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以鸡的红细胞DNA含量(2.50 pg/N)为标准对照,利用流式细胞仪测定了1 000尾六合龙池中鲫鱼的红细胞核DNA含量。鲫鱼采用T型标技术标记并测定了上述鱼的形态特征。结果表明:其中120尾鲫鱼的红细胞核相对DNA含量接近290,占12%,880尾样品接近330占总数的88%;二倍体龙池鲫鱼的DNA含量为3.82 pg/N,三倍体龙池鲫鱼的DNA含量为4.34 pg/N,可知所测龙池中鲫鱼是由二倍体和三倍体组成的混合群体;同时测定了上述鱼的侧线鳞数量,也可作为辨别二倍体和三倍体龙池鲫鱼的参考标准之一。所采用的T型标记法,在培育三周后龙池鲫鱼的存活率为100%,脱牌率为1.2%。 相似文献
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草海鲫DNA含量与倍性 总被引：1，自引：0，他引：1
为研究草海鲫的倍性及核DNA含量特性,以鸡(Gallus sp.)红细胞DNA含量(2.5 pg/N)为标准、鲫(Car-assius auratus auratus)和普安鲫(C.auratus gibelio(Bloch))子一代为参照,采用流式细胞术测定了25尾草海鲫的红细胞核DNA含量。结果显示:25尾草海鲫的核DNA检测直方图明显分为两种类型,其核DNA绝对含量分为3.92 pg/N和5.44 pg/N两种值,DNA指数(DI)分别为0.99和1.37,其核DNA含量与鲫和普安鲫子一代接近,符合二倍体和三倍体特征。综合分析表明草海鲫是由多种倍体组成、具有核DNA含量特性的混合群体,是贵州省已知除普安鲫和正安鲫外的又一种独特的鲫鱼类型,加强其繁殖方式和资源增殖保护研究具有重要意义。 相似文献
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洞庭青鲫产于湖南省澧县北民湖,因个体大且背部青灰而得名,其快速生长的特性和异于普通鲫的体型令作者怀疑前人报道的"二倍体群体"结果。为此,从银鲫微卫星文库中筛选9个位点构建微卫星鲫倍性鉴定体系,同时采用流式细胞术和染色体核型分析完成了洞庭青鲫倍性鉴定。结果显示,建立的微卫星鲫倍性鉴定体系能够100%区分二倍体、三倍体和四倍体鲫,微卫星基因分型结果显示136尾洞庭青鲫均为三倍体,各位点的等位基因数为1～3,样本基因型包括AAA、AAB/ABB、ABC 3种类型;洞庭青鲫血细胞DNA平均含量为159.42±5.64,与二倍体红鲫的血细胞DNA平均含量(102.43±3.54)比值(DI)为1.56∶1;流式细胞术与微卫星体系判定结果匹配度100%;染色体核型分析显示洞庭青鲫染色体数为3n=156±,核型公式为3n=39m+36sm+81sta,NF=231。建立了适用于鲫倍性鉴定的微卫星标记体系,且系统地证实了洞庭青鲫为三倍体鲫品种。 相似文献
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将性成熟的鲤鲫杂交鱼一代（F1）的雌鱼与雄性红鲫鱼杂交,获得了回交鲫子代,分析了平均体质量94.2g的1龄回交鲫子一代的细胞染色体核型,测定了其DNA含量。肾细胞直接制片法表明：回交鲫子代染色体由147条组成,即3n=147,NF=222,其核型公式为：3n=51m＋24sm＋27st＋45t。流式细胞记数法结果表明：在20尾鱼中有14尾回交鲫子代细胞的DNA含量是对照鱼（红鲫鱼）的1.5倍,占总鱼数的70%;6尾在2～3倍体之间,非常接近三倍体,占总鱼数的30%。本结果与其细胞染色体核型分析结果基本一致,说明该鱼是以三倍体为主的回交种。 相似文献
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微卫星分离模式显示雄性三倍体鲫产生非整倍体精子 总被引：1，自引：1，他引：0
三倍体鲫(Carassius auratus)行天然雌核发育,其自然种群中却有较高比例的雄性个体,这些雄性个体的性腺发育正常,能产生有活力的精子。而且其精子的DNA含量约为体细胞的一半,显示三倍体鲫精子发生过程中可能经历了均等的减数分裂。流式细胞术虽然能够较准确地测定细胞群的平均DNA含量,但是却很难检测到单个精子中的个别染色体增减,要明确回答雄性三倍体鲫产生的精子是否为整倍体需要定量地检测单个精子的遗传组成。本研究用微卫星标记检测以雌性鲤(Cyprinus carpio)与雄性三倍体鲫为亲本构建的杂种家系的基因型,结果发现母本鲤的多态位点在子代中呈孟德尔分离,父本三倍体鲫具有三套鲫基因组,其等位基因在子代中呈随机分离。上述研究结果提示:三倍体鲫起源于二倍体鲫的同源加倍,而非二倍体鲫和鲤的种间杂交;三倍体鲫通过染色体的随机分离产生非整倍体的精子,其精子发生过程中没有均等的减数分裂。三倍体鲫行雌核发育生殖,却可能并非起源于种间杂交且群体中的雄性个体可育,因而是单性生殖鱼类中的一个特例。 相似文献
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通过光学显微镜对染色体数为150±的三倍体和染色体数为100的二倍体银鲫(Carassius ouratus gibclio Bloch)的精巢组织学结构进行了比较观察.三倍体和二倍体银鲫的精巢组织学结构基本相同,属于小叶型,都是由外膜和实质构成,各精小叶呈辐射状分布,一个小叶由数个精小囊组成.其精原细胞存在于精小叶内壁上,精母细胞和未成熟的精子细胞位于精小囊中,精子成熟后从精小囊进入小叶腔.三倍体银鲫成熟精子的体积为(11.8±2.8)μm3,二倍体平均为(6.8±1.8)μm3,二者的比例接近3:2.结果表明三倍体银鲫的精巢能够发育成熟,其精子发生过程正常,经过减数分裂,能产生正常的精子;因此三倍体的黑龙江银鲫是具有双倍性特征的多倍体群体. 相似文献
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为进一步了解贝尔鲫(Carassiusauratusgibelio‘Buir’)的遗传学特性,采用红细胞测量法对贝尔鲫的倍性进行测定,贝尔鲫有三倍体和二倍体2种倍性,其红细胞长径分别为(15.23±0.46)μm和(12.21±1.46)μm,红细胞长径之比为1.25。采用PHA和秋水仙素胸腔体内注射,以头肾组织为材料,低渗-空气干燥法制片,对三倍体的贝尔鲫通过染色体核型进行分析。结果表明,三倍体贝尔鲫染色体组由156条染色体组成,核型公式3n=156,42 m+48 sm+27 st+39 t,NF=246,发现有小染色体。 相似文献
