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1.
自动定氮仪测定水产品中的挥发性盐基氮   总被引：1，自引：0，他引：1  
采用自动定氮仪测定法研究了罗非鱼(Tilapia niloticus)、蓝圆鲹(Decapterusmaruadsi)、凡纳滨对虾(Litopenaeus vannamei)和近江牡蛎(Crassostrear ivularis)4种水产样品处理的高氯酸溶液浓度和浸提时间及其蒸馏前样液放置时间对挥发性盐基氮(TVBN)测定的影响。结果表明:以0.6mol·L-1高氯酸溶液均质样品2min后测定4种水产品中TVBN,样品加标回收率在98.42%～100.18%之间,相对标准偏差在1.40%以下。其测定结果与GB/T5009.44蒸馏法相比,不存在显著性差异,且操作简便、快速。  相似文献   

2.
分光光度法测定水产品中甲醛含量的研究   总被引：3，自引：0，他引：3  
研究采用乙酰丙酮分光光度法测定水产品中的甲醛含量，对样品的前处理过程进行了比较系统的探讨，确定了比色测定参数，并对其用于快速测定水产品中甲醛含量的可行性进行了讨论。实验结果表明，用冰浴浸泡法前处理样品时，最佳浸泡时间为10min，样液pH值用100g·L^-1氢氧化钾溶液调至6；沸水浴中最佳显色时间为3min，比色波长为412nm；当甲醛含量在0～2．5μg·mL^-1范围内时，该方法具有很好的线性关系（R^2=0．9998）；与蒸馏法前处理样品相比，该方法的加标回收率比较高，在89．50％～94．25％之间，而前者为64．17％～76．92％；该方法的RSD（％）为2．93％，样品的最低检出浓度为0．9mg·kg^-1。  相似文献   

3.
为测定水产品中呋喃唑酮代谢物(AOZ)的残留量,采用2-硝基苯甲醛进行衍生,乙酸乙酯提取AOZ。通过样品中残留的AOZ和酶标板上预包被的抗原竞争抗体,加入酶标二抗后与底物显色,测得样品中AOZ的残留量。测定了四组水产品中AOZ的残留量,测定浓度均小于1μg/kg,结果为阴性。向空白样品中分别添加0.5μg/kg、1.5μg/kg和2μg/kg的AOZ标准品,回收率为90%、109%和101%。因此得出结论:采用酶联免疫法测定水产品中AOZ残留量操作简单,检测时间短,结果准确,是一种适合大批量水产样品筛选的检测方法。  相似文献   

4.
样品的前处理方法直接影响到无机元素测定结果的准确性。本研究探讨了高压消解罐消解、微波消解和湿法消解等3种前处理方法对水产品中无机元素测定的影响,利用电感耦合等离子体发射光谱仪(ICP-OES)测定12种元素(钾、钠、钙、铁、镁、锰、铜、锌、钡、铝、磷、硼)含量,采用紫菜、扇贝和大虾等具有代表性的标准物质进行验证并与标准参考值进行了比较;对于标准物质和实际样品性状差异较大的扇贝和大虾,同时对其实际样品进行测定,进行加标回收率测试。实验结果表明,3种消解方法的消解效果均能满足日常检测工作需要,标准物质测定结果基本在参考值范围内,实际样品与标准物质的实验结果一致。但是微波消解法的测定结果在3种前处理方式中最为理想,不仅前处理过程所受环境干扰最小,同时测定结果更接近参考值,回收率在90%~102%之间。综合比较认为,微波消解法更适合扇贝、大虾、紫菜等水产品中无机元素测定的前处理要求。  相似文献   

5.
邱伟强  陈刚  陈舜胜  谢晶 《水产学报》2011,35(11):1745-1752
建立了水产品中6种ATP关联化合物的离子对反相高效液相色谱(IP-RPLC)检测方法,确定了缓冲液的最佳pH、流速和浓度,并对方法的准确度、精确度和检测限进行了测定.采用10％的高氯酸分离提取样品,用KOH溶液中和后进行HPLC分析.采用Waters 2695色谱系统,Thermo ODS-2 Hypersil(250 mm ×4.6 mm,5μm)色谱柱,柱温为25℃;以10％甲醇,90％ 0.05 mol/L磷酸盐溶液为流动相,磷酸盐溶液含9 mmol/L四丁基氢氧化氨(TBA),并用1 mol/L的磷酸调pH至6.5,采用等度洗脱,流速为0.9 mL/min;检测波长为254 nm.结果表明:6种ATP关联化合物在13 min内完全分离;在2～400 μg/mL范围内线性关系良好,相关系数在0.9994～1.0000之间;方法最低检测限(信噪比S/N =3)在0.1～0.4 μg/mL之间;加标平均回收率为82.2％ ～110.0％,相对标准偏差为4.2％ ～9.5％.本方法可用于水产品中ATP、ADP、AMP、IMP、Hx和HxR等6种ATP关联化合物的同时测定和分析.  相似文献   

