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1.
使用不同浓度的高氯酸溶液对罗非鱼(Tilapia niloticus)、蓝圆(Decapterus maruadsi)、南美白对虾(Litopenaeusvannamei)和近江牡蛎(Crassostrea rivularis)4种水产品的肌肉样品进行前处理,并采用蒸馏法测定样品提取液中挥发性盐基氮(TVBN)的含量,研究了高氯酸溶液浓度、浸提时间和蒸馏前样品的放置时间对测定的结果影响。结果表明,以0.6 mol.L-1高氯酸溶液均质样品2 min后测定4种水产品中TVBN,样品加标回收率在98.35%~100.80%,相对标准偏差在1.53%以下。这种方法所得结果与GB/T 5009.44蒸馏法相比,不存在显著性差异,且操作简便、快速。[中国水产科学,2006,13(1):146-150] 相似文献
2.
为全面了解兰州鲇(Silurus lanzhouensis)肌肉品质,建立了兰州鲇肌肉中肌苷酸含量的高效液相色谱测定方法。样品经5%pH 6.5～6.8的高氯酸溶液提取,C18反相色谱柱分离,254 nm波长处测定,外标法定量,测定了兰州鲇、鲇(Silurus asotus)、黄河鲤(Cyrinus carpio)3种鱼类肌肉中的肌苷酸含量。结果显示:该方法线性关系良好,相关系数r≥0.999;灵敏度高,检出限为2.5×10-4g/kg;加标回收率≥94.0%;方法精密度好,RSD≤2.5%。兰州鲇、鲇和黄河鲤的肌苷酸含量分别为1.18 g/kg、0.733 g/kg和0.504 g/kg。 相似文献
3.
鳙鱼肉中土腥昧物质的测定方法 总被引：2，自引：0，他引：2
本研究通过微波蒸馏提取、固相微萃取(SPME)富集和气相色谱-质谱联用(GC/MS)分析的方法,实现了对鳙(Aristichthys nobilis)鱼肉中土腥味物质的定量测定.实验对微波蒸馏提取、SPME法富集鱼肉中土腥味物质的条件进行了优化,确定最佳条件为微波功率350W,10g样品蒸馏时间为8min,氮气流速60mL/min;萃取时间30min,萃取温度60℃,NaCl加入量4:1(V:W),搅拌速度1 500 r/min.结果表明,使用SPME富集土味素(Geosmin)时,回收率为95.4%.检测限为1.0 ng/L,线性范围为5～100 ng/L;采用优化后的微波蒸馏-SPME-GC/MS方法测定鳙鱼肉中的土味素时,回收率为57%;经该法测定10月份青岛市场市售鳙鱼肉中土味素平均含量为5.4μg/L. 相似文献
4.
《中国水产科学》2010,(5)
本研究通过微波蒸馏提取、固相微萃取(SPME)富集和气相色谱-质谱联用(GC/MS)分析的方法,实现了对鳙(Aristichthys nobilis)鱼肉中土腥味物质的定量测定。实验对微波蒸馏提取、SPME法富集鱼肉中土腥味物质的条件进行了优化,确定最佳条件为微波功率350W,10g样品蒸馏时间为8min,氮气流速60mL/min;萃取时间30min,萃取温度60℃,NaCl加入量4:1(V:W),搅拌速度1500r/min。结果表明,使用SPME富集土味素(Geosmin)时,回收率为95.4%,检测限为1.0ng/L,线性范围为5～100ng/L;采用优化后的微波蒸馏-SPME-GC/MS方法测定鳙鱼肉中的土味素时,回收率为57%;经该法测定10月份青岛市场市售鳙鱼肉中土味素平均含量为5.4μg/L。 相似文献
5.
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
6.
《中国渔业质量与标准》2019,(2)
贝类毒素标准样品的制备是保障贝类质量安全的基础,本研究以有毒贻贝(Mytilus edulis)为原料,探究麻痹性贝类毒素标准样品的制备技术。以1%乙酸溶液提取贻贝中的麻痹性贝类毒素,采用羟丙基葡聚糖凝胶柱(Sephardex LH20)净化后收集目标馏分,再经高效液相色谱以TSK-GEL Hillic Amide-80色谱柱(4.6 mm×250.0 mm,5.0μm)分离、纯化,根据麻痹性贝类毒素的保留时间收集色谱峰流出液,连续制备合并馏分,40℃减压蒸馏浓缩近干,用75%乙腈水(含0.25%甲酸)溶解,即制得毒素标准样品溶液。分别采用四极杆/离子阱复合质谱与标准物质的多级质谱信息进行匹配,以高分辨质谱获得的精确质量数进行定性确证,样品溶液所含的麻痹性贝类毒素为4种膝沟藻毒素,分别为膝沟藻毒素-1-4 (Gonyautxins-1-4, GTX14)和膝沟藻毒素-2-3(Gonyautxins-2-3, GTX23)。均匀性实验中,经F检验表明在95%的置信区间范围内样品均匀性良好。稳定性考察实验中,标准样品在4℃和-18℃两种环境条件下储存6个月稳定性较好。标准样品经8家实验室联合定值,并评定了定值结果的不确定度。本研究制得的麻痹性贝类毒素标准样品为GTX 1(3 663μg/L)GTX4(1 147μg/L)和GTX 2(1 884μg/L)GTX3(797μg/L)的混合溶液,溶剂为75%乙腈水(含0.25%甲酸),为国内贝类毒素标准样品研发提供了技术支撑。[中国渔业质量与标准,2019,9(2):62-70] 相似文献
7.
