食物与水环境因子对草鱼(Ctenopharyngodon idellus C.et Ⅴ)脆化过程的影响

结合生产实际,探讨了普通鲩鱼向脆肉鲩转变的过程和实质,提出用"断裂应力δρ"作为脆肉鲩脆化程度的划分标准,并实验研究了不同水温、水流速度、水化学因子和蚕豆饲料投喂量等因素对脆肉鲩生长和品质的影响.结果表明,以脆肉鲩不同部位组织热变性蛋白质的断裂应力δρ为指标的脆化程度主要由蚕豆饲料摄食量所决定,脆肉鲩养殖的良好条件为放养规格1.50～2.00kg/尾,放养密度150～170尾/666.7 m2,,水温在18℃以上;摄食量达到3.962～5.263 kg/kgbw时,可实现饲料系数约为6,脆化程度指标δρ为0.422～0.611 kg/cm2的合格商品脆肉鲩.水体水化学因子等环境条件只对草鱼脆化起间接辅助作用,它们通过改变草鱼的摄食量和营养(能量)转化率,影响机体正常的生理活动而导致草鱼肌肉蛋白合成与积累不同等表达出来,良好的水环境质量利于脆肉鲩养殖.普通鲩鱼脆化养殖的最佳养殖条件为适当的饲料投喂剂量(4.3kg/kgbw),适宜的水环境因子条件(水温(30±2)℃、DO≥5mg/L、pH在5.8～6.2之间).为进一步完善脆肉鲩养殖生产操作流程,提高脆肉鲩养殖技术,合理调控投饲量和养殖水环境因子,从而提高脆肉鲩品质和养殖效益进行了讨论.     

食物与水环境因子对草鱼(Ctenopharyngodon idellus C.et V)脆化过程的影响

结合生产实际,探讨了普通鲩鱼向脆肉鲩转变的过程和实质,提出用“断裂应力δρ”作为脆肉鲩脆化程度的划分标准,并实验研究了不同水温、水流速度、水化学因子和蚕豆饲料投喂量等因素对脆肉鲩生长和品质的影响。结果表明,以脆肉鲩不同部位组织热变性蛋白质的断裂应力δρ为指标的脆化程度主要由蚕豆饲料摄食量所决定,脆肉鲩养殖的良好条件为:放养规格1.50～2.00 kg/尾,放养密度150～170尾/666.7 m²,,水温在18℃以上;摄食量达到3.962～5.263 kg/kgbw时,可实现饲料系数约为6,脆化程度指标δρ为0.422～0.611　kg/cm2的合格商品脆肉鲩。水体水化学因子等环境条件只对草鱼脆化起间接辅助作用,它们通过改变草鱼的摄食量和营养（能量）转化率,影响机体正常的生理活动而导致草鱼肌肉蛋白合成与积累不同等表达出来,良好的水环境质量利于脆肉鲩养殖。普通鲩鱼脆化养殖的最佳养殖条件为适当的饲料投喂剂量（4.3kg/kgbw）,适宜的水环境因子条件(水温(30±2)℃、DO≥5mg/L、pH在5.8～6.2之间)。为进一步完善脆肉鲩养殖生产操作流程,提高脆肉鲩养殖技术,合理调控投饲量和养殖水环境因子,从而提高脆肉鲩品质和养殖效益进行了讨论。     

