不同饲料类型和放养密度对乌鳢生长特性及营养品质的影响

为了解不同饲料类型和放养密度对体质量(136.62±5.34)g的乌鳢Channa argus生长及营养品质的影响,采用围隔养殖试验法,研究了3种放养密度(15 000、30 000、45 000 ind./hm2)和2种饲料类型(冰鲜鱼和配合饲料)对乌鳢生长性能、生物学性状和肌肉营养成分的影响。结果表明:冰鲜鱼投喂组乌鳢的增重率、特定生长率显著高于配合饲料投喂组(P<0.05),饵料系数显著低于配合饲料投喂组(P<0.05),成活率无显著性影响(P>0.05),放养密度对乌鳢增重率、特定生长率、饵料系数和成活率均无显著性影响(P>0.05);饲料投喂组乌鳢的肥满度、肝体指数和脏体指数显著高于冰鲜鱼投喂组(P<0.05),放养密度对其无显著性影响(P>0.05),但饵料类型与放养密度二者的交互作用对脏体指数影响显著(P<0.05),对肥满度和肝体指数无显著性影响(P>0.05);饲料类型、放养密度对乌鳢肌肉的水分、灰分、粗蛋白质和粗脂肪无显著性影响(P>0.05);各试验组乌鳢肌肉中的18种氨基酸含量除脯氨酸外无显著性差异(P>0.05);氨基酸评价表明,投喂配合饲料的乌鳢肌肉蛋白质品质优于投喂冰鲜鱼的乌鳢,且以低密度养殖时最佳;脂肪酸分析表明,投喂配合饲料的乌鳢饱和脂肪酸(SFA)含量显著高于投喂冰鲜鱼(P<0.05),但二十碳五烯酸(EPA)和二十二碳六烯酸(DHA)等9种多不饱和脂肪酸(PUFA)含量显著低于投喂冰鲜鱼组(P<0.05);投喂冰鲜鱼相对于投喂配合饲料,可提高养殖乌鳢生长性能,改善生物学性状,降低肝体指数、脏体指数和肥满度,对肌肉氨基酸总量、必需氨基酸总量无显著性影响(P>0.05);3种放养密度对乌鳢生长性能和营养成分无显著性影响(P>0.05)。研究表明,配制饲料时可参考冰鲜鱼的营养成分,降低碳水化合物含量,增加不饱和脂肪酸添加量,以提升养殖乌鳢营养品质。     

影响我县仔猪生长的饲料营养因素分析

当前,受市场价格的影响,我县生猪生产面临前所未有的市场冲击,生猪市场价格下滑,生产成本不断提高,严重影响了养殖户的积极性,本文就我县生产实际,对仔猪生长缓慢的几个原因进行分析,希望能给养殖户提供一些帮助,缩短养殖周期,降低生产成本,提高养殖效益。     

饲料中不同添加剂组合对锦鲤生长和体色的影响

为研究饲料中不同添加剂组合对锦鲤Cyprinus carpio(初始体质量为195.88 g±0.98 g)生长和体色的影响,并与日本优质锦鲤商品饲料进行增重和增色效果对比,进行了增重和增色两部分试验,其中增重部分以三色锦鲤为研究对象,探讨了试验增重饲料与商品增重饲料对其生长的影响,增色部分以红白锦鲤为研究对象,探讨了试验对比饲料、试验增色饲料和商品增色饲料对其体色的影响,各组均设3个重复,试验周期为60 d,每隔15 d测定锦鲤的生长和体色指标。结果表明:添加L-肉碱、血球蛋白粉、螺旋藻和枯草芽孢杆菌的试验饲料对三色锦鲤的促生长效果与商品增色料无显著性差异(P>0.05),但试验饲料具有更低的饲料系数;添加虾青素、螺旋藻和枯草芽孢杆菌的试验饲料对红白锦鲤体色的增艳效果与商品增色料无显著性差异(P>0.05);投喂两种试验增色料和商品增色料的锦鲤体表各部位对色素的沉积程度相似。研究表明,采用不同添加剂组合的两种试验饲料与日本优质锦鲤饲料的功效水平相当,能够分别满足对锦鲤快速增重和增色的要求。     

