草鱼肠道芽孢杆菌的鉴定及产酶能力分析

从100 g左右的健康草鱼(Ctenopharyngodon idellus)肠道中分离出3株疑似芽孢杆菌(Bacillus)菌株(G1、G2、G3),并通过对其进行生理生化特征、16S rDNA全序列和产酶能力的分析,筛选出1株高产酶能力的益生菌株。结果显示:G1、G2和G3菌株与枯草芽孢杆菌在16S rDNA序列相似性≥99%的水平上聚为同一分支,结合形态观察和生理生化特征,最终鉴定G1、G2和G3菌株均为枯草芽孢杆菌(Bacillus subtilis);以水解圈直径/菌落直径比值评定了G1、G2和G3菌株的产纤维素酶、淀粉酶和蛋白酶的能力,其中G1菌株产纤维素酶、淀粉酶和蛋白酶能力(比值分别为2.9、2.2和3.3)均高于G2、G3菌株,具有作为益生菌的潜力。     

草鱼脆化过程中肌肉品质变化

为了研究草鱼(Ctenopharyngodon idellus)脆化过程中肌肉品质变化对脆肉鲩(C.idellusC.et V)脆性形成规律的影响,在草鱼脆化过程中定期采样,比较研究了肌肉基本化学成分、质构特性、鱼肉蛋白质组成、肌肉氨基酸组成及营养价值评价等的变化规律。结果显示：脆肉鲩的水分、粗脂肪质量分数均显著低于普通草鱼(P0.05),粗蛋白、粗灰分质量分数比普通草鱼高;与普通草鱼相比,脆化后肌肉的肌原纤维蛋白、肌浆蛋白和基质蛋白质量分数分别增加了10.88%、15.41%和80.53%;脆肉鲩的硬度、咀嚼性、弹性和粘着性显著高于普通草鱼(P0.05);脆肉鲩肌肉的TAA、EAA、UAA最高分别为203.5gL-1、85.6 gL-1、79.1 gL-1,均显著高于普通草鱼(P0.05)。研究表明在草鱼脆化过程中,肌肉品质指标均有不同程度的变化,且这些变化是导致脆肉鲩脆性改变的重要因素。     

草鱼鱼种对胆碱需要量的研究

用不含胆碱的饲料饲养草鱼鱼种，草鱼鱼种生长减慢，饲料效率降低，肝脏脂肪浸润，血浆总脂，甘油三脂，胆固醇和磷脂含量降低，随着饲料中胆碱含量的添加，草鱼生长和饲料效率改善，肝脏脂肪含量降低，血浆总脂、甘油三脂、胆固醇，磷脂含量回升。当饲料中胆碱添加量达到０．３％以上时，草鱼生长率最高，肝脏脂肪含量，血浆总脂、甘油三脂，胆固醇，磷脂与摄食天然饲料（浮萍）的草鱼基本相同。在本研究条件下，建议草鱼鱼种饲料中     

Bacterial communities in Chinese grass carp (Ctenopharyngodon idellus) farming ponds

Bacterial communities in the water column and sediment of 12 commercial grass carp (Ctenopharyngodon idellus) farming ponds were analysed. At the same time, physical and chemical environmental parameters were measured, including secchi depth (SD), total nitrogen (TN), total phosphorus (TP) and chemical oxygen demand (COD_Mn). From 12 water samples and 12 sediment samples, 39 different ribotypes were detected with PCR‐denaturing gradient gel electrophoresis (PCR‐DGGE). The ribotype richness showed that bacterial species in the water column differed among these ponds, and the result of sequencing further revealed the dominant and common bacterial species. In total, 32 bacterial species belonging to seven phyla (Proteobacteria, Bacteroidetes, Actinobacteria, Cyanobacteria, Acidobacteria, Fibrobacteres and Fusobacteria) were identified. Ordination via canonical correspondence analysis (CCA) on the DGGE data and environmental parameters indicated that the composition of bacterial community was significantly influenced by SD.     

