The effect of approach direction and pace on flight distance of beef breeding cows

The aim of this study is to determine the effect of approach direction and pace on flight distance of beef breeding cows. Five Japanese Black breeding cows were used as experimental cattle. Three approach directions were tested; that were the approach toward the head of the test cow from the front direction (FRONT), the approach toward to the foreleg of the test cow from the right or left (SIDE) and the approach toward to hind‐leg of the test cow diagonally from the right or left rear (BACK). Three levels of approach pace were also tested; that were the approach at a pace of 7 km/h, the approach at a pace of 4 km/h, and the approach at a pace of 1 km/h. The shortest distance between observer and cow's at the moment of the cow's withdrawal was defined as the flight distance. The flight distance in FRONT was significantly shorter than that in SIDE. The effect of the approach pace was significant. The faster an observer approached to cow, the greater the flight distance shown by the cow. The manner of approach to cattle markedly affects the flight distance. Therefore, the manner of approach to cattle must be standardized to measure flight distance for sharing results obtained by several researchers under various conditions.     

An additional life-history tactic of masu salmon: Migration of parr to coastal habitats

Alternative life-history tactics of masu salmon Oncorhynchus masou are well documented. Subsequent to the freshwater parr stage (age ≥ 1 + years), an anadromous form migrates to the sea after smolting, while a resident form matures without seaward migration. In addition to this typical migratory dimorphism, anecdotal reports based on field observations have indicated that some underyearling masu salmon use estuarine waters. However, no empirical evidence indicates saltwater utilisation and subsequent survival in the early parr stage. Here, we used otolith microchemistry to examine whether a portion of masu salmon parr in northern Japan enters coastal habitats. The otolith Sr:Ca ratios of most juveniles collected from six rivers had consistently low values, indicating that masu salmon parr inhabiting these rivers stay only in freshwater. In contrast, in individuals from a steep-gradient river the Sr:Ca ratios increased at about a 200-µm distance from the otolith core. These results suggest that some masu salmon parr might use brackish water or sea water temporarily. In addition, three masu salmon parr were found in another steep river where a culvert located only ten metres from the river mouth completely blocked upstream migration for spawning. The Sr:Ca ratios in these fish increased at about >200 µm from the otolith core, indicating the parr had immigrated to the non-natal river from the sea. Such flexible behaviour at an early life stage may contribute to the spatial expansion of masu salmon, and the movement could moreover help to stabilise its population dynamics.     

Life-history variation in relation to nest site abundance in males of the freshwater goby Tridentiger brevispinis

Abstract –  Age at maturity in males of the freshwater goby Tridentiger brevispinis , a species with exclusive paternal care, was investigated in two populations in Lake Biwa, Japan, that differed markedly in nest site abundance. At Ohmi-maiko, where nest sites were scarce, most males matured at age 3, and mean body size of males guarding eggs in nests was larger than that of males sampled randomly (including both guarding and nonguarding males) in the population. Conversely, at Minamihama, where nest sites were abundant, many males matured at age 1, and there was no difference in body size between guarding males and males collected randomly. The slope of regression lines between body size of the guarding male and the number of eggs in his nest was greater in Ohmi-maiko than in Minamihama. These results suggest that the shortage of nest sites enhances reproductive success in larger males, probably through male–male competition for nest sites and female mate choice for larger males. I conclude that in nest spawners, the availability of nest sites should strongly affect life-history traits of males through sexual selection.     

Sodium alginate supplementation modulates gut microbiota,health parameters,growth performance and growth‐related gene expression in Malaysian Mahseer Tor tambroides

This study investigated the effects of sodium alginate supplementation on gut microbiota composition, health parameters, growth performances and growth‐related gene expression of Malaysian mahseer. Five test diets were formulated by supplementing 0%, 0.1%, 0.2%, 0.4% and 0.8% sodium alginate. Triplicate groups of juvenile Tor tambroides (2.19 ± 0.05 g) were stocked in 15 aquaria (20 individuals per aquarium) and fed at 3.0% body weight per day for 60 days. PCoA and UPGMA analysis showed that gut bacterial community were more convergence in higher sodium alginate‐supplemented diets. The percentage of Porphyromonadaceae, Bacteroides, Plesiomonas and Shewanella were substantially higher and Aeromonas, Entomoplasmatales and Prevotellaceae were drastically lower in higher sodium alginate (0.2%–0.8%) diets. Sodium alginate supplementation (≥0.2%) significantly improved the haematocrit value and respiratory burst activity of T. tambroides. Growth performances and feed utilization were significantly higher in 0.2%–0.4% sodium alginate‐supplemented diets. The increased growth rate of T. tambroides was governed by both hyperplastic and hypertrophic muscle growth. Real‐time PCR data demonstrated that most of the growth‐related genes were significantly upregulated in 0.2%–0.4% sodium alginate‐supplemented diet. Finally, it can be concluded that sodium alginate should be supplemented at 2 g/kg in practical fish feed formulation.     