鸡蛋壳品质的饲料营养调控技术

鸡蛋壳品质的饲料营养调控是以饲养标准为基础,结合鸡群生产、健康水平、饲养条件和环境变化,通过日粮中增加大颗粒钙质供应、利用生物学效价高的微量元素氨基酸螯合物和增加维生素D_3、降低过多的氯元素、减少应激影响,并以有效磷调控日粮钙磷比例、按鸡群体况调整饲料营养,为产蛋鸡提供有利于健康和改善蛋壳品质的饲料营养保障,增加经济效益。     

饲料中的营养物质对猪肉品质的影响

随着人们生活水平的不断提高,消费者对肉质提出了更高的要求。对猪肉的要求不仅是卫生,还要求瘦肉率高、口感好。文章主要综述了饲料中营养物质成分对猪肉品质的影响,概括了改善猪肉品质的方法。     

影响猪肉品质的遗传及营养因素研究

随着生活水平的提高,消费者对肉品质和风味的要求越来越高。猪肉品质常用肌肉p H、肉色、系水力、肌内脂肪含量等指标进行评定,其主要受遗传、营养和饲养、屠宰加工处理等因素影响,其中遗传性状和营养水平是影响肉品质的主要因素。因此,文章主要从遗传性状和营养水平两方面对猪肉品质的影响作以论述。     

饲料中添加混合益生菌对幼参生长、消化酶活力和体壁营养组成的影响

为探讨在饲料中添加混合益生菌对刺参Apostichopus japonicus幼参生长、消化酶活力和体壁营养组成的影响,以体质量为(0.54±0.06)g幼参为试验对象,研究了投喂含益生菌(1×105cells/g梅奇酵母C14+1×105cells/g红酵母H26+1×107cells/g芽孢杆菌BC26)饲料(益生菌组)和基础饲料(对照组)后,幼参肠道异养细菌数量和弧菌数量,以及幼参生长、肠道消化酶活力和体壁营养组成的变化。结果表明:在试验第4周和第8周时,益生菌组幼参肠道异养细菌数量显著高于对照组(P<0.05);益生菌组幼参特定生长率和肠道胃蛋白酶、胰蛋白酶、淀粉酶和脂肪酶活力均较对照组显著提高(P<0.05);益生菌组幼参比对照组具有较高的体壁粗蛋白质及糖分含量(P<0.05);投喂含益生菌饲料的幼参肠道弧菌数量显著低于投喂基础饲料的幼参(P<0.05);饲养8周时,益生菌组幼参体壁灰分含量显著低于对照组(P<0.05)。研究表明,饲料中补充混合益生菌可促进幼参生长和消化酶活力,并影响其体壁营养组成。     

