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。     

转谷氨酰胺酶对鲢鱼鱼丸品质特性的影响

为了探究转谷氨酰胺酶（TG酶）对鲢鱼鱼丸品质影响,本研究测定了TG酶添加量、温度、时间的变化对鲢鱼鱼丸持水性、色泽、质构特性、感官品质的影响。结果表明TG酶的添加可以明显提高鱼丸持水性、质构特性和感官品质,但对色泽无明显影响;随着温度升高,鱼丸持水性、色泽、质构特性、感官品质总分均呈先上升后下降的趋势;随着时间延长,鱼丸持水性、色泽、质构特性、感官品质总分均呈上升趋势,而后趋于平缓。TG酶对鲢鱼鱼丸品质有显著的改善作用。     

鲢鱼体内挥发性成分测定及其产生机理初探

采用顶空固相微萃取(HS—SPME)和气相色谱—质谱联用法(GC—MS),测定了鲢鱼体内的挥发性成分,并测定了鲢鱼体内脂肪氧化酶与不饱和脂肪酸花生四烯酸的反应产物。结果表明,鲢鱼体内脂肪氧化酶与底物花生四烯酸反应产生的物质主要有己醛、1-辛烯-3-醇、2-辛烯醛、2-壬烯醛、2,4-癸二烯醛等,反应产物与鲢鱼体内主要的挥发性成分基本吻合。本试验通过产生的主要反应产物的量来间接定量酶的活性,其中鱼鳞酶的相对活性最强,其他依次为鱼鳃酶、鱼血酶、鱼肉酶和内脏酶。     

顶空固相微萃取与气质联用法分析鲢肉中风味成分

以我国重要食用的淡水鱼之一,鲢为原料。采用聚二甲基硅氧烷二乙烯苯(PDMS DVB)涂层的固相微萃取头萃取鱼肉中的挥发性成分,并通过气质联用仪分析鉴定鱼肉中的气味成分。结果表明:固相微萃取技术有效地吸附了鱼肉中的挥发性成分,经NIST质谱数据库检索和文献对照,共检出并确定48种成分,所检出物质的分子量范围大部分处于90～250MW之间,并且这些成分多是一些羰基类及醇类化合物,其总百分含量高达88.23%,其中以1 辛烯3醇的百分含量最多,为18.95%,1 辛烯3醇一般表现为土味、蘑菇味。其次是一些直链的饱和醛类,如己醛、庚醛、辛醛、壬醛、葵醛等,而这些醛类通常产生一些令人不愉快、辛辣的刺激性气味,并且普遍存在于淡水鱼中。     

水库放养白鲢暴发斜管虫病防治一例

2004年4月,内蒙古自治区赤峰市沙那水库暴发斜管虫病,造成白鲢鱼种严重死亡。由于对症下药、及时治疗,病得到控制。2005-2007年,根据鱼类春季洄游特点,提前泼药预防,没有再出现鱼种大量死亡现象;本文对白鲢斜管虫发病情况和治疗效果进行了总结。     

放养不同数量白鲢对罗氏沼虾池塘蓝藻水华及水质的影响

该文旨在探讨在罗氏沼虾养殖后期放养白鲢对池塘水质及浮游植物种类与数量的影响。试验选取规格为80尾/kg白鲢鱼种,按放养数量分别为0(1号塘)、1000尾/667m^2(2号塘)、1500尾/667m^2(3号塘)、2000尾/667m^2(4号塘),投放到4个养殖条件相近的罗氏沼虾池塘中,每隔10d检测池塘水质指标和浮游藻类,共5次。结果显示,池塘pH值呈先下降后稳定的趋势;各组溶氧均有显著的提升;2号和4号池塘透明度提升速率明显高于对照组;各组氨氮、亚硝含量变化不明显。各组化学需氧量(CODCr)、总氮、总磷、修正营养状态指数(TSIM)均呈下降趋势,且试验组下降幅度高于对照组,其中4号池塘下降最为明显。试验组池塘蓝藻下降幅度均高于对照组,且随着投放鲢鱼数量的增大,蓝藻占水体浮游植物的百分比越小。结果表明,在罗氏沼虾养殖后期放养白鲢,能够改善养殖水体环境,降低水体富营养化程度,有效控制蓝藻水华的发生。