饲喂蚕豆对草鱼抗氧化能力及免疫机能的影响

投喂蚕豆100d左右, 草鱼肌肉的弹性和咀嚼性增强, 肌肉品质显著改善, 此种模式养殖的草鱼俗称脆肉鲩。实验比较了投喂蚕豆与商用配合饲料的草鱼, 在养殖过程中(30d、60d、100d)机体抗氧化能力及免疫机能的异同, 以了解脆肉鲩肌肉品质改变过程中鱼体的生物学变化。实验结果表明, 投喂蚕豆显著影响了草鱼血清总抗氧化能力(T-AOC)、血清丙二醛(MDA)含量及肝胰脏超氧化物歧化酶(SOD)活力, 但对肝胰脏T-AOC、MDA含量、谷胱甘肽(GSH)含量及血清SOD活力无显著影响。实验30d和60d时, 投喂蚕豆的草鱼机体抗氧化能力强于投喂配合饲料的草鱼, 但实验100d时两种养殖模式的草鱼机体抗氧化能力无显著差异。投喂蚕豆对草鱼免疫机能有一定的影响, 实验100d时, 投喂蚕豆的草鱼血液红细胞数量(RBC)及白细胞数量(WBC)显著高于投喂配合饲料的草鱼。投喂蚕豆的草鱼血清TP、ALB、GLB含量在实验30d时显著低于投喂配合饲料的草鱼, 在实验60d时与投喂配合饲料的草鱼无显著差异, 在实验100d时又显著低于投喂配合饲料的草鱼。投喂蚕豆显著影响了草鱼脾指数及脾脏中免疫相关基因的表达, 实验末期, 在投喂蚕豆的草鱼脾脏中IL-1、MHC Ⅱ、IFN-1、TNF-的表达量显著高于投喂配合饲料的草鱼。以上结果表明, 投喂蚕豆初期鱼体抗氧化能力增强, 随着投喂时间的增加, 鱼体抗氧化能力降低至与投喂配合饲料相当的水平; 投喂蚕豆使草鱼产生了免疫应答。       

蚕豆及其提取物对草鱼生长、肌肉成分和血清生化指标的影响

正草鱼(Ctenopharyngodon idella)是我国淡水养殖的重要经济鱼类。生产实践和研究表明,投喂蚕豆可使草鱼肉质变得结实而有韧性,称"脆肉鲩"或"脆化鲩";表现为肌肉硬度、耐咀性、弹性、回复性和黏着性的显著增加~[1—3]。然而到目前为止,尚不清楚究竟是蚕豆中的何种成分使草鱼肉质发生了显著改变。目前已知蚕豆中含有多种活性成分     

脆化草鱼(Ctenopharyngodon idellus C.et V)的病理生理生态学

分别就形态、生态和病理学性状对处于脆化终极阶段(LD₅₀≥6.67kg/kgbw)的草鱼与普通草鱼进行比较分析。高度脆化的草鱼在生态学上出现明显变化,体长和体重的指数方程W=aln显著不同于普通草鱼,DO阈值由平均值0.54mg/Ｌ上升到平均值1.68mg/Ｌ,CO2麻醉浓度(呼吸抑制值)由194mg/Ｌ高浓度下降到52.42～65.36mg/Ｌ, Root效应及Broh效应显著改变。解剖分析表明,草鱼脆化过程是渐进性组织病变的生理过程,包括各系统器官的功能性病变,最终使过度脆化的草鱼由于血液循环障碍直接导致死亡。草鱼脆化死亡具有明显的饲料（蚕豆）累积剂量——效应反应的毒理学规律,脆化草鱼的体长与体重的指数方程W =18.1719L2.4360可作为华南地区商品脆肉鲩标准的参考。研究结果将为脆化草鱼规模化集约养殖和提高脆化草鱼长途运输成活率提供参考。     

脆化草鱼(Ctenopharyngodon idellus C.et V)的病理生理生态学

分别就形态、生态和病理学性状对处于脆化终极阶段（LD50≥6．67kg／kgbw）的草鱼与普通草鱼进行比较分析。高度脆化的草鱼在生态学上出现明显变化,体长和体重的指数方程W=al^n显著不同于普通草鱼,DO阈值由平均值O．54mg／L上升到平均值1．68mg／L,CO2麻醉浓度（呼吸抑制值）由194mg／L高浓度下降到52．42～65．36mg／L,Root效应及Broh效应显著改变。解剖分析表明,草鱼脆化过程是渐进性组织病变的生理过程,包括各系统器官的功能性病变,最终使过度脆化的草鱼由于血液循环障碍直接导致死亡。草鱼脆化死亡具有明显的饲料（蚕豆）累积剂量——效应反应的毒理学规律,脆化草鱼的体长与体重的指数方程W=18．1719L^2.4360可作为华南地区商品脆肉鲩标准的参考。研究结果将为脆化草鱼规模化集约养殖和提高脆化草鱼长途运输成活率提供参考。     

