Sub-Lethal Effects of Fenvalerate on the Development,Fecundity, and Juvenile Hormone Esterase Activity of Diamondback Moth,Plutella xylostella （L.）

The toxicities of fenvalerate （20% EC） to the 3rd instar larvae of diamondback moth （DBM）, Plutella xylostella （L.）, reared on three host plants viz., radish, oilseed rape, and cabbage were tested. The LC50 values of fenvalerate to the 3rd instar larvae of DBM varied with host plants, however, there wasn＇t any significant difference among them （P〉 0.05）. Similarly, DBM fed on three host plants had same pupal weight, pupal period, pupation rate, adult emergence rate, female ratio, and fecundity. The activity of juvenile hormone esterase （JHE, EC 3.1.1.1） in the 3rd instar larvae of DMB did not significantly vary with host plants, either. These suggested that DBM had similar fitness on the three host plant species. When fed on the host plants pretreated with fenvalerate at the concentrations equivalent to LC20, LC50 and LC50, the pupation rate, pupal weight, adult emergence rate, female ratio, fecundity, and JHE activity of the tested insects were declined as compared with insects in control treatments fed on the same host plant species. Furthermore, the pupal period of the tested insects was extended after fenvalerate treatment. The decrease in JHE activity after fenvalerate treatment in the tested insects could partly explain the changes in the mentioned growth parameters. Whether the role of fenvalerate in the inhibition of JHE activity could serve as a new way to control DBM needs further investigation.     

饲料中大豆卵磷脂/鱼油比例对斜带石斑鱼稚鱼生长发育及肠道组织的影响

为探讨饲料中不同大豆卵磷脂/鱼油比例对斜带石斑鱼稚鱼成活率、生长行为、饲料利用以及肠道组织学的影响,本实验设计了4种添加不同大豆卵磷脂/鱼油比率的微颗粒饲料：0%/22%（饲料1）,5%/14%（饲料2）,10%/8%（饲料3）以及15%/7%（饲料4）,饲喂斜带石斑鱼稚鱼。每种实验饲料均设3个平行。试验持续40d。结果表明,饲料中不同大豆卵磷脂/鱼油比例对斜带石斑鱼稚鱼生长以及成活率有显著影响（P≤0.05）。饲料3和饲料4的增重分别为：（449.6±11.4）g和（588.3±61.7）g,显著高于饲料1的数值（185.0±2.5）（P≤0.05）。饲料1鱼体脂肪含量为：（154.7±12.8）g·kg-1,显著低于其他饲料组（P≤0.05）,但其鱼体蛋白含量为（728.3±25.5）g·kg-1,显著高于其他饲料组。饲料效率、肥满度、特定生长率、摄食量和蛋白质效率以及终末体重中,4种饲料之间无显著性差异。随饲料卵磷脂/鱼油比例升高,石斑鱼稚鱼肠道脂滴生成数量出现下降,且在饲料4中未观察到肠道脂滴。研究表明斜带石斑鱼稚鱼生长发育阶段需要较高的饲料卵磷脂/鱼油比例（如：15%/7%）。     

半封闭循环水养殖系统中高体革鯻养殖密度研究

在半循环水养殖系统中研究了养殖密度对体重为50～100 g的高体革鯻苗种的影响。试验设置3个密度组:低密度组100尾/m3(5 kg/m3)、中密度组260尾/m3(13 kg/m3)和高密度组360尾/m3(18 kg/m3)。研究表明:各密度组中试验鱼的生长表现出了明显的差异,生长效率、特定生长率和日增重随着养殖密度的升高而明显降低;大小变动系数和饵料系数随着养殖密度的升高而明显增加。对试验鱼的生理指标分析表明,试验初期,密度对试验鱼血清中的皮质醇、补体C3、谷草转氨酶(ALT)和谷丙转氨酶(AST)有显著影响;试验结束时,3个密度组试验鱼血清中的皮质醇、谷草转氨酶和谷丙转氨酶没有明显差异。综合对检测指标的结果分析,认为本试验条件下,体重50～100 g的高体革鯻幼鱼的比较适宜的养殖密度是260尾/m3。研究亮点:(1)高体革鯻是近年来逐渐引起关注的优良淡水养殖品种,比较适合高密度集约化养殖,但关于其适宜养殖密度的研究尚未见报道。研究高体革鯻幼鱼的适宜养殖密度,希望为生产提供理论基础。(2)不仅分析了常规的生长指标和生理指标,将部分生产指标一并纳入分析,作为评价养殖密度适宜性的标准。     

