Search Results (5)

The influence of dietary glutamate (Glu) was evaluated in a 56-day feeding trial on the growth performance and flesh quality of largemouth bass (Micropterus salmoides). A total of 1170 fish (average body weight 24.05 ± 0.22 g) were randomly allocated into six groups, with three replicates per group. They were fed diets containing Glu in levels of 11.40% (G1), 11.88% (G2), 12.53% (G3), 13.27% (G4), 14.33% (G5), and 15.62% (G6). We found that, over a 56-day feeding period, the final body weight (FBW) of largemouth bass was about 4–5 times the IBW. The FBW, percent weight gain (PWG), specific growth rate (SGR), feed efficiency (FE), and protein efficiency ratio (PER) initially increased and then decreased with elevating dietary Glu levels. Likewise, protein content, lipid content, apparent digestibility coefficient of dry matter (ADC_D), and apparent digestibility coefficient of protein (ADC_P) followed a similar pattern. Supplementation with Glu significantly improved the hepatosomatic index (HSI), viscerosomatic index (VSI), and relative gut length (RGL). Moreover, dietary Glu augmentation noticeably enhanced flesh composition such as muscle protein, ash, lipid, amino acid contents, and polyunsaturated fatty acids (PUFAs). Furthermore, dietary Glu supplementation enhanced muscle physicochemical quality (such as drip loss and pH), textural properties (adhesiveness and cohesiveness), and biochemical indices such as total protein (TP) and salt-soluble protein, while decreasing muscle cathepsin B (CtsB) and lactate dehydrogenase (LD) contents, thereby improving flesh quality. In conclusion, these findings suggest that Glu plays a crucial role in enhancing both growth performance and muscle quality in largemouth bass. The optimal dietary requirement for juvenile largemouth bass was estimated to be approximately 125.1 g/kg of diet based on SGR analysis. Full article

In order to study the muscle quality of different crustaceans, we aim to provide a comprehensive assessment of their muscle quality characteristics as a theoretical reference. In this work, seven major species of farmed and consumer crustaceans were selected, including crayfish (Procambarus clarkii), freshwater prawns (Macrobrachium rosenbergii), pacific white shrimp (Litopenaeus vannamei), black tiger shrimp (Penaeus monodon), kuruma prawns (Penaeus japonicus), river prawns (Macrobranchium nipponense), and Chinese shrimp (Penaeus chinensis). Their morphometric parameters, nutritional composition, textural properties, and physical and chemical indexes were comparatively analyzed. The results showed that the meat content (MC, about 14.78%) of crayfish was significantly lower than that of the other six species. By contrast, pacific white shrimp had the highest MC, although the MCs of black tiger shrimp, kuruma prawns, and Chinese shrimp are greater than 40%. All seven crustacean species were high in protein and low in fat, while pacific white shrimp had the highest crude protein, crude lipid, and crude ash content compared to the other crustaceans. The content of threonine (Thr) was the highest in crayfish. The content of methionine (Met) and lysine (Lys) was the highest in freshwater prawns. The content of isoleucine (Ile), leucine (Leu), and non–essential amino acid (NEAA) was the highest in pacific white shrimp. C18:2n-6 (linoleic acid, LA) was the highest in freshwater prawns and pacific white shrimp; C18:3n-3 (linolenic acid, LNA), C20:4n-6 (arachidonic acid, AA), unsaturated fatty acids (UFA), and monounsaturated fatty acids (MUFA) were all the highest in crayfish; and polyunsaturated fatty acids (PUFA) was the highest in freshwater prawns, but the content was not significantly different from crayfish, pacific white shrimp, black tiger shrimp, and Chinese shrimp. Pacific white shrimp had the highest values for hardness, cohesiveness, gumminess, and chewiness. The redness values of crayfish, black tiger shrimp, and Chinese shrimp were significantly higher than those of the other three species except kuruma prawns. Compared to other crustaceans, river prawns had the highest drip loss and cooking loss. Black tiger shrimp and Chinese shrimp had the lowest cooking loss rates. The research shows that the tail muscle of the seven species of crustaceans is rich in protein, essential amino acids, unsaturated fatty acids and low in fat, representing a high-quality protein. Among these crustaceans, the main essential amino acids and essential fatty acids in the tail muscle of pacific white shrimp, freshwater prawns, and crayfish are higher in content and better in nutritional value. Full article

