罗氏沼虾氨基脲分布特征及贮藏变化研究

氨基脲(Semicarbazide, SEM)为一种有毒物质,是判断呋喃西林是否违规使用的标记性残留物。为探讨甲壳类水产品中氨基脲的检出情况,采用高效液相色谱-串联质谱联用法(High performance liquid chromatography-mass spectrometry, HPLC-MS/MS)对罗氏沼虾(Macrobrachium rosenbergii)中的SEM进行了检测。结果显示,罗氏沼虾不同部位均检出SEM,其中头胸甲和虾壳等甲壳部位SEM检出值较高[平均(32.02±3.75)和(26.85±13.90)μg·kg^-1],肌肉和肝脏的SEM检出值较低[平均(1.35±0.67)和(5.56±0.87)μg·kg^-1],均超过我国现行规定的残留限量标准(1μg·kg-1);罗氏沼虾虾壳和虾肉中的SEM检出值随贮藏时间的增加而减小,甲壳组织中SEM检出值始终高于1.0μg·kg^-1,而不同贮藏温度对罗氏沼虾中SEM检出值影响较小。因此,以SEM为标志物对罗氏沼虾进行呋喃西林残留检测时,应考虑样品...     

鱼种池套养罗氏沼虾技术

<正> 近几年,名优品种养殖迅猛发展,市场需求增加。尤其罗氏沼虾需求日趋增大。1998年,邯郸市水产技术推广站进行了鱼种池套养罗氏沼虾试验,收效甚佳。试验池面积0.67hm~2,养殖周期120d收获草、鲢鱼种2861kg(其中,草鱼种2142kg,鲢719kg),平均规格50g,罗氏沼虾525kg,平均规格38g,总产值达88720元,经济效益十分显著。现将试验情况介绍如下:     

运动强度对罗氏沼虾运动行为和能量代谢的影响

为查明运动过程中罗氏沼虾的行为特征及其与肌肉能量代谢的关系,实验设置了对照、低、中、高4种不同强度的游泳和弹跳实验,研究了运动后罗氏沼虾的行为、能量来源和相关代谢酶活性。游泳强度通过在特定时间内设置不同的水流速度来确定,对照、低、中、高强度的水流速度分别为0 (自由运动)、5 (200 min)、10 (200 min)和15 cm/s (游泳至疲劳)。弹跳强度通过在特定时间内设置不同触碰频率来确定,对照、低、中、高强度的触碰频率分别为0 (自由运动)、0.033 (5 min)、0.050 (5 min)和0.067 Hz (弹跳至疲劳)。结果显示,罗氏沼虾各运动组游泳足和尾肢的最大摆动频率和最大摆动幅度均显著高于对照组。各运动强度组肌肉蛋白质含量与对照组之间无显著差异,肌肉糖原含量均显著小于对照组,低强度游泳组肌肉甘油三酯含量小于对照组。中、高强度游泳组游泳足肌肉乳酸脱氢酶(LDH)活性和乳酸含量显著高于对照组,低强度游泳组游泳足肌肉丙酮酸脱氢酶、苹果酸脱氢酶和脂肪酶活性显著高于对照组。无论弹跳强度高低,罗氏沼虾腹部肌肉LDH酶活性和乳酸含量均显著高于对照组。研究表明,罗氏沼虾通过...     

甲壳类水产品中呋喃西林代谢物氨基脲的本底调查及来源分析

通过对常见甲壳类水产品中呋喃西林代谢物氨基脲本底含量的调查及来源分析,为水产品质量安全监管提供依据。本研究运用液相色谱-串联质谱法,对常见的4种甲壳类水产品中本底氨基脲的含量进行测定。结果表明,在4种甲壳类水产品中,日本沼虾和罗氏沼虾中氨基脲检出率达100%,日本沼虾中氨基脲平均检出值为6.92μg/kg,罗氏沼虾中氨基脲平均检出值为2.52μg/kg,均超过现行残留限量,而凡纳滨对虾和中华绒螯蟹中的氨基脲含量较低。本研究的结果为甲壳类水产品中氨基脲残留限量的制定提供了数据支持。     

