青虾红体综合症病原研究

采用常规的细菌分离法，从患红体综合症的青虾肝胰腺和肌肉组织中各分离到一个菌体，两个菌株的生长和生化特性完全一致，定名为青虾980910，以该菌株人工感染健康青虾，可引起虾发病死亡，表明为病原菌，该菌株革兰氏染色阴性，短杆状，弧形，有一根细长的鞭毛，经API－20E试条生化分析，鉴定为拟态弧菌，药敏试验显示，该病原菌对环丙沙星，氟派酸，荼啶酸，利复平等敏感。     

Epibionts and parasites of Macrobrachium rosenbergii and Metapenaeus dobsoni from Gosthani estuary

Juveniles of two species of commercially important prawns, Metapenaeus dobsoni (Miers) and Macrobrachium rosenbergii (De Man) collected from Gosthani estuary, Bheemunipatnam near Visakhapatnam, India during the period August 1995 to August 1996 were subjected to a detailed study with a view to identifying the various species of epibionts and parasites and to monitor the seasonal changes in the occurrence and abundance of common species of ciliates and larval helminths. A wide range of protozoan and metazoan parasite species was encountered in the prawns. The protozoans were represented by epicommensal ciliates belonging to the genera Zoothamnium, Epistylis, Acineta, Vorticella, an unidentified apostome ciliate and two species of gregarines. The metazoan parasites included metacercariae of families Opecoelidae and Microphallidae, a larval cestode, a larval nematode and two species of bopyrid isopods. Altogether eight species were found infecting M. rosenbergii and 11 species infected M. dobsoni. A majority of the parasite species infected both the hosts. The peritrichous and apostome ciliates constituted the dominant members of the parasite fauna, occurring on both species of prawns as epibionts with high prevalence and density. All the other infections were rarely encountered. Infections with gregarines were restricted to M. dobsoni while those of microphallid metacercariae were found only in M. rosenbergii. Zoothamnium infections were more common on M. rosenbergii than on M. dobsoni. Apparent differences in the parasite fauna, attributed to differences in the behaviour of the two species, were noted. Seasonally Zoothamnium infections were at their peak during monsoon and post-monsoon months and these infections appear to be governed directly by salinity of the habitat and indirectly by the rainfall. Apostome ciliate infections were at their peak during the months November and February. Opecoelid metacercarial infections were confined to the period August to February, with peak during summer months.     

盐度对罗氏沼虾代谢率的影响

测定了4个盐度水平(0‰,3‰,6‰,12‰)下罗氏沼虾雌雄成虾在饥饿状态下的耗氧率和排氨率．结果表明,随着盐度的增高,罗氏沼虾雌雄成虾耗氧率和排氨率都有增高趋势,在3‰盐度时,罗氏沼虾的耗氧率和排氨率最低;在同一盐度水平下,雌虾的耗氧率和排氨率较雄虾高．     

柠檬酸稀土对青虾卵子孵化的影响

研究了柠檬酸稀土对青虾Macrobrachiumnipponense卵子孵化的影响,结果表明:当柠檬酸稀土的浓度为0.1～0.6mg/L时,孵化率无显著差异;当柠檬酸稀土的浓度为1.2～4.8mg/L,孵化率比对照组高10.6%～26.2%,当柠檬酸稀土的浓度大于9.6mg/L后,孵化率显著降低.卵子对柠檬酸稀土的饱和吸收量为7.95μg/粒.     

亚油酸对培养日本沼虾肝胰腺细胞的影响

对日本沼虾肝胰腺细胞进行培养,采用M199 (GIBCO BRL) 细胞培养基加质量分数为10%的胎牛血清,添加的补充成分有:NaCl,NaHCO3,MgCl2,CaCl2,葡萄糖,青霉素和链霉素.同时对pH和渗透压两因子进行了研究,结果表明pH 7.0～7.2、渗透压为600 μmol/g时,细胞长势最好.以此作为培养条件,在培养基中加入促细胞生长因子的亚油酸,发现其促生长作用明显,其中亚油酸浓度为16×10-5 mol/L时,促进作用最好.日本沼虾肝胰腺细胞共继代2次,存活时间约45 d.     

