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1.
刘忠颖  陈远 《水产科学》1999,18(3):17-20
在15.0℃、17.5℃和19.0℃3个温度梯度下,各试验组纪体的生长速度和成活率6.3μm/d,8.6μm/d、9.3μm/d;61.0%、70.5%、23.0%。投附着基经22d培养各试验组稚贝规格(壳长×壳高)分别平均为620μm×595μm、705μm×680μm、745μm×710μm;各组生长速度和附着后成活率分别为17.7μm/d、21.6μm/d、23.4μm/d;35.4%、34  相似文献   

2.
本文研究了铜,锌离子在球等鞭金藻的培养液中最佳存在活度。采用了一种新的海水处理方法,除去海水中的重金属离子,同时,计算了培养液中铜,锌离子活度,结果表明,金藻培养液中,铜,锌离子的最佳活度为10^-13.57-10^-8.80mol/L和0-10^-6.00mol/L;铜离子表现了对金藻生长繁殖的必需性,而锌离子未表现出对金藻生长繁殖的必需性;当铜,锌离子活度分别大于10^-8.80和10^-6.  相似文献   

3.
中华绒螯蟹RAPD扩增条件及个体间遗传差异   总被引:5,自引:0,他引:5  
该项研究优化了河蟹RAPD反应体系,初步确定:Taq酶用量为IU,引物浓度0.35μmol/L,dNTPs浓度100μmol/L模板量50-100ng,MgCl2浓度2.5mmol/L,退火温度38℃,得出同一养殖群中不同个体河蟹遗传差异在20%以下。  相似文献   

4.
放养4.5-6kg/m^3,饲养期约100天,单产27-32.6kg/m^2,饲养系数1.3-1.75,成本利润56.9%-75.2%,能量转换率17.9%-23.9%,试验表明在我国北方网箱养武昌鱼能取得较高的经济效益。  相似文献   

5.
孔雀绿对湛江叉鞭金藻的毒性效应   总被引:2,自引:0,他引:2       下载免费PDF全文
吴以平 《水产学报》1998,22(1):67-71
在20℃和30℃下,用含有不同浓度(0.02~0.10μg/L)孔雀绿的海水,在室内用一次培养法培养湛江叉鞭金藻,测定了4天内金藻的生长速率、叶绿素a、胡萝卜素和蛋白质含量。结果表明,0.02μg/L的孔雀绿对金藻有轻微影响,浓度≥0.04μg/L的孔雀绿能使金藻的生长速率、叶绿素a、胡萝卜素和蛋白质含量明显减少。温度对孔雀绿的毒性有明显影响,温度越高,毒性越大。  相似文献   

6.
对虾养殖实验围隔中的固氮作用及其氮输入   总被引:2,自引:0,他引:2  
齐振雄 《水产学报》1999,23(1):40-44
1997年6~10月,以乙炔还原法进行了不同放养模式下对虾养殖实验中生物固氮作用的测定。结果表明,各围隔中,对虾单养(Y-4)和对虾+海湾扇贝(Y-5)的固氮作用较高,均值分别为2.62μgN/(L·hr)和2.65μgN/(L·hr);对虾+罗非鱼+缢蛏(T-5)的最低,为1.53μgN/(L·hr),对虾+缢蛏(Y-6)和对虾+罗非鱼(Y-7)的分别为2.30μgN/(L·hr)和1.89μgN/(L·hr)。各围隔中固氮速率较高与水体有效氮含量较低及有效氮磷比值不高有关。水层固氮蓝藻主要为蓝球藻(Chrococus)和念珠藻(Nostoc)。估算各围隔实验期间固氮作用输入分别为Y-4∶17.72g;Y-5∶19.63g;Y-6∶9.05g;Y-7∶10.59g;T-5∶7.99g。  相似文献   

7.
斑节对虾封闭式育苗技术研究   总被引:2,自引:0,他引:2  
斑节对虾封闭式育苗的主要技术措施:育苗池中密布气石5.5个/m2;抽取大潮期海水经砂滤后入池,育苗过程中不添水换水;调节苗池光照强度约0.6~1μE/m-2·S-1;投喂优质饵料6次/d,混投优质中肋骨条藻和亚心形扁藻,掌握适当的投饵量;每天定时投放10×10-6的光合细菌等。试验结果,平均单位水体出苗量为5.7万尾/m3,成活率56.3%。  相似文献   

