dcELISA检测泥鳅、鲫肌肉中氯霉素残留方法的应用

应用直接竞争酶联免疫吸附试验方法（dcELISA）快速定量测定泥鳅、鲫肌肉中氯霉素（CAP）残留量。氯霉素浓度在0．05～10ng/g范围内具有良好的线性关系，线性方程为y=-0．33—1．88x，r^2=0．995，向样品中分别添加0．1、0．3、0．9ng/g3个浓度水平的氯霉素标准品，泥鳅样品的平均回收率分别为87．2％、88．9％、93．0％，鲫样品的平均回收率分别为86．1％、79．9％、99．0％，最低检测限为O．05ng/g，批内变异系数为8．0％，批间变异系数为7．2％，结果表明该方法灵敏度高，重复性好，适合在泥鳅、鲫肉样中氯霉素残留筛选检测。     

高压液相色谱-质谱联用法测定牙鲆中氯霉素残留量

采用高压液相色谱-电喷雾离子阱质谱法（HPLC-MS—Ion Trap）对牙鲆中氯霉素残留量进行了研究。用乙酸乙酯作为提取溶剂，采用液-液萃取法提取样品中氯霉素，经浓缩净化处理后直接进样分析。质谱条件为，碎裂电压115V，锥孔电压25V，二级质谱电压0．9V，智能碎裂模式（SPS）。对氯霉素标准液进行了定性分析，得到氯霉素的一级分子离子峰m／z 321和m／z 323及二级质谱特征离子峰m／z 194、m／z 257和m／z 176。以m／z 257和m／z 194的峰面积之和代表氯霉素的质谱峰面积，以此峰面积进行定量计算。在0．1～10μg／kg浓度范围内得到线性方程y=13180．1X＋5048．2，相关系数0．99961；方法的检测限为0．1μg／kg；样品添加回收率98．29／6～111．49／6，相对标准偏差（n=3）7．8％～10．2％；并测定了8个牙鲆样品，氯霉素残留量为0．99～5．62μg／kg。     

酶联免疫(ELISA)法测定水产品中呋喃唑酮代谢物AOZ的残留

采用MaxsignalTM AOZ快速检测试剂盒检测水产品中呋喃唑酮代谢物。通过对精密度、回收率和检测限等项目的测定，验证了方法的可行性。呋喃唑酮代谢物标准液在0．05ng／mL～4．5ng／mL范围内具有良好的线性，微孔板孔间变异系数为3．2％～7．7％。样品批内变异系数为5．2％～8．4％，批间变异系数为6．3％～8．9％，平均回收率为94．5％～98．4％。试剂盒的理论检测下限为0．05μg／Kg。该方法灵敏度高，重复性好，适用于水产品中呋喃唑酮代谢物残留的检测。     

分光光度法测定水产品中甲醛含量的研究

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。     

气相色谱-质谱法测定海水及水产品中的莠去津

本文采用有机溶剂萃取的提取方法,利用气相色谱一质谱选择离子检测,建立了海水及水产品中莠去津的检测方法。该方法在0．001-0．5μg/L的范围内具有良好的线性范围,线性相关系数为0．9996;在海水和水产品中的检出限（S／N=3）分别为0．001μg/L和0．001mg／kg;在加标回收率试验中,海水中莠去津回收率为95．8％-113．2％,水产品中莠去津回收率为83．1％～92．6％;相对标准偏差（n=6）均小于4．4％。     

气相色谱-质谱法测定水产品中氟胺氰菊酯残留量

本文建立了水产品中氟胺氰菊酯残留量的气相色谱-质谱测定方法。样品经正己烷-丙酮（体积比2：1）超声提取、冷冻除脂、中性氧化铝固相萃取柱净化后,用气相色谱-质谱法进行测定和确认,外标法定量。在优化实验条件下,氟胺氰菊酯在10．0～400．0μg·L^-1范围内线性关系良好,相关系数为0．9999,检出限为2．0μg·kg^-1,定量限为4．0μg·kg^-1。在4．0、8．0和40．0μg·kg^-1加标水平下,鲤（Cyprinus carpio）、草鱼（Ctenopharyngodon ideUus）和凡纳滨对虾（Penaeus vannamei Boone）可食部分为基质的平均回收率为87．92％～98．37％,相对标准偏差为0．96％～4．97％。该方法操作简单、灵敏度高、净化效果理想、重珊陛好,可满足水产品中氟胺氰菊酯的定性定量检测的要求。     