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二、三倍体虹鳟肌肉组织结构及营养成分的比较 总被引：1，自引：0，他引：1
选取相同养殖条件下3个不同体质量组的二倍体虹鳟和三倍体虹鳟,其中每组二倍体和三倍体虹鳟各10尾,分析其肌肉常规营养成分、氨基酸含量和肌纤维密度及直径,以比较二倍体和三倍体虹鳟的肌肉品质特性差异。试验结果表明,随着体质量的增加,二倍体、三倍体虹鳟肌纤维密度均降低,而肌纤维直径增大;二倍体虹鳟肌纤维直径小于三倍体,密度大于三倍体(P0.05)。随着体质量的增加,二倍体和三倍体虹鳟肌肉水分含量和粗灰分含量减少,而粗蛋白、粗脂肪含量显著增加;三倍体虹鳟粗蛋白和粗脂肪含量显著高于同组二倍体(P0.05),水分和粗灰分含量略低于二倍体,均差异不显著(P0.05)。二倍体和三倍体虹鳟肌肉中谷氨酸含量均最高,三倍体虹鳟总氨基酸含量、必需氨基酸含量以及鲜味氨基酸含量高于二倍体;根据营养价值评价结果,二倍体和三倍体虹鳟均为蛋氨酸和胱氨酸总量最高,第一限制性氨基酸均为苯丙氨酸。整体上来说,二倍体虹鳟和三倍体虹鳟均为优质蛋白源,二倍体虹鳟嫩度优于三倍体,但随着体质量的增加,三倍体虹鳟肌肉在营养成分上较均衡,且鲜美度要优于二倍体,有更好的食用价值及营养价值。 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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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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Qin-Cheng Huang Di‐Gen Qin Bei‐Ping Tan Tao Du Yuan-Zhi Yang Qi-hui Yang Shu‐Yan Chi Xiao-hui Dong 《Aquaculture Research》2020,51(2):816-827
A 5 × 3 factorial growth trial was conducted to evaluate optimal dietary protein and lipid levels (dietary protein level, DP; dietary lipid level, DL) for juvenile Sillago sihama (S. sihama) (2.0 ± 0.02 g, initial weight). Fish were fed 15 diets containing 5 DPs (350, 400, 450, 500 and 550 g/kg) and 3 DLs (60, 90 and 120 g/kg) for 8 weeks. The interaction between proteins and lipids significantly influenced the feed conversion ratio, condition factor, body composition, antioxidant indices and lipase activity (p < .05). DP 450 g/kg showed the highest average final body weight. DPs 500 and 550 g/kg significantly decreased the protein efficiency ratio (p < .05). DL 120 g/kg showed the highest percentage weight gain. The low feed conversion ratio was found in diets P45L12, P55L9 and P55L12. Diet P45L12 showed high superoxide dismutase activities. DP 450 g/kg showed the lowest average malondialdehyde content. Lipase activity was increased by increasing DP (p < .05) with a fall at DP 550 g/kg. Under the present experimental conditions, the optimal DP for S. sihama was 450 g/kg under the DL 120 g/kg. 相似文献
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Cholecalciferol (Vitamin D3) increased plasma inorganic phosphate concentration in American eels,Anguilla rostrata, in a dose-dependent fashion. This response was more marked in phosphate loaded fish. In control as well as phosphate loaded
eels the hyperphosphatemic response to D3 was associated with a sharp reduction in renal phosphate clearance relative to14C-polyethelene glycol (PEG) clearance. Glomerular filtration and urine flow rates were not affected by D3. As renal phosphate clearance, even in phosphate loaded eels, never significantly exceeded that of PEG, it is suggested that
D3 reduced the relative clearance rate of phosphate by increasing renal phosphate reabsorption rather than by reducing the tubular
secretion of phosphate. 相似文献