青鱼和草鱼葡萄糖耐量的比较研究

选用典型的淡水肉食性鱼类青鱼(Mylopharyngodonpiceus)和草食性鱼类草鱼(Ctenopharyngodonidellus)为对象进行糖耐量初步实验。青鱼和草鱼的体重分别为(63±3)g和(46±2)g,在实验室适应4周后禁食24h,以高剂量(H)1.67g/(kg体重)和低剂量(L)0.42g/(kg体重)灌喂葡萄糖,比较研究其代谢反应。结果显示,2种鱼灌喂不同剂量葡萄糖后都出现持久的高血糖,青鱼血糖含量高于灌喂相同剂量的草鱼,灌喂剂量越高,血糖含量越高。草鱼组及青鱼L组在灌喂葡萄糖后血浆总氨基酸和甘油三酯先降后升,但青鱼H组口服葡萄糖后血浆总氨基酸和甘油三酯先升高。青鱼H组和草鱼H组在灌喂葡萄糖后最初1h和2h肝糖原含量分别下降至2.62%和5.46%。实验结果提示,青鱼糖耐量比草鱼低;高糖负荷后两种鱼的内分泌调节规律可能不同;较高葡萄糖负荷还引起应激反应,应激反应的强弱可能与糖耐量大小呈反比,与负荷剂量呈正比。     

不同脆化阶段草鱼肌肉的显微结构观察和质构特性分析

脆肉鲩作为广东特色水产品之一,其养殖中常出现"不脆"、"半脆"现象,严重制约其产业发展。为探索可鉴定脆度的指标,文章结合生产(饲喂120 d蚕豆+30 d饲料),每30 d采集1次肌肉,检测其感官脆度、肌纤维结构、质构特性的变化。随着脆化时间增加,蚕豆组草鱼感官脆度不断增加(P0.05),肌纤维直径逐渐减小、密度逐渐增大(P0.05);60 d后蚕豆组草鱼质构特性(硬度、弹性、咀嚼性、内聚性、胶黏性)均显著高于对照组(P0.05)。转投30 d饲料对感官脆度、肌纤维结构、质构特性均无显著影响(P0.05)。相关性分析表明,硬度、弹性、咀嚼性、胶黏性与感官脆度的相关性更高(R~20.90,P0.05)。结果表明,硬度、弹性、咀嚼性、胶黏性可用于脆肉鲩的脆度评价,转投30 d饲料不影响其脆度。     

A review of intestinal microbes in grass carp Ctenopharyngodon idellus (Valenciennes)

Grass carp, Ctenopharyngodon idellus, harbours complex intestinal bacterial communities, which are important in several physiological processes of their host. Intestinal microbiota of grass carp have been previously described in numerous studies. However, an overview on the bacterial community diversity, including their establishment, their functions in host's nutritional processes and immune‐related responses, and use as probiotics, is absent. This study aimed to summarize the current understanding of the grass carp intestinal microbiota. In this review, we provide general information on the establishment and composition of intestinal microbial communities and factors influencing the diversity of gut microbiota. Also, this review covers the dietary effects of probiotics, prebiotics and/or synbiotics on the grass carp intestinal microbial communities and physiological characteristics. Although our knowledge of the grass carp intestinal microbiota is expanding rapidly, further studies on the factors affecting the diversity of intestinal microbes, interactions between intestinal microbiota and their hosts and application of probiotics/prebiotics/synbiotics in aquaculture industry, are needed.     

地衣芽孢杆菌De在优质草鱼养殖中的应用研究

运用综合对比分析法探讨了地衣芽孢杆菌Bacillus licheniformis De在优质草鱼（Ctenopharyngodon idellus）养殖中的应用效果,其评价指标分别为成活率、水体pH、透明度、溶解氧及水中氨氮、硝酸盐浓度等。结果表明,施用地衣芽孢杆菌De可在一定程度上使水体环境和养殖生产性能得到优化,提高养殖草鱼的成活率,显著降低水体透明度及水中氨氮、硝酸盐含量（P〈0．05）,使水体pH、溶解氧有利于草鱼的生长。其中施菌组较对照组的成活率、水体pH、溶解氧分别提高了3．2％、3．9％、25．5％,而水体透明度、氨氮及亚硝氮浓度则分别降低了38．5％、74．6％、69．3％。     

亚硝酸盐对草鱼红细胞渗透脆性的影响

研究不同浓度亚硝酸盐(0.5、1.0、2.0 mg/L)及不同处理时间(24、72、120、168、264 h)对草鱼(Ctenopharyngodon idellus)红细胞渗透脆性的影响.结果表明:与对照组比较,实验各组草鱼红细胞脆性最小抵抗值、最大抵抗值极显著升高(P＜0.01); 2.0 mg/L浓度组红细胞渗...     

