Study on the Change of Muscle Proteins During the Half-Dried Salt-Cured Silver Carp (Hypophthalmichthys molitrix) Processing

Changes in the muscle protein during processing of half-dried salt-cured silver carp (Hypophthalmichthys molitrix) was studied. Sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) assay indicated that hydrolysis of the muscle proteins took place during processing, particularly at the drying stage. Further in vitro assay on the activities of Cathepsins B and L, which are related to the degradation of the myofibrillar proteins, indicated that Cathepsins B and L still had high activity at the last stage. Total soluble nitrogen (TSN) and nonprotein nitrogen (NPN) showed significant decrease (p < 0.05) and then increased during the drying stage (p < 0.05), which may be caused by the degradation of the myofibrillar proteins and other insoluble proteins. Furthermore, the retained enzymatic activity of Cathepsins B and L may contribute to the proteolysis. Our research indicates that heat pump drying is a novel drying method that can produce the traditional flavor of dried aquatic products, and the formation of high-quality flavor may be due to the degradation of the myofibrillar proteins and water-soluble proteins.     

清水下塘的鲢苗生长试验

研究了清水下塘的鲢苗生长情况。结果表明，在15天的饲养期内，清水下塘的鲢苗相对生长率低于正常的鲢苗相对生长率。     

不同处理条件下鲢鱼糜凝胶水分状态和微观结构的特征

为探讨超高压改善低盐鲢(Hypophthalmichthys molitrix)鱼糜凝胶品质的机制,利用低场核磁共振(low field nuclear magnetic resonance,LF-NMR)、差示扫描量热法(differential scanning calorimeter,DSC)、傅里叶红外光谱(fourier transform infrared spectroscopy,FT-IR)以及扫描电镜分析比较了超高压低盐鱼糜凝胶[300 MPa,1.5%氯化钠(NaCl)]与常压低盐鱼糜凝胶(0.1 MPa,1.5%NaCl)以及常压普通鱼糜凝胶(0.1 MPa,2.5%NaCl)在水分状态和微观结构上的差异。DSC结果表明超高压低盐鱼糜凝胶可冻结水的冰点降低,结合水含量(17.58%)较低盐对照组(10.89%)显著提高;LF-NMR表明超高压低盐鱼糜凝胶弛豫时间T21、T23和T24左移,不易流动水的含量(76.65%)较低盐对照组(67.29%)提高了9.39%;超高压处理能使低盐鱼糜凝胶形成光滑、连续、均匀的三维网络结构。因此,超高压处理(300 MPa,10 min)能够提高低盐鲢鱼糜凝胶结合水含量、改善微观结构。     

半胱胺对育成期银狐生长性能的影响

为研究半胱胺对育成期银狐生长性能的影响,选用2月龄左右、健康银黑狐仔狐224只（公母各半）。其中公狐体重在2.50 kg左右（P＞0.05）,母狐体重在2.10 kg左右（P＞0.05）。随机分200只（公母各半）为试验组,剩余24只（公母各半）为对照组。饲养试验持续时间大约为3个月（从2004年6月10日~8月31日）。采用复因子试验设计中的析因试验设计,为二因子有重复的试验设计。在5个不同半胱胺添加时间间隔（1、3、5、7和9 d）中分别添加5个不同数量的半胱胺（每千克体重添加10、40、70、100和130 mg）。对照组分为12个重复,每个重复2只（公母各半）。试验测定了银狐的采食量、饲料转化率及体增重。结果表明,在25个组合中只有每间隔5 d按70 mg/ kg体重浓度添加1次半胱胺组可使银狐体增重及饲料转化率达到最高,分别比对照组提高15.08%（P＜0.05）和20.21%（P＜0.01）。整个试验组银狐采食量都低于对照组, 其中70 mg/kg体重5 d组采食量比对照组降低4.52%( P＜0.05）。     

数字普惠金融与新型农业经营主体经济韧性：赋能还是负能？

为破解新型农业经营主体普遍存在的融资难、风险大及稳定性低等难题,基于全国9省（自治区）1 021个新型农业经营主体调研数据,采用熵值法测度新农主体经济韧性,并对数字金融的普惠效应展开研究。结果表明：1）新农主体经济韧性普遍较弱,不同类型新农主体经济韧性存在显著差异。2）数字普惠金融通过促进纵向多元化经营和融资稳定性赋能新农主体经济韧性的同时,也会提升横向多元化经营水平,负能新农主体经济韧性。3）数字普惠金融对不同经营类型新农主体经济韧性的“赋能”作用存在门槛效应,当新农主体经营规模跨越门槛值后,数字普惠金融对新农主体经济韧性的“赋能”作用将明显降低。因此,在提升新农主体经济韧性过程中,本研究建议应优化数字普惠金融产品、强化金融机构数字普惠金融建设、准确定位数字普惠金融受众群体。     

