镉暴露对鲢幼鱼游泳行为影响的研究

为了探讨水体镉(Cd)污染对鱼类的生态毒理效应,在实验室条件下,测定了不同浓度Cd(0、0.36、0.73、1.09和1.46 mg/L)暴露对鲢(Hypophthalmichthys molitrix)幼鱼半致死浓度、组织(肝、鳃、肌肉)Cd累积量、相对临界游泳速度(Ucrit)、以及耗氧率(MO_2)的影响。结果显示:Cd暴露导致重金属在幼鱼组织中累积,与对照组比较,Cd在鳃和肌肉中累积量差异不显著;肝脏中累积量差异显著,暴露浓度为0.73 mg/L时肝脏中镉累积量最高。鲢幼鱼相对临界游泳速度随着Cd暴露增加显著降低,浓度为1.46 mg/L时Ucrit为对照组的69.75%。临界游泳速度与鳃和肌肉组织中镉累积量呈显著负相关,相关系数分别为-0.96(P=0.01)和-0.90(P=0.04)。Cd暴露导致鲢幼鱼耗氧代谢范围增加,暴露浓度为0.73 mg/L时耗氧代谢范围较对照组增加了19.32%。低浓度Cd暴露导致鳃和肌肉损伤,并引起鲢幼鱼游泳过程中耗氧代谢效率降低,有氧运动能力和游泳能力下降。     

Alternative protein blends as a replacement for fish meal in diets for white seabass,Atractoscion nobilis

An 8‐week feeding trial was conducted to determine the effectiveness of replacing fish meal (FM) with blends of alternative proteins in diets for white seabass (WSB, Atractoscion nobilis) at a starting weight of 5.6 g. Five diets were formulated with 400–440g kg^?1 crude protein (380g kg^?1 digestible). These included a high 520g kg^?1 FM control diet, a series of three diets with a sequential replacement of FM containing 410g kg^?1, 510g kg^?1 and 630g kg^?1 of a soy‐based protein blend (SPC) and 200g kg^?1, 100g kg^?1 and 0g kg^?1 FM, respectively and a fifth diet containing 550g kg^?1 of a corn‐based protein blend (CGM) and 100g kg^?1 FM. Survival was highest in the FM control group at 99% but all other performance measures (weight gain, feed conversion ratio, specific growth rate and protein retention efficiency) were worse than the other treatment groups. Weight gain reached a maximum of 595% in the SPC 200g kg^?1 FM treatment group. Performance decreased as inclusion of the soy‐based protein blend increased. The CGM treatment performed comparably to the SPC 100g kg^?1 FM treatment among all measures, except for survival, which was higher in the CGM 100g kg^?1 FM treatment. With nutrient levels and alternative protein blends used in this study, FM can be reduced to 100g kg^?1 of the diet for WSB without reductions in performance.     

非离子氨和亚硝态氮对鳙幼鱼的急性毒性试验

在水温(20.0±0.2)℃、pH值(7.66±0.03)、溶解氧5 mg/L的条件下,采用半静水试验方法研究了非离子氨和亚硝态氮对平均体长(5.88±0.16)cm、平均体质量(3.42±0.22)g的鳙幼鱼的急性毒性效应。结果表明,受到非离子氨和亚硝态氮胁迫后,鳙幼鱼出现呼吸急促、游动失去平衡、抽搐、侧翻、体色变深、活力降低等中毒症状,直至最后死亡,其死亡率与非离子氨、亚硝态氮浓度和胁迫时间之间存在明显的剂量效应和时间效应关系。非离子氨和亚硝态氮对鳙幼鱼96 h半致死浓度分别为0.727 mg/L和79.180 mg/L,安全浓度分别为0.073 mg/L和7.918 mg/L。相对于非离子氨,鳙幼鱼对亚硝态氮的耐受性更强。     

黄斑星天牛和光肩星天牛幼虫两种同功酶的测定

对黄斑星天牛和光肩星天牛的血清蛋白同功酶和过氧化物同功酶测定结果,可以看出两种天半的这两种同功酶种间差异表现在Ａ区１～２条酶带宽窄、深浅的差异,而总体的差异不大,说明这两种天牛是近缘种类。     

杨树对黄斑星天牛的抗性研究

采用在抗虫鉴定圃内人工接种的方法研究各种杨树对黄斑星天牛抗性,结果表明:白杨派树种毛白杨、河北杨等抗虫,黑杨派、青杨派及其某些杂种杨树尤金杨、Ⅰ—214、陕林2号、大官杨等感虫。在实验基础上提出了30种杨树对黄斑星天牛的抗性序列。     

黄斑星天牛循环系统的形态解剖

黄斑星天牛(Anoplophora nobilis Ganglballer)循环系统属开放式循环,由一条纵贯背血窦中央的背血管组成。幼虫、蛹和成虫的背血管均包括心脏和动脉两部分。心脏由一系列稍膨大的心室组成,心室的数目与腹部体节的数目基本一致,幼虫为8个,成虫、蛹为6个。每个心室两侧各有一对翼肌以扇形的尖端部分附着于体壁的节间膜上,蛹的翼肌肌丝不发达。     

