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1.
应用半静态双箱模型室内模拟实验, 研究三疣梭子蟹(Portunus trituberculatus)体内镉(Cd)的蓄积特异性; 并通过分析钙离子(Ca2+)对三疣梭子蟹可食用部位镉(Cd)富集和释放影响, 提出三疣梭子蟹 Cd 污染防控建议。通过双箱动力学模型对三疣梭子蟹体内 Cd 含量变化进行非线性拟合, 得到富集速率常数 k1和排出速率常数 k2, 进而得到生物富集系数(BCF)和生物学半衰期(B1/2)。结果显示, 1 μg/L、5 μg/L 和 50 μg/L Cd 暴露组三疣梭子蟹肝胰腺组织对 Cd 的 BCF 明显高于肌肉组织, 三疣梭子蟹肝胰腺组织中 BCF 和 k1 均随水体中 Cd 浓度的增加而增加, 1 μg/L, 5 μg/L 和 50 μg/L Cd 暴露组对 Cd 的 BCF 分别为 12.16、112.77 和 260.11; 肌肉组织中吸收速率常数 k1 与释放速率常数 k2 均随水体中 Cd 浓度的增加而增加, 由低到高 Cd 暴露组对 Cd 的 BCF 分别为 1.85、2.45 和 1.97。各浓度暴露组肝胰腺中 Cd 暴露风险指数(THQ)除 1 μg/L 组外, 均大于 1, 存在严重健康暴露风险; 各浓度暴露组肌肉中的 THQ 均小于 1, 没有明显的健康暴露风险。另外, Ca2+对三疣梭子蟹肝胰腺和肌肉中 Cd 富集和释放影响的实验结果表明, Ca2+的加入能够有效降低三疣梭子蟹肝胰腺和肌肉对 Cd 的富集, 并促进肝胰腺对 Cd 的释放。本研究结果为三疣梭子蟹 Cd 污染防控和食用方案的提出提供了理论基础。 相似文献
2.
《水产科学》2021,(4)
将全甲宽(140.02±15.14) mm经暂养净化的成熟雌三疣梭子蟹放在500 L的聚乙烯水族箱中,加入由砷酸钠和三氧化二砷母液配制成三价无机砷和五价无机砷质量浓度分别为0.01 mg/L和0.10 mg/L的海水。对照组为无机砷质量浓度为(1.18±0.16)μg/L的过滤新鲜海水,不添加无机砷。半静态的暴露7 d富集试验中,每隔24 h换水1次,第1、3、5、7天随机取梭子蟹3只,立即解剖分离出肝胰腺、性腺和肌肉组织,于超低温冰箱中-80℃保存,用于测定3种可食组织中总砷的含量。28 d释放试验中,各试验箱中换成自然海水,每隔24 h完全换水1次,第7、14、21、28天随机取梭子蟹3只,立即解剖分离出上述3种可食组织,同样方法处理和测定,研究三疣梭子蟹在不同质量浓度三价无机砷和五价无机砷暴露7 d和释放28 d后的生物富集和释放转化规律。试验结果显示,三疣梭子蟹的可食组织对2种无机砷的富集能力较弱,肝胰腺组织中总砷含量在富集试验期间呈现先显著升高后降低的趋势,而在肌肉组织与性腺组织中均无明显的富集趋势,在释放试验期间,性腺和肝胰腺组织中总砷含量呈下降趋势,肌肉组织中总砷含量变化不明显。对照组三疣梭子蟹3种可食组织中砷的主要存在形态不同,肌肉与性腺中的砷主要以砷甜菜碱和二甲基砷形态存在,而肝胰腺中的砷主要以砷甜菜碱形态存在。试验结果表明,三疣梭子蟹对三价无机砷的生物利用度高于五价无机砷,无机砷主要积累在肝胰腺组织中,而肌肉与性腺组织中无无机砷累积。 相似文献
3.
