克氏原螯虾X器官-窦腺复合体的组织学观察

应用组织切片技术观察了克氏原螯虾眼柄神经内分泌系统的结构,研究了XO-SG复合体的分布.结果表明,克氏原螯虾眼柄神经内分泌系统主要组成部分为X器官-窦腺复合体.X器官分布在视神经节上,由Ⅰ～Ⅵ型6种神经分泌细胞构成,均为单级神经元.Ⅰ～Ⅵ型分泌细胞类型及数量在不同生长期存在差异.窦腺位于视内髓与视端髓之间的背内侧,由窦腺壁和中央血窦腔组成;窦腺壁由神经分泌细胞的末梢、神经胶质细胞及其突起交织而成.     

克氏原螯虾不同发育阶段卵巢中EST同工酶比较

[目的]研究克氏原螯虾(Procambarus clarkii)卵巢成熟过程EST的变化。[方法]采用聚丙烯酰胺凝胶电泳方法,分析了卵黄形成期和成熟期卵巢中酯酶同工酶(EST)的表达情况。[结果]所研究的两个阶段卵巢中EST同工酶的表达可分为Ⅰ、Ⅱ、Ⅲ共3个区。其中Ⅰ区和Ⅱ区卵黄形成期EST表达较强,酶带明显比成熟期浓,尤其是Ⅰ区,卵黄形成期EST同工酶的表达最强。相反,在Ⅲ区,成熟期EST酶带明显比卵黄形成区浓。[结论]在克氏原螯虾卵子成熟过程中,EST基因的表达存在时间差异性。     

多重周期饥饿后克氏原螯虾的补偿生长及生理指标变化

[目的]探讨克氏原螯虾的生理指标与其饥饿补偿生长的相关关系。[方法]通过分组饲养试验研究了不同周期性饥饿对试验螯虾生长和生理指标的影响。[结果]72d后,SR22、SR44和SR66组的螯虾体重极显著高于对照组,SR11组的螯虾体重和对照组无显著差异;各处理组螯虾的单周期特殊生长率均高于对照组。SR11、SR22和SR44组螯虾SOD活性和存活率与对照组无显著差异。随着饥饿时间的增加,螯虾的消化酶活性、含肉率和肌糖原含量在SR00、SR11、SR22和SR44组极显著上升,在SR66、SR88、SR1212和SR1818组极显著下降;其肝糖原含量和肝体比在SR00、SR11、SR22和SR44组呈上升趋势。SR66和SR88组螯虾的消化酶活性极显著高于对照组。SR44组的肠胃淀粉酶和蛋白酶活性最高。螯虾的肝体比、肌糖原含量、肝糖原含量均在SR44组达到极大值,在SR1818组达到极小值。[结论]该研究为提高克氏原螯虾的养殖收益奠定了理论基础。     

克氏原螯虾暴发病细菌性病原的研究

从患暴发病的克氏原螯虾(Procambarus clarkii)的肝胰腺中分离到3株细菌.人工注射感染显示,KSAX-3分离菌在浓度1010cfu/mL时可使95%以上健康克氏原螯虾死亡;在106cfu/mL浓度时可导致70%的健康克氏原螯虾死亡,并使克氏原螯虾出现明显的与自然条件下相似的疾病症状,试验结果表明该分离菌为克氏原螯虾致病菌.KSAX-3菌的主要生理生化特性为:革兰氏阴性,单鞭毛,发酵葡萄糖,甘露醇、氧化酶、鸟氨酸脱羧酶、赖氨酸脱羧酶阳性,精氨酸脱羧酶、水杨酸、枸橼酸盐(西蒙氏)阴性,在含0%、10%NaCl的普通培养基中不生长,在含2%、4%、6%、8%NaCl的普通培养基中生长,在30℃、35℃、40℃、42℃条件下生长良好.鉴定该菌为副溶血弧菌(Vibrio parahaemolyticus).药敏试验结果表明,该菌对盐酸土霉素、盐酸四环素、环丙沙星、诺氟沙星、金霉素、硫酸卡那霉素、交沙霉素、烟酸诺氟沙星等8种药物敏感.     

美国路易斯安那州的克氏原螯虾产业发展概述

阐述了美国路易斯安那州的克氏原螯虾产业的概况,包括路易斯安那州的螯虾养殖业发展简史、螯虾历年的渔获状况、近十年来的螯虾批发价格统计及典型的养殖模式等,为国内克氏原螯虾业发展提供借鉴。     

Comparative acute toxicity of neonicotinoid and pyrethroid insecticides to non‐target crayfish (Procambarus clarkii) associated with rice–crayfish crop rotations

BACKGROUND: Most insecticides used to control rice water weevil (Lissorhoptrus oryzophilus Kuscel) infestations are pyrethroids. However, pyrethroids are highly toxic to non‐target crayfish associated with rice–crayfish crop rotations. One solution to the near‐exclusive reliance on pyrethroids in a rice–crayfish pest management program is to incorporate neonicotinoid insecticides, which are insect specific and effective against weevils but not extremely toxic to crayfish. This study aimed to take the first step to assess neonicotinoids as alternatives to pyrethroids in rice–crayfish crop rotations by measuring the acute toxicities of three candidate neonicotinoid insecticides, clothianidin, dinotefuran and thiamethoxam, to juvenile Procambarus clarkii (Girard) crayfish and comparing them with the acute toxicities of two currently used pyrethroid insecticides, lambda‐cyhalothrin and etofenprox. RESULTS: Neonicotinoid insecticides are at least 2–3 orders of magnitude less acutely toxic (96 h LC₅₀) than pyrethroids to juvenile Procambarid crayfish: lambda‐cyhalothrin (0.16 µg AI L^?1) = etofenprox (0.29 µg AI L^?1) ? clothianidin (59 µg AI L^?1) > thiamethoxam (967 µg AI L^?1) > dinotefuran (2032 µg AI L^?1). CONCLUSION: Neonicotinoid insecticides appear to be much less hazardous alternatives to pyrethroids in rice–crayfish crop rotations. Further field‐level neonicotinoid acute and chronic toxicity testing with crayfish is needed. Copyright © 2009 Society of Chemical Industry     