宁夏光肩星天牛、黄斑星天牛天敌昆虫的研究

宁夏光肩星天牛和黄斑星天牛天敌昆虫自然种群很少,主要有花绒穴甲寄生天牛的老熟幼虫、蛹、成虫,柿树螟蛾捕食天牛卵,寄生蝇、虱蝇类寄生天牛幼虫和蛹,姬小蜂寄生天牛蛹．花绒穴甲是大型杨树天牛最有价值的优势天敌种,在宁夏很多地区有少量发现．该虫自然扩散能力弱,分布狭窄,在生态条件较好的地区寄生率较高,其它昆虫偶尔发现有寄生和捕食现象,但数量极少．     

鲢肌球蛋白重链球状结构域的cDNA克隆及结构解析

根据已经获得的两种鲢肌球蛋白重链同工型基因(低温型sc-w和高温型sc-s)在3′端展现的明显差异,设计了2个特异性的反向引物,以鲤科鱼类肌球蛋白重链5′端的保守序列为正向引物,通过Long-PCR对编码鲢两种肌球蛋白重链同工型的球状结构域(Subfragment-1,S1)的全长基因进行了克隆和测序,并推断出它们一级结构的氨基酸序列。研究结果表明,sc-w与sc-s在S1的初级结构上显示80.5%的同源性、与已经报道的草鱼低温型(gc10)有97.2%的高同源性;sc-s则与草鱼中间型(gcI)和高温型(gc30)显示了分别为98.4%和97.1%的高同源性。低温型的sc-w和gc10在S1初级结构上展现的特有变异主要发生在43个氨基酸残基位点,其中15个属保守性残基。对S1区域中两个功能性的表面环loop1(与ATP结合位点有关)和loop2(与肌动蛋白结合位点有关)的结构解析发现,sc-w和gc10在两个表面环的长度、残基电荷分布和氨基酸组成等方面与其它同工型之间存在明显差异,揭示了这两个表面环的结构差异可能影响了栖息于不同环境温度下的淡水鱼的肌球蛋白分子马达功能。分子系统树的分析结果进一步证明,鱼类栖...     

鲢鳙放养对水体微生物碳源利用影响的围隔试验

利用Biolog技术就滆湖原位围隔内鲢鳙放养密度和比例对水体微生物碳源利用的影响进行了研究。结果显示,在试验阶段后期不同围隔内水体微生物对碳源总量的利用相对于试验中期有较明显的变化。未放养鲢鳙的对照组(A0)在试验后期对于碳源总量的利用低于各实验组(A_1:鱼密度40 g/m~3、鲢鳙比7∶3;A_2∶40 g/m~3、3∶7、A_3∶80 g/m~3、7∶3和A_4∶80 g/m~3、3∶7)。试验中期和后期,利用比例较高的碳源类型均为聚合物。主成分分析表明,试验后期不同围隔水体微生物群落碳代谢方式具有显著差异。其中,与主成分1显著相关的碳源主要有16种,分别属于聚合物、糖类、羧酸、氨基酸。实验中期和后期围隔水体微生物碳代谢多样性指数Shannon物种多样性指数、丰富度指数和Pielou均匀度指数均存在显著差异,代谢多样性指数最高的是实验组A1,实验组A4碳代谢多样性指数相对较低。根据鳙的绝对生物量、多样性指标以及对碳源的总量利用,可以得出以鲢鳙主导的微型生态系统中,鳙的绝对生物量对于水体微生物影响更加显著。     

Effects of algae particle size on the breathing and feeding of filter‐feeding silver carp (Hypophthalmichthys molitrix Val.)

A variety of parameters associated with breathing and feeding of silver carp were measured in response to declines in dissolved oxygen (DO) levels when the fish were fed microalgae Padorina morum (PM group) and Chlorella ellipsoidea (CE group), respectively, to explore the relationship between breathing and feeding while filtering microalgae particles at different DO levels. The results indicated that (i) respiratory frequency (f_R) of the fish in CE group were higher significantly than those in PM group at DO levels of 0.98–7.49 mg/L (P < 0.05); respiratory stroke volume (V_S.R), gill ventilation (V_G) and V_G/VO₂ the fish in two groups began to increase sharply while DO levels declined to below 4.04 mg/L (P < 0.05); oxygen extraction efficiency (EO₂) of the fish in two groups increased significantly with decline of DO levels from 7.49 mg/L to 0.98 mg/L (P < 0.05); (ii) the infiltration rate (FR) and filtering efficiency (E) of the fish in two groups began to decrease significantly while DO levels declined to below 4.04 mg/L (P < 0.05); clearance rate (CR) of fish in PM group was sixfold higher than that in CE group at DO levels of 0.98–7.49 mg/L (P < 0.05). In addition, antifiltering response appeared at DO levels of 2.21 mg/L and 0.98 mg/L in both groups. This study indicated that ‘filtration effect’ is dominant when the fish filter algae particles larger than its gill raker gaps, while the ‘food sinking effect’ is dominant when the fish filter algae particles smaller than its gill raker gaps.