Growth and maturation in sterlet <Emphasis Type="Italic">Acipenser ruthenus</Emphasis> under high concentrations of dissolved oxygen

This study investigates the effect of high dissolved oxygen concentrations (DO) on sterlet Acipenser ruthenus maturation. Two groups, each comprising 246 individuals of 8-month-old juvenile sterlets, were reared for 37 months under high DO (group H, mean DO of 11.2 mg/L) or normal DO (group C, mean DO of 7.3 mg/L). Significant differences in body weight were observed between group H (638.7?±?191.9 g) and group C (572.2?±?151.9 g) in 12 months (P?<?0.05). Growth until 12 months occurred at a specific growth rate of 0.6%/day for group H and at 0.5%/day for group C. The food conversion rate of groups H and C was 5.2 and 5.8, respectively. The gonadosomatic index of group H was 3.1?±?1.1 for females and 3.1?±?9.7 for males, and showed no significant difference with group C (3.0?±?0.7 for females and 2.8?±?8.9 for males, P?>?0.05) in 24 months. Significant differences in follicle diameter in mature females were also observed. Group H included 68 mature females, with an average follicle diameter of 2318.0?±?175.3 µm, whereas group C included 56 mature females, with a smaller average follicle diameter of 2152.3?±?287.0 µm (P?<?0.001). However, the polarization index in group H (0.194?±?0.049) was higher than that in group C (0.178?±?0.042) (P?<?0.05). These results suggest that, for sterlet, rearing conditions with high DO can affect growth of both the body and follicle diameter of fish compared to normal rearing conditions.     

Reduction of formaldehyde emission from plywood using composite resin composed of resorcinol–formaldehyde and urea-modified scallop shell nanoparticles

More than 200,000 tons of scallop shells are disposed annually alone in Japan. Nanoparticles derived from scallop shells have the potential to adsorb gaseous formaldehyde; therefore, such discarded shells have now been tested as additive filler in plywood adhesive by mixing high specific surface area, urea-modified shell nanoparticles with a resorcinol–formaldehyde resin. With this procedure, it was found that the emission of formaldehyde from the resulting plywood could be substantially reduced. The urea-modified scallop shell nanoparticles were prepared by two different methods: (1) a dry method where the shells were treated by planetary ball-grinding under ambient conditions—a completely dried powder was obtained after addition of the surface-modifying urea solution; (2) a moist method by treating dry ground shell particles in a wet grinding process with the urea solution, followed by centrifugation to obtain a paste. The specific surface area of the nanoparticles obtained by both treatments was 42 ± 3 m²/g. Measurement of the subsequent formaldehyde emission showed that the addition of the modified scallop shell nanoparticles substantially reduced the formaldehyde emission from plywood. The reduction of the specific mass uptake of urea depends on the nanoparticles which especially was the case when resins containing nanoparticles processed by the moist method were used.     

Feasibility of near-infrared spectroscopy for online multiple trait assessment of sawn lumber

Near-infrared (NIR) spectroscopy coupled with multivariate analysis was applied to estimate multiple traits of sawn lumber. The effects of the lumber conveying speed (LCS) and measurement resolution of spectra (MRS) on the calibrations were examined. NIR spectra ranging from 1300 to 2300 nm were acquired at LCSs of 10, 20, and 30 m/min and at MRSs of 2, 4, and 16 nm. Prediction models of bending strength (F _b), modulus of elasticity in bending tests (E _b), dynamic modulus of elasticity (E _fr), and wood density (DEN) were developed using partial least-squares (PLS) analysis. LCS and MRS did not significantly influence the calibration performance for any wood property. The regression coefficients also showed no clear differences for any of the conditions. This indicates that the important explanatory variables included in the models are not greatly influenced by these measurement conditions. PLS2 analysis results, when presented graphically, allowed easy interpretation of the relationships between wood mechanical properties and chemical components, e.g., bending strength and stiffness were mainly related to polysaccharides cellulose and hemicellulose. NIR spectroscopy has considerable potential for online grading of sawn lumber, despite the harsh measurement conditions.     

