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51.
鲤鱼棘头虫病的病理及预防   总被引:1,自引:1,他引:1  
本文报导了病鱼的组织(肠、肝、胰、肾)病理变化,及血液(血清的钠、钾、氯化物、肌酐、尿素氮、谷草转氨酶总活力及谷草转氨酶同工酶。白细胞血式)病理变化,从而阐明了引起病鱼慢性死亡,而累计死亡率又高达60%的机理。查明了病原(崇明长棘吻虫)的中间寄主是模糊裸腹溞,找到了用生石灰或漂白粉清塘、在发病地区用鱼种池培育的鲤鱼鱼种的有效预防方法。  相似文献   
52.
The aims of this experiment were (1) toquantify the ability of grass carp to processduckweed and (2) to assess indirect changes inwater chemistry and phytoplankton community,caused by grass carp feeding. Yearling grass carp sized 126 ± 7.7 mm (TL) and19.6 g in weight were kept in 9 laminate tanksof 1 m3 for 14 days. Two stockingdensities (2 and 6 fish per m3) anda control without fish were used. Standard growthrate (SGR) of grass carp fed exclusively onduckweed was 0.70% body weight (BW) d–1and food conversion ratio (FCR) reached 2.0(average water temperature =21.1 ± 3.8 °C). Daily food intakewas 0.2 g of duckweed dry weight (DW), i.e.,1% of average BW of grass carp. SGR ofduckweed growing in 20 × 20 cm floatingenclosures, differed significantly[F(6,2) = 417.9; p = 0.002] between the twostocking densities of grass carp and thecontrol tanks (without fish). Mean SGR ofduckweed was 0.02 g g–1 day–1 and thehighest SGR was recorded in the control tanks.Both decrease in NH4-N and increase inNO2-N concentrations differedsignificantly between the treatments[F(2,2) = 45.3; p = 0.02 and F(2,2) = 19.2; p = 0.04 respectively]. Changes in other nitrogenand phosphorus components (NO3-N, TN, TPand PO4-P) caused by stocking of grasscarp were not significant. Biomass ofphytoplankton, dominated by filamentous algaeand blue-greens, increased proportionately tostocking density of grass carp. Althoughduckweed has a large potential for nutrientremoval, the most common pathway for thenutrients released through grass carp grazingif duckweed cover is loose is theirincorporation into phytoplankton biomass.  相似文献   
53.
The effect of an 80-day maintenance-feeding period on the acute stress response of common carp, Cyprinus carpio, to net confinement was determined. Fish were raised on an optimal feeding level of 20 g food/kg of metabolic fish weight per day (g/kg0.8 day−1) until 124 days post-hatch (dph). Feeding in group one (L>H) was then reduced to maintenance levels, i.e. 5 g/kg0.8 day−1 until 204 dph, when the feeding was again increased to 20 g/kg0.8 day−1. In group two (H>L), the feeding level was reduced from 20 to 5 g/kg0.8 day−1 on day 146. All fish were sampled at 226 dph. Food ration had significant effects on the growth rate and food conversion values with fish fed the high ration performing better than those on a lower level. Prior to the application of the stressor, only plasma levels of triglycerides were lower in fish fed a low food ration (H>L). Feeding history influenced the onset of the stress response with stressor-induced elevations of plasma cortisol, glucose and free fatty acids being higher in fish fed a high ration compared with those fed a low ration prior to sampling. These results suggest that feeding history through modification of the energy reserves can influence the onset of the acute stress response.  相似文献   
54.
作者观察了鲤、团头鲂精子在0(去离子水)-300毫渗渗透压的D-半乳糖,D-葡萄糖和D-果糖溶液中的活动情况。结果表明,在这三种单糖溶液里,鲤、团头鲂精子活动的变化规律是一致的。精子快速运动和寿命的时间是以在D-半乳糖溶液中为最长。这两种鱼精子对这三种单糖的吸收、利用存在差别。  相似文献   
55.
A 57‐day growth experiment was conducted with juvenile gibel carp (13.48 ± 0.10 g) in a flow‐through system to study the effect of dietary phosphorus on growth performance, body composition, nutrition utilization, phosphorus loading and enzymes activities. Seven semipurifed diets were formulated to contain 0.07 (the basal), 2.27, 5.32, 8.10, 12.06, 15.24 and 19.48 g available phosphorus/kg diet. The results showed that specific growth rate, body length and feed efficiency significantly increased in the fish fed diets containing 0.07 to 15.24 g available P/kg diet (< .05). Ash and P content increased in fish fed diets containing 0.07–12.06 P g/kg (< .05) and then levelled off, while moisture, crude protein and lipid had no significant difference (> .05). The protein retention efficiency increased in the fish fed with diets 0.07–5.32 g/kg P (< .05) and then reached a plateau. The P content in faeces was higher in fish fed diets containing 15.24 and 19.48 g available P/kg. Total P concentration in tank water increased in fish fed 0.07–12.06 g available P per kg diet (< .05). The plasma P was higher in the fish fed with 15.24 g available P/kg diet (< .05), triglycerides was lower in the fish fed diet containing 15.24 and 19.48 g available P/kg (< .05), no significant differences were observed in plasma Ca, plasma glucose and calcitonin (> .05). Based on SGR, whole body P content and FE, dietary available P requirement for juvenile gibel carp were 13.37, 13.97 g/kg and 15.06 respectively.  相似文献   
56.