氢化物原子荧光法测定水产品中的砷、汞

采用氢化物原子荧光法测定水产品中的砷、汞。在0～12μg／mL浓度范围内As、Hg标准曲线相关系数达0．999。As检出限为0．2μg／L，Hg为0．3μg／L，As回收率在100％-162％之间，Hg回收率在124％～152％之间。     

气相色谱法测定鸡蛋中氯霉素残留量

研究了鸡蛋中氯霉素残留的气相色谱测定方法。样品经乙酸乙酯提取后，用Sylon BFT衍生化，进电子捕获检测仪（ECD）测定，外标法定量．结果表明，方法的线性范围在1．0～300ng／mL之间，平均回收率达93．4％，平均相对标准偏差5．5％，检测限为0．1μg／kg。     

酶联免疫（ELISA）法测定水产品中氯霉素残留量

建立水产品中氯霉素残留量的酶联免疫检测方法。比较不同样品处理方法对检测结果的影响，通过对检测范围、精密度、回收率等项目的测定，验证了方法的可靠性。氯霉素标准在0．05ng／ml-4．05ng／ml范围内具有良好的线性，板问变异系数小于16．4％，样品测定的变异系数为9．4％-13.8％，乙腈水提取方法的回收率在84％-116％之间。     

高效液相色谱-荧光检测法测定水产品中15种多环芳烃

建立了高效液相色谱荧光检测法同时测定水产品中15种多环芳烃（polycyclic aromatic hydrocarbons,PAHs）的方法。通过液相色谱柱、荧光激发和发射波长等条件的优化,实现了15种多环芳烃组分基线完全分离和荧光高灵敏度检测。在优化的试验条件下,检测的15种多环芳烃中萘、苊和芴的检出限为0．5μg·kg^-1,苯并[b]荧蒽、二苯并[a．h]蒽和苯并[g,h,i]茈的检出限为2．0μg·kg^-1,其余化合物的检出限为1．0μg·kg^-1;在检测的15种多环芳烃中,菲、蒽、芘、苯并[a]蒽、崫、苯并[a]芘、茚并[1,2,3-cd]芘在0．001～0．500mg·L^-1质量浓度范围,其余化合物在0．002～1．000mg·L^-1质量浓度范围,呈良好的线性相关,相关系数R^2〉0．995;样品加标水平分别为2．0μg·kg、10．0μg·kg^-1和100．0μg·kg^-1时回收率为71．1％-98．4％,相对标准偏差（RSD）〈10％。该检测方法重现性高,检测灵敏度和准确度均满足分析要求。     

Association between the interannual variation in the oceanic environment and catch rates of bigeye tuna (Thunnus obesus) in the Atlantic Ocean

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.     

Growth performance,digestive enzyme activity and immune response of Japanese sea bass,Lateolabrax japonicus fed with fructooligosaccharide

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.     

Rare serotype occurrence and PFGE genotypic diversity of Streptococcus agalactiae isolated from tilapia in China

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.     

Evaluation of a Fast Method Based on the Presence of Two Restriction Sites in the Mitochondrial ND5 (mt ND5) Gene for the Identification of Scomber Species

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.     

Growth hormone (GH) and reproduction: a review

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.     

Purification and partial characterization of GtHs (cfLH and cfFSH) from Indian walking catfish (Clarias batrachus) (L.) and development of a homologous ELISA for cfLH

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.     

Controlled infection of Poecilia reticulata Peters (guppy) with Tetrahymena by immersion and intraperitoneal injection

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).