Response of cholecystokinin and digestive enzyme mRNA levels to various feed ingredients in yellowtail Seriola quinqueradiata

Cholecystokinin (CCK) is the key regulator hormone that stimulates the secretion of digestive pancreatic enzymes in vertebrates. In fish, little is known about the mechanism of induction of CCK in the digestive tract by feed ingredients. To investigate the response of CCK and digestive enzymes to fish feed ingredients in yellowtail Seriola quinqueradiata, we performed a number of experiments in which we measured the mRNA levels of CCK, trypsin, and lipase after oral administration of a single bolus of the ingredients. We administered fish meal and fish oil in experiment 1; high and low concentrations of fish meal in experiment 2; and five different dietary protein sources (fish meal, soybean meal, soy protein concentrate, corn gluten meal, and glutamic acid fermentation by-products) in experiment 3. In experiments 1 and 3, only fish meal significantly increased the mRNA levels of CCK and digestive enzyme. In experiment 2, a high concentration of fish meal [20?% (w/v)] significantly increased CCK and trypsin mRNA levels, but a low concentration of fish meal [1?% (w/v)] did not. These results suggest that high concentrations of fish meal (the protein source in fish feed) has the most potent effect on stimulation of CCK synthesis and secretion of digestive enzymes in yellowtail.     

Utilization patterns of estuarine and marine habitats by the halfbeak Zenarchopterus dunckeri at Iriomote Island,southern Japan,evaluated from otolith microchemistry

Estuarine and marine habitat use patterns in the halfbeak Zenarchopterus dunckeri were examined at Iriomote Island, southern Japan, by analyzing otolith Li/Ca and Sr/Ca ratios. The ranges of both Li/Ca and Sr/Ca ratios in juvenile Z. dunckeri from the maximum (30 psu) to minimum (0.5 psu) salinity levels of brackish water estimated from rearing experiments, were compared with those of wild individuals collected from upstream and downstream stations in the Urauchi River estuary. The majority of wild-caught individuals had invariable Li/Ca and Sr/Ca ratios along an otolith transect from the core to the posterior edge, which fell within the otolith Li/Ca and Sr/Ca ranges estimated for estuarine individuals in the rearing experiments, suggesting that such individuals developed within the estuary without migrating to a marine environment at any time, although some downstream-dwelling fish had higher otolith elemental ratios than the predetermined estuarine ranges in the mid transect section. The latter fish may have been accidentally flushed from the estuary into the sea by heavy flood events, subsequently returning to the estuary. The overall results suggested that Z. dunckeri is essentially an estuarine resident, completing its life cycle within an estuarine system.     

Discovery and genetic analysis of non-bitter Tartary buckwheat (Fagopyrum tataricum Gaertn.) with trace-rutinosidase activity

In a screening of about 500 lines of Tartary buckwheat, we identified lines that contained no detectable rutinosidase isozymes using an in-gel detection assay. We confirmed that seeds of these individuals had only a trace level of in-vitro rutinosidase activity. To investigate the heritability of the trace-rutinosidase characteristic, we analyzed the progeny of crosses between rutinosidase trace-lines, ‘f3g-162’, and the ‘Hokkai T8’. The F₂ progeny clearly divided into two groups: those with rutinosidase activity under 1.5 nkat/g seed (trace-rutinosidase) and those with activity over 400 nkat/g seed (normal rutinosidase). The segregation pattern of this trait in F₂ progeny exhibited 1 : 3 ratio (trace-rutinosidase : normal rutinosidase), suggesting that the trace-rutinosidase trait is conferred by a single recessive gene; rutinosidase-trace A (rutA). In addition, sensory panelists evaluated the bitterness of flour from trace-rutinosidase individuals and did not detect bitterness, whereas flour from normal rutinosidase individuals was found to have strong bitterness. Although at least three bitter compounds have been reported in Tartary buckwheat seeds, our present findings indicate that rutin hydrolysis is the major contributing factor to bitterness. In addition, the trace-rutinosidase line identified here, ‘f3g-162’, is a promising material for generating a non-bitter Tartary buckwheat variety.     

Post-mortem evaluation of expanded polytetrafluoroethylene (ePTFE) used in mitral valve repair in dogs

Mitral valve repair is one of the treatment options for mitral regurgitation. Expanded polytetrafluoroethylene (ePTFE) is a polymer that has been widely used in cardiovascular surgery. In this case series, we report the autopsy and histological findings in 6 dogs that underwent cardiopulmonary bypass for mitral annuloplasty using ePTFE sheets and chordoplasty using ePTFE sutures.From May 2005 to October 2009, 3 female and 3 male dogs with severe mitral regurgitation underwent mitral valve repair. This case series included 3 Cavalier King Charles spaniels, 2 Maltese, and 1 Shih Tzu. The survival period after surgery was 19–72 (35 ± 19) months.In all the cases, autopsy revealed that the ePTFE sheets and sutures were not damaged and well integrated into the surrounding highly differentiated, connective tissues. Low-power microscopy revealed that in all cases, the tissues surrounding the ePTFE sheet in the mitral valve annulus had almost completely been covered by granulation tissue. No inflammatory infiltrate or thrombogenesis was observed around the ePTFE in any of the cases.There was no evidence of reactive changes in the region surrounding the ePTFE. These results suggest that ePTFE has excellent tissue compatibility and durability and can be effectively used for canine mitral valve repair.     

