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排序方式: 共有246条查询结果,搜索用时 15 毫秒
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Soy protein concentrate as a substitute for fish meal in diets for juvenile Acanthopagrus schlegelii: effects on growth,phosphorus discharge and digestive enzyme activity
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Hameeda Kalhoro Jing Zhou Ying Hua Wing‐Keong Ng Lian Ye Jinzhi Zhang Qingjun Shao 《Aquaculture Research》2018,49(5):1896-1906
The current high demand and cost of fish meal (FM) necessities the evaluation of alternative plant protein ingredients in diets of farmed marine fish. A 56‐day feeding trial was performed to study the effects of replacement of FM with soy protein concentrate (SPC) in diets of Acanthopagrus schlegelii. Diets were prepared at levels of 0%, 30%, 47.5%, 65%, 82.5% and 100% SPC, respectively, replacing FM. The results indicated no significant differences (p > .05) in % weight gain (WG) and specific growth rate of fish fed S30% to S82.5% diets compared with the control diet while, further inclusion at 100% significantly depressed growth performance. SPC inclusion and phytase supplementation significantly affected the phosphorous discharge (P‐load) showing lowest value (3.83 ± 0.53 g/kg WG) in S100% compared to control (14.79 ± 0.37 g/kg WG) and in fish fed S30% diet (13.24 ± 0.89 g/kg WG) (p < .05). The results of this study showed that FM could be substituted up to 82.5% by SPC in the diet of Acanthopagrus schlegelii fingerlings (5.53 ± 0.12 g) without any adverse effects. Phytase supplementation SPC based diets could be effective in reducing the phosphorus load in the aquatic culture environment. 相似文献
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Chin Soon Lionel Ng Tai Chong Toh Kok Ben Toh James Guest Loke Ming Chou 《Aquaculture Research》2014,45(11):1852-1860
The dietary habits of the sea urchin Salmacis sphaeroides and the gastropod Trochus maculatus in ex situ mariculture were examined. Fouling algal assemblages on terracotta tiles were exposed to the grazers and compared. Except for Day 0, the assemblages on Days 2, 13 and 27 differed significantly across treatments. S. sphaeroides rapidly consumed most algae, leaving an assemblage dominated by turf algae and bare tile. T. maculatus primarily fed on green filamentous algae, resulting in an even distribution of other algal functional groups, while control tiles were dominated by green filamentous algae. Using three representative fouling algae species (Bryopsis corymbosa, Hypnea spinella and Lobophora variegata), the consumption rates of both grazers and dietary preferences of S. sphaeroides were examined through a single‐diet and a choice experiment respectively. The single‐diet experiment revealed differential algal consumption rates for S. sphaeroides (H. spinella = B. corymbosa > L. variegata) and T. maculatus (B. corymbosa > H. spinella = L. variegata). The choice experiment showed that S. sphaeroides preferred H. spinella over the other two species. These experiments highlighted the importance of understanding the dietary habits of grazers as this has direct implications on their effectiveness as biological controls of fouling macroalgae in mariculture. 相似文献
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Ng A Parker ML Parr AJ Saunders PK Smith AC Waldron KW 《Journal of agricultural and food chemistry》2000,48(11):5612-5617
The structure and mechanical properties of onions are important factors affecting their textural quality. The onion bulb consists of several layers of pigmented, papery scales surrounding fleshy storage scales that comprise an upper epidermis, an intermediate parenchyma tissue, and a lower epidermis. The purpose of this study was to examine the chemical composition of cell walls from the papery scales and outer fleshy scales of onion (Allium cepa L. cv. Sturon) in relation to their mechanical properties. Cell-wall material (CWM) was prepared from the component tissues and analyzed for its carbohydrate and phenolic composition. The CWMs were rich in uronic acid and glucose, with smaller quantities of arabinose, galactose, and xylose. In the fleshy scales, the lower epidermis contained relatively more galactose-rich pectic polysaccharides, whereas the upper epidermis and the papery scales contained virtually no galactose. Analysis of mechanical properties showed that the order of strength of the tissues was papery scales > fleshy scales, which were in the order lower epidermis > upper epidermis > intermediate parenchyma. The upper epidermis of fleshy scales was stronger in the vertical than the horizontal direction, and both orientations showed negligible notch sensitivity. Cyclohexane-trans-1,2-diaminetetraacetate-induced vortex-induced cell separation of the intermediate layer of fleshy scales indicated that calcium cross-linking may play an important role in cell-cell adhesion. A small but significant amount of ferulic acid was found in the walls, predominantly in the thick cuticle of the lower epidermis of fleshy scales. Alkali-labile wall-bound flavonoids were also detected. 相似文献
