克氏原螯虾酚氧化酶部分生化特性的研究

以克氏原螯虾(Procambarus clarkii)酚氧化酶(PO)为材料,采用L-DOPA为反应底物,分光光度计测定不同温度和pH条件下PO活力,研究克氏原螯虾PO的特性,为其免疫学研究及优化PO准确测定方法提供依据。结果显示PO活力最高时的温度为35℃,低于和高于35℃活力逐渐下降,45℃以上活力迅速下降;0℃仍具有最高活力的24%。在pH4.0～9.5内PO均具有活力,鳃组织最佳pH5.5,血清最佳pH6.5。因此测定克氏原螯虾PO活力的最佳参数为温度35℃,pH5.5(鳃)或6.5(血清)。以上结果说明冰浴终止反应法测定克氏原螯虾PO活力会影响结果的准确性,要慎用。     

克氏原螯虾温室大棚规模化繁育技术及工艺

本文详尽阐述了克氏原螯虾温室大棚规模化繁育技术,包括繁育设施的建造、工厂化人工诱导繁殖,规模化网箱育苗技术等,为克氏原螯虾育苗生产提供借鉴。     

全价配合饲料条件下克氏原螯虾幼体及成体消化酶的活力研究

[目的]探讨全价配合饲料条件下克氏原螯虾幼体及成体消化酶的活性。[方法]取克氏原螯虾幼体全消化道组织,成体胃、肠组织,对克氏原螯虾蛋白酶、淀粉酶、脂肪酶、纤维素酶等消化酶活性进行测定。[结果]克氏原螯虾幼体的淀粉酶活性较高,胃蛋白酶活性较低;纤维素酶和脂肪酶活性相差不大,且活性均小于淀粉酶活性。成体的胃和肠中蛋白酶及淀粉酶比活力均较高,而纤维素酶和脂肪酶的比活力较低,且蛋白酶比活力为胃大于肠,淀粉酶比活力为肠略大于胃,纤维素酶和脂肪酶比活力在胃和肠中无明显差异。[结论]该研究为克氏原螯虾的水产养殖中专用饲料的开发提供了参考资料。     

Lack of acute toxicity of an anthraquinone bird repellent to non-target crayfish (Procambarus clarkii) associated with rice-crayfish crop rotations

Aeroz™ (9,10-anthraquinone (AQ)), a chemical rice seed treatment that effectively deters birds from depredating newly planted fields, could be an important management tool that enables rice producers to plant earlier in the season and increase yields. This bird repellent, while non-lethal to birds, has unknown toxicity to crayfish that often are closely integrated with rice production in southern regions of the USA. This study was conducted to assess if AQ, the active ingredient in Aeroz™, could be acutely toxic to the red swamp crayfish Procambarus clarkii (Girard), the crayfish species most often associated with rice cultivation, via seed ingestion and/or through their contact with chemical in pond water. Mortality data from a 96 h feeding study indicate that AQ-treated (1.76% by wt) rice seed was not acutely toxic to juvenile (∼3 mo.) crayfish through the ingestion exposure route. In addition, a 96 h aquatic acute toxicity test showed that the LC₅₀ of AQ in juvenile crayfish is >85 μg L⁻¹ and above the water solubility limit of AQ. These results indicate that very minimal, if any, acute toxicity would be observed in juvenile crayfish if exposed to AQ via ingestion or dissolved or suspended in the water column.     

克氏原螯虾AFLP反应体系的建立

以克氏原螯虾DNA为材料,对AFLP分析中的基因组酶切时间、选择性扩增中预扩增产物稀释倍数、Mg~(2+)浓度等3个因素进行了比较.结果表明,基因组用EcoR I和MseI双酶切5h,选择性扩增的PCR反应体系中Mg~(2+)1.5 mmol/L是进行克氏原螯虾AFLP分析的最佳反应条件,能够得到丰富稳定的带纹.而预扩增产物稀释倍数对选择性扩增没有明显影响.该体系的构建为AFLP技术在克氏原螯虾相关研究中的应用奠定了基础.     