饲料中蛋白质含量对花生长和消化的影响

在水温(22±3)℃下,将体重5.90 g的花Hemibarbus maculatus放养在网箱(60 cm×60 cm×120 cm)中,投喂蛋白质含量分别为25.0%、31.0%、37.0%、43.0%、49.0%(质量分数,下同)的5种饲料,饲养100 d。结果表明:饲料中蛋白质含量为33.42%³8.79%时,鱼的特定生长率和蛋白质效率最高,饲料系数最低(P<0.05);蛋白质的含量从25.0%升到37.0%时,鱼肌肉中蛋白质含量(53.18%升到57.97%)达最大值;当饲料中蛋白质含量从25.0%升到31.0%时,鱼肌肉中脂肪含量(14.36%升至17.10%)达最大值;当饲料蛋白质含量为49.0%时,鱼肌肉中蛋白质(54.14%)和脂肪(15.37%)含量降低。当饲料中蛋白质含量由25.0%升到37.0%和43.0%时,肠道中脂肪酶和蛋白酶的活性先升高,后降低;而饲料中蛋白质含量对肠道淀粉酶活性的影响不显著(P>0.05)。花由鱼种至食用鱼阶段,饲料中蛋白质含量为38.79%38.79%时,鱼的特定生长率和蛋白质效率最高,饲料系数最低(P<0.05);蛋白质的含量从25.0%升到37.0%时,鱼肌肉中蛋白质含量(53.18%升到57.97%)达最大值;当饲料中蛋白质含量从25.0%升到31.0%时,鱼肌肉中脂肪含量(14.36%升至17.10%)达最大值;当饲料蛋白质含量为49.0%时,鱼肌肉中蛋白质(54.14%)和脂肪(15.37%)含量降低。当饲料中蛋白质含量由25.0%升到37.0%和43.0%时,肠道中脂肪酶和蛋白酶的活性先升高,后降低;而饲料中蛋白质含量对肠道淀粉酶活性的影响不显著(P>0.05)。花由鱼种至食用鱼阶段,饲料中蛋白质含量为38.79%³3.42%较适宜。     

圈养幼龄野生动物的营养需求和饲料管理

圈养幼龄野生动物的生长发育与该阶段的营养科学与均衡密不可分。目前,幼龄野生动物的相关营养研究不成熟,很多研究是基于家畜家禽的营养研究,但野生动物营养需要又有别于家畜家禽,因此圈养幼龄野生动物的营养需求和饲料管理研究十分必要。文章主要从圈养幼龄野生动物的营养需求、饲料管理两方面作以综述。     

2种生长调节剂对高粱生长、产量和品质影响的研究

通过对高粱喷施不同剂量矮壮素、乙烯利溶液进行田间试验,旨在探明矮壮素、乙烯利溶液对高粱生长、产量和品质的影响。实验采用两因素四水平随机区组设计,3次重复,于拔节期喷施(2014年7月5日)。乙烯利、矮壮素各设6个浓度梯度,乙烯利稀释倍数分别为100倍、200倍、400倍、800倍、1000倍及清水对照;矮壮素稀释倍数分别为100倍、250倍、400倍、550倍、700倍及清水对照。结果表明,2种生长调节剂的主要作用是能够抑制赤霉素的生物合成而控制植株的伸长生长,乙烯利(抽穗期)对高粱植株矮化作用分别比对照提高29.32%、34.58%、21.80%、21.8%、2.18%;乙烯利(成熟期)对高粱植株矮化作用分别比对照提高21.07%、22.16%、19.77%、18.63%、12.11%;矮壮素(抽穗期)对高粱植株矮化作用分别比对照提高5.43%、13.18%、3.10%、3.88%、8.53%;矮壮素(成熟期)对高粱植株矮化作用分别比对照提高9.94%、29.19%、13.64%、18.01%、14.91%。喷施不同浓度乙烯利、矮壮素对高粱籽粒品质均有一定的影响。乙烯利以稀释200倍喷改善高粱籽粒品质效果最为明显,矮壮素以稀释250倍效果明显。喷施乙烯利的矮化效果较喷施矮壮素显著,但是在改善高粱光合指标、叶绿素含量、产量方面差别不大。在生产上,通过拔节期喷施乙烯利、矮壮素可有效控制高粱株高,实现增密增产。     

Comparison of annual energy performances with different ventilation methods for temperature and humidity control

Stratum ventilation has been proposed to accommodate elevated indoor temperatures recommended by governments in East Asia. TRNSYS is used for computation of the space cooling loads, sensible and latent, as well as system energy consumption. Typical configurations of an office, a classroom and a retail shop in Hong Kong are investigated. Desiccant dehumidification with and without solar assistance is utilized for the air treatment under displacement ventilation and stratum ventilation, while simple reheating is adopted under mixed ventilation. Compared with mixing ventilation and displacement ventilation, stratum ventilation derives its energy saving potential largely from the following five factors: the reduction in ventilation, dehumidification and transmission loads, prolonged free cooling period and increased the COP of the chillers. For the office, the year-round energy saving is found to be substantial at 20% and 40% without the need for solar energy provision when compared with displacement ventilation and mixing ventilation respectively. For the classroom and retail shop, the year-round energy saving is at about 25% and at least 37% with the aid of solar energy provision when compared with displacement ventilation and mixing ventilation respectively.     

