减蛋综合征病毒33K蛋白基因克隆及结构分析

纯化的减蛋综合征病毒（ＥＤＳＶ）ＤＮＡ经ＨｉｎｄⅢ水解、０．８％琼脂糖电泳后,回收各ＤＮＡ条带并克隆至ｐＢｌｕｅｓｃｒｉｐｔＫＳ载体,建立了ＥＤＳＶ基因文库,对３３Ｋ蛋白基因进行了分析。本研究证实,ＥＤＳＶ３３Ｋ蛋白基因含有２个外显子,与羊腺病毒（ＯＡＶ）３３Ｋ蛋白比较,Ｎ端编码产物的同源性为３０．８％,Ｃ端的为６０％。用ＲＴ－ＰＣＲ扩增３３ＫｍＲＮＡ和ｃＤＮＡ克隆及序列分析证实,ＥＤＳＶ３３Ｋ蛋白含有８２碱基（ｎｔ）的内含子,去掉内含子３３Ｋ蛋白基因能形成完整的ＯＲＦ,其编码产物由１７７氨基酸（ａａ）组成,推测分子质量为２．０６×１０４,与人５型腺病毒和ＯＡＶ的同源性分别为２８．１％和４４．７％。     

The use of brushwood bundles as fish spawning media

Salford Quays is a redeveloped freshwater dockland, which initially constituted part of the grossly polluted Manchester Docks, Manchester, UK. Such water bodies are characterized by a lack of suitable spawning sites and littoral refuges, and this will act to reduce fish recruitment. To redress this, a variety of artificial spawning substrates were introduced to these waters. Spawning structures were made from bundles of different types of thin brushwood suspended from the dock walls. Roach, Rutilus rutilus (L.), spawned on bundles of willow, Salix alba (L.), and spruce, Pilea abies (L.), branches, whilst perch, Perca fluviatilis L., spawned on bundles of willow, sycamore, Acer pseudoplatanus (L.), spruce and plastic netting. Unused bundles were made up of lime, Tilia platyphyloss (Scop.), pear willow, Pyrus salicitolia (Pall.), and laurel, Laurus nobilis (L.). Perch spawning began around 20 May and showed a preference for open structures (between one and three ribbons per bundle). Roach spawning began about 10 days after perch and showed a preference for dense bundles of spruce (geometric mean egg density 1.5 cm^{? 2} spruce). The use of such structures in fisheries management is discussed.     

鸡产蛋下降综合征病毒内蒙分离株的生物学特性研究

对鸡产蛋下降综合征病毒内蒙古地区分离株进行了生物学特性测定和血清学鉴定,结果表明,Ｂ４、Ｎ３株与１２７株均能抵抗乙醚、氯仿和胰蛋白酶,而在对酸、碱、温度及甲醛的稳定性测定中,Ｎ３株ＥＤＳ７６病毒对这些因素抵抗力强于Ｂ４株和１２７株,而Ｂ４株和１２７株ＥＤＳ７６病毒对这些因素的抵抗力基本相同,说明不同ＥＤＳ７６病毒株间理化特性上存在有差异。血清学试验结果表明,Ｂ４、Ｎ３株与１２７株ＥＤＳ７６病毒的血清学关系非常相近。     

鸡霍乱口服弱毒活疫苗免疫对鸡群产蛋量的影响

应用R1-23鸡霍乱口服弱毒活疫苗,分别在苏北地区的四个养禽场的不同品种产蛋鸡群中进行试验,以研究该口服弱毒活疫苗免疫接种后对鸡群产蛋量的影响。结果表明,产蛋鸡群口服该弱毒活疫苗后,对产蛋率没有明显影响,整体统计结果为十0.04％。但就某一鸡群而言,服苗后可能发生产蛋率下降,幅度在0.16％～0.83％之间,这主要取决于鸡的品种、产蛋周龄,鸡群健康状况以及饲养管理水平。     

温度、盐度、pH值对褶皱臂尾轮虫休眠卵孵化率的影响

通过单因素和正交设计的试验方法研究了温度、盐度、pH对褶皱臂尾轮虫休眠卵孵化率的影响.试验结果表明,适宜休眠卵孵化的温度为29℃,盐度为20、pH为9.0; 各因素中影响孵化率的顺序依次是:盐度>温度>pH,温度与盐度之问存在较为显著的交互作用,最佳的孵化条件组合是:温度34℃.盐度10,pH 8.0.     