《海洋渔业》2014,(4)
采用半静态双箱动力学模型研究三疣梭子蟹(Portunus trituberculatus)对苯并[a]芘(benzo[a]pyrene,BaP)的生物富集,通过对富集与排出过程中三疣梭子蟹体内BaP的动态监测,并对监测结果进行非线性曲线拟合,得到三疣梭子蟹的吸收速率常数K1、排出速率常数K2、生物富集因子BCF、富集平衡浓度CAmax、生物学半衰期B1/2等动力学参数;拟合结果得到BaP的各动力学参数分别如下:K1为14.67~26.08、K2为0.09~0.14、CAmax为9.31~73.35、BCF为163.00~196.29、B1/2为4.95~7.70 d。对模型的拟合优度检验结果显示,在BaP暴露条件下三疣梭子蟹对BaP的生物富集数据符合双箱动力学模型,模型的拟合优度良好。比较结果得出:三疣梭子蟹对不同浓度的BaP吸收速率常数K1及生物富集系数BCF基本随外界水体中暴露浓度的增加而降低;排出速率常数K2与外界水体暴露浓度无明显关系;理论平衡条件下生物体内BaP含量CAmax随着外界水体中BaP暴露浓度的增加而增大,且基本成正相关。实验结果表明BaP暴露条件下双箱动力学模型在一定条件下是可以应用于三疣梭子蟹的富集动力学研究的。 相似文献
4.
苯并[a]芘、菲在缢蛏体内的生物富集与释放 总被引：1，自引：0，他引：1
为了研究苯并[a]芘(Bap)、菲PHE在缢蛏体内的富集及释放过程的动力学特征,通过双箱动力学模型对富集(15 d)与释放(9 d)过程进行非线性曲线拟合,获得缢蛏对BaP、PHE的吸收速率常数k1、释放速率常数k2、生物富集因子BCF、平衡状态下生物体内BaP含量CAmax、生物学半衰期B1/2。结果显示,缢蛏对BaP的富集能力高于PHE,BaP增加幅度分别为0.45 ng/(kg·d)(40 μg/L实验组)、0.33 ng/(kg·d)(20 μg/L实验组)、0.23 ng/(kg·d)(10 μg/L实验组);PHE增加幅度分别为0.33 ng/(kg·d)(30 μg/L实验组)、0.25 ng/(kg·d)(20 μg/L实验组)、0.18 ng/(kg·d)(10 μg/L实验组)。BaP、PHE的富集、清水释放均为前期迅速,后期缓慢。缢蛏对BaP、PHE的k1范围分别为0.39~0.52,0.30~0.43,平均值分别为0.44和0.36,均随BaP、PHE暴露浓度的增大而减少;k2范围分别为0.001 6~0.001 7,0.002 8~0.003 3,平均值分别为0.001 6和0.003 0,无明显的变化趋势;BCF范围分别为243.96~306.28,105.73~130.85,平均值分别为268.18和118.57,均随BaP、PHE暴露浓度的增大而减少;CAmax范围分别为3 062.76~9 758.25 μg/kg,1 308.54~3 171.84 μg/kg,平均值分别为5 969.08和2 287.71 μg/kg;B1/2范围分别为407.73~433.22 d,210.68~248.06 d,平均值分别为421.20和232.04 d,均随BaP、PHE暴露浓度的增大而增大。 相似文献
5.
通过非靶向代谢组学方法对比分析暴露于 0.3 mg/L 三价砷(As3+)、0.3 mg/L 五价砷(As5+)环境中 96 h 的雌性成体三疣梭子蟹(Portunus trituberculatus)代谢物组成及含量的变化, 探究 As3+、As5+对三疣梭子蟹鳃组织毒性相关分子机制。结果发现, 经 0.3 mg/L As3+暴露共获得 100 个差异代谢产物, 主要富集于 ABC 转运体、花生四烯酸代谢、蛋白质消化吸收、氨基酸代谢及氨酰基-tRNA 的生物合成等代谢通路; 经 0.3 mg/L As5+暴露共获得 59 个差异代谢产物, 主要富集于 ABC 转运体、氨基酸代谢、氨酰基-tRNA 的生物合成、谷胱甘肽代谢等代谢通路。根据筛选出的差异代谢物的生理功能及其涉及的代谢通路分析, 探究 As3+、As5+对三疣梭子蟹鳃组织毒性作用的分子机制及三疣梭子蟹的响应调控机制, 为后期深入研究致毒机制提供理论依据。 相似文献
6.