基于AMESim自适应大流量安全阀动态特性影响因素研究

通过对某型自适应大流量安全阀的结构及工作原理的分析，建立了自适应大流量安全阀的数学模型；利用AMESim16.0软件搭建安全阀的仿真模型，得到了一级直动阀与一级锥阀的压力、流量、位移、阀芯速度等动态特性对比曲线；通过设置不同的二级阀芯弹簧刚度、差动腔容积等关键参数，探究自适应大流量安全阀动态特性的影响因素。结果表明：一级锥阀的压力超调率及流量超调率都低于一级直动阀，压力稳定时间、阀芯最大位移及最大速度都是一级锥阀的小；适当增大二级阀芯的弹簧刚度及差动腔的容积都可得到动态性能更加优良的自适应大流量安全阀。     

Comparison of different uncertainty techniques in urban stormwater quantity and quality modelling

Urban drainage models are important tools used by both practitioners and scientists in the field of stormwater management. These models are often conceptual and usually require calibration using local datasets. The quantification of the uncertainty associated with the models is a must, although it is rarely practiced. The International Working Group on Data and Models, which works under the IWA/IAHR Joint Committee on Urban Drainage, has been working on the development of a framework for defining and assessing uncertainties in the field of urban drainage modelling. A part of that work is the assessment and comparison of different techniques generally used in the uncertainty assessment of the parameters of water models. This paper compares a number of these techniques: the Generalized Likelihood Uncertainty Estimation (GLUE), the Shuffled Complex Evolution Metropolis algorithm (SCEM-UA), an approach based on a multi-objective auto-calibration (a multialgorithm, genetically adaptive multi-objective method, AMALGAM) and a Bayesian approach based on a simplified Markov Chain Monte Carlo method (implemented in the software MICA). To allow a meaningful comparison among the different uncertainty techniques, common criteria have been set for the likelihood formulation, defining the number of simulations, and the measure of uncertainty bounds. Moreover, all the uncertainty techniques were implemented for the same case study, in which the same stormwater quantity and quality model was used alongside the same dataset. The comparison results for a well-posed rainfall/runoff model showed that the four methods provide similar probability distributions of model parameters, and model prediction intervals. For ill-posed water quality model the differences between the results were much wider; and the paper provides the specific advantages and disadvantages of each method. In relation to computational efficiency (i.e. number of iterations required to generate the probability distribution of parameters), it was found that SCEM-UA and AMALGAM produce results quicker than GLUE in terms of required number of simulations. However, GLUE requires the lowest modelling skills and is easy to implement. All non-Bayesian methods have problems with the way they accept behavioural parameter sets, e.g. GLUE, SCEM-UA and AMALGAM have subjective acceptance thresholds, while MICA has usually problem with its hypothesis on normality of residuals. It is concluded that modellers should select the method which is most suitable for the system they are modelling (e.g. complexity of the model’s structure including the number of parameters), their skill/knowledge level, the available information, and the purpose of their study.     

