酵母细胞壁多糖和硫化氢对罗氏沼虾 3 种免疫酶活性的影响简

正虾类病害是严重影响虾类养殖业发展的一个重要因素,而虾类疾病的发生与养殖水体环境的恶化有明显的关系[1,2],因此重视水体生态环境质量,关注环境因子对虾蟹类非特异性免疫的影响,已成为新的研究热点[3,4]。硫化氢是水产动物养殖水体中常见的有毒害作用的物质,也是一个重要的监测养殖水环境的化学指标,硫化氢污     

Isolation and characterization of microsatellites in giant freshwater prawn Macrobrachium rosenbergii

Microsatellite loci were characterized in a freshwater prawn from enriched genomic library using six biotinylated probes: (AG)₁₀, (TG)₁₀, (CAA)₁₀, (CAG)₁₀, (GAT)₁₀ and (TAC)₁₀. Primers for DNA amplification were designed and synthesized for 20 loci. Ten loci were polymorphic with the number of alleles ranging from five to 17 alleles per locus and the observed heterozygosity ranging from 0.27 to 0.83 per locus. Developed microsatellite primers should prove useful for selective breeding programs and population genetic studies of freshwater prawn.     

罗氏沼虾苗肌肉白浊病病原的初步研究

收集罗氏沼虾肌肉白浊病典型病虾苗 ,进行细菌分离、除菌组织悬液制备及人工感染试验、超薄切片、病毒粗提取 ,结果表明 :从白浊病病虾的肌肉、肝胰腺中分离到的细菌以5× 1 0 8CFU/mL浓度浸泡感染正常沼虾苗不能复制疾病 ;病虾除菌组织过滤液以 1∶5 0、1∶2 5 0浓度浸泡感染正常虾苗 ,7d后可发病 ,并出现典型的肌肉白浊病症状 ,氯仿处理不能破坏病毒的感染力 ;病虾超薄切片电镜观察发现肌肉间隙组织中存在 2 1— 2 3nm大小的球状病毒 ,病虾组织浆经氯仿处理、PEG沉淀、磷钨酸负染后可见到大量 2 2— 2 4nm大小的球状病毒颗粒。上述结果表明罗氏沼虾肌肉白浊病是一种由病毒引起的疾病。     

罗氏沼虾亲虾越冬池中不同基质上微生物群落多样性分析

【目的】了解罗氏沼虾亲虾越冬时循环养殖系统对水质的调控效果,探明其中微生物群落的作用。【方法】采集循环养殖系统运行88 d后的越冬池池水、池中人工水草(普通纤维膜)以及外置式生物滤器中的纳米纤维膜等3种不同基质上的微生物,利用DNA抽提、PCR扩增和定量以及高通量Mi Seq测序技术等对3种不同基质上的微生物进行16S r RNA基因序列V4-V5区的测定和分析,并根据测序得到的双端测序读长(Pair-end reads)进行质量控制和过滤,之后进行操作分类单元(OTU)聚类分析,并基于OTU对微生物群落的多样性指数和群落结构进行分析;每3-4 d对越冬池池水水质进行监测。【结果】养殖池塘的水质保持在良好的状态,其中氨氮和亚硝氮浓度控制在0.17±0.08 mg/L和0.28±0.15 mg/L;不同基质上的微生物组成和多样性都不相同。在3种基质上共检测并鉴定出细菌64种,隶属于9门64属,包括变形菌门(Proteobacteria)、放线菌门(Actinobacteria)、拟杆菌门(Bacteroidetes)、绿弯菌门(Chloroflexi)、厚壁菌门(Firmicutes)、浮霉菌门(Planctomycetes)、硝化螺旋菌门(Nitrospirae)、酸杆菌门(Acidobacteria)和绿菌门(Chlorobi)。从属水平上对3种基质上的细菌进行分析,发现养殖池水中含量最高的为丛毛单菌科下的一个未分类类群(Comamonadaceae_unclassified),其也是3种基质的共有优势类群;普通纤维膜上为Inhella,纳米纤维膜上则是小纺锤状菌属(Fusibacter)。3种基质上细菌群落多样性顺序为:纳米纤维膜普通纤维膜养殖池水。通过对亲虾越冬养殖全过程的水质监测,发现越冬期间亲虾池水质始终保持在良好状态,并且在循环水系统开启约40 d后水质达到了相对稳定的状态。【结论】通过在育苗池中悬挂人工水草,配合内含纳米纤维膜的外置式生物滤器,可使罗氏沼虾越冬亲虾池保持良好的水质。随着新型材料科学的发展,开发出适用于水产养殖业的滤料很有必要。     

Heterochrony in mandible development of larval shrimp (Decapoda: Caridea)—A comparative morphological SEM study of two carideans

Mandible development in the larval stages I–V of two palaemonid shrimp species, Palaemon elegans and Macrobrachium amazonicum, was analyzed using scanning electron microscopy, light microscopy, and confocal laser scanning microscopy. In contrast to the zoea I of P. elegans, first‐stage larvae of M. amazonicum are nonfeeding. At hatching, the morphology of the mandibles is fully expressed in P. elegans, while it appears underdeveloped in M. amazonicum, presenting only small precursors of typical caridean features. In successive zoeal stages, both species show similar developmental changes, but the mandibular characters of the larvae in M. amazonicum were delayed compared to the equivalent stages in P. elegans, especially in the development of submarginal setae and mandible size. In conclusion, our results indicate heterochrony (postdisplacement) of mandible development in M. amazonicum compared to that in P. elegans, which is related to initial lack of mandible functionality or planktivorous feeding at hatching, respectively. This conclusion is supported by comparison with other palaemonid zoeae exhibiting different feeding modes. Our data suggest that an evolutionary ground pattern of mandible morphology is present even in species with nonfeeding first‐stage larvae. J. Morphol. 275:1258–1272, 2014. © 2014 Wiley Periodicals, Inc.     