大豆分离蛋白对幼建鲤肝胰脏发育及消化道蛋白酶活力的影响

研究了大豆分离蛋白（SPI）对10～35g幼建鲤Cyprinus carpio Var．Jian肝胰脏发育及消化道蛋白酶活力的影响。结果表明：饲料中用SPI替代鱼粉蛋白水平对幼建鲤肝胰指数、肝胰脏中的胰蛋白酶、凝乳蛋白酶活力以及肠道中胰蛋白酶、凝乳蛋白酶活力影响极显著（P＜0．01）或显著（P＜0．05）,随着SPI替代鱼粉蛋白比例的增加,蛋白酶活力均极显著下降（P＜0．01）,肝胰指数显著升高（P＜0．05）。用SPI替代鱼粉蛋白后,可引起幼建鲤消化能力下降,肝胰脏和肠道等消化器官的发育受阻,胰蛋白酶和凝乳蛋白酶的活力降低,饲料利用率下降;SPI中胰蛋白酶抑制因子是引起上述症状的重要因素之一。     

模型礁对幼鲍、幼海胆行为的影响

在水温为(18±0.5)℃、盐度为34.3、pH为8.3的养殖条件下,通过观测试验水槽内幼鲍Haliotis和幼海胆Hem icentrotus pulcherrimus在无模型礁和有模型礁状况下的行为反应,探讨了适合幼鲍、幼海胆栖息的模型礁的结构与形状,并统计分析了4种不同结构的PVC模型礁对幼鲍、幼海胆的聚集率。结果表明:模型礁对水槽内幼鲍、幼海胆的分布均有影响,对幼鲍和幼海胆均有聚集作用,Ⅰ型和Ⅳ型模型礁对幼鲍的聚集效果较好,最高聚集率可达60%和53%;Ⅰ型模型礁对幼海胆的聚集效果较好,最高聚集率可达53%。     

羽毛肽粉对瓦氏黄颡鱼稚鱼生长、体成分和消化酶活性的影响

为研究羽毛肽粉替代鱼粉对瓦氏黄颡鱼Pelteobagrus vachelli幼鱼生长、体成分和消化酶活力的影响,以基础饲料为对照,分别在基础饲料中添加5%、10%、15%、20%羽毛肽粉,饲喂初始体重(25±2)g试验鱼60d。结果表明,试验黄颡鱼增重率、特定生长率随羽毛肽粉添加水平升高呈先升后降趋势,添加水平为10%时,增重率达到最大值117.48%。当添加水平为15%、20%时,增重率、特定生长率显著下降(P0.05);摄食总量随着羽毛肽粉的添加水平也呈先升后降趋势,在10%时,摄食总量达到最大值。饲料系数随着羽毛肽粉添加水平增加呈升高趋势,5%添加组与对照组无显著性差异(P0.05),其余各组均显著高于对照组(P0.05);羽毛肽粉在20%添加水平内对瓦氏黄颡鱼幼鱼体蛋白质、灰分、脂肪、水分无显著性影响(P0.05);试验黄颡鱼肝胰腺胰蛋白酶活力随羽毛肽粉添加水平的升高呈升高趋势,5%添加水平组与对照组无显著差异(P0.05),但显著低于其余各组(P0.05);试验黄颡鱼肠胰蛋白酶活力与肝胰腺蛋白酶活力呈相似的变化趋势,当添加水平达15%时,肠胰蛋白酶活力与胰胰蛋白酶活力比值显著下降(P0.05);不同添加水平羽毛肽粉对试验黄颡鱼淀粉酶活性无显著性影响(P0.05);5%羽毛肽粉添加组的肠、肝胰腺脂肪酶活力最低,显著低于其他羽毛肽粉添加组与对照组(P0.05);羽毛肽粉添加水平至10%时,肠脂肪酶活力与对照组无显著性差异(P0.05),至15%时,肝胰脏脂肪酶活力与对照组无显著差异(P0.05);羽毛肽粉添加组瓦氏黄颡鱼肠胃蛋白酶活性显著高于对照组(P0.05),15%、20%添加组5%、10%添加组对照组,各组间肝胰腺胃蛋白酶活性无显著性差异。在瓦氏黄颡鱼饲料中可以适量添加羽毛肽粉,添加水平在10%以内时,可以显著提高瓦氏黄颡鱼摄食量,促进其生长。     