《渔业科学进展》2015,(3)
利用双箱模型模拟了虾夷扇贝在混合暴露条件下富集、释放铅和镉的动力学特征,通过测定不同规格虾夷扇贝、不同组织富集、释放过程中铅和镉的含量并进行非线性拟合,获得不同生长阶段虾夷扇贝对铅和镉的生物富集系数BCF、吸收速率常数k1、释放速率常数k2、生物学半衰期B1/2以及不同组织中铅和镉的富集参数。结果显示,大、小两种规格虾夷扇贝对铅的BCF分别为1671、896,对镉的BCF分别为7433、1123;不同规格虾夷扇贝对铅、镉的BCF顺序为:大规格小规格;相同规格虾夷扇贝BCF:镉铅,表明虾夷扇贝对镉的富集能力强于铅;铅、镉的B1/2为:大规格小规格,说明大规格的虾夷扇贝对铅、镉的代谢排出能力更强;铅在虾夷扇贝各组织中的富集顺序依次为:鳃内脏团闭壳肌,镉的富集顺序依次为:内脏团鳃闭壳肌。 相似文献
7.
以菲律宾蛤仔(Ruditapes philippinarum)为实验对象,基于双箱动力学模型,研究了菲律宾蛤仔肌肉和内脏组织对0~#柴油和南海流花原油的生物富集特征。采用OgirinPro 8.5软件对富集结果进行非线性拟合,获得了2种油品的吸收速率常数(k_1)、释放速率常数(k_2)、生物富集系数(BCF)、理论平衡时石油烃质量分数(CAmax)和生物学半衰期(B1/2)等动力学参数。结果表明,菲律宾蛤仔对0~#柴油和南海流花原油的k_1分别为0.921~9.74和3.43~64.2,k_2分别为0.092 8~0.134和0.100~0.189,BCF分别为6.87~94.56和34.30~379.88,CAmax分别为17.18~67.62 mg·kg~(-1)和30.38~595.24 mg·kg~(-1),B_(1/2)分别为5.17~7.47 d和3.67~6.93 d。菲律宾蛤仔对0~#柴油和南海流花原油的k_1和BCF均随着水体中石油烃浓度的增大而减小,k_2和B1/2与水体中石油烃浓度无明显相关性,CAmax随着水体中石油烃浓度的增加而增大。通过比较菲律宾蛤仔2种组织对2种油品的生物富集过程,发现菲律宾蛤仔对南海流花原油的生物富集能力强于对0~#柴油的富集能力,而内脏对石油烃的生物富集能力高于肌肉。 相似文献
8.
海水和饲料中Pb在凡纳滨对虾体内的富集与释放特性 总被引：1，自引：0，他引：1
为获知海水和饲料中重金属Pb与凡纳滨对虾(Litopenaeus vannamei)各组织间的富集与释放特性,应用生物富集双箱动力学模型,模拟凡纳滨对虾分别在海水中Pb浓度为0.0015 mg/L(B0)、0.0080 mg/L(B1)、0.0466 mg/L(B2)和0.2302 mg/L(B3),饲料中Pb浓度为2.089 mg/kg(A0)、2.750 mg/kg(A1)、6.103 mg/kg(A2)和14.520 mg/kg(A3)的驯养过程中,其肝胰腺、外骨骼和肌肉对Pb的生物富集与释放特性,为Pb在凡纳滨对虾体内的分布、富集和迁移提供理论依据,为其安全生产提供指导意义。同时通过非线性拟合得到凡纳滨对虾对海水和饲料中Pb的富集速率常数K1、排出速率常数K2、生物富集系数BCF、生物半衰期B_(1/2),富集平衡时生物体内Pb含量CAmax等动力学参数。结果显示:(1)投喂任一浓度饲料时,B0、B1、B2组凡纳滨对虾肌肉、外骨骼和肝胰腺组织中Pb含量均小于限量值0.5 mg/kg,而在B3海水浓度中,随着投喂饲料浓度的增大,各组织中Pb累积量高于限量值(0.5 mg/kg)的时间出现得越来越早;肝胰腺中Pb的释放速率高于肌肉和外骨骼的释放速率。