杂交鳢(乌鳢♂×斑鳢♀)及其亲本血液指标的比较分析

本研究采用血细胞分析仪、流式细胞仪和血涂片制作方法,对杂交鳢及其亲本血液指标进行了比较分析。结果显示,杂交鳢(Channa argus♂×C.maculata♀)与其亲本相比,表现出明显杂种优势:在血液红细胞数目、白细胞数目、血红蛋白含量和血细胞比容上,杂交鳢都比亲本高,差异显著(P<0.05);在红细胞体积上,杂交鳢均比亲本小,差异显著(P<0.05);杂交鳢及其亲本血液中都含有较少比例的DNA合成期(S期)细胞,但彼此差异不显著(P>0.05)。     

The effect of C/N ratio on bacterial community and water quality in a mussel‐fish integrated system

A 30‐day experiment was conducted to evaluate the effect of C/N ratio on water quality and bacterial community in an integrated system comprising one molluscan species (pearl mussel Hyriopsis cumingii) and two fish species (gibel carp Carassius gibelio and silver carp Hypophthalmichthys molitrix) at five C/N ratios (6, 8, 10, 12 and 14). The mussel and fishes were reared in the experimental tanks (400 L), but gibel carp received formulated feed. Water quality in the experimental tanks was analysed on day 0, 10, 20 and 30, and bacterial community in the water column and sediment was analysed on day 30. Total nitrogen, total phosphorus and total organic carbon accumulated in the tanks over time. Ammonia and nitrite decreased with the increase in C/N ratio. Bacterial community in the water column and sediment changed at the phylum and genus levels with the increase in C/N ratio, and the critical C/N ratio causing a functional shift of bacterial community occurred at 10 in water column and 12 in sediment. The increase in C/N ratio benefited the growth of both potential probiotics and pathogenic bacteria. The high C/N ratio enhanced the bacterial functions of chemoheterotrophy and hydrocarbon degradation, but depressed the functions of nitrification and denitrification in the water column and sediment respectively. This study reveals that the C/N ratio can be used as a tool to manipulate the bacterial community and water quality in the mussel‐fish integrated system.     

三种免疫添加剂对草鱼非特异性免疫功能的影响

在饲料中添加不同剂量的Vc、酵母多糖和壳聚糖,连续投喂42d,并在试验的第14、28、35和42天取样检测,研究其对草鱼血清溶菌酶活性、血清超氧化物歧化酶活性（SOD）活性、血清碱性磷酸酶（AKP）活性、补体C3、含量丙二醛（MDA）含量和血液白细胞吞噬活性共6种指标的影响。结果显示：实验组与对照组相比,饲料中添加Vc可以提高血清溶菌酶活性、SOD活性、AKP活性、补体C3含量和血液白细胞吞噬活性高,并降低MDA含量。添加酵母多糖可以提高血清溶菌酶活性、AKP活性、补体C3含量和血液白细胞吞噬活性,并降低MDA含量,但不能提高SOD活性。添加壳聚糖可以提高血清溶菌酶活性、SOD活性、AKP活性、补体C3含量和血液白细胞吞噬活性,但不能降低MDA含量。饲料中添加Vc、酵母多糖和壳聚糖均对草鱼的非特异性免疫功能具有一定的促进作用。     

Pathogenicity of halophilic Vibrio harveyi in giant freshwater prawns (Macrobrachium rosenbergii De Man)