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Cheng Qing Zhou Chao Ng Charles Wang Wao Tang Chaosheng 《Journal of Soils and Sediments》2020,20(2):756-762
Journal of Soils and Sediments - Temperature has a significant influence on water retention curve (WRC) because temperature affects surface tension of water and volumetric behaviour of soil.... 相似文献
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Soon FF Ng LM Zhou XE West GM Kovach A Tan MH Suino-Powell KM He Y Xu Y Chalmers MJ Brunzelle JS Zhang H Yang H Jiang H Li J Yong EL Cutler S Zhu JK Griffin PR Melcher K Xu HE 《Science (New York, N.Y.)》2012,335(6064):85-88
Abscisic acid (ABA) is an essential hormone for plants to survive environmental stresses. At the center of the ABA signaling network is a subfamily of type 2C protein phosphatases (PP2Cs), which form exclusive interactions with ABA receptors and subfamily 2 Snfl-related kinase (SnRK2s). Here, we report a SnRK2-PP2C complex structure, which reveals marked similarity in PP2C recognition by SnRK2 and ABA receptors. In the complex, the kinase activation loop docks into the active site of PP2C, while the conserved ABA-sensing tryptophan of PP2C inserts into the kinase catalytic cleft, thus mimicking receptor-PP2C interactions. These structural results provide a simple mechanism that directly couples ABA binding to SnRK2 kinase activation and highlight a new paradigm of kinase-phosphatase regulation through mutual packing of their catalytic sites. 相似文献
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1. The most important area in Singapore for native aquatic fauna and flora is a relatively intact 5 km2 patch of freshwater swamp forest in Nee Soon. 2. The Nee Soon Swamp Forest contains 48% of the primary freshwater fish, 71% of the amphibian, 28% of the reptile and 34% of the bird fauna of Singapore. The swamp also has the highest percentage of native and threatened freshwater fish and crustacean species on the island, as well as being the main (if not the only) habitat of the aquatic plant Hydrostemma. It is also the last refuge of two mammals, the Banded Leaf Monkey, Presbytis femoralis femoralis, and the Cream-coloured Giant Squirrel, Ratufa affinis affinis. 3. The threats to the swamp forest are discussed, and proposals are made to establish the swamp forest as Singapore's second major nature reserve. 4. Study of the swamp forest is essentially still at a survey and discovery phase. The research priorities are to establish detailed species lists, the status of endangered species and the extent of buffer zones. 5. The swamp forest is administered primarily by the newly established National Parks Board, but several other government organizations also have jurisdiction over the land, causing some problems in the management of the swamp. The roles of the university and non-governmental organizations in conducting surveys, drafting recommendations and educating the general public are detailed. 相似文献
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Jonathan M. Gray Bin Wang Cathleen M. Waters Susan E. Orgill Annette L. Cowie Ee Ling Ng 《Soil Use and Management》2022,38(1):229-247
Digital soil maps of soil organic carbon (SOC) sequestration potential resulting from a hypothetical 10% relative increase in long-term vegetation cover are presented at 100-m resolution across the state of New South Wales (NSW) in southeast Australia. This land management outcome is considered realistically achievable for many land managers, using strategies such as revegetation, grazing management or crop residue management. A mean state-wide potential increase of 5.4 Mg ha−1 over the 0- to 30-cm depth interval was derived. Assuming a 20-year period of re-equilibration, this equates to an average SOC increase of 0.27 Mg ha−1 year−1. Sequestration potential is systematically influenced by a combination of climate, soil parent material and current vegetation cover, for example only 1.6 Mg ha−1 SOC under dry conditions in sandy, infertile soil material with sparse vegetation cover, compared with 15.9 Mg ha−1 under wet conditions in clay-rich, fertile soil material with moderate–high vegetation cover. The outputs could be used to identify locations of highest sequestration potential and thereby help prioritize areas and inform decisions on sequestration programmes. Future application of the method at field scale with high levels of accuracy, together with strategic sampling, may provide statistically reliable estimates of carbon sequestration, for application in carbon trading schemes such as Australia's Emissions Reduction Fund. The modelling involved a conceptually transparent ‘space-for-time substitution’ process. Multiple linear regression (MLR) and random forest (RF) modelling techniques were applied, but only MLR gave consistently meaningful results. The apparent failing of RF in this application warrants further examination. 相似文献