Setal morphology of the grooming appendages of Macrobrachium rosenbergii (Crustacea: Decapoda: Caridea: Palaemonidae) and review of decapod setal classification

Setae are vital in grooming activities and aiding in the removal of epibionts and sedimentary fouling from the body surfaces of decapod crustaceans. Thus, the setal structures and their arrangement on the grooming appendages and sensory structures of the commercially important shrimp, Macrobrachium rosenbergii, were examined using scanning electron microscopy. Macrobrachium rosenbergii is extensively grown in aquaculture and exhibits unique male morphological forms, termed morphotypes. The three male morphotypes are termed blue‐clawed males, orange‐clawed males, and small‐clawed or undifferentiated males and all three differ in their dominance, behavior, body morphology, and reproductive success. Seven setal types, two of which have never been described in the literature, are identified on the grooming appendages (third maxillipeds, first, second, and fifth pereopods) and antennae: simple, serrate, serrulate, spiniform, pappose, crinoid, and spinulate. The latter two setae are newly identified. Certain setal types, such as serrate and serrulate setae were located and associated with specific grooming appendages such as the first pereopods. The types of setae on the grooming appendages varied among females and male morphotypes and the novel setal types (crinoid and spinulate) were found only on two of the male morphotypes. A literature review of terminology related to the structure of setae and setal types in decapod crustaceans is offered as the usage of various terms is ambiguous and conflicting in the literature. The intention of this review is to provide future authors with a comprehensive collection of terms and images that can be used to describe various aspects of setal morphology in decapods. J. Morphol. 275:634–649, 2014. © 2014 Wiley Periodicals, Inc.     

The effects of chemical and visual communication, space availability, and substratum color on growth of the juvenile freshwater prawn Macrobrachium rosenbergii (De Man)

The effects of chemical and visual communication, space availability, and substratum color on the growth of juvenile Macrobrachium rosenbergii (De Man) were studied by recording the changes in average weight and length of prawns kept at controlled densities in the laboratory for periods of 6 wk of in communal and individual compartments with constant unidirectional water currents. Chemically mediated growth inhibition increased in proportion to the number of prawns ahead of a given compartment in the water current. Since ammonia and nitrite concentrations were below reported toxic values, progressive accumulation and transmission through water currents of some other chemically mediated growth inhibitor may explain the observed differences in growth rates between compartments. Growth slowed with increasing prawn density (communal areas) and with decreasing individual compartment size (individual areas). Prawns held in contiguous individual compartments, allowing visual communication, exhibited a significantly (P < 0.01) more rapid growth rate than prawns reared in visually isolated compartments. Growth rates for individuals kept on black substrates were significantly greater (P < 0.05) than those of prawns held in aquaria with white or blue substrates. When substrates composed of all three colors in alternating bands were used, prawns showed a significant preference (P < 0.01) for black backgrounds during the afternoon and for the water column during the morning. Possible implications of these findings to the intensive aquaculture of M. rosenbergii are discussed.     

Delivery of hatching larvae to estuaries by an amphidromous river shrimp: tests of hypotheses based on larval moulting and distribution

1.  Amphidromous shrimps live and breed in freshwater rivers and streams, but their larvae require development in sea water. Larvae may hatch upstream and then drift to the sea, although in some species females have been reported to migrate to the coast before larvae are released. Here, we tested the relative importance of larval drift and female migration in Macrobrachium ohione (Decapoda: Palaemonidae) in a distributary of the Mississippi River in Louisiana, U.S.A.
2.  Newly hatched (stage-1) larvae are nonfeeding and will not moult to stage 2 (first feeding stage) without encountering salt water. A factorial experiment was conducted in the laboratory to test the effects on moulting to stage 2 of (i) time spent by stage-1 larvae in fresh water before (ii) exposure to and maintenance in water of different salinity. Larvae kept in fresh water for 1 or 3 days before a change to saline water at 6 or 10 ppt showed a greater frequency of moulting than those kept for longer (5 days) in fresh water or changed to less saline water (2 ppt). Non-moulting larvae died or were moribund within 11 days of hatching.
3.  The relative abundance of stage-1 larvae was measured with plankton tows at two locations in the river c. 150 km apart, one near the sea and one upstream. Larval abundances near the sea were significantly greater than those upstream.
4.  The results indicate that hatched larvae of M. ohione have a limited period in which to drift in fresh water before reaching water sufficiently saline to stimulate moulting to the first feeding stage. Female migrations may play an important role in delivering larvae of amphidromous species from large continental river systems in which distances to the sea are great, while larval drift alone may be sufficient in species living in short streams, like those found in many small mountainous tropical islands.