移民、杂合与互文——从《贝奥武夫》看早期英国民族共同体的诞生

口口相传并于公元1000年前后成文的英国史诗《贝奥武夫》与英国早期史学著作如《英吉利教会史》和《盎格鲁-撒克逊编年史》以及古斯堪的纳维亚神话故事和诗歌之间存在较为隐秘的互文关系。《贝奥武夫》的作者以互文的方式实现了世俗的“英雄世界”与基督教的“宇宙世界”之间的联通,建立了基督传教士与“野蛮人”之间的对话关系。本文认为,《贝奥武夫》可被视为早期英国民族共同体诞生的寓言,集中体现了武装入侵后,盎格鲁-撒克逊人构建民族共同体的文化模型与道德范式的文学叙事策略;在欧洲移民的背景下,盎格鲁-撒克逊人对日耳曼、基督教和斯堪的纳维亚三种文化的杂合及其英国本土化共同促成了早期英国民族共同体的诞生。     

不同饵料对厚壳贻贝稚贝生长、存活及淀粉酶活性的影响

为了解不同饵料对厚壳贻贝Mytilus coruscus稚贝生长、存活及消化能力的影响,在温度为18℃、盐度为30的条件下,使用单一湛江等边金藻、青岛大扁藻及其二者的混合饵料(体积比为1∶1)分别投喂壳长为1.31 mm±0.05 mm的厚壳贻贝稚贝,并检测其21 d内的存活率、壳长、壳高、湿质量、特定生长率和淀粉酶活力变化。结果表明:在不同饵料条件下,稚贝的存活率均大于93%,不同处理组间无显著性差异(P>0.05);饲养14 d以上时,各饵料组稚贝的壳长、壳高、特定生长率、湿重和淀粉酶活力均为混合饵料组高于其他饵料组;试验结束时,混合饵料组稚贝的各项生长指标及淀粉酶活力均显著高于两个单一饵料组(P<0.05)。     

Indoor air quality at restaurants with different styles of cooking in metropolitan Hong Kong.

Indoor air quality (IAQ) of a restaurant has increasingly received a lot of public concerns in Hong Kong. Unfortunately, there is limited data about the IAQ of Hong Kong restaurants. In order to characterize the current IAQ of local restaurants, four restaurants in metropolitan Hong Kong including a Korean barbecue style restaurant, a Chinese hot pot restaurant, a Chinese dim sum restaurant and a Western canteen were selected for this study. The results of this study showed that the mean concentrations of CO2 at restaurants with gas stoves for food cooking in dining areas exceeded the range from 40 to 60% indoor CO2 concentrations at restaurants without gas stoves in dining areas. The average levels of PM10 and PM2.5 at the Korean barbecue style restaurant were as high as 1442 and 1167 microg/m3, respectively. At the Korean barbecue and Chinese hot pot restaurants, the levels of PM2.5 accounted for 80-93% of their respective PM10 concentrations. The 1-h average levels of CO observed at Korean barbecue style and hot pot restaurants were 15,100 and 8000 microg/m3, respectively. Relatively high concentrations of CO2, CO, PM10, PM2.5 benzene, toluene, methylene chloride and chloroform were measured in the dining areas of the Korean barbecue style and the Chinese hot pot restaurants. The operations of pan-frying food and boiling food with soup in a hot pot could generate considerable quantities of air pollutants.     

Comparison of strategies to improve indoor air quality at the pre-occupancy stage in new apartment buildings

Indoor air quality of new apartment buildings, which is known to cause Sick Housing Syndrome, has become a major concern among apartment residents as well as construction companies in Korea. Recently, the Indoor Air Quality Management Act, a regulation that limits concentration levels of formaldehyde and five volatile organic compounds in new apartment buildings, has been implemented. In this study, the effects of ventilation and decomposing agents were investigated and compared, which could be used at the pre-occupancy stage as solutions to high VOCs concentration levels in new apartment buildings. Six housing units were investigated under different conditions to assess the extent of the improvement in indoor air quality. The results demonstrate that ventilation is an effective way to control indoor air pollution caused by VOCs emissions, and the effect of decomposing agents on improving indoor air quality depends on the types of VOCs.     

地下汽车库通风排烟不同方式的比较

根据已经开始执行的汽车库设计新规范,对地下汽车库通风排烟几种相应的可行方式进行了说明和比较,分析了这些方式的优缺点以及设计中需要注意的问题。