8.
于1996~1997年,用6-DMAP抑制太平洋牡蛎受精卵第二极体的释放,诱导产生三倍体,最高诱导率为93.8%。该实验组胚胎孵化率为81.0%,D形幼虫畸形率为17.6%。实验选用L9(34)设计,进行三因素三水平的正交试验:6-DMAP浓度,设300、450和600μmol/L等三水平;诱导时机(观察静止状态的受精卵,以受精卵出现第一极体的百分率指示),设10%、30%和50%等三水平;诱导持续时间,设10、15和20min等三水平,试验设三次重复。解剖法获取精卵,人工授精。染色体倍性检查采用染色体计数法。根据正交试验直观分析结果,得出诱导太平洋牡蛎三倍体各因素的最优水平组合:当30%受精卵出现第一极体时,将受精卵浸泡在含6-DMAP450μmol/L的海水中10min;三因素的主次顺序:6-DMAP浓度→诱导时机→诱导持续时间。6-DMAP的浓度和诱导时机对三倍体诱导率的影响显著;但诱导持续时间影响不显著。部分试验组得到4.2%~13.6%的四倍体和10%左右的非整倍体,这种情况可能与受精不同步抑制第一极体释放而导致的染色体多极分离有关。  相似文献   

9.
泥鳅和大鳞副泥鳅营养成分分析   总被引:24,自引:3,他引:21  
赵振山  印杰 《水利渔业》1999,19(2):16-17
对泥鳅和大鳞副鳅肌肉的营养成分进行测定。泥鳅的水分,灰分,脂肪,蛋白质的含量分别为78.21%、1.12%、2.31%、17.55%;大鳞副泥鳅的分别为78.80%、1.13%、2.57%、17.40%。它们的17种氨基酸含量分别为16.11%和13.78%,其中9种必需氨基酸含量分别为7.02%和6.29%。,经比较分析,两种泥鳅营养丰富,其中,泥鳅的营养价值要高于大鳞副泥鳅。  相似文献   

10.
1试验条件1.1 设施、设备育苗池14个,有效面积 420 m2,规格 5m ×6 m×1.3 m;M级沙滤池 2个,规格 5 m×2m×1.5 m;海边沙滤井 1口;单胞藻培养池 16个,规格 3 m×5 m×0.8 m;12 m3/h罗茨鼓风机1台;蒸发量为2t/h的锅炉1台。1.2 试验材料 饵料为人工培育的等鞭金藻、牟氏角毛藻、青岛大扁藻、异胶藻及海洋酵母。亲蚶系采自浙江乐清人工养殖的3龄泥蚶,规格160粒/kg。2试验方法2.1催产、孵化用沙滤海水冲刷掉亲蚶外壳上的犯及沉垢,然后用500×10-6的高…  相似文献   

11.
12.
Previously, we reported 10 PEGE types of 85 tilapia Streptococcus agalactiae(GBS), which shifted from Streptococcus iniae in China, by using PEGE method. Presently, larger and more representative tilapia GBS were isolated, for the ?rst time in China, to characterize their serotypes and genetic diversities more precisely than had done before. 168 GBS strains were distributed in ?ve provinces of China, in which Guangdong, Guangxi and Hainan were the major ones, holding36.9%(62/168), 37.5%(63/168) and 19.6%(33/168), respectively. Serotypes, Ia, Ib and III, were observed in these strains and the most predominant one was Ia(95.2%), which mainly distributed in Guangdong, Guangxi and Hainan. Ia initially occurred in 2009, it shoot up to 32.1% in 2010,but decreased to 16.1% in 2011 before went up to 45.2% in 2012. Ib sporadically occurred during2007–2011, III onlyoccurred in 2012. 14 different PFGE types, including 4 new types(N, O,P and Q), were observed, in which B, D, F and G were the predominant types, holding 83.9%(141/168) of the total GBS strains. Ia corresponded to 11 PFGE types(A–H, N–P), in which type D predominated(51%). Ib represented 3 genotypes(I, J and Q) and III harbored only 2genotypes(N and F). Type N and Fsynchronously presented in Ia and III. In summary, the genetic diversity of tilapia GBS varied by serotypes and changed with geographical locations and years.Although Iastillpredominated, new rareserotypeIII alreadyoccurred in China.  相似文献   