长江草鱼多态微卫星位点的分离及后备亲鱼的遗传多样性分析

本研究采用磁珠富集法分离了10对具有多态性的草鱼(Ctenopharyngodon idellus)微卫星位点,并对140条长江野生草鱼组成的后备亲鱼群体的遗传结构进行了分析。结果显示:本试验得到的草鱼微卫星序列主要是以2个碱基为重复单位、重复次数在5～22之间的多重复单元,重复次数在10次以上的微卫星序列较易得到多态性;77个微卫星座位中,完美型、非完美型和混合型微卫星标记所占的比例分别为87.01%、2.60%和10.39%;群体遗传分析显示,10个多态性微卫星座位中,除了GC39座位外,其它座位都符合哈迪-温伯格平衡,适用于草鱼群体的遗传结构分析;每个座位检测到3～8个等位基因,平均有效等位基因数为3.9302,多态信息含量在0.4129～0.8107之间变动,平均为0.6678,除了GC78座位为中度多态外,其他9个座位均为高度多态。基因分化系数、Shannon指数、平均观测杂合度和平均期望杂合度的平均值分别为0.3457、1.4262、0.9511和0.7193,表明该群体的遗传多样性比较丰富。     

草鱼贮藏过程中导电特性变化规律的研究

运用物理特性-伏安法测定了不同频率下冰鲜和解冻草鱼的阻抗,分析在不同贮藏时间下阻抗的相对变化值(Q值)的变化特点。结果显示:从1 kHz增大到10 kHz,冰鲜和解冻草鱼的阻抗均随着频率的增大而减小,冰鲜草鱼的阻抗相对变化值(Q值)明显大于解冻草鱼。冰鲜草鱼在第1、2、4、7、10天的阻抗相对变化Q值分别为:28.89%、25.10%、17.01%、11.65%、10.37%,而冷冻7、14、30 d后解冻草鱼的最大Q值分别为4.34%、4.18%、4.63%。结果表明:以Q值10%为界限,快速鉴定冰鲜草鱼和解冻草鱼是基本可行的。     

不同脂肪源饲料对草鱼稚鱼生长的影响

不同脂肪源饲料对草鱼稚鱼生长的影响刘玮，徐萍，任本根，龚纲明（江西省科学院生物资源研究所，南昌３３００２９）关键词草鱼，鱼饲料，必采脂肪酸ＥＦＦＥＣＴＳＯＦＤＩＥＴＳＣＯＮＴＡＩＮＩＮＧＤＩＦＦＥＲＥＮＴＬＩＰＩＤＳＯＮＧＲＯＷＴＨＯＦＪＵＶＥＮＩＬ...     

Quantifying the dietary potassium requirement of subadult grass carp (Ctenopharyngodon idellus)

A growth trial lasting for 12 weeks was conducted in 21 net cages to determine the dietary potassium (K) requirement of subadult grass carp (Ctenopharyngodon idellus) (Average weight: 331.3 g). Seven isonitrogenous and isoenergetic semi‐purified diets were compounded with different dietary K level. The specific growth rate (SGR) of fish was significantly (P < 0.05) improved by dietary K supplementation, SGR and the gill Na⁺‐K⁺ ATPase activity increased first and then decreased (P < 0.05) as dietary K level increased. The highest SGR and gill Na⁺‐K⁺ ATPase activity values were both observed at 6.38 g kg^?1 group. Dietary K level showed significant (P < 0.05) effect on serum superoxide dismutase (SOD) and glucose (GLU), the maximum values of SOD and GLU were in 8.42 and 6.38 g kg^?1 group, respectively. The body lipid content of the 6.38 g kg^?1 group was significantly (P < 0.05) lower than that of the control. However, the ash content in the 8.42 g kg^?1 group was significantly higher than those in the 1.21, 2.21, 4.41 and 6.38 g kg^?1 group. When dietary protein was 320 g kg^?1 and the waterborne potassium ranged from 6.86 to 9.10 mg L^?1, the dietary K requirement for subadult grass carp judged from SGR and gill Na⁺‐K⁺ ATPase activity is 5.38 and 7.41 g kg^?1 diet, respectively.     

