphasis Type="Italic">Acidovorax</Emphasis>

Bacterial fruit blotch of cucurbits is a destructive disease caused by Acidovorax avenae subsp. citrulli, which is a typical seedborne pathogen. In seed health testing for this disease, we have detected many strains of Acidovorax with some differences from A. avenae subsp. citrulli. Their 16S rRNA sequences were divided into six types. The most common sequence was completely consistent with that of A. avenae subsp. avenae originally isolated from rice. The other sequences were over 99% similar but not identical to those of A. avenae subsp. avenae and A. avenae subsp. citrulli. Some commercialized antibodies against A. avenae subsp. citrulli reacted with several of these strains. Some of these strains incited yellow spots or brownish water-soaked lesions mainly on young true leaves of cucumber and squash after spray inoculation. Histological observations showed that these strains entered the leaf tissues of cucurbit plants through stomata and multiplied in the intercellular spaces of parenchymatous tissues as well as in the vascular tissues. The amount of bacterial multiplication and spread in the tissues differed among the strains, presumably reflecting their ability to induce symptoms. These isolated strains are therefore different from A. avenae subsp. citrulli, and their potential threat to the cultivation of cucurbits is lower than that of A. avenae subsp. citrulli.     

Growth performance,carcass characteristics,fatty acid composition and CLA concentrations of lambs fed diets supplemented with different oil sources

Quality food for human consumption will always be the aim for animal producers. Quantity and composition of fat deposits (fatty acid profile) strongly influences meat quality in ruminants, especially via increasing conjugated linoleic acid (CLA) concentration, which is known to have beneficial anticarcinogenic, antiatherogenic, antidiabetic and cholesterol reduction properties for human health. Awassi lambs are one of the main and most consumed meat sources in the Middle East area; however, studies addressing the fat content of CLA and methods to enhance its concentrations in this breed are still rare. For this reason, the aim of this study was to evaluate the effect of adding two different oil sources (soybean oil (SBO) and sunflower oil (SFO) at two levels (1.8 and 3%)) on growth performance, carcass characteristics and fatty acid profile of fat in Awassi lambs. Oil supplementation had no effect on growth performance or carcass characteristics, while fatty acid composition changed according to the site of extraction. CLA concentrations were increased in the tail fat deposit, with 1.8% SBO and in intermuscular fat deposit with 3% SFO. Intermuscular fat is the one most naturally consumed by humans, serving to improve food quality.     

Age validation and growth variability of Japanese flounder <Emphasis Type="Italic">Paralichthys olivaceus</Emphasis> off the Pacific coast of northern Japan

ABSTRACT:   This study examined age and growth of Japanese flounder Paralichthys olivaceus off the Pacific coast of northern Japan, and determined whether the growth patterns of male and female fish in northern (40–41°N) and southern (37–38°15'N) waters differ. In total 8095 specimens were collected between January 1999 and December 2005. Zonation consisting of opaque and translucent bands on the otolith was evident. Within each opaque band a thin and clear check (ring mark) was observed in all specimens examined. Monthly change in the frequency of appearance of a ring mark on the outer margin of the otolith indicates that ring marks form between July and August. The von Bertalanffy growth model showed a sexual dimorphism in growth, as females grew faster and reached a larger size than males. The growth patterns obtained by tracking the observed total length for monthly collections showed a rapid increase in total length between August and October. Spatial variation in the growth pattern of male and female fish between northern and southern waters was evident, as southern fish were significantly larger than northern counterparts during 1.25–3.00 years post hatch.     

Biomass and taxonomic composition of micronekton in the western tropical–subtropical Pacific

The biomass distribution, community structure and species composition of the dominant micronektonic animals were determined in the western tropical Pacific, using day/night sampling from upper 200 m depth with a commercial midwater otter trawl in fall‐winter of 1994, 1995 and 1997. Night‐time micronekton biomass was significantly higher than daytime biomass except for a few cases. All the night‐time catches had similar taxonomic composition, dominated by myctophid fishes, small squids, shrimps and euphausiids. Night‐time micronekton biomass in the upper 200 m was assumed to be higher in the North Equatorial Counter Current than in the North Equatorial Current, reflecting the zooplankton biomass distribution which micronektons feed on at night. A total of 42 species of myctophid fishes, 34 species of squids, 27 species of shrimps and six species of euphausiids were collected. Community types of each dominant taxonomic group were classified by cluster analysis based on the species composition. A station located north of the subtropical convergence zone was distinct from other tropical stations south of the convergence zone, having significantly different species composition in three of the four dominant taxonomic groups (myctophids, squids and shrimps). The interaction between the larvae of commercially important fishes and micronektonic animals is discussed.     

Primary hemangiosarcoma of the humerus in a Maltese dog

A 14-year-old intact male Maltese dog was presented with a history of pain and swelling of the left upper forelimb and lameness for 3 weeks. Hematological and radiographical examinations showed regenerative anemia and osteolysis of the humerus. Fine needle aspiration biopsy detected epithelioid- and fibroblast-like anaplastic cells with blood components. A hemorrhagic and osteolytic malignant tumor was suspected, and the affected forelimb was amputated. Histopathologically, the dog was diagnosed with primary hemangiosarcoma of the humerus. Thereafter, metastatic lesions appeared in the skin, and the dog was euthanized 1 month after the operation.