采用解剖观察、组织切片及人工催情等方法,研究芙蓉鲤鲫(Cyprinus capiofurong.♀×Carassius auratus red var.♂)的性腺发育及繁殖性能。结果显示:解剖观察,芙蓉鲤鲫性腺发育异常的个体占83.64%,性腺外观基本正常的个体占16.36%。组织学观察,芙蓉鲤鲫性腺可分三类:两性嵌合体占21.13%,其中以精巢为主的16.90%,以卵巢为主的4.23%,它们性腺发育迟缓,在繁殖季节成熟系数也没有明显变化,性腺多为一侧发育或两侧不对称,两种性腺细胞均不能成熟;雌性个体占40.84%,在生殖季节卵巢可发育到第IV时相,但未见其细胞核发生偏移;雄性个体,占38.03%,在生殖季节只能发育到精子细胞阶段,不能产生成熟的精子。经人工催产,芙蓉鲤鲫少部分个体有发情产卵行为但不能正常受精。结果表明芙蓉鲤鲫为两性败育类型。  相似文献   
57.
根据Gen Bank中鲤春病毒血症病毒(SVCV)糖蛋白全基因序列设计特异性引物,以SVCV欧洲株病毒核酸为模板,通过RT-PCR方法获得欧洲株SVCV-G基因,克隆至p PICZαA,构建p PICZαASVCV1540表达质粒。以限制性内切酶Sac I线性化p PICZαASVCV1540后通过化学法转化毕赤酵母感受态细胞X33和GS115,添加1%甲醇进行诱导表达,SDS-PAGE电泳分析表达产物显示其分子质量为70 ku。Western Blot分析显示该蛋白可以被SVCV山羊多抗识别,表明目的蛋白具有反应原性。  相似文献   
58.
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。  相似文献   
59.
鲤鱼血淋巴细胞培养及染色体制备条件探索   总被引:7,自引:0,他引:7  
从鲤鱼侧线鳞处静脉采血于含有肝素的一次性注射器中,采用RPMI1640全培养基进行体外淋巴细胞培养。通过对采血后细胞培养时间、秋水仙素浓度及加入时间、低渗时间及温度等条件的摸索,建立了较成熟的培养鱼类血淋巴细胞的实验方法。  相似文献   
60.
In the uplands of northern Vietnam, culture of grass carp contributes significantly to income and household food security of Black Thai farmers. Maize is one of the most important upland crops and barnyard grass is the most important weed in the paddy rice fields. Thus, these are frequently used by small‐scale fish farmers as fish feed. An 8‐week feeding trial was conducted simultaneously in a recirculation and in a respirometric system to determine the digestibility and metabolizability of the nutrients of maize leaves and barnyard grass, to assess their crude protein, lipid and energy conversion and to estimate the energy allocation in grass carp. The following diets were used: diet ‘A’ (reference diet) containing 39% crude protein with 19.8 MJ kg?1 gross energy; diets ‘B’, ‘C’ and ‘D’, which contained the same amount of the reference diet as the control diet, supplemented with a known amount of dried barnyard grass, dried maize leaves or fresh maize leaves, respectively. Five fish were assigned to each treatment in each experimental unit. Reference and test diets were fed to fish and faecal samples were collected and the oxygen consumption was measured in order to set up an energy budget of the fish over the whole experimental period. The weekly development of the body weight was recorded. The body weight gain of the fish fed diet D was significantly higher than that of the group fed diet A, which also in turn was significantly higher than that of fish fed diet B or C. The apparent digestibility coefficients (ADC) of nutrients and gross energy for the different experimental diets in fish kept in the aquaria were, for diets A, B, C and D respectively, 94.1%, 60.9%, 70.5% and 84.7% for protein, 91.3%, 60.7%, 76.8% and 71.8% for lipid; 95.9%, 44.5%, 60.6% and 69.1% for gross energy. The partial ADC of plant leaf ingredients were determined and barnyard grass and dried maize leaves were found to be not only poorly digestible but having negative impact on the digestibility of the reference diet, while fresh maize leaves were well digested. The results of the present study indicated that fresh maize leaves have a good potential to be used as supplement in diets for grass carp.  相似文献   
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