This study was conducted to evaluate the effect of replacing soybean meal (SBM) by low protein floc meal (LPFM; 24% CP) in tilapia diets on growth performance, feed utilization and fish chemical composition. Three isonitrogenous and isocaloric diets were formulated; control diet (C; without LPFM), FM 25 (25% of SBM protein was substituted by LPFM) and FM 50 (50% of SBM protein was substituted by LPFM). Nine 55l circular plastic tanks were stocked by 12 fish to form three experimental groups. No differences in tilapia performance were observed between the control and the FM 25 diet. Chemical composition of fish did not differ significantly among treatments except for protein and selenium contents where the highest values were recorded in the control treatment. The highest mineral content was recorded in floc collected from the control tanks, while calcium content showed its highest value in floc collected from FM 50 effluent. These data indicate that replacing soybean meal with LPFM up to 25%, had no negative effect on growth performance and potentially may improve the system sustainability. Meanwhile, the adverse effect of more inclusion of LPFM in tilapia diet may be attributed to the higher content of ash. In other word, minerals seem to cause more energy utilization in fish fed floc meal since it is needed to maintain osmotic homeostasis.
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排序方式： 共有11条查询结果，搜索用时 182 毫秒
1.
直立堤前海床的局部冲刷 总被引：2，自引：0，他引：2
对不规则波作用下直立堤前海床的局部冲刷进行了研究。研究了由于波浪作用导致床面的底沙运动,从而造成提前海床的局部冲刷,即所谓的“相对粒沙”的情况。报导了;(1)堤前海床面为水平、堤下无基床情况下的堤前局部冲刷,以及堤下有明基床时基床尺度对堤前局部冲刷的影响;(2)堤前海床面为斜坡面时堤前的局部冲刷,以及当堤下有明基床时基床尺度对堤前局部冲刷的影响;(3)从波浪作用下床面边界层的理论分析出发,对于在不规则波作用下,离堤面愈远处的冲刷坑深度愈小的事实给出了解释。 相似文献
2.
在外海修筑架空式建筑物时,波浪力常常是重要的外荷载之一,为合理地进行结构设计,需要妥善地定出其所受的波浪力。关于作用在圆形桩、柱上的波浪力问题,国内外已进行过广泛的研究,本文第一作者也曾探讨过这些问题,这些研究成果的简明概括,已列入我国的有关规范[1],至于波浪对竖直矩形墩柱的作用问题,第一航务工程局设计研究院和大连工学院曾进行过系统的实验研究,可是在理论上,国内外都还缺乏必要的研究,其主要困难,在于边界条件较难处理。 相似文献
3.
This paper presents a brief review of the results on the interaction between waves and muddy bottom obtained during the last decade including the results obtained by the author at the Coastal Engineering Laboratory of Tianjin University. 相似文献
4.
构建考虑多维特征的城市居民非通勤出行群体画像概念模型,提出一种按序结合相关系数矩阵与二阶聚类的方法,以进行非通勤出行群体画像。利用苏州市手机信令数据,基于非通勤出行时空规律和社会属性将城市居民出行者进行群体划分,并结合城市居民非通勤出行群体画像概念模型对不同类型非通勤出行群体进行多维度解析。结果显示：① 城市居民出行者可划分为：活跃?波动?工作日主导型群体、非活跃?稳定?均衡型群体。② 不同类型非通勤出行群体画像在多维特征上存在显著差异。③ 根据群体画像标签关联分析,除显性关联外,群体画像不同标签间存在隐性关联。 相似文献
5.
都龙锡锌铟多金属矿床位于华南板块西南缘之滇东南老君山矿集区南部,是中国重要的锡锌铟多金属资源产地,构造控矿特征明显。对铜街、曼家寨两个典型矿段及外围构造变形分析及控矿构造解析表明:区内各地质体之间均为构造接触,构造变形主要存在伸展滑脱及左行走滑等构造样式;F0、F1、F2三条南北向断裂组成的早白垩世伸展滑脱构造控制了矿区的矿化蚀变及矿体空间产出形态,是矿区最主要的控矿构造;成矿后北西向马关—都龙左行走滑断裂为破矿构造,但其正断的性质使矿区受剥蚀程度相对较低,对矿床保存有利。根据控矿构造组合特征及区域构造背景建立了构造控矿模式,认为矿区南部深部、西部寒武系地层与新寨岩组深部为进一步寻找锡锌铟矿的有利区域,矿区深部找矿潜力较大。 相似文献
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8.