池塘饲养鱼类优化结构及其增产原理 Ⅲ.池养草鱼适宜生长的食物结构及其需求量

在实验室以浮萍和苏丹草为青饲料,颗-1(蛋白质17％)和颗-2(蛋白质25％)为精饲料进行交叉梯度试验,用特定生长率、饲料总生长效率、蛋白质效率等作为评价指标,试验结果表明:草鱼种所需青饲料与颗-1、颗-2的适宜比例范围分别为20—50,1和15—30:1。根据上述试验结果,兼顾草鱼在不同季节的营养需求和控制池塘水质,调整各阶段青、精饲料的投喂量,于1987—1989年进行了池塘对比饲养试验,结果表明,青、精饲料的平均投喂量分别为11.25×10~4—12.00×10~4kg/ha和11.25×10~3—12.00×10~3kg/ha,试验池草鱼生长率、总体鱼增重量分别为常规池的1.4和1.5倍。     

鲩鱼Ctenopharyngodon idellus鱼种生长阶段蛋白质最适需要量的研究

采用蛋白质梯度饲养法,进行了三期试验。试验饲料分别以酪蛋白和鱼肉蛋白为蛋白源,饲料蛋白质含量范围为0.44-50.16%,在水温26-30.5℃条件下,研究了鲩鱼鱼种生长阶段(平均体重2.4-8.0克)在日投喂量占体重5-9%情况下,饲料蛋白质最适需要量,经采用直线回归和抛物线回归计算确定为22.77-27.66%。鲩鱼对饲料蛋白质利用率,随饲料蛋白质含量增高而下降,成负的直线相关关系:Y=29.2786-0.5296X。在蛋白质最适需要量范围,鲩鱼对蛋白质利用率波动于14.72-17.11%。       

鲩鱼Ctenopharyngodon idellus鱼种生长阶段蛋白质最适需要量的研究

采用蛋白质梯度饲养法,进行了三期试验,试验饲料分别以酪蛋白和鱼肉蛋白为蛋白源,饲料蛋白质含量范围为0．44—50．16％,在水温26～30．5℃条件下,研究了鲩鱼鱼种生长阶段(平均体重2．4—8．0克)在日投喂量占体重5—9％情况下,饲料蛋白质最适需要量,经采用直线回归和抛物线回归计算确定为22．77—27．66％。鲩鱼对饲料蛋白质利用率,随饲料蛋白质含量增高而下降,成负的直线相关关系：Y=29．2786-0．5296X。在蛋白质最适需要量范围,鲩鱼对蛋白质利用率波动于14．72-17．11％。     

不同饵料养殖黄喉拟水龟效果的研究

用5种不同的饵料(中华鳖配合饲料、蚯蚓、鲢鱼肉、福寿螺肉和河蚌肉)分别投喂黄喉拟水龟幼龟,结果表明,①投喂中华鳖配合饲料的黄喉拟水龟,其增重速度最快,平均日增重和蛋白质效率都最高,且耗料增重比最低,其后依次是: 蚯蚓＞鲢鱼肉＞福寿螺肉＞河蚌肉.②投喂福寿螺肉的黄喉拟水龟,其饵料成本最低,其后依次是: 中华鳖配合饲料＞蚯蚓＞河蚌肉＞鲢鱼肉.③中华鳖配合饲料是养殖黄喉拟水龟较好的饵料,但福寿螺、蚯蚓来源方便,也不失为养殖黄喉拟水龟的好饵料.     