溴氰菊酯对克氏原螯虾肌肉组织的毒性研究

为研究溴氰菊酯对克氏原螯虾的毒性效应及致毒机制,实验将克氏原螯虾成虾暴露于农药溴氰菊酯0.5、0.1和0.005μg/L三个浓度的药液中24h后,采用透射电镜观察克氏原螯虾肌肉组织超微结构损伤情况,并以细胞色素氧化酶活力(CCO)、乳酸脱氢酶活力(LDH)和乳酸(LD)含量为生物标志物评价溴氰菊酯对克氏原螯虾肌细胞呼吸产能功能的影响。结果显示,三个浓度的溴氰菊酯都会造成肌细胞超微机构不同程度的损伤,且浓度越大损伤越严重,损伤主要表现为肌原纤维断裂、肌浆网溶解,线粒体溶解。此外,三个浓度的溴氰菊酯都会对CCO活力、LDH活力和LD含量产生影响。其中0.1 μg/L的溴氰菊酯在6~24 h的暴露处理过程中会对肌肉的CCO活力产生极显著的抑制作用(P<0.01), LDH活力增强,乳酸含量上升。研究表明,0.5、0.1和0.005μg/L溴氰菊酯可以造成克氏原螯虾肌细胞超微结构损伤,激活细胞的厌氧呼吸,在组织中产生大量的乳酸,乳酸的蓄积会对造成细胞酸化而加重对细胞的毒性。     

一株克氏原螯虾雷氏普罗威登斯菌的分离鉴定与联合药敏试验

为了探明克氏原螯虾(Procambarus clarkii)5—6月死亡的病因并制定相应的治疗方案,本试验从患病克氏原螯虾肝胰腺中分离到1株病原菌(L20190509),通过生理生化特征、16S rRNA序列分析和进化树进行鉴定,通过琼脂扩散法测定了该菌株的药物敏感性,进一步研究了抗菌药物与天然化合物的联合抑菌作用.结...     

低pH胁迫对克氏原螯虾鳃和肝胰腺酶活力及组织结构的影响

采用石蜡切片技术,结合生物酶的测定,以体重(25.88±4.40)g的克氏原螯虾(Procambarus clarkii)为研究对象,研究了低pH胁迫对克氏原螯虾鳃和肝胰腺生理代谢与组织结构的影响。在得出96 h LC50的基础上,将克氏原螯虾暴露于半致死浓度pH水体中96 h,以pH7.6作为对照,并于胁迫后0 h、2 h、8 h、24 h、96 h采集鳃和肝胰腺样品,测定鳃部分代谢酶和肝胰腺主要抗氧化指标,并对鳃和肝胰腺组织进行切片观察。实验结果表明,pH 96 h LC50为3.675。低pH暴露后,实验组鳃Na~+-K~+-ATP酶和乳酸脱氢酶(lactate dehydrogenase,LDH)活力逐渐升高,细胞色素氧化酶(cytochrome oxidase,COO)活力逐渐下降;肝胰腺超氧化物歧化酶(superoxide dismutase,SOD)和过氧化氢酶(catalase,CAT)活力呈现先上升后下降的变化趋势,丙二醛(malondialdehyde,MDA)在肝胰腺中的累积量显著增加(P0.05)。切片结果表明,低pH胁迫引起克氏原螯虾鳃组织中呼吸上皮细胞逐渐脱落,角质层受损;肝胰腺组织中B细胞及其内部转运泡体积增大,转运泡内颗粒物质增多,肝小管结构受损。研究结果表明,低pH胁迫会对克氏原螯虾生理代谢产生影响,并引起组织缺氧;虾体氧化防御功能在胁迫前期被诱导激活,但在胁迫后期受到一定抑制;低pH胁迫可以引起克氏原螯虾鳃和肝胰腺组织结构损伤。     

Shadow area and partitioning influencing mortality,healthiness and growth of juvenile Red Swamp Crayfish Procambarus clarkii (Decapoda)

Crayfish show both shelter‐seeking behaviour and agonistic behaviour. Agonistic interactions among crayfish combatants can be triggered and released by the access of shelter, which is a necessary resource for crayfish. The use of shadow as a shelter has not been thoroughly tested in experiments. In this study, we provided the Red Swamp Crayfish Procambarus clarkii (Girard) with different shadow area and shadow partition to test if shadow can act as a solid shelter. Eleven different treatments designed with different shadow area and partition, and 2640 juvenile crayfish were used. The survival rate increased with the increase of shadow area ratio. The shadow area contributed less to the body weight gain and the number of the survivals without injury. The growth variance of the juveniles under shadow conditions was significantly lower than those maintained without providing shadow. Under the recent experimental settings, generally, more partitioned shadow resulted in lower mortality. With 60% shadow area, more partitioned shadow led to higher body weight gain. The more the partition was provided, the fewer were the injury events, and the lower body weight variance observed. Our experiments indicated that both area and partition of the shadow influenced the growth of juvenile Red Swamp Crayfish.