Vanadium–titanium ore possesses significant mining and utilization value. The basicity of vanadium–titanium sinter has a direct impact on the formation, location, thickness, permeability, and heat exchange of the cohesive zone in the blast furnace. This paper investigated the influence of increasing the basicity of the sinter on the comprehensive burden’s cohesive dripping properties in the blast furnace, while keeping the final slag basicity constant. This study was conducted through cohesive dripping property experiments. The findings indicated that as the sinter basicity in the comprehensive burden structure increased and the corresponding increase in the proportion of pellets occurred, the softening performance of the comprehensive burden improved, the cohesive zone became thinner, the lower edge of the cohesive zone shifted upward, and the softening melting properties became better in general. With an increase in the sinter basicity, the dripping difference pressure of the comprehensive burden decreased, and the dripping rate firstly increased and then decreased. An increase in the sinter basicity of the comprehensive burden structure promoted V reduction, and the V element yield and Cr element yield of the sinter were both increased; the optimal sinter basicity was 2.5, and the corresponding pellet proportion was 42%. Full article

The loss of permeability affects the reduction of the ferrous burden in the cohesive zone of a blast furnace (BF). Vanadia–titania magnetite (VTM) burden of various chemical compositions have different metallurgical properties. The reduction and softening-melting-dripping properties of different kinds of VTM were investigated. The results showed that the core of sinter or pellet is indirectly reduced to wustite and (Fe,Ti)O_x, and the periphery contains interlinked metallic iron and CaSiO₃ in the cohesive zone. Wustite and (Fe,Ti)O_x are directly reduced in the melting-dripping zone. The aggregate (Fe, V, Cr) present in the non-dripping causes a loss of valuable components. With the increase in TiO₂ content, the substrate phase of molten slag changes from melilite to titanaugite, and the mass of dripping decreases gradually. In addition, the permeability index S increased and the melting zone widened, which indicates that the increase in TiO₂ content negatively affected the melting-dripping performance. The mass of the dripping is directly proportional to the pellet ratio. Considering the adverse effect of TiO₂ on softening-melting-dripping properties, it is recommended that high TiO₂ VTM is smelted while mixed with ordinary ores or with an increased pellet ratio in the burden structure. Full article

This study examines litter accumulation and associated soil fertility islands under kūpaoa (Dubautia menziesii) shrubs, common at high elevations in Haleakalā National Park (Maui, Hawai’i). The main purposes were to: (i) Analyze chemical and physical properties of kūpaoa leaf-litter, (ii) determine soil changes caused by organic-matter accumulation under plants, and (iii) compare these with the known pedological effects of silversword (Argyroxiphium sandwicense) rosettes in the same area. Surface soil samples were gathered below shrubs, and compared with paired adjacent, bare sandy soils; two soil profiles were also contrasted. Litter patches under kūpaoa covered 0.57–3.61 m² area and were 22–73 mm thick. A cohesive, 5–30-mm-thick soil crust with moderate aggregate stability developed underneath litter horizons; grain aggregation was presumably related to high organic-matter accumulation. Shear strength and compressibility measurements showed crusts opposed significantly greater resistance to physical removal and erosion than adjacent bare soils. As compared to contiguous bare ground areas, soils below shrubs had higher organic matter percentages, darker colors, faster infiltration rates, and greater water-retention capacity. Chemical soil properties were greatly altered by organic matter: Cations (Ca²⁺, Mg²⁺, K⁺), N, P, and cation-exchange capacity, were higher below plants. Further processes affecting soils under kūpaoa included microclimatic amelioration, and additional water input by fog-drip beneath its dense canopy. Substrate modifications were more pronounced below D. menziesii than A. sandwicense. Organic matter and available nutrient contents were higher under shrubs, where soils also showed greater infiltration and water-retention capacity. These trends resulted from contrasting litter properties between plant species, as kūpaoa leaves have higher nutrient content than silversword foliage. Different litter dynamics and reproduction strategies may also explain contrasting soil properties between the monocarpic rosettes and polycarpic kūpaoa. By inducing substantial substrate changes, Dubautia shrubs alter—or even create—different microhabitats and exert critical control on alpine soil development at Haleakalā. Full article