Intensive culture of grass carp and hybrid grass carp larvae

Intensive culture of grass carp and hybrid grass carp (Ctenopharyngodon idella x Aristichthys nobilis ) larvae was conducted under Florida (U.S.A.) conditions. The influence of different rearing facilities (indoor tanks, outdoor tanks and cages) and different methods of fish feeding using live zooplankton and artificial food was tested. High survival (86–100%) and satisfactory grass carp growth (47–56 mg) were obtained in the outdoor tanks and cages during the 10–day experiment. It is believed, that the technique described can be used after some improvements for commercial–scale grass carp larvae rearing. Low survival (1–3%) was obtained in the hybrid culture experiment even though satisfactory growth rates (84–212 mg) were obtained after 13 days. High mortality was attributed to genetic abnormalities caused by hybridization. The hybrid does not appear to be a promising fish for culture.     

The relationship between feeding preferences and consumption rates in grass carp and grass carp × bighead carp hybrids

The relationship between food preference hierarchy and consumption rate was examined for the grass carp, Ctenopharygodon idella , and its Fl hybrid (grass carp × bighead carp). Preferences of both types of fish were similar, although hybrids consumed vegetation at a much lower rate. For both, relative preference in feeding trials with mixed plant species was significantly correlated with consumption rate in monospecific feeding experiments. No correlations were found between preference and caloric content, protein content or relative water content. The hypothesis is proposed that preference hierarchies reflect relative handling times of different food types and that these fish maximize 'through-put' by preferentially consuming plant species which can be most rapidly ingested.     

The grass carp for weed control

The agricultural and recreational use of waterways is decreased by a too luxurous growth of various species of aquatic plants. Weed control has to be carried out at least once every year. The old-fashioned hand-cutting has nearly been abandoned, due to shortage of manpower and high costs. For the same reasons mechanical weed control methods are not very popular everywhere. Possibilities for chemical control of aquatic weeds in Dutch waterways are restricted.The grass carp (Ctenopharyngodon idella) could offer an inexpensive biological alternative. Experiments showed, that this fish is an efficient weedcontrol agent under Dutch circumstances. It is presumed, that its impact on various functions of the surface water is less (or at least less rigorous) than that of modern mechanical or chemical methods. Still it is felt, that this impact (side-effects) should be investigated thoroughly before introduction of this exotic species into our aquatic environment. For this reason a Working Party was formed within the framework of the Dutch Agricultural Research Council, section Weed Research.Preliminary results indicate that the grass carp does not eradicate plant-species; in the experiments remnants of the original vegetation remained, so that recovery was possible. Furthermore the macrophytic diversity was only slightly decreased. These observations indicate that the grass carp shows very little selectivity in type of food and in space. From a biological point of view this is rather ideal for any weed control agent. Up till now no clear influence on the composition or quantity of the microflora was found.The quantity of macrofauna and macrobenthos decreased in grass carp plots, for unknown reasons, but the rate of diversity does not differ from the rate of diversity in the control plots. Influence of grass carp stocking on growth, survical and breeding of endemic fishes will be studied in the coming years.     

Immunization with recombinant baculovirus expressing the VP6 protein of grass carp reovirus induces immunity in grass carp

Grass carp reovirus（GCRV）,a member of the genus Aquareovirus in the family Reoviridae（Attoui H,et al,2002）,is one of the most virulent aquareoviruses iden-tified so far,leading to high fatality rates（up to 85%）of fingerlings and yearlings of grass carp（Fang Q,et al,2007）.No commercial vaccines against GCRV infection have been developed as yet.     