周期性饥饿再投喂对大菱鲆幼鱼生长、生化组成和能量收支的影响

在水温为17～19℃条件下,分别以鲜杂鱼(x)和配合饲料(p)为饵料,采用一直投喂(对照组)和周期性饥饿1 d再投喂6 d(S1F6)、饥饿2 d再投喂5 d(S2F5)3种投喂方式,研究投喂不同饵料时周期性饥饿再投喂对大菱鲆Scophthalmus maximus幼鱼(体质量为7.80 g±0.01 g)生长、生化组成和能量收支的影响,试验共进行42 d。结果表明:投喂配合饲料时,S1F6p和S2F5p组均具有完全补偿生长现象;投喂鲜杂鱼时,S1F6x组具完全补偿生长现象,S2F5x具部分补偿生长现象;投喂配合饲料和鲜杂鱼时,周期性饥饿再投喂处理的大菱鲆幼鱼均通过饲料转化效率和摄食率共同提高来实现其补偿生长,且各试验组的鱼体成分和对照组均无显著性差异(P>0.05);与对照组相比,试验处理组幼鱼的生长能比例均有所增加,而代谢能比例均有所减少;无论是处理组还是对照组,鲜杂鱼的投喂效果均优于配合饲料。     

叶酸对铅中毒幼年大鼠中枢神经系统的保护作用

通过研究铅对大鼠中枢神经元的损伤以及应用叶酸后的影响，探讨了叶酸对铅中毒条件下中枢神经元的保护作用。将健康清洁级初断乳3周龄SD大鼠随机分为铅染毒组，叶酸给药组及生理盐水组。各组于处理后第2、3、4周取材。铅染毒组、叶酸给药组每组各30只，生理盐水组12只，共72只。测量血铅，分别进行海马和小脑组织的H—E染色及凋亡抑制基因Bcl—2、凋亡基因Bax的蛋白免疫电泳，并作光密度分析。结果，通过对各个时间段各组血铅测定，可得叶酸给药组血铅含量低于铅染毒组。铅染毒组Bcl-2蛋白表达量少于给药组，而Bax多于给药组，H—E染色结果铅染毒组神经细胞数量明显少于叶酸给药组。结果表明，叶酸可降低铅中毒大鼠的血铅浓度，并具有一定抗细胞损伤作用，对铅中毒大鼠的中枢神经元具有一定的保护作用。     

浅议市级图书馆服务少年儿童读者

结合市级图书馆的实际和少年儿童读者的特点,就市级图书馆为少年儿童读者服务的问题进行阐述,指明了素质教育背景下市级图书馆儿童读者工作的重要性及发展方向。     

Detection efficiency and habitat use to inform inventory and monitoring efforts: juvenile coho salmon in the Knik River basin,Alaska

Imperfect detection associated with sampling gear presents challenges for wildlife inventory and monitoring efforts. We examined occupancy dynamics and habitat use of juvenile coho salmon, Oncorhynchus kisutch, in shallow lake environments over a summer and early fall season in the Knik River area of south central Alaska using models which control for and estimate sampling gear detection efficiency. In addition, we present statements for the probability that observed absences at a survey site or from a survey area (a collection of sites) are true absences given some amount of sampling effort and analysts' beliefs about site occupancy and sampling gear detection efficiency which can be used to guide inventory and monitoring efforts for juvenile salmon or other wildlife and plant species. Occupancy modelling results demonstrate that minnow traps were effective at sampling juvenile coho in shallow lake environments, with a mean probability of detection across the study period of 0.68 (i.e., probability of detecting the presence of juvenile coho given that they are present at a trap site; SE = 0.03). Juvenile coho salmon migrated into shallow water lakes in late summer and early fall, presumably to seek out overwinter habitat. N‐mixture modelling examination of habitat use demonstrated that once in shallow lake environments, juvenile coho were widely distributed across a range of microhabitats, with some evidence for preference for shallower depths and warmer water temperatures.