不同虾的组织中氨基脲存在形态及含量分析

氨基脲在虾甲壳组织中普遍存在,同时又是呋喃西林的代谢标志物,在利用氨基脲检测结果判定虾中是否是由于使用呋喃西林导致氨基脲残留时,往往会造成判定结果错误,易给养殖者和贸易均造成巨大损失,因此需要对虾中内源性氨基脲的存在状况进行深入全面的分析。本实验研究了不同来源虾类不同组织中氨基脲含量水平、存在形态和组织分布特征,对比分析了海水虾和淡水虾组织中氨基脲含量的差异及野生环境和人工养殖环境中日本沼虾组织中氨基脲的含量差异。结果显示：氨基脲在虾的不同组织中浓度从高到低依次为：甲壳>眼柄>鳃>肌肉>头胸部>肝胰腺;虾肌肉组织中氨基脲总量含量为ND(未检出)～(16.91±1.89)μg/kg,肌肉组织中结合态氨基脲含量为ND～(2.26±0.97)μg/kg。虾肌肉组织结合态氨基脲在氨基脲总量中所占比例分别为ND～33.79%,甲壳组织中结合态氨基脲所占比例分别为ND～84.48%。甲壳、眼柄、鳃等虾的角质化组织中氨基脲结合态的比例大于肌肉组织中氨基脲结合态的比例。甲壳组织和眼柄组织中氨基脲主要以结合态形式存在,肌肉、鳃、肝胰腺和头胸部组织中氨基脲主要是以游离态形式存...     

日本沼虾养殖过程中氨基脲存在特征研究

为探究不同生长时期养殖日本沼虾(Macrobrachium nipponense)体内氨基脲(Semicarbazide,SEM)的存在特征与变化规律,从养殖池塘采集不同生长时期日本沼虾样品,对各组织中SEM含量进行测定。结果表明:不同生长阶段日本沼虾样品中均有SEM检出,肌肉、甲壳、附肢、眼柄、鳃、肝胰腺中总SEM含量分别为(6.88±0.15)^17.11±0.62、(107.30±1.10)^306.09±8.69、(243.90±8.55)^{532.31±26.27}、(85.27±3.19)^122.82±2.60、(48.43±2.13)^85.60±1.33、(13.51±1.15)^25.94±1.78μg/kg,呈现:附肢>甲壳>眼柄>鳃>肝胰腺>肌肉的含量分布特征。SEM在肌肉和肝胰腺中主要以游离态形式存在,游离态SEM所占平均比例分别为67.35%和72.4%,在甲壳、眼柄、附肢、头胸部和鳃中主要以结合态形式存在,结合态SEM所占平均比例分别为89.50%、87.16%、85.68%、80.48%和73.30%。随着养殖过程进行,肌肉中总SEM含量总体逐渐降低,甲壳和附肢中总SEM含量呈现总体上升的变化趋势。研究结果可为甲壳类水产品中SEM残留限量标准的修订和采样技术规范的制订提供基础数据。     

植物甾醇对罗氏沼虾生长性能、消化酶、肌肉品质及氨基酸组成的影响

选取初始体重为(0.32±0.02) g的罗氏沼虾450尾,随机分为5组,每组设3个重复,每个重复30尾虾。以基础饲料为对照组,分别于基础饲料中添加10 mg/kg、20 mg/kg、40 mg/kg、400 mg/kg植物甾醇,饲养试验为期70天。试验结果表明:①与对照组相比,添加20 mg/kg、40 mg/kg和400 mk/kg植物甾醇组罗氏沼虾的终末体重、增重率和特定生长率显著高于对照组(P 0.05),添加40 mk/kg组的饲料系数显著低于对照组和添加10 mg/kg和400 mg/kg组(P 0.05),添加40 mk/kg组的肥满度显著高于对照组和添加10 mg/kg和400 mg/kg组(P 0.05)。②添加20 mg/kg和40 mg/kg植物甾醇其肝脏脂肪酶活性显著高于对照组(P 0.05),对肝脏蛋白酶和淀粉酶活性则没有显著影响(P 0.05)。③添加20 mg/kg、40 mg/kg和400 mg/kg植物甾醇组罗氏沼虾的含肉率显著高于对照组(P 0.05),添加40 mg/kg和400 mg/kg植物甾醇显著降低了滴水损失(P0.05)。④添加20 mg/kg、40 mg/kg和400 mg/kg植物甾醇显著提高了罗氏沼虾肌肉粗蛋白质含量(P 0.05),添加40 mg/kg和400 mg/kg植物甾醇显著提高了罗氏沼虾肌肉谷氨酸和甘氨酸含量(P 0.05)。在本试验条件下,在罗氏沼虾基础饲料中添加40 mg/kg植物甾醇可获得最佳生长性能和肌肉品质。     