13.
Growth hormone (GH) and reproduction: a review   总被引:5,自引:0,他引:5  
Interaction between growth and reproduction occurs in many vertebrates and is particularly obvious at certain stages of the life cycle in fish. Endocrine interactions between the gonadotropic axis and the somatotropic axis are described, the potential role of GH being emphasised. A comparative analysis of these phenomena in mammals, amphibians and fish, suggests a specific role of GH in the physiology of puberty, gametogenesis and fertility. It also shows the original contribution made by studies on the fish model in this field of investigations.  相似文献   

14.
The environmental processes associated with variability in the catch rates of bigeye tuna in the Atlantic Ocean are largely unexplored. This study used generalized additive models (GAMs) fitted to Taiwanese longline fishery data from 1990 to 2009 and investigated the association between environmental variables and catch rates to identify the processes influencing bigeye tuna distribution in the Atlantic Ocean. The present findings reveal that the year (temporal factor), latitude and longitude (spatial factors), and major regular longline target species of albacore catches are significant for the standardization of bigeye tuna catch rates in the Atlantic Ocean. The standardized catch rates and distribution of bigeye tuna were found to be related to environmental and climatic variation. The model selection processes showed that the selected GAMs explained 70% of the cumulative deviance in the entire Atlantic Ocean. Regarding environmental factors, the depth of the 20 degree isotherm (D20) substantially contributed to the explained deviance; other important factors were sea surface temperature (SST) and sea surface height deviation (SSHD). The potential fishing grounds were observed with SSTs of 22–28°C, a D20 shallower than 150 m and negative SSHDs in the Atlantic Ocean. The higher predicted catch rates were increased in the positive northern tropical Atlantic and negative North Atlantic Oscillation events with a higher SST and shallow D20, suggesting that climatic oscillations affect the population abundance and distribution of bigeye tuna.  相似文献   

15.
Protein and amino acid composition of the mantle of juvenile O ctopus vulgaris (Cuvier, 1797) during fasting for 27 days were determined. Average protein content of octopus mantle was of 711.19 ± 46.80 g kg?1 DW, and it decreased with increasing fasting days. The non‐essential amino acids content was higher (486.18 ± 11.08 g kg?1 protein) than essential amino acids (425.82 ± 9.15 g kg?1 protein) at the start of the experiment (unstarved animals). The results suggest that the amino acid profile of the mantle where the most abundant amino acids are Arg, His, Lys, Gly, Leu and Pro could indicate a prolonged fasting condition (>20 days) or poor nutrition of O . vulgaris. This study supports the idea of using mantle for metabolic needs of starved O . vulgaris suggesting that the degradation pathway of amino acids to pyruvate and tricarboxylic acid cycle intermediates was favoured contrary to the degradation pathway of ketogenic amino acids. Special considerations should be taken concerning Thr, Ile, Ser, Ala, Asx (Asp, Asn), Glx (Glu, Gln) (because of their fast intake) and Lys and His (due to their stable contents) during a prolonged period of fasting.  相似文献   

16.
The endemic, anadromous cyprinidChalcalburnus tarichi is the only fish species known to occur in alkaline Lake Van (Eastern Anatolia, Turkey). EightC. tarichi were maintained individually in Lake Van water (17 – 19°C; pH 9.8; 153 mEq·I–1 total alkalinity; 22 total salinity) and tank water samples analyzed for 24 h in 2 to 4 h intervals. At zero time, < 1µM ammonia was present and urea was undetectable in the tank water; at 24 h, total ammonia and urea made up 114±32 and 35±25µM, respectively. Over the experimental period, ammonia-N and urea-N excretion averaged 1041±494 and 607±169moles·kg–1 fish·h–1, respectively. The extent of urea excretion was highly variable between specimens. Uric acid excretion was not detectable.Urea was present at high concentrations in all tissues and plasma (25 – 35moles·g–1·ml–1) of freshly caughtC. tarichi; total ammonia content of the tissues was by a factor of 1.9 (liver) to 3.0 (brain) lower. High arginase activity (2.4±0.2 U·min–1·g–1) was detected in the liver ofC. tarichi but ornithine carbamoylphosphate transferase, a key enzyme of the ornithine-urea-cycle, was absent. Ureagenesis is likely through degradation of arginine and/or uricolysis. High glutamine synthetase activity (11±0.6 U·min–1·g–1) and low ammonia content in brain suggest that, like other teleosts,C. tarichi has an efficient ammonia detoxification in the brain, but in no other tissue.Nitrogenous waste excretion at alkaline pH is discussed. The ability ofC. tarichi to excrete high levels of ammonia at extremely alkaline pH is unique among teleosts studied so far. The mechanism of ammonia excretion under Lake Van conditions remains to be elucidated.  相似文献   