Cloning of the grass carp growth hormone cDNA

We have constructed a cDNA library in lamda gt11 using mRNA isolated from the pituitary glands of the grass carp (Ctenopharyngodon idellus). Based on the published sequence of the rainbow trout growth hormone cDNA, we synthesized two oligonucleotide probes. One of these hybridized strongly with a specific mRNA fragment from the grass carp pituitary. Using this probe, we have isolated six positive clones carrying an insert of approximately 1.2 Kb. By restriction enzyme digestion, all the clones were determined to be identical. Sequence determination on one of them indicated that it has an open reading frame coding for 210 amino acids. Both the nucleotide and translated amino acid sequence are highly homologous to those of the salmon growth hormone and the common carp. A putative signal peptide consisting of hydrophobic amino acids can be identified at the 5' end of the sequence. A polyadenylation signal, ATTAAA, was also present 12 base upstream from the poly A tail.     

草鱼前体脂肪细胞的原代培养

构建脂肪细胞体外培养体系,研究脂肪细胞分化过程,是探讨动物脂质代谢规律的重要手段.目前,哺乳动物方面,自20世纪60年代起至今,国内外已成功构建了大鼠[1,2]、人[3,4]、牛[5,6]和猪[7,8]的前体脂肪细胞体外培养模型,鱼类方面的工作则开始不久.     

草鱼、鲢和瓦氏黄颡鱼幼鱼感应流速的比较

在21±1℃水温下,使用自行制作的鱼类游泳行为测试槽,采用流速递增的方法测定了草鱼(Ctenopharyngodon idellus)(体长9.64±3.12 cm,体重20.97±16.71 g)、鲢(Hypophthalmichthys molitrix)(体长10.60±3.45 cm,体重24.37±18.61 g)和瓦氏黄颡鱼(Pelteobagrus vachelli)(体长11.54±1.46 cm,体重20.98±6.94 g)幼鱼个体的感应流速.结果表明:草鱼、鲢和瓦氏黄颡鱼幼鱼的感应流速分别是(8.21±0.68)、(6.74±0.84)和(33.11±3.06) cm·s-1,相对感应流速分别是(0.91±0.22)、(0.67±0.15)和(2.9±0.29) BL·s-1;鲢和草鱼幼鱼的感应流速差异不显著(P＞0.05),但瓦氏黄颡鱼比草鱼和鲢幼鱼感应流速大近4倍,差异显著(P＜0.05);因此,草鱼和鲢幼鱼较瓦氏黄颡鱼幼鱼对流速的感应更敏感.本实验结果可为设计鱼道、确定拖网速度等提供一定的科学指导.     

Molecular characterization of glutathione peroxidase gene from the liver of silver carp, bighead carp and grass carp

The cDNAs encoding glutathione peroxidase (GPx) were cloned and sequenced from the liver of three Chinese carps with different tolerance to hepatotoxic microcystins, phytoplanktivorous silver carp (Hypophthalmichthys molitrix) and bighead carp (Aristichthys nobilis), and herbivorous grass carp (Ctenopharyngodon idellus). Using genome walker method, a 750 bp 5'-flanking region of the silver carp GPx gene was obtained, and several potential regulatory elements were identified in the promoter region of the GPx gene. The silver carp GPx gene was widely expressed in all tissues examined. Despite phylogenetic analysis, assigning this newly described carp GPx to the group of mammalian GPx2, the carp GPx seems more similar to GPx1 from a physiological point of view. The constitutive expression pattern of the three carp liver GPx gene, shows a positive relationship with their tolerance to microcystins.     

Differential expression of two C‐type lectins in grass carp Ctenopharyngodon idella and their response to grass carp reovirus

The cDNAs of two C‐type lectins in grass carp Ctenopharyngodon idella, galactose‐binding lectin (galbl) and mannose‐binding lectin (mbl), were cloned and analysed in this study. Both of them exhibited the highest expression level in liver, whereas their expression pattern differed in early phase of embryonic development. Following exposure to grass carp reovirus (GCRV), the mRNA expression level of galbl and mbl was significantly up‐regulated in liver and intestine.