共查询到20条相似文献，搜索用时 62 毫秒
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EDTA对紫彩血蛤幼虫发育的影响 总被引：7，自引：0，他引：7
本文研究了ＥＤＴＡ对紫彩血蛤幼虫生长,存活和变态的影响。结果表明,所有试验的ＥＤＴＡ浓度均能促进幼虫生长,前期３．０×１０＾－６浓度组生长最快,幼虫平均壳长由对照组的２３５．６μｍ增至２３９．７μｍ,后期则以１．０×１０＾－６浓度且生长最快,幼虫平均壳长由对照组的２４７．４μｍ增至２５３．０μｍ;０．５×１０＾－６－５．０×１０＾－６ＥＤＴＡ均能提高幼虫的存活率和变态率,其中以１．０×１０＾－６效 相似文献
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红螯螯虾对硫酸铜和孔雀石绿耐受性的研究 总被引：4，自引：0，他引：4
测定了红螯螯虾虾苗对硫酸铜和孔雀石绿的耐受性，结果表明，２４ｈＬＣ５０分别为６３．８２×１０＾－４％和１３．７８×１０＾－４％；４８ｈＬＣ５０分别为２３．３７×１０＾－４％和４．８４×１０＾－４％；９６ｈＬＣ５０分别为１５．０７×１０＾－４％和２．６５×１０＾－４％；安全浓度分别为０．９４×１０＾－４％和０．１８×１０＾－４％。 相似文献
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嗜水气单胞菌苗免疫接种试验表明，室温３０℃时，试验鱼注射接种１．８～２．７×１０８个／尾的灭活菌苗，８－１０天后即产生较强的免疫力，注射接种１％一１‰的灭活组织苗０．２－０．３ｍｌ／尾，６－８天后即产生较强的免疫力，两者的保护力均达９２％以上，浸泡相当于１．８×１０６个／ｍｌ的脂多糖粗提物（ＬＰＳ），１０—１２天后产生的保护力可达７０％左右。不同温度的接种试验表明，水温３０℃时接种比１５℃时接种，免疫力的形成早４—７天。大池试验表明，灭活苗苗接种鱼的免疫时效达６个月以上。 相似文献
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镉对罗氏沼虾组织转氨酶活性及组织结构的影响 总被引：33，自引：2，他引：33
对罗氏沼虾（Ｍａｃｒｏｂｒａｃｈｉｕｍｒｏｓｅｎｂｅｒｇｉｉ）成虾六种组织的谷丙转氨酶（ＧＰＴ）和谷草转氨酶（ＧＯＴ）活性正常值作了测定，其中心脏和绿腺的ＧＰＴ和ＧＯＴ活性较高，鳃和肝胰脏次之，卵巢和肌肉较低。不同镉离子浓度（０．３７、０．７４和１．４８×１０－６）对罗氏沼虾的急性中毒试验表明，受水中０．７４和１．４８×１０－６Ｃｄ２＋影响，心脏、鳃和肝胰脏的ＧＰＴ和ＧＯＴ活性显著降低；绿腺的ＧＰＴ和ＧＯＴ活性在０．７４×１０－６组显著升高。组织学观察显示，Ｃｄ２＋中毒引起鳃丝增粗，鳃丝血腔扩大；肝小管严重萎缩，肝细胞解体；绿腺细胞解体，迷路结构消失。 相似文献
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我们自１９９６年开始，在虾池中进行了大面积养蟹技术研究，并获得了良好的效果，现报告如下：１材料与方法１．１池塘条件秦楼办事处万平口虾场５个池塘，面积分别为２０亩、２５亩、３０亩，水深１～１．５ ｍ，泥沙底质。水质良好，进、排水方便。１．２清池肥水池塘冬闲时，封池曝晒２０～３０天后清淤。１月下旬进水浸没滩面。使用“敌杀死”０．１～０． ２×１０－６，清除以杂蟹类为主的甲壳类敌害生物。３月上旬，当池水温度达８～１０℃时，使用２０～２５×１０－６的茶籽饼清除害鱼。毒性消失后，注入用６０目筛绢网过滤的海水… 相似文献
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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
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Association between the interannual variation in the oceanic environment and catch rates of bigeye tuna (Thunnus obesus) in the Atlantic Ocean 
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下载免费PDF全文 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
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Liping Li Rui Wang Wanwen Liang Xi Gan Ting Huang Yan Huang Jian Li Yunliang Shi Honglin Luo Ming Chen 《广西水产科技》2014,(1)
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
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Iciar Martinez Amaya Velasco Ricardo Pérez-Martín Eskil Forås Michiaki Yamashita Carmen G. Sotelo 《Journal Of Aquatic Food Product Technology》2013,22(4):289-297
The purpose of this work was to evaluate the suitability of a method based on the presence of two restriction sites (for Hae III and Hindf I) in the mitochondrial NADH dehydrogenase subunit 5 (mt ND5) gene to identify Scomber species. The evaluation was performed on 144 reference and market samples by sequencing of the entire 505-bp fragment of the mt ND5 gene and of a 464-bp fragment of the Kocher fragment of the cytochrome b gene (mt Cytb). Sequence analysis of any of the two fragments allows the identification of each of the four Scomber species, but S. japonicus and S. colias had the same restriction sites at the ND5 amplicon and would not have been differentiated by this analysis. Similarly, loss of the Hae III site in some S. scombrus individuals would have misidentified them as not being Scomber. All the market products were correctly labeled except one acquired in Spain labeled as originating in the Atlantic and containing S. japonicus. 相似文献
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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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Growth hormone (GH) and reproduction: a review 总被引：5，自引：0，他引：5
Florence Le Gac Odile Blaise Alex Fostier Pierre-Yves Le Bail Maurice Loir Brigitte Mourot Claudine Weil 《Fish physiology and biochemistry》1993,11(1-6):219-232
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
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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
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Controlled infection of Poecilia reticulata Peters (guppy) with Tetrahymena by immersion and intraperitoneal injection 下载免费PDF全文
下载免费PDF全文 G Sharon M Pimenta‐Leibowitz M C L Vilchis N Isakov D Zilberg 《Journal of fish diseases》2015,38(1):67-74
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
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