Construction of a linkage map and identification of DNA markers linked to Fom-1, a gene conferring resistance to Fusarium oxysporum f.sp. melonis race 2 in melon

Resistance to Fusarium oxysporum f.sp. melonis race 2 is conferred by a single dominant gene, Fom-1 in melon. Here, we identified DNA markers tightly linked to Fom-1 that could be used for marker assisted selection in breeding programs. First, we developed 125 F₂ plants derived from the cross between melon lines P11 (fom-1fom-1) and MR-1 (Fom-1Fom-1). Using the F₂ population, we constructed a linkage map including 14 SSR markers which had not been mapped previously. Fom-1 was confirmed to be allocated to linkage group 7. Then, we identified four AFLP markers using bulked segregant analysis. The AFLP marker TAG/GCC-470 was completely linked to Fom-1 and other three markers were mapped near Fom-1. TAG/GCC-470 and TCG/GGT-400 were respectively converted to STS and CAPS markers. Usefulness of DNA markers was confirmed in the analysis with several melon cultivars and lines.     

Adventitious root formation of two <Emphasis Type="Italic">Abies</Emphasis> species on log and soil in an old-growth subalpine forest in central Japan

We assessed stem burial and adventitious root formation of two late-successional species, Abies mariesii and A. veitchii, in central Japan. In a plot (5 × 5 m), all seedlings between 8 and 24 cm tall were excavated: six A. mariesii seedlings in soil, and six and four A. veitchii seedlings in soil and on logs, respectively. For each sampled seedling, the number of terminal bud scars (TBS) was counted on the aboveground and belowground stems. Stem length was measured, and divided into aboveground and belowground stems. Among the three groups (A. mariesii seedlings in soil and A. veitchii seedlings in soil or on logs), there was no significant difference in height or total root weight (sum of adventitious roots and primary roots), but diameter at ground level and number of TBS were significantly different. Counting TBS on the aboveground stem of seedlings in soil underestimated seedling age, whereas the estimate was much closer to the true age for seedlings on logs. Seedlings in soil formed more adventitious roots than seedlings on logs. A large proportion of the stem was buried in humus for seedlings in soil, while most of the stem was not buried in humus for seedlings on logs. These results suggest that substrate affects adventitious root formation, the formation of which is important to shade tolerance. Thus, our preliminary results suggest that consideration of adventitious root formation is necessary to understand seedling bank dynamics and estimate seedling ages of these Abies species in spatially heterogeneous old-growth subalpine forests.     

Effect of decay on shear performance of dowel-type timber joints

Monotonic and reversed cyclic loading tests were conducted on dowel-type timber joints with varying degrees of wood decay due to Fomitopsis palustris (Berk. et Curt.), a brown rot fungus, and the effect of decay on various shear performances of dowel-type joints was investigated. For joints affected by the brown rot fungus, the initial stiffness, yield load, and maximum load of dowel-type joints were significantly decreased, even with a small mass loss of wood. The reductions in shear performance were the largest for initial stiffness, followed by yield load and maximum load, in that order. For a 1% reduction of the yield load, initial stiffness and maximum load showed reductions of 1.15% and 0.77%, respectively. When dowel-type joints that had been exposed to the brown rot fungus were subjected to reversed cyclic loading, the gap between the dowel and the lead hole of the wood was increased and equivalent viscous damping was decreased. These results indicate that decay around the dowel lead hole especially affects the load-displacement behavior at small displacement level, and dowel-type joints under cyclic loading have very low resistance to forces acting on the wooden structure. Part of this report was presented at the 5th Symposium on Timber Bridges of the Japan Society of Civil Engineers, Tokyo, July 2006; the 56th Annual Meeting of the Japan Wood Research Society, Akita, August 2006; and the Annual Meeting of the Architectural Institute of Japan, Fukuoka, August 2007     

Correlation between the proportion of stained eggs and the number of mites (Dermanyssus gallinae) monitored using a ‘non‐parallel board trap’

The poultry red mite (Dermanyssus gallinae) is a serious problem for the poultry industry worldwide. However, the relationship between the mite population and the damage that they cause is still unclear. In this study, the mite population in poultry houses was examined using an established trap method, and the risk of blood‐stained eggs caused by the mites was assessed. Traps were placed once a week outside the egg channels and/or on the floor in two poultry farms in Fukuoka Prefecture, Japan, from April 2012 to July 2014. The numbers of blood‐stained eggs and total eggs were counted at weekly intervals. The results showed that the number of mites increased from April to May, and reached a peak around the beginning of June when the average temperature and humidity were >24°C and 70–90%, respectively. In the segmented model, the correlation between the proportion of blood‐stained eggs and the number of mites or temperature was positive over a threshold. In conclusion, our established trap method is useful for monitoring mites and can be used to predict when poultry farms should be treated to prevent appearance of blood‐stained eggs.     

Digestibility of common reed (Pharagmites communis Trin.) silage as ruminant feed and effects of inclusion levels in the diet of breeding cows on feed intake,ruminal fermentation and blood metabolites

To examine the digestibility of common reed (Pharagmites communis Trin.) silage and effects of inclusion levels in the diet of breeding cows on nutrient intakes, ruminal fermentation and nutrient status, two digestion trials using four sheep and cows, respectively, at the maintenance stage were conducted. In the trial using sheep, common reed silage contained 20% crude protein (CP) and 50% total digestible nutrients (TDN) on a dry matter basis. In the trial using cows, treatments were the control (92.4% Sudangrass hay and 7.6% soybean meal) and CS25, CS50 and CS80 (replacing 25%, 50%, and 80% of the control with silage, respectively). The intake and sufficiency rate of CP increased by increasing the silage level in the diet (P < 0.05), and the CP requirements of cows at maintenance was satisfied in CS80. In contrast, the sufficiency rate of TDN decreased in CS80, although it was 99.8%. Ruminal pH and NH₃‐N concentration changed among the treatments (P < 0.05); however, the blood metabolites were not affected by silage. The results indicated that including common reed silage of up to 80% in the diet of breeding cows was possible and did not have adverse effects on the blood metabolites.