Toxicity of the antifouling biocide Sea-Nine 211 to marine algae, crustacea, and a polychaete

We evaluated the acute toxicity of the antifouling biocide Sea-Nine 211 to the algae Chaetoceros calcitrans, Dunaliella tertiolecta, Tetraselmis tetrathele, and Skeletonema costatum, the crustacea Tigriopus japonicus and Portunus trituberculatus, and the polychaete Perinereis nuntia. The algae, and especially the diatoms C. calcitrans and S. costatum, were sensitive to Sea-Nine 211 toxicity, with the average acute toxicity values being 0.32, 3.9, 1.6, 0.22, 1.6, 12, and 27 μg/l for C. calcitrans, D. tertiolecta, T. tetrathele, S. costatum, T. japonicus, P. trituberculatus, and P. nuntia, respectively. A sediment toxicity test for Sea-Nine 211 using the polychaete P. nuntia revealed demonstrated that the 14-day median lethal concentration was 110 μg/kg dry-wt sediment and that growth was the most sensitive indicator. The chronic toxicity values of Sea-Nine 211 for the diatoms C. calcitrans and S. costatum were within the range of reported Sea-Nine 211 concentrations in seawater in coastal Japan, and the toxicity values for P. nuntia were within the reported concentrations in sediment. Based on these results, Sea-Nine 211 may have toxic effects on some sensitive species residing in the coastal areas of Japan, but the ecological risk posed by Sea-Nine 211 would appear to be confined to a limited area of Japanese coastal waters.     

Exclusion of cytoplasmic fragments in flow cytometric analysis of lymph node samples from dogs with lymphoma using membrane-permeable violet laser-excitable DNA-binding fluorescent dye (DyeCycle Violet)

Background: Cytoplasmic fragments derived from fragile neoplastic lymphocytes are common in samples of lymph nodes collected from dogs with lymphoma. These cytoplasmic fragments interfere with accurate gating of target cells and quantification protocols used for flow cytometry because of their variable size and expression of lymphoid cell surface antigens on their membranes. Objective: The aim of this study was to develop a method to efficiently exclude cytoplasmic fragments from flow cytometric analysis of canine lymph nodes in which lymphoma was present. Methods: Single‐cell suspensions of neoplastic cells were prepared from biopsy samples and fine‐needle aspirates of lymph nodes from 23 dogs with lymphoma. Suspensions were stained using a violet laser‐excitable (405 nm) membrane‐permeable DNA‐binding fluorescent dye (DyeCycle Violet [DCV]), incubated with antibodies against CD3, CD5, CD21, CD22, and CD45, and then stained with 7‐amino‐actinomycin D (7‐AAD), an argon‐excitable (488 nm) membrane‐impermeable DNA‐binding fluorescent dye. Multiparameter flow cytometry was used for analysis based on selective uptake and laser‐activated fluorescence of these dyes. Results: Cytoplasmic fragments, which were DCV‐negative and CD45‐positive, and dead cells, which were positive for 7‐AAD, were efficiently separated from neoplastic cells. Conclusion: Staining with DCV is a useful method to improve flow cytometric gating methods and quantitative analyses of lymph node samples from dogs with lymphoma.     

Cloning of bovine MAIL and its mRNA expression in white blood cells of Holstein cows

Molecule possessing ankyrin-repeats induced by lipopolysaccharide (MAIL) is known as an IkappaB protein induced after administration of bacterial lipopolysaccharide (LPS) to mice. In the present study, we cloned bovine MAIL cDNA and examined its mRNA expression in white blood cells isolated from Holstein cows. Bovine MAIL had more than 80% amino acid identities with murine and human MAILs, highly conserved ankyrin-repeat motifs and PEST-like sequences. Bovine MAIL mRNA was undetectable in isolated peripheral white blood cells, but rapidly induced (<1h) after stimulation by LPS and lipid A in vitro in a dose-dependent manner. The lipid A-induced MAIL mRNA expression was found in polymorphonuclear cells, monocytes/macrophages and total lymphocytes, but not in T-lymphocytes. MAIL mRNA was also induced in vivo in peripheral blood leukocytes of cows after intramammary injection of Escherichia coli derived from coliform mastitis. Thus, bovine MAIL, as rodent MAILs, is induced by inflammatory stimuli in specific immune cells in vitro and in vivo, suggesting a role in inflammatory responses to bacterial infection in cattle.     

Metagenomic analysis using 16S ribosomal RNA genes of a bacterial community in an urban stream,the Tama River,Tokyo

In an effort to determine genus- or species-level taxonomic profiles and diversity of bacterial consortia in the Tama River around urban Tokyo, next-generation sequencing technology targeting a 16S ribosomal RNA (rRNA) gene amplicon was employed. Metagenomic analysis performed by an Ion Personal Genome Machine after sequentially filtering samples through 5-, 0.8- and 0.2-μm filters yielded 1.48 Gb of 16S sequences (average 2.38 M reads/sample). The results indicated that half of the bacterial sequences belonged to Proteobacteria, followed by Bacteroidetes, Actinobacteria and Cyanobacteria. Flavobacterium (Bacteroidetes), possibly including a potential fish pathogen, was the most numerous genera in the Tama River metagenome, and accounted for?~?16% of assigned 16S reads, followed by Mycobacterium. Other dominant bacterial genera including Zoogloea, Sediminibacterium, Hyphomicrobium, Sphingopyxis, Thiothrix and Lysobacter, were thought to be associated with waste water and sludge. MiSeq metagenomic analysis revealed that environmental factors, particularly water temperature, influenced the bacterial composition throughout the year, with a strong negative correlation observed for Proteobacteria and a positive correlation for Bacteroidetes. In terms of bacterial genera, Flavobacterium was positively correlated with temperature, while Polaromonas, Pseudomonas and Bradyrhizobium were negatively correlated with this, suggesting dynamic change in the free-living bacterial population throughout the year and versatile adaptation strategies in relation to environmental factors.