草鱼成纤维细胞gcngr1基因的表达分析

Ngr1(nogo-66 receptor)是在哺乳类上发现的一种神经元受体,可调节轴突的可塑性并抑制损伤中枢神经系统(CNS)的再生,最新研究还发现它是哺乳动物呼肠孤病毒(mammalian reovirus)的神经受体。草鱼呼肠孤病毒(grass carp reovirus,GCRV)可引发草鱼(Ctenopharyngodon idellus)出血病导致高死亡率,开展GCRV受体相关研究可有助于了解病毒的致病机制。该研究在草鱼吻端成纤维细胞(PSF)中克隆到草鱼ngr1 c DNA序列(下文简称为gcngr1),发现其与哺乳动物呼肠孤病毒神经受体基因Ngr1有相似的结构序列;采用q RT-PCR方法检测该基因在PSF细胞的表达情况,结果显示受草鱼呼肠孤病毒(GCRV-GD108株)感染后gcngr1 m RNA的表达量显著上升,与病毒的增殖趋势基本一致;病毒经病毒抗体孵育后再感染PSF细胞,细胞中病毒的增殖水平下降,gcngr1m RNA的表达量也显著下降。该研究结果提示gcngr1与病毒的感染相关,为进一步分析gcngr1是否为GCRV神经元受体提供依据。     

草鱼肝胰脏组织部分EST的鉴定及分类

本研究构建了草鱼（Ctenopharyngodon idellus）肝胰脏组织的cDNA文库，并对768个随机挑选的克隆进行部分测序，获得了567个ESTs。BLAST结果表明，457个Esrs与GenBank中已经鉴定的130个基因具有较高的同源性，其中有5个基因是已经报道的，125个是草鱼中首次鉴定的基因；110个和未鉴定的基因具有相对较低的同源性，称为假定蛋白。根据编码产物的功能可以将这些基因分为：代谢（41），基因表达及其蛋白质合成（56），细胞及机体防御（18），细胞信号传导与细胞通讯（11），细胞结构与运动（4）。     

草鱼Stefin克隆表达、纯化及活性特征鉴定

文章克隆了草鱼(Ctenopharyngodon idellus)Stefin c DNA全长序列,全长294 bp,编码97个氨基酸,无二硫键,N端存在高度保守的Gly(3、4)残基及QXVXG(45~49)序列,比对结果显示其氨基酸序列与Burton's mouthbrooder(Haplochromis burtoni)Stefin A1一致性最高,为47.5%。进化树分析表明草鱼Stefin A与Burton's mouthbrooder(Haplochromis burtoni)、southern platyfish(Xiphophorus maculatus)、Colisa chuna(Trichogaster chuna)、lamprologini(Neolamprologus brichard)、elephant shark(Callorhinchus milii)及bicolor damselfish(Stegastes partitus)Stefin A聚为一类。将构建的原核表达载体Stefin-Pet30a转入E.coli BL21,以1 mol·L-1IPTG诱导表达重组Stefin蛋白,而后经梯度尿素洗涤和镍亲和层析纯化,并分别利用SDS-PAGE和TSK-GEL G2000SWxl高效液相色谱检测诱导及纯化效果,SDS-PAGE结果显示重组Stefin蛋白得到高度纯化,最终呈现相对分子量11.4 k D的单一条带;其在高效液相上保留时间25.98 min处亦呈单一活性峰,纯度为96.28%。以荧光合成肽底物(Z-Phe-Arg-MCA)测活法鉴定重组草鱼Stefin对鲤鱼组织蛋白酶B、L的抑制活性,发现该重组蛋白对二者均体现了明显的抑制活性。     

Analysis of bacterial diversity in the intestine of grass carp (Ctenopharyngodon idellus) based on 16S rDNA gene sequences

In the current study, we assessed bacterial diversity in the gut content of pond-reared grass carp (Ctenopharyngodon idellus), in the associated habitat environments (pond water and sediment) and in the ingested food (commercial feed and the reed Phragmites australis) by analysing 16S rDNA sequences from clone libraries. The highest bacterial diversity was observed in the gut content and was determined by the total number of operational taxonomic units, Shannon diversity index (H), Shannon equitability index (E_H), Coverage (C_good) and rarefaction curves calculated from the 16S rDNA gene libraries. Our data indicated that allochthonous gut microbes of grass carp were distinctively different from the corresponding environmental microbes. The pairwise similarity coefficient (C_s) for microbe communities between gut content and ingested food was higher than for those between the gut content and habitats, indicating that the allochthonous microbiota identified in the intestines of grass carp were phylogenetically closer to those in the ingested food than to those in the habitat. Based on our study and previous research, we suggest that the digesta of grass carp harbours a microbiota phylogenetic core of Proteobacteria and Firmicutes and this observation deserves further investigations with respect to a potential pool of probiotics to grass carp.     