6.
为获得一种快速测定水产品中酰胺醇类抗生素残留的方法,本研究建立了QuECHERS结合超高效液相色谱串联质谱(UPLC-MS/MS)测定氯霉素(CAP)、氟苯尼考(FF)和甲砜霉素(TAP)残留的方法,并对其基质效应进行了评价。结果表明,该方法下CAP、FF在0. 1～100. 0 ng/mL以及TAP在0. 5～100. 0 ng/mL质量浓度范围内线性关系良好,相关系数大于0. 999 8。CAP和FF检测限(LOD)和定量限(LOQ)分别为0. 10和0. 50μg/kg; TAP检测限(LOD)为0. 50μg/kg,定量限(LOQ) 1. 00μg/kg。3种酰胺醇类抗生素在1. 0、5. 0和10. 0μg/kg 3个添加水平下的平均回收率在(84. 5±4. 64)%～(106. 1±8. 69)%之间,日内精密度为3. 17%～9. 74%,日间精密度为2. 26%～7. 90%。同时在该检测方法下,评价了待测物浓度和基质浓度对基质效应的影响。结果发现,除CAP在1. 00～100. 00 ng/mL质量浓度范围内的基质效应可以忽略以外,随目标物浓度的降低,其基质效应值逐渐减小;随着样品基质浓度的增加,基质效应从基质增强变为基质抑制。因此,在检测水产品中酰胺醇类抗生素残留时均要考虑基质效应对检测结果的影响,建议采用基质标准曲线进行定量校准,以确保检测结果的准确性。该方法快速、准确、重复性好、环境友好且操作简单,可用于水产品中酰胺醇类抗生素残留量的测定。  相似文献   

7.
建立一种测定水产品中利福平药物残留的超高效液相色谱—串联质谱检测方法。样品用乙腈—二氯甲烷(6∶4,体积比)提取剂提取,通过100 mg C18+100 mg PSA分散固相萃取净化,以3 mmol/L乙酸铵溶液(含0.05%甲酸)和乙腈为流动相进行梯度洗脱,采用电喷雾离子源正离子多反应监测模式测定,内标法定量分析。检测结果显示,利福平在1~20μg/kg质量浓度内呈良好的线性关系,相关系数r≥0.9986,方法检出限为0.3μg/kg,定量限为1.0μg/kg,对罗非鱼、凡纳滨对虾、中华鳖进行加标回收试验,回收率为90.17%~101.07%,相对标准偏差为3.11%~7.66%,该方法简单、快速、准确,适用于水产品中利福平残留的确证和定量分析,为监管利福平药物的违规使用提供便捷、有效的技术支持。  相似文献   

8.
建立了水产品中三磷酸腺苷(ATP)、二磷酸腺苷(ADP)、腺苷酸(AMP)、肌苷酸(IMP)、次黄嘌呤核苷(HxR)和次黄嘌呤(Hx)6种ATP关联化合物的高效液相色谱检测方法。样品中的ATP关联物经高氯酸提取并用氢氧化钠调节pH值至6.0-6.4后,以AQ-C18(250 mm×4.6 mm,5μm)柱为分析柱,0.02 mol/L KH2PO41-0.02 mol/L K2HPO4(V/V=1/1)的缓冲液为流动相进行洗脱,在254 nm波长下用高效液相色谱进行检测,外标法定量。研究表明,ATP、ADP、AMP、IMP和HxR线性范围为0.2-40.0μg/ml,Hx线性范围为0.1-20.0μg/ml,相关系数均大于0.999 0;ATP、ADP、AMP、IMP和HxR检出限为5.00 mg/kg,Hx检出限为2.5 mg/kg(S/N=3);对真鲷、鱼师鱼、鲑鱼、凡纳滨对虾和梭子蟹5种水产品进行3个浓度水平的加标实验,回收率在85.5%-105%之间,相对标准偏差(RSD)小于12.9%。实验结果表明,该方法简便、准确,适合于水产品中ATP关联物的测定。  相似文献   

9.
三、醋酸对壳聚糖水解性的影响: 壳聚糖大多溶解在醋酸溶液中使用,为此,我们测定了壳聚糖分别在10%和20%浓度的醋酸溶液中,并在不同温度及不同时间下其降解性的变化。结果如下: 1.壳聚糖样品的初始[η]=2.83ml/g,在  相似文献   

10.
实验检测了条和红鳍红鲌在30℃下贮存48 h内每隔6 h的挥发性盐基总氮(TVBN)和9种生物胺(尸胺、腐胺、组胺、酪胺、5-羟色胺、亚精胺、精胺、多巴胺和章鱼胺)含量的变化,并对TVBN和生物胺含量与时间的相关性进行分析,以期为淡水水产品类饵料安全投喂和人类食品安全提供基础资料。结果显示,两种鱼在相同贮存条件下TVBN和生物胺含量均存在一定差异。其中,TVBN含量均随着贮存时间的延长而逐渐增加且与时间存在明显的相关性。红鳍红鲌除在42 h时TVBN含量低于■条外,其他时间均高于■条。在30℃贮存下,■条和红鳍红鲌的TVBN含量均在12 h时超过30 mg/100 g,因此,这两种鱼在12 h后不推荐食用。尸胺、腐胺、酪胺和组胺是这两种鱼主要的生物胺类型,且有随贮存时间延长含量显著增高的趋势,并与时间呈显著性相关,可推荐用于评价此两种水产品食用安全的生物胺类型。除此之外,在可测到的生物胺中,红鳍红鲌的尸胺和组胺含量明显高于■条,且红鳍红鲌体内的5-羟色胺与时间也呈显著性相关。  相似文献   

11.
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.
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.
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15.
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   

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.
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.
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.
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.
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   

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