LHRHa‐induced ovulation of the endangered‐Caspian brown trout (Salmo trutta caspius) and its effect on egg quality and two sex steroids: testosterone and 17α‐hydroxyprogestrone

To induce synchronized ovulation, migrating wild Caspian brown trout (Salmo trutta caspius) females were treated with two interperitoneal injections of Des‐Gly¹⁰, d ‐Ala⁶ LHRH (LHRHa), given 3 days apart. Two injections of 100 μg kg^?1 body weight of this hormone effectively induced ovulation. Within 27 days from the second injection, all fish injected with 100 μg kg^?1 LHRHa had ovulated compared with 54.5% of the controls. The mean time to ovulation was reduced significantly (P<0.05) from 31.67±4.84 days in control fish and 28.83±7.31 days in sham‐treated fish to 16.36±1.61 days in fish injected with 100 μg kg^?1 LHRHa. The fertilization rate in 50 and 100 μg kg^?1 LHRHa‐injected fish was significantly lower than that in the control fish (P<0.05). In fish injected with 50 and 100 μg kg^?1 LHRHa, significant (P<0.05) changes in testosterone (T) and 17α‐hydroxyprogestrone (OHP) levels were observed. After the second LHRHa injection, the fish injected with 100 μg kg^?1 showed the highest serum levels of testosterone and OHP. These results demonstrate that the use of LHRHa can effectively reduce the mean time to ovulation and induce synchronized ovulation in Caspian brown trout.     

Fertilization success and blastomere morphology as predictors of egg and juvenile quality for domesticated Atlantic cod,Gadus morhua,broodstock

We investigated if simplified routines based on blastomere morphology and fertilization success can be used as predictors of egg and embryo viability in Atlantic cod, and abnormal blastomere morphology is related to juvenile deformities. Egg morphology data from 312 families that were produced by hand stripping of gametes were used. Fertilized eggs from all families were separately incubated in 25 L incubators. Blastomere morphology and fertilization success were assessed at 16–32 cell stage. Embryo mortality was measured until hatch. Fertilization success showed a significant positive correlation with the proportion of normal blastomere and 74% of the variation in the incidence of blastomere abnormality was explained by fertilization success. Juvenile deformities were positively correlated with blastomere abnormality and 8% of the variation in juvenile deformities was explained by incidences of blastomere abnormality. To our knowledge, this is the first direct evidence showing that incidences of blastomere abnormalities may be related to cod juvenile deformities. Our results suggest that fertilization success and the occurrence of blastomere abnormalities could be easily adopted by commercial cod hatcheries for the early determination of egg quality.     

Efficacy of formalin and povidone–iodine disinfection techniques on the eggs of three marine finfish species

Surface disinfection trials were performed on eggs from three marine finfish species: California yellowtail (CYT; Seriola lalandi), white seabass (WSB; Atractoscion nobilis) and California halibut (HA; Paralichthys californicus). All three species were spawned from captive populations maintained at the Hubbs‐SeaWorld Research Institute (HSWRI). Five disinfection treatments were used for each species; Treatment 1 included 100 mg L^?1 of formalin (F100) for 60 min (current HSWRI treatment), Treatment 2 included 1000 mg L^?1 of formalin for 15 min (F1000), Treatment 3 included povidone–iodine of 50 mg L^?1 for 15 min (PI50), Treatment 4 included povidone‐iodine of 100 mg L^?1 for 10 min (PI100) and Treatment 5 involved a control with no chemical treatment (CONT). For each treatment, the per cent egg hatching rate, per cent survival to first feeding and notochord length at the time of hatching to the nearest 0.1 mm were recorded. Bacteria were also cultured from eggs after treatment to determine the effectiveness of each treatment in reducing the bacterial counts (CFU mL^?1). Treatments F100, F1000 and CONT yielded the highest hatch rates for each species (70–80%), whereas treatments PI50 and PI100 yielded the lowest hatch rates (0–2%). There were no significant differences in survival to first feeding or notochord length, which suggests that the disinfection treatments did not have a negative effect on the yolk sac larvae. The PI50 and PI100 treatments had the lowest bacterial colony counts, showing almost zero bacterial growth. The highest bacterial growth occurred in the F100, F1000 and CONT treatments. Based on the results from this study, the F100 treatment provided the best balance of disinfection and larval health for CYT, WSB and HA.     