Two biomass preparation methods provide insights into studying microbial communities of intestinal mucosa in grass carp (Ctenopharyngodon idellus)

Animal digestive tract is habitat for a large number of autochthonous microbiota, which play central roles in multiple biological and physiological processes of the host. In this study, two different micro‐biomass preparation methods were employed to evaluate the diversity of intestinal mucosa‐associated microbiota in grass carp (Ctenopharyngodon idellus). Genomic DNAs were isolated either directly from intestinal mucosal samples (group A), or from micro‐biomass after microbial dissociation (group B). Community richness, diversity and evenness indices were all higher in group B, but differences were not statistically significant (P = 0.97, P = 0.33, P = 0.34 respectively). Furthermore, group B samples exhibited an increased ratio of bacterial DNA in comparison with group A samples, but the difference was also not statistically significant (P = 0.74). In addition, there were no statistically significant differences between the two groups (P > 0.05) at the taxonomic level. Our results support previous findings that there exists a great abundance of the intestinal mucosa‐adherent microbiota in the grass carp; among these, Proteobacteria, Firmicutes, Bacteroidetes, Actinobacteria, Spirochaetes and Fusobacteria were the most common phyla. Within these microbiota, Paenibacillus, Bacteroides, Bacillus and Cetobacterium genera comprise the majority of the community, implicating their functional importance (e.g. as probiotics) to their host. Our results contribute towards a better understanding of the intestinal microbial profile of grass carp. Both micro‐biomass preparation techniques proved to be feasible for studying mucosa‐adherent microbiota of grass carp; however, the second method (group B) provides a protocol that is somewhat more effective than the first method (group A).     

投饲蚕豆对草鱼生长和肌肉品质的影响

分别以配合饲料、浸泡蚕豆、发芽蚕豆喂养体质量为(530±20)g的草鱼(Ctenopharyngodon idellus)77 d,以考察投饲蚕豆对草鱼生长和肌肉品质的影响.结果表明,配合饲料组、浸泡蚕豆组和发芽蚕豆组草鱼的增重率分别为83.08%、55.01%和62.82%,饵料系数分别为2.03、2.96和2.70,投饲浸泡蚕豆或发芽蚕豆显著降低了草鱼增重率(P<0.05),增加了饲料系数(P<0.05):与配合饲料组相比,浸泡蚕豆组和发芽蚕豆组草鱼肌肉粗脂肪含量和肌肉失水率显著降低(P<0.05),胶原蛋白含量和肌纤维直径显著增加(P<0.05);肌肉游离氨基酸中呈味氨基酸的含量显著下降(P<0.05),而必需氨基酸含量显著增加(P<0.05);肌肉的硬度和黏性也有了显著提高(P<0.05).上述结果表明,饲喂蚕豆可显著改善草鱼肌肉品质,但同时降低了草鱼生长性能.[中国水产科学,2008,15(6):1 042-1 049]     

不同水平的蚯蚓和蚯蚓粪对草鱼消化能力的影响

本研究首次在基础饲料中添加不同浓度的蚯蚓(5%、7.5%、10%)和蚯蚓粪(2%、4%、6%),饲养平均体重(54.03±0.15)g的草鱼100d,研究蚯蚓和蚯蚓粪对草鱼消化能力的影响。结果表明:添加7.5%～10%蚯蚓和6%蚯蚓粪显著提高了草鱼肝胰脏和前肠中胃蛋白酶、胰蛋白酶、淀粉酶和脂肪酶的活性,以添加7.5%蚯蚓效果最好;采用石蜡切片技术观察各试验组草鱼前肠肠道内部结构,结果表明,添加7.5%～10%蚯蚓可显著提高草鱼肠道褶皱高度、宽度和基层厚度。综上所述,在提高草鱼消化能力方面,以饲料中添加7.5%蚯蚓的效果最好。