(2)用SPSS18.0对饲料Pb含量、海水浓度、富集时间进行三因素重复测量方差分析显示,饲料浓度、海水浓度和富集时间对凡纳滨对虾各组织中Pb的富集含量出现显著性差异[除了饲料浓度对凡纳滨对虾外骨骼组织中Pb富集主效应达到边缘显著(F=2.351,P=0.071)],且饲料、海水及时间交互效应分析显示,三者交互作用显著。(3)用SPSS18.0对不同组织中Pb的富集含量、饲料浓度、海水浓度和富集时间进行多元回归分析,结果显示:在凡纳滨对虾各组织间Pb富集过程中,海水中Pb浓度的贡献率大于饲料中Pb浓度的贡献率。(4)达到平衡状态下,投喂A0饲料浓度,生长在B0~B3组海水中,凡纳滨对虾肌肉组织中Pb含量为0.128~2.981 mg/kg,肝胰腺组织中Pb含量为0.399~4.765 mg/kg;生物学半衰期(B_(1/2))范围分别为5~7 d和3~7 d。投喂A2饲料浓度,生长在B0~B3组海水中,凡纳滨对虾肌肉组织中Pb含量为0.380~1.000 mg/kg,肝胰腺组织中Pb含量为0.288~5.355 mg/kg;生物学半衰期(B_(1/2))范围分别为2~7 d和2~5 d。理论平衡浓度下,肝胰腺组织中含量均大于肌肉。 相似文献
9.
应用双箱动力学模型模拟了菲律宾蛤仔在Pb、Zn、Cu、Cd、Cr、Hg和As 7种重金属混合暴露条件下,内脏团、鳃、斧足及基部和外套膜组织对重金属的生物富集与释放实验,并通过非线性拟合得到菲律宾蛤仔各组织对7种重金属的富集速率常数k1、排出速率常数k2、生物富集系数BCF、生物半衰期B1/2、富集平衡时生物体内重金属含量CAmax等动力学参数。结果表明,1)重金属在菲律宾蛤仔不同组织器官中的富集具有选择性,理论平衡状态下,Cu、Cd、As、Pd在各组织的含量分布(CAmax):内脏团斧足及基部鳃外套膜;Cr分布规律(CAmax):内脏团鳃斧足及基部外套膜;Hg分布规律(CAmax):斧足及基部外套膜鳃内脏团;Zn分布规律(CAmax):斧足及基部鳃外套膜内脏团。2)菲律宾蛤仔对不同重金属的富集系数存在显著差异(P0.05),对Cu富集程度最高,其富集系数范围为1514.0-4818.0;其次是Cd和Hg,富集系数范围分别为104.5-975.4,255.9-447.4;As、Cr、Pb、Zn离子在菲律宾蛤仔体内富集程度较低,其富集系数均在300以内。3)菲律宾蛤仔对重金属的释放能力较差,双箱动力学模型可较好地反映混合暴露条件下菲律宾蛤仔对重金属的富集特征,但不适合对其释放特征进行描述。 相似文献
10.
利用双箱模型模拟了虾夷扇贝在混合暴露条件下富集、释放铅和镉的动力学特征,通过测定不同规格虾夷扇贝、不同组织富集、释放过程中铅和镉的含量并进行非线性拟合,获得不同生长阶段虾夷扇贝对铅和镉的生物富集系数BCF、吸收速率常数k1、释放速率常数k2、生物学半衰期B1/2以及不同组织中铅和镉的富集参数。结果显示,大、小两种规格虾夷扇贝对铅的BCF分别为1671、896,对镉的BCF分别为7433、1123;不同规格虾夷扇贝对铅、镉的BCF顺序为:大规格>小规格;相同规格虾夷扇贝BCF:镉>铅,表明虾夷扇贝对镉的富集能力强于铅;铅、镉的B1/2为:大规格>小规格,说明大规格的虾夷扇贝对铅、镉的代谢排出能力更强;铅在虾夷扇贝各组织中的富集顺序依次为:鳃>内脏团>闭壳肌,镉的富集顺序依次为:内脏团>鳃>闭壳肌。 相似文献
11.