The effects of water source and secondary water treatment on flame angelfish Centropyge loriculus (Günther) reproduction

This study was conducted to determine whether water source and water treatment affected flame angelfish (Centropyge loriculus) reproduction. Flame angelfish broodstock were maintained and monitored for reproductive performance (fecundity, egg fertilization rates and egg viability) in either untreated well‐water (WW), sterilized ocean water (OW) or WW treated by intensive recirculation treatment (biological filtration, protein skimming, UV sterilization and mechanical filtration) (RAS). Results of this experiment indicated that although pairs maintained in WW initially exhibited good spawning performance, fecundity, egg fertilization rates and egg viability declined after 25 weeks. Treatment of WW by recirculation did not significantly improve flame angelfish reproductive performance with only moderately improved fecundity compared with pairs in the WW treatment. In contrast, pairs held in sterilized OW exhibited significantly greater fecundity, egg fertilization rates and egg viability from week 25 onwards than pairs in either the WW or RAS treatments. However, in the process of developing OW biosecurity protocols, we found that sterilization of OW using chlorine at levels >25 mg L^?1 (30 min) negatively affected flame angelfish egg fertilization rates indicating that alternative methods of water sterilization may be warranted.     

Roles of microalgae on total egg production over female lifespan and egg incubation time,naupliar and copepodite survival,sex ratio and female life expectancy of the copepod Bestiolina similis

We examined the effects of 10 microalgal diets on a range of productivity‐related parameters of Bestiolina similis. The diets tested included four monoalgal diets: Tahitian strain Isochrysis sp. (T‐Iso), Pavlova salina (Pav), Tetraselmis chuii (Tet) and the diatom Chaetoceros muelleri (Chaet), five binary diets: Tet+Pav, T‐Iso+Tet, T‐Iso+Pav, Chaet+Tet and Chaet+Pav and a tri‐algal diet: T‐Iso+Tet+Pav. Except for sex ratio, microalgal diets significantly affected all parameters examined (P<0.05). The shortest egg incubation time was found for the tri‐algal diet treatment (1.91±0.04 days) while the longest (2.41±0.09 days) was from the monoalgal diet Tet. Survival at the naupliar stage ranged from the highest of 86.3±1.0% for the tri‐algal diet to a complete mortality for the Tet diet. Naupliar survival was consistently higher than that of copepodite stages for all diets examined and ranged from 86.3±1.0% for the tri‐algal diet to a complete mortality for the Tet diet. Copepodite survival was the highest for the T‐Iso treatment (69.0±4.3%) while Chaet+Tet produced the lowest survival (8.8±1.2%). Sex ratio of B. similis was strongly skewed towards females. Adult female life expectancy was highly dependent on diet. The shortest lifespan (3.1±0.3 days) of the Tet treatment was only about half of that of Pav (6.3±0.6 days) and the tri‐algal diet (5.9±0.4 days). Daily egg production during female lifespan was generally lower on the first day, but peaked over the subsequent days before decreasing towards the end of their lifespan. The highest total egg output over female lifespan was produced by the tri‐algal diet (156.0±11.5 eggs female^?1), while the lowest output came from the diet Tet (20.7±2.8 eggs female^?1).