In this study, the phenotypic and pathogenic properties in freshwater host were characterized in 14 strains of halophilic Vibrio harveyi isolated from infected marine black tiger shrimp, Penaeus monodon. The lysogenic phenotype was assayed via prophage excision and mitomycin C induction. The bacteria were grouped into two types, corresponding to lysogenic and non‐lysogenic strains. The pathogenicity was determined via direct injection of bacterial cultures into post‐larval juvenile giant freshwater prawns, Macrobrachium rosenbergii De Man. All of the infected prawns showed similar symptoms and inflamed hepatopancreas. The V. harveyi isolates derived from the first‐injected infected prawns were re‐isolated and re‐injected into healthy giant freshwater prawns, in which they retained similar infectivity. Both lysogenic and non‐lysogenic Vibrio spp. showed identical virulence associated with 100% mortality within one day post‐injection. TEM micrographs showed hepatopancreatic nuclear deformation and lipid breakdown caused by lysogenic γ‐hemolytic VL19 and non‐lysogenic β‐hemolytic V33. However, the V33 strain was associated with severely disrupted mitochondria. None of the V. harveyi strains was able to produce a biofilm. Together, our findings indicate that the lysogenic and non‐lysogenic halophilic V. harveyi isolated from marine shrimps may use different virulence factors that are responsible for their pathogenicity in freshwater prawns.     

外源性Vc对普安银鲫仔鱼抗氧化酶活性的影响

将维生素C添加到普安银鲫的孵化水体中,维生素C浓度设置为20、25、30和35 mg/L,记录孵化率及仔鱼存活率,测定各浓度组中普安银鲫(Carassius auratus gibelio)仔鱼发育过程中超氧化物歧化酶(SOD)、过氧化氢酶(CAT)和谷胱甘肽过氧化物酶(GSH-Px)的活性,研究维生素C(Vc)对普安银鲫仔鱼发育的影响。结果显示:SOD和CAT的活性随着普安银鲫仔鱼发育时间的延长而增加,而GSH-Px活性则随着发育时间的延长而降低;30 mg/L的Vc溶液能显著(P0.05)提高普安银鲫仔鱼SOD、CAT和GSH-Px活性,且SOD的活性在出膜72 h后开始显著降低(P0.05),而CAT和GSH-Px则无显著变化(P0.05)。结果表明:普安银鲫仔鱼中抗氧化作用以SOD和CAT为主;适宜浓度的Vc添加到普安银鲫的育苗水体中能提高仔鱼的抗氧化能力。     

中华鲟ASDIGIRR与ASTRAF6基因的克隆与表达

中华鲟是处在硬骨鱼类与软骨鱼类之间的中国古老的珍稀鱼类之一,但在人工繁殖和养殖过程中,容易受到不同疾病的危害,因此,需要深入研究其免疫调控,为其疾病预防提供理论依据。单个免疫球蛋白白细胞介素-1受体相关分子(SIGIRR)和肿瘤坏死因子受体相关因子6(TRAF6)是toll样受体(TLR)信号通路的2个重要的信号转导元件。本研究鉴定了中华鲟的SIGIRR和TRAF6的同源物,分别命名为ASDIGIRR (Acipenser sinensis DIGIRR)和ASTRAF6 (A. sinensis TRAF6),并研究它们在正常组织中的表达和Poly(I:C)诱导后的表达模式。结果显示,ASDIGIRR和ASTRAF6在健康鲟的10个组织中均有表达,且分别在肠道和头肾组织中表达量最高;用Poly (I:C)孵育中华鲟脾脏细胞后,ASDIGIRR在3 h时的表达量显著下调,在6 h时恢复至正常水平,后在24 h显著上调达到最高值,随后开始下调,至48 h时仍显著高于对照组,而ASTRAF6在6 h达到最高表达量,维持到24 h后再下调,48 h时下降至最低水平。研究表明,ASDIGIRR和ASTRAF6在中华鲟抵御病原入侵的免疫防御过程中起着重要作用。     