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
12.
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
13.
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
14.
15.
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
16.
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
17.
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
18.
William King V David L. Berlinsky Craig V. Sullivan 《Fish physiology and biochemistry》1995,14(6):489-500
Plasma estradiol-17 (E2), testosterone (T), 17,20-dihydroxy-4-pregnen-3-one (DHP) and 17,20,21-tri-hydroxy-4-pregnen-3-one (20-S) levels were measured by radioimmunoassay (RIA) in white perch (Morone americana) and white bass (M. chrysops) that were induced to undergo final oocyte maturation (FOM) with human chorionic gonadotropin (hCG). Plasma DHP levels increased in females of both species in association with oocyte germinal vesicle migration (GVM) and germinal vesicle breakdown (GVBD) and decreased thereafter. Plasma 20-S levels also increased with oocyte GVM in white bass, but were several-fold lower than DHP levels. Circulating E2 and T levels were greatest during GVM and GVBD in both species and decreased to low levels during oocyte hydration and ovulation. Follicles from white perch and white bass which received a priming injection of hCG in vivo, produced both DHP and 20-S in vitro after exposure to hCG and their oocytes underwent GVBD. Ovarian incubates from unprimed fish of either species produced only E2 and T and their oocytes did not complete GVBD. Oocytes from unprimed bass, but not perch, matured when follicles were exposed to hCG in vitro. Both trilostane and cycloheximide blocked in vitro production of DHP and 20-S and oocyte GVBD by white perch follices. DHP and 20-S were equipotent inducers of FOM in the GVBD bioassay. None of several other structurally-related steroids tested were effective within a physiological range of concentrations. These results indicate a role for DHP and 20-S in the control of FOM in white perch and white bass. 相似文献
19.
Cardiac,ventilatory and metabolic responses of two ecologically dissimilar species of fish to waterborne cyanide 总被引：1，自引：0，他引：1
Changes in heart rate, ventilatory activity and oxygen consumption were determined in trout (Salmo gairdneri) and brown bullhead catfish (Ictalurus nebulosus) during exposure to a steadily increasing concentration of waterborne cyanide selected to produce death in 8–9 hours for each species. The lethal cyanide concentration for the bullheads was an order of magnitude higher than for trout. Trout developed an immediate and gradually increasing bradycardia throughout the exposure period. Cyanide produced tachycardia in the bullhead followed by a gradual onset of bradycardia as the concentration of cyanide was raised. Pericardial injection of atropine (a muscarinic cholinergic antagonist) indicated that bradycardia in the trout was due initially to increased vagal tone but later due to the direct effect of cyanide on the heart. Hyperventilation in the trout persisted throughout the exposure period, although the rate and amplitude fluctuated and was variable between individual fish. During the last hour of exposure (highest cyanide concentration), ventilation was characterized by rapid, shallow breaths followed by a sudden respiratory arrest. The bullheads exhibited hyperventilation during the first 3 hours of exposure followed by a gradual, linear drop in ventilation rate and amplitude until death occurred. Cardiac and ventilatory responses in both species were attributed to stimulation of central and peripheral chemoreceptors by cyanide. Evidence is presented which suggests the initial response in the bullheads was due, at least in part, to gustatory stimulation by the cyanide. Oxygen consumption of the trout remained above pre-exposure levels for the majority of the test period. Oxygen consumption in the bullhead paralleled the changes in heart and ventilatory rates. Whole-body lactate levels of fingerlings of both species during cyanide exposure were measured to estimate the extent of anaerobiosis. Whole-body lactate levels were much greater in the bullheads than the trout, indicating a higher capacity for anaerobiosis, possibly due to a greater fuel supply. Overall, the trout responded to cyanide in a manner similar to that produced by environmental hypoxia whereas the bullheads experienced a gustatory stimulus which masked the hypoxia-like response. 相似文献
20.
Sandra García‐Garrido Ismael Hachero‐Cruzado Carlos Rosas Pedro Domingues 《Aquaculture Research》2013,44(11):1741-1751
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