Structure and composition of the continental crust in East China 总被引：14，自引：0，他引：14
Shan Gao Tingchuan Luo Benren Zhang Hongfei Zhang Yinwen Han Zidan Zhao Hartmut Kern 《中国科学D辑(英文版)》1999,42(2):129-140
Crustal structures of nine broad tectonic units in China, except the Tarim craton, are derived from 18 seismic refraction
profiles including 12 geoscience transects. Abundances of 63 major, trace and rare earth elements in the upper crust in East
China are estimated. The estimates are based on sampling of 11 451 individual rock samples over an area of 950 000 km2, from which 905 large composite samples are prepared and analyzed by 13 methods. The middle, lower and total crust compositions
of East China are also estimated from studies of exposed crustal cross sections and granulite xenoliths and by correlation
of seismic data with lithologies. All the tectonic units except the Tarim craton and the Qinling orogen show a four-layered
crustal structure, consisting of the upper, middle, upper lower, and lowermost crusts. P-wave velocities of the bulk lower
crust and total crust are 6.8–7.0 and 6:4–6.5 km/s, respectively. They are slower by 0.2–0.4 km/s than the global averages. The bulk lower crust is suggested to be
intermediate with 58% SiO2 in East China. The results contrast with generally accepted global models of mafic lower crusi. The proposed total crust
composition in East China is also more evolved than previous estimates and characterized by SiO2=64%, a significant negative Eu anomaly (Eu/Eu* = 0.80), deficits in Sr and transition metals, a near-arc magma La/Nd ratio
(3.0), and a calculatedμ(238U/204Pb) value of 5. In addition, it has the following ratios of element pairs exhibiting similar compatibility, which are identical
or close to the primitive mantle values: Zr/Hf=37, Nb/Ta=17.5, Ba/Th=87, K/Pb=0.12x104, Rb/Cs=25, Ba/Rb=8.94, Sn/Sm=0.31, Se/Cd=1.64, La/ As=10.3, Ce/Sb=271, Pb/Bi=57, Rb/TI=177, Er/Ag=52, Cu/Au=3.2×104, Sm/Mo=7.5, Nd/W=40, CI/Li=10.8, F/Nd=21.9, and La/B=1.8.
Project supported by the National Natural Science Foundation of China (Grant Nos. 49625305, 49573183, 49673184, 49794043),
the State Comission of Education, the Ministry of Geology and Mineral Resources of China (Grant No. 850514), the Open Laboratory
of Constitution, Interaction and Dynamics of the Crust-Mantle System, and the Alexander-von-Humboldt Foundation of Germany. 相似文献
9.
Mabroke Rania S. El-Husseiny Osama M. Zidan Abd El-Naem F. A. Tahoun Al-Azab Suloma Ashraf 《中国海洋湖沼学报》2019,37(1):313-320
10.
Numerical Study of Behavior of Circular Footing on Geogrid-Reinforced Sand Under Static and Dynamic Loading 总被引：3，自引：1，他引：2
A. F. Zidan 《Geotechnical and Geological Engineering》2012,30(2):499-510
A series of axi-symmetry models using finite element analyses were performed to investigate the behavior of circular footings
over reinforced sand under static and dynamic loading. Geogrid was modeled as an elastic element and the soil was modeled
using hardening soil model which use an elasto-plastic hyperbolic stress–strain relation. Several parameters including number
of geogrid layers, depth to the first geogrid layer, spacing between layers and load amplitude of dynamic loading are selected
in this paper to investigate the influence of these parameters on the performance of reinforced systems under both static
and dynamic loads. The numerical studies demonstrated that the presence of geogrid in sand makes the relationship between
contact pressure and settlement of reinforced system nearly linear until reaching the failure stage. The rate of footing settlement
decreases as the number of loading cycles increases and the optimum values of the depth of first geogrid layer and spacing
between layers is found 20% of the footing diameter. Some significant observations on the performance of footing-geogrid systems
with change of the values of parametric study are presented in this paper. 相似文献
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