君山银针之奇

君山银针以形、色、香、味俱美著称于世。本文在前人研究的基础上,从传奇的起源、奇特的环境、奇巧的工艺、奇趣的“茶舞”、奇异的文化等五方面探讨了君山银针的神奇,深入剖析了君山茶文化,提倡以茶怡情,以茶修身,弘扬高洁、刚柔相济、求索奉献的君山银针精神。     

养殖与野生银鲳精巢发育形态学和组织学的初步比较

采用组织学与形态学等方法研究养殖与野生银鲳(Pampus argenteus)精巢结构、细胞形态、发育过程的异同点。结果表明:银鲳精巢结构为典型的小叶型结构,由精小叶、精小囊、小叶间质、小叶腔和输出管构成;生殖细胞可划分为5类;精巢发育与其他海水鱼类一样,可划分为6个时期。通过实验得知,养殖银鲳个体普遍小于野生银鲳的个体,且同等大小个体的养殖银鲳的精巢发育也不如野生银鲳精巢饱满,推测可能由于营养和环境温度的差异所造成。     

The effects of dietary digestible protein and digestible energy content on protein retention efficiency of juvenile silver perch Bidyanus bidyanus (Mitchell)

Effects of varying dietary digestible protein (DP) and digestible energy (DE) on protein retention efficiency (PRE), weight gain, protein deposition and carcass composition for silver perch (Bidyanus bidyanus, Mitchell) were studied. Using digestibility data for silver perch, we formulated three series of diets with different DE contents (13, 15 or 17 MJ DE kg^?1). For each series, a ‘summit’ diet containing an excess of protein for silver perch (based on previous research) and a ‘diluent’ diet with only 10–13% DP were formulated. By blending the summit and diluent diets together in different ratios, five diets with different DP contents were produced for each DE series. A commercial diet was also included to give 16 experimental diets in total. Eight juvenile fish (mean initial weight 1.2 g) were stocked into each of 64 × 70‐L acrylic aquaria and then each of the 16 diets was randomly allocated to four replicate aquaria. Tanks were supplied with partially recirculated water (75%) at 25–27°C. Fish were fed restrictively, twice per day, based initially on 3.5% body weight day^?1 with 40% of the ration given at 08:30 hours and 60% given at 15:00 hours for 59 days. Quadratic functions were fitted to each energy series to describe the relationship between DP content of diets and PRE (the asymptote of these functions were used to predict maximum PRE). For low DE (13 MJ kg^?1), mid‐DE (15 MJ kg^?1) and high DE (17 MJ kg^?1), the dietary DP contents to give maximum PRE were 24.7%, 26.1% and 30.1% respectively. Carcass fat decreased with increasing DP and increasing DP:DE ratio. Varying the dietary protein and DE also influenced other indices of fish performance. ‘Optimum’ dietary protein therefore depends on several factors. For fish fed, restrictively, the protein content needed to maximize PRE is lower than the content needed to maximize weight gain or minimize carcass fat. For fish fed to satiation, the lowest protein content for maximum weight gain is lower than for fish fed restrictively.     

增温水体对鲢、鳙的生长、血液及生理指标的影响

陡河水库纳入电厂热排水后,年均水温升高3℃左右。根据水温及等温线分布情况,将库区划分为增温区、弱增温区、自然水温区三个区域。通过一年的定点网箱监测,结果表明:自然水温区鱼类生长最好,其次为增温区,弱增温区最差。增温不仅改变了鱼类生长,而且鱼类血液及生理指标也发生了改变。     

第三方支付平台与在线支付的实现

第三方支付平台作为独立于交易各方的公正的、权威的、值得信赖的第三方支付机构,在我国发展非常迅速。对于电子商务企业,借助于第三方支付平台可以轻松解决在线支付的难题。选择第三方支付平台应慎重考虑,结合企业实际情况选择合适的解决方案。