克氏原螯虾大颚器促性腺发育作用研究

[目的]研究克氏原螯虾（Procamharus clarkia）大颚器的组织学特点,探讨其大颚器在性腺发育过程的作用。[方法]采用大颚器和性腺组织的离体联合培养法,用卵黄发生期的克氏原螯虾大颚器刺激不同发育期的克氏原螯虾性腺。[结果]2处理组卵巢的最大卵径为（0．32±0．05）mm和（0．27±0．06）mm,2对照组卵巢的最大卵径为（0．24±0．05）mm和（0．20±0．05）mm;2处理组精巢的精母细胞直径为（13．09±0．75）μm和（12．93±0．98）μm,2对照组精巢的精母细胞直径为（10．29±1．00）μm和（10．02±0．68）μm。[结论]数据显示处理组的性腺细胞均比对照纽的性腺细胞显著增大（P〈0．05）,表明大颚器的功能性物质具有促进性腺细胞发育的作用,支持大颚器作为促性腺生长发育腺体的观点。     

Juvenile Procambarus clarkii farmed using biofloc technology or commercial feed in zero‐water exchange indoor tanks: A comparison of growth performance,enzyme activity and proximate composition

A 60‐day study comparing the growth performance; proximate composition and the digestive, immune and antioxidant enzyme activities of juvenile red swamp crayfish (Procambarus clarkii) reared using biofloc technology (the biofloc group) or a commercial diet (the control group) in zero‐water exchange indoor tanks was performed. A commercial diet was fed to both groups, and the daily feeding amount in the biofloc group was 40% less than that in the control group. Wheat bran and glucose were used in the biofloc group to ensure a C/N ratio >15 and the same feeding energy as that given to the control group. After 60 days of feeding, the final weight, weight gain and specific growth rate in the biofloc group were significantly higher than those in the control group. Furthermore, proximate composition analysis showed that the total hepatopancreatic lipid and ash contents of the biofloc group were significantly higher than those of the control group, and the intestinal and hepatopancreatic pepsin activities in crayfish in the biofloc group were higher than those in crayfish in the control group. Moreover, higher hepatopancreatic lipase and cellulase activities were observed for the biofloc group than for the control group. Biofloc technology promoted the health of the crayfish in terms of their immune and antioxidant enzyme activities. Based on the results of this study, biofloc technology is more effective than traditional commercial diets for the farming of juvenile crayfish.     

低pH胁迫对小龙虾SOD活性及生存的影响

为了探讨低pH值对小龙虾免疫功能的影响,为养殖小龙虾的抗病力提供科学依据,本试验在低pH持续作用条件下,采用超氧化物歧化酶试剂盒检测超氧化歧化酶的活性,并测定了低pH对小龙虾的毒性作用。试验结果表明：在低pH的持续作用下,SOD活力随时间成正比下降,不同梯度的低pH值能够明显降低克氏原螯虾血液SOD活力,在试验过程中除pH6.12的酶活力在24h时达到最小值,其他组在48h均到达到最小值。暴露在pH2.16酸性溶液中48ｈ,小龙虾血清的超氧化物歧化酶活性降至65.83%,pH4.18中的小龙虾血清的超氧化物歧化酶活性降至76.25%,pH6.12中的小龙虾血清的超氧化物歧化酶活性降至91.94%,差异显著(p＜0.05)。低pH能显著降低小龙虾的免疫功能。小龙虾在低pH值的酸性环境养殖中出现死亡现象,过低的pH导致死亡率增加,时间越久死亡率越高。     

Growth performance and muscle composition response to reduced feeding levels in juvenile red swamp crayfish Procambarus clarkii (Girard, 1852)

Overfeeding in aquaculture can lead to suboptimal growth and increased production costs. Red swamp crayfish, Procambarus clarkii, is one of the most noteworthy species cultured in China, but little information is available on the optimal feeding levels of this species, especially in ponds cultured with macrophytes. In this study, we tested the effects of five different feeding levels (20%, 40%, 60%, 80% and 100% satiation) of an artificial diet on growth performance and muscle composition of juvenile P. clarkii in 15 concrete ponds cultured with the macrophyte Hydrilla verticillata (three replicates for each treatment). The results showed that growth performance decreased only when feeding levels were below 60% satiation. Muscle composition analysis revealed that the moisture and ash contents of muscle did not vary significantly with feeding levels but that the lipid and protein contents of muscle significantly decreased when P. clarkii was fed to 40% satiation. Stable isotope analysis suggested a shift in crayfish diets to easily available H. verticillata when feeding levels decreased. With this study, we hope to encourage crayfish farmers to reduce feeding levels and increase natural food items such as macrophytes in cultured ponds to maximize crayfish yields and reduce production costs.     

河北滨海稻区稻田养殖克氏原螯虾模式初探

开展了河北滨海稻区稻田养殖克氏原螯虾模式的试验,对该区域稻田养殖的克氏原螯虾产量、规格、成本、利润等进行了分析,并对该模式的构建、运行过程中出现的问题进行了探讨。结果表明,在稻虾共作模式中,克氏原螯虾每公顷产量约为750-1200kg,成虾体长90mm左右,体重30g左右；每公顷水稻和虾的总利润为77598.6-109098.6元。比单一种稻模式每公顷的总利润高75264.597-106764.597元。