养殖青虾“红鳃病”病原的研究

从养殖虾的肝、鳃分离的细菌进行生理生化鉴定、药物敏感及感染试验等 ,结果表明：经细菌学鉴定二株病原菌,均为嗜水气单胞菌 Aeromonas hydrophila;对虾的半数致死量 LD50分别为 1.68× 104个 /只、 3.95× 103个 /只;细菌对药物的敏感性有明显差异。     

不同波长光照对日本沼虾视觉的影响

被剪去触角的日本沼虾经过暗适应12h后，在不同波长的红光(750nm)，黄光(580nm)蓝光（400nm)，绿光(560nm)下，其平均摄食量差异极显著。在红光和绿光光照区域内的平均摄食量为65．71％和61．15％，远大于蓝光和黄光光照区域内的41．86％和33．08％。同样经过12h的暗适应后，在无饵料的情况下，日本沼虾的趋光行为为红光的频次最高。     

水温对罗氏沼虾和青虾心率及组织中镁的影响

罗氏沼虾的心率随水温的降低而变化,在17℃时只有79次 min,为30℃的1 3;其血清Mg的含量随水温的降低而升高,肌肉中Mg有降低的趋势,但差异不明显。青虾心率在水温从24℃到17℃时,无明显改变;血清Mg随水温的降低而升高,但变化幅度小于罗氏沼虾。     

罗氏沼虾(Macrobrachium rosenbergii)血细胞的分类与组成

目的:对罗氏沼虾的血细胞进行分类,研究各类血细胞的组成情况.方法:从罗氏沼虾心脏取血制血涂片,经瑞氏染色后光镜观察.结果:根据血细胞的形态、核质比、细胞质颗粒的大小与分布以及染色情况,可将罗氏沼虾的血细胞分为:①透明细胞,其胞质中无明显颗粒,核质比大;②半颗粒细胞,其胞质中含有明显的颗粒,颗粒大小不均,分布不均匀,核质比小;③颗粒细胞,其胞质中含有明显的颗粒,颗粒大小均一,分布均匀,核质比小.结论:罗氏沼虾的血细胞可分为透明细胞、半颗粒细胞和颗粒细胞3类,它们在血细胞中所占比例依次为:颗粒细胞<半颗粒细胞<透明细胞.     

低氧胁迫对日本沼虾呼吸代谢和抗氧化能力的影响

为阐明低氧胁迫对日本沼虾呼吸代谢和氧化代谢的影响,并初步探讨其作用机制及日本沼虾的抗氧化响应机制,将日本沼虾暴露于低氧((2±0.2)mg/L,8 h)而后恢复常氧水平((7±0.2)mg/L,2.5 h).结果显示:与对照组(保持常氧水平)相比,随着低氧暴露时间延长,日本沼虾肝胰腺和肌肉组织细胞色素氧化酶(CCO)和琥珀酸脱氢酶(SDH)活力显著下降(p0.05),延胡索酸还原酶(FRD)和乳酸脱氢酶(LDH)活力显著上升(p0.05);总抗氧化能力(T-AOC)和过氧化氢酶(CAT)活力显著上升(p0.05),超氧化物歧化酶(SOD)活力显著下降(p0.05).恢复常氧阶段,CCO,SDH,FRD,LDH,CAT和SOD活力逐渐恢复到正常水平,T-AOC在恢复常氧1 h时显著降低(p0.05),而后恢复到正常水平.低氧胁迫使得有氧代谢减弱,无氧代谢增强,以维持机体能量需求;T-AOC和CAT活力增加而SOD活力降低,是日本沼虾适应低氧环境所采取的一种抗氧化策略.