Emergence and behaviors of acid-tolerant Janthinobacterium sp. that evolves N2O from deforested tropical peatland

Using a soilless culture system mimicking tropical acidic peat soils, which contained 3 mg of gellan gum and 0.5 mg NO₃^?-N per gram of medium, a greenhouse gas, N₂O emitting capability of microorganisms in acidic peat soil in the area of Palangkaraya, Central Kalimantan, Indonesia, was investigated. The soil sampling sites included a native swamp forest (NF), a burnt forest covered by ferns and shrubs (BF), three arable lands (A-1, A-2 and A-3) and a reclaimed grassland (GL) next to the arable lands. An acid-tolerant Janthinobacterium sp. strain A1-13 (Oxalobacteriaceae, β-proteobacteria) isolated from A-1 soil was characterized as one of the most prominent N₂O-emitting bacteria in this region. Physiological characteristics of the N₂O emitter in the soilless culture system, including responses to soil environments, substrate concentration, C-source concentration, pH, and temperature, suggest that the N₂O emitting Janthinobacterium sp. strain A1-13 is highly adapted to reclaimed open peatland and primarily responsible for massive N₂O emissions from the acidic peat soils. Regulation of N₂O emitters in the reclaimed peatland for agricultural use is therefore one of the most important issues in preventing the greenhouse gas emission from acidic peat soil farmlands.     

Effects of Chilled Storage,Freezing Rates,and Frozen Storage Temperature on Lipid Oxidation in Meat Blocks from Cultured Bluefin Tuna Thunnus thynnus

ABSTRACT

The effects of a short chilled storage period before freezing, frozen storage temperature, and freezing rate on lipid oxidation of bluefin tuna (Thunnus thynnus) meat during frozen storage were investigated. After 12-months storage, all samples had increased in peroxide value though they were less at the lower temperatures (?45 and ?60°C). Peroxide values in all samples stored at ?20°C increased after 3 months storage, particularly those processed and stored 51 h after harvest. The lowest increase in peroxide value occurred in the samples frozen rapidly 3 h after harvest. Vitamin E levels decreased faster during frozen storage at ?20°C. There were no apparent differences in levels of triacylglycerides nor in n-3 fatty acid levels between treatments, storage periods, and storage temperatures. After 12-months storage, headspace oxidative volatiles were highest in samples stored at ?20°C and lowest in those stored at ?60°C. Lipid oxidation in tuna meat stored at ?45°C is similar to that at ?60°C, and rapid freezing rather than slow freezing should be used.     

Effects of live feed containing Panagrellus redivivus and water depth on growth of Betta splendens larvae

Panagrellus redivivus is a nematode with a high protein content and low‐cost production. It is successfully used in the larviculture of shrimp, however, it has not yet been evaluated as feed for Betta splendens larvae. Thus, the objective of this study was to evaluate P. redivivus as feed for betta larvae maintained at different depths of water. The experiment was based on a completely randomized 3 × 2 factorial design, represented by two feed types and one alternating feeding regime plus two water depths (2.5 and 5.0 cm). The Artemia feed promoted the highest weight gain, followed by the alternating feeding regime. The single use of the nematode as live feed produced the poorest weight gain. The water depth and the feeding method influenced the specific growth rate (SGR). At a depth of 2.5 cm, the alternating feeding promoted similar SGR compared to fish fed with Artemia only. Furthermore, at the greater water depth an improvement in SGR was observed in fish fed Artemia only, but the similarity to alternating feeding regime remains. Thus, the inclusion of nematode is an appropriate and lower cost feed strategy for the betta larviculture independent of water depths.     

Alta Russet: An early-maturing, high-quality russet cultivar for wedge-cut french fry production

Alta Russet (Russet Nugget × Ranger Russet) is an early-maturing cultivar, with high yield and excellent processing quality (fry color and dry matter) coupled with a tuber size and shape profile ideal for the manufacture of wedge-cut french fries. In the western Canadian regional trials harvested 110 days after planting, the yield of the new cultivar was similar and the specific gravity superior to that of Russet Burbank. In multi-harvest date trials conducted under irrigated conditions in southern Alberta (Canada) the yield of Alta Russet was superior to Russet Burbank and Shepody and similar to Ranger Russet (Amisk) when harvested at 95 and 110 days after planting. The tuber specific gravity of the new cultivar was superior to Russet Burbank, Shepody, and Ranger Russet (Amisk) at 95 days after planting. At 110 days after planting tuber specific gravity was similar to Ranger Russet (Amisk), but superior to Russet Burbank and Shepody. Fry color was generally superior to Russet Burbank in the western Canadian regional trials and in the multi-harvest trials was generally similar to Russet Burbank, Shepody, and Ranger Russet (Amisk). Alta Russet produces excellent fry color out of long-term storage at 8 C and acceptable color at 6 C. External and internal defects occurred at very low levels in all trials. Alta Russet is resistant to common scab and Verticillium wilt, moderately resistant to early blight and Fusarium wilt and susceptible to Fusarium dry rot and late blight. The new cultivar shows clear symptoms when infected with bacterial ring rot.