红螯光壳螯虾组织蛋白酶L基因的克隆及维生素C对其表达的影响

为深入了解红螯光壳螯虾组织蛋白酶L基因的表达特性及维生素C对其表达的影响,实验利用RACE-PCR技术及荧光定量PCR技术,从红螯光壳螯虾肝胰腺中克隆得到组织蛋白酶L基因cDNA全长序列,命名为CqCatL(GenBank登录号:KJ913663),同时检测了该基因在红螯光壳螯虾各个组织及添加了不同浓度维生素C的组别中的表达。结果显示,该基因全长1 810 bp,开放阅读框长度为1 026 bp,编码341个氨基酸残基,预测的分子量和等电点(pI)分别为37.63 ku和5.17。同源性分析结果显示,该基因编码的蛋白与其他虾蟹类有较高的相似性,说明组织蛋白酶L基因在甲壳动物具有较高的保守性。组织荧光定量PCR结果显示,CqCatL基因在红螯光壳螯虾的多个组织中均有表达,其中肝胰腺中表达量最高,其次为血细胞,在肠及触角腺中也有一定量的表达。在基础饲料中添加不同水平的维生素C后,CqCatL基因的表达量也存在明显差异,其中维生素C添加量为400 mg/kg的组别中该基因的表达量最高。研究表明,组织蛋白酶L基因在红螯光壳螯虾的生长发育过程中有重要的作用,且其表达量受维生素C的影响。     

海洋贝类提取物对血管平滑肌细胞增殖的影响

采用20％胎牛血清（FBS），碱性成纤维细胞生长因子（bFGF)所诱导的大鼠VSMCs增殖模型，观察了海洋贝类提取物（ESs)对血管平滑肌细胞（VSMCs)增殖的影响。将培养的5－8代细胞接种于96孔板，除正常组加入含0．4％FBS的M199培养液外，其他组均加入含20％FBS培养液（或含50ng/ml bFGF的0．4％FBS培养液），同时给药组分别加入含有25，50，100μl/ml浓度的ESs，孵育48h后，以细胞计数，结晶紫染色及MTT比色法VSMCc生长情况。结果表明，与模型组比较，ESs各剂量组VSMCs的增殖受到明显抑制（P＜0．05，P＜0．01）。ESs对20％FBS和bFGF所致的VSMCs增殖具有明显抑制作用，并存在剂量依赖关系。     

中国对虾体内维生素C的含量及其变化

维生素C又名抗坏血酸,它是对虾生长、代谢及维持正常生理功能所必需的有机化合物。对维生素C的需求量则因对虾的个体大小、生长率、成熟度和环境因子的不同而异。缺乏维生素C不仅影响对虾蜕皮和伤口愈合,而且还会导致患病或降低抗御不良环境的能力。到目前为止,我国养殖对虾配合饵料中所添加的维生素C数量多参照国外虾类的标准,尚无切合中国对虾特点的添加标准,这对我国的     

Nutrient digestibility studies in Heteropneustes fossilis (Bloch), Clarias batrachus (Linnaeus) and C. gariepinus (Burchell)

The apparent digestibility coefficient (ADC %) for protein in catfishes, Clarias batrachus (Linnaeus) (16–18 cm; 45–50 g), C. gariepinus (Burchell) (21–22 cm; 60–65 g) and Heteropneustes fossilis (Bloch) (10–12 cm; 10–15 g) was estimated for nine feedstuffs of plant and animal origin. Fat digestibility was tested for C. batrachus and C. gariepinus, wherein the influence of feeding frequency on protein digestibility was also examined. The digestibility trials were conducted with triplicate groups of 25 fish each in 70‐L polyvinyl indoor flow‐through (1–1.5 L min^?1) circular tanks (water volume=55 L). Fish were fed to satiation daily, at 08:00 and 18:00 hours, and faecal matter was collected through slow siphoning. For studying the effect of feeding frequency, fish were fed the experimental diets at 08:00, 11:00, 14:00 and 17:00 hours. The protein digestibility of the feedstuffs varied significantly within each test species. However, the protein digestibility values for most of the ingredients tested were comparable between the three catfish species. The most efficient utilization of protein in these fishes was noted for soybean meal followed by lab‐prepared fishmeal. The lowest protein digestibility was recorded for rice bran. Similarly, the utilization of fat from the feedstuffs was also significantly different within each of the two species, C. batrachus and C. gariepinus. Fat digestibility of feed ingredients was similar between the two species. With respect to the fat, soybean meal, lab‐prepared fishmeal, full‐fat soybean meal and dried fish were more efficiently utilized, while the lowest fat digestibility was obtained for rice bran. A marked decline in protein utilization was observed in the two species where the feeding frequency was increased from two to four times a day.