17.
Two gonadotropins (GtH; Qa and Qb) were purified by gel filtration and ion exchange chromatography from the pituitaries of Indian walking catfish (Clarias batrachus). The presence of GtH during purification was assessed by in vitro oocyte maturation and in vivo steroidogenic activity, and their identities were determined by elution profiles, molecular weight, biological activities and yield. The molecular weights of Qa and Qb were 37 and 42 kDa, respectively, and composed of distinct subunits (Qa: 20 and 14 kDa and Qb: 26 and 18 kDa). Polyclonal antibodies raised against Qa immunostained Qa, Qb and pituitary GtH cells. A competitive Qa‐ELISA was developed whose sensitivity was 6.25 ng mL?1 (1.25 ng well?1) with intra‐ (3.5%) and inter‐ (12.4%) assay coefficients of variation. Displacement curves parallel to the standard were obtained with plasma and pituitary extracts of catfish, Qb and carp GtHII. The assay was validated by measuring the plasma Qa levels after LHRH treatment and in relation to ovarian growth in the female catfish during different reproductive phases. Based on the results, Qa and Qb corresponded to fish LH and FSH respectively. The findings will increase the knowledge of the mechanisms controlling fish reproduction and identification of sensitive phases in fish in captivity for hormonal manipulation.  相似文献   

18.
19.
Tetrahymena is a protozoan parasite, which infects guppy, Poecilia reticulata Peters, and causes substantial economical losses in commercial farms worldwide. Studies of guppy infected by Tetrahymena require standardized infection protocols. The LD50 for Tetrahymena infection of guppies by intraperitoneal (IP) injection was calibrated, and the level obtained was 946 parasites per fish. Guppy infection with Tetrahymena by immersion, imitating the natural route of infection via the integument, was studied under normal or stress conditions. Exposure to cold and netting (CNI) and to cold only (CI) followed by immersion exposure to 10 000 Tetrahymena per mL resulted in 22.5% and 19.2% mortality, respectively, as compared to 14.2% and 10% in groups that were netted only (NI) or non‐stressed (I). Histopathology revealed that immersion infection resulted in a systemic infection. Lysozyme levels, measured 3 weeks after infection, were significantly higher in the CNI group (288 μg per mg protein) compared with CI‐, NI‐ and I‐treated groups (94.5, 64 and 62.3 μg mg?1, respectively). There was no evident parasite immobilization activity in body homogenates, suggesting no development of acquired immunity. Re‐infection by IP injection revealed no increase in protection in any of the treatment groups, mortality range of 56.3–75%, higher than in the non‐exposed control (40.6% mortality).  相似文献   

20.
In this experiment, a feeding trial was performed to determine the effects of fructooligosaccharide (FOS) on growth performance, digestive enzyme activity and immune response of Japanese sea bass, Lateolabrax japonicus juveniles (initial weight 38.3 ± 0.5 g), and the fish were examined following feeding with six levels of FOS (0, 0.5, 1, 2, 4 and 6 g/kg) for 28 days. Significant enhancement of weight gain (WG) and specific growth rate (SGR) was found in fish fed 1 g/kg FOS incorporated diets (p < .05), while the feed conversion ratio (FCR) in the 1, 2 g/kg FOS groups reduced significantly compared with the control (p < .05). Besides, the crude lipid in the 4, 6 g/kg FOS groups increased significantly compared with the control (p < .05). On the other hand, the erepsin and lipase activities significantly elevated in intestine of fish fed 2 g/kg FOS (p < .05) and the lysozyme activity in serum of fish fed 2 g/kg FOS were significantly higher than that in the control (p < .05). Moreover, the alkaline phosphatase activities in serum of fish fed 0.5, 1, 2 g/kg FOS were significantly higher than in control (p < .05). Regression analysis showed that the relationships between dietary FOS levels and either SGR, FCR, erepsin or lysozyme activities were best expressed by regression equations, and the optimal inclusion levels are 1.37, 1.80, 3.06, 3.11, 1.93 and 1.80 g/kg for SGR, FCR, erepsin, lipase, lysozyme and total superoxide dismutase activities, respectively. Overall, this study revealed that FOS incorporated diets could beneficial for L. japonicus culture in terms of increasing the growth, digestion and immune activities. Under the present experimental condition, the optimal supplementary level of FOS in the diet of L. japonicus is 1–3 g/kg.  相似文献   

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