稻田养值罗氏沼虾试验

利用稻田养殖罗氏沼虾，放养体长2．5cm的虾苗，经4个月养殖，平均规格达18．2g，亩产25．2kg，成活率40．72％。水稻亩产476．5kg。每亩纯收入1822元。试验表明，稻田养殖罗氏沼虾是增产增收的好途径。     

不同脂肪源对罗氏沼虾生长及体组织常见组分的影响

用5种不同脂肪源组合的饲料(Ⅰ.鱼油0.5%+豆油2.5%;Ⅱ.鱼油0.5%+菜籽油2.5%;Ⅲ.鱼油0.5%+花生油2.5%;Ⅳ.鱼油0.5%+亚麻油2.5%;Ⅴ.豆油1.5%+亚麻油1.5%)投喂体重为(2.22±0.04)g的罗氏沼虾(Macrobrachium rosenbergii)40 d,研究不同脂肪源对其生长及全虾和肌肉中水分、粗蛋白、粗脂肪含量的影响。结果显示:在生长方面,第Ⅴ组的罗氏沼虾增重显著高于Ⅱ组和Ⅲ组(P<0.05),Ⅰ组和Ⅳ组增重也显著大于Ⅱ组(P<0.05)。在体成分方面,Ⅰ组全虾总水分含量最低,显著低于Ⅲ组和Ⅳ组(P<0.05),其他各组间无显著差异(P>0.05);Ⅴ组全虾粗脂肪含量最高,显著高于其他各试验组(P<0.05);Ⅲ组全虾粗蛋白含量显著低于Ⅰ组、Ⅱ组及Ⅴ组(P<0.05);Ⅳ组肌肉总水分含量显著高于其他各组;肌肉粗脂肪和粗蛋白含量各试验组之间差异不显著(P>0.05)。     

中华绒螯蟹-日本沼虾池塘套养大规格罗氏沼虾模式氮磷收支及养殖效果研究

为揭示中华绒螯蟹(Eriocheir sinesis)-日本沼虾(Macrobrachium nipponense)池塘内套养不同密度的大规格罗氏沼虾(M.rosenbergii)的氮磷收支变化及养殖效果,评价其生态和经济效益,确定最佳套养密度,本研究在中华绒螯蟹(10kg/667 m²)-日本沼虾(15kg/667 m²)套养池塘内每667 m²分别投放规格为75～80只/kg的罗氏沼虾5kg(T1)、15kg(T2)和25 kg(T3),并定期监测罗氏沼虾生长情况,计算池塘氮磷收支,分析成本和收益。结果显示：T1罗氏沼虾生长速度要快于T2和T3;饲料为池塘氮、磷输入的主要来源,分别占T1、T2和T3氮输入的(81.99±2.14)%、(81.94±2.20)%和(81.91±2.21)%,磷输入的(85.16±2.33)%、(84.99±2.31)%和(84.85±2.40)%;水生植物是主要支出方式,分别占T1、T2和T3氮支出的(61.21±1.93)%、(56.99±2.03)%和(52.05±1.89)%,磷...     

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.     

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).     

Involvement of gonadal steroids in final oocyte maturation of white perch (Morone americana) and white bass (M. chrysops): in vivo and in vitro studies

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.     

Cardiac,ventilatory and metabolic responses of two ecologically dissimilar species of fish to waterborne cyanide

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.     

An overview of stress physiology of fish transport: changes in water quality as a function of transport duration

This study brings an integrated analysis about the relationship between water deterioration and its physiological consequences in live fish transport. The analysis was focused on the transport water and its deterioration, and physiological challenges imposed on the fish. Usual commercial handling procedures employed to mitigate fish stress during transport were discussed. Future topics of research for the establishment of safer fish transport protocols were proposed. Transport was classified into short (≤8 h) or long transport (>8 h). The main issue in short transports should be the prevention of water pH reduction, while in long transports it is the increase in ammonia. Plasma cortisol is the most employed marker for stress and is acutely elevated upon short episodes of transport, but remains elevated even in long‐transport events. Plasma glucose is perhaps a better marker for handling stress. Plasma lactate, pH, osmolality CO₂ and ions should be more often evaluated. Plasma Na⁺ and Cl^‐ are very useful markers of acidosis, due to their respective exchange for H⁺ and , for acid–base regulation. The establishment of species‐specific transport protocols should be preceded by such combined analyses of water and physiological parameters.