离子对反相高效液相色谱法同时检测水产品中6种ATP关联化合物 总被引：6，自引：3，他引：3
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
8.
脱酸与脱腥条件对烤鳗油品质的影响 总被引：1，自引：0，他引：1
用正交试验法设计碱 (NaOH)加入量以优化烤鳗油的脱酸条件 ,并对脱酸后的酸价、过氧化值和收得率进行测定以评价其质量。运用减压水蒸气蒸馏法对烤鳗油进行脱腥处理 ,以气相色谱 -质谱 (GC -MS)联用技术测定经脱腥后烤鳗油的脂肪酸组成。结果显示 ,烤鳗油最佳脱酸条件为 0 .0 5 %过量碱 ,原碱质量分数 13.0 4 % ,温度6 0℃ ,处理时间 35min。经活性陶土脱色 ,可得到符合食用油标准的精炼烤鳗油 ,收得率为 80 % ;脱腥条件为温度180℃、压力 - 0 .0 9MPa ,水蒸气蒸馏处理 ,得到基本保持高不饱和脂肪酸组分的脱腥烤鳗油 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.
海豚组织中多氯联苯（PCBs）气相色谱测定的改良方法研究 总被引：4，自引：0，他引：4
研究和建立了一种测定海豚体内不同组织中多氯联苯(PCBs)前处理的改良方法,即将海豚组织分为低脂样品和高脂样品,分别经萃取、净化、浓缩等处理后,用Agilent6890N型气相色谱仪、63Ni放射源ECD检测器测定,采用保留时间定性和峰面积外标法定量。结果显示,加标回收率为75.8%~119.2%,精密度为5.6%~11.2%,方法检出限为0.126~0.642ng.g-1,说明该方法的准确性、可重复性符合海洋生物体痕量有机污染物分析要求。海豚组织样品的实际测定结果表明,该方法适合海豚体内PCBs含量的分析测定。 相似文献
11.
Conceição LE Aragão C Dias J Costas B Terova G Martins C Tort L 《Fish physiology and biochemistry》2012,38(1):119-141
Little research has been done in optimizing the nitrogenous fraction of the fish diets in order to minimize welfare problems.
The purpose of this review is to give an overview on how amino acid (AA) metabolism may be affected when fish are under stress
and the possible effects on fish welfare when sub-optimal dietary nitrogen formulations are used to feed fish. In addition,
it intends to evaluate the current possibilities, and future prospects, of using improved dietary nitrogen formulations to
help fish coping with predictable stressful periods. Both metabolomic and genomic evidence show that stressful husbandry conditions
affect AA metabolism in fish and may bring an increase in the requirement of indispensable AA. Supplementation in arginine
and leucine, but also eventually in lysine, methionine, threonine and glutamine, may have an important role in enhancing the
innate immune system. Tryptophan, as precursor for serotonin, modulates aggressive behaviour and feed intake in fish. Bioactive
peptides may bring important advances in immunocompetence, disease control and other aspects of welfare of cultured fish.
Fishmeal replacement may reduce immune competence, and the full nutritional potential of plant-protein ingredients is attained
only after the removal or inactivation of some antinutritional factors. This review shows that AA metabolism is affected when
fish are under stress, and this together with sub-optimal dietary nitrogen formulations may affect fish welfare. Furthermore,
improved dietary nitrogen formulations may help fish coping with predictable stressful events. 相似文献
12.
The magnitude of nitrogen fixation in an inorganic fertilized and cereal fed system (fish pond) was measured by an in situ application of the acetylene reduction method. The effects of inorganic fertilization were intensively examined. In comparison with natural lakes, the fish ponds exhibited a relatively low fixation rate. The midday nitrogen fixation rate was usually less than 30 μg at N·m?2·h?1. The total income was equal to 5.7 kg N·ha?1 or 0.575 g N·m?2 for the growing season. Fish-induced bioperturbation and nitrogen fertilization, in the form of inorganic and organic fertilizers and foods, are considered to be the major regulatory factors in nitrogen fixation. 相似文献
13.
本实验以非生物絮团养殖模式作为对照,研究了生物絮团凡纳滨对虾养殖模式中,水质因子氨氮和亚硝酸氮的变化规律。结果表明:试验组的生物絮团沉积量至第35天达到峰值(15.93±0.31)m L/L,而后保持相对稳定状态,对照组的生物絮团量一直处于极低水平(1.5 m L/L),两组之间差异显著(P0.05);对照组氨氮含量至第35天达到峰值(1.05±0.19)mg/L,试验组氨氮含量增加缓慢,至第60天时仅为(0.37±0.04)mg/L,显著低于对照组(P0.05);在实验的前15天,实验组和对照组的亚硝酸氮含量无显著差异(P0.05),随后试验组亚硝酸氮含量增速减慢并趋于稳定,而对照组则直线上升,对照组亚硝酸氮含量显著高于试验组(P0.05)。 相似文献
14.
Balances of phosphorus and nitrogen in carp ponds 总被引：1，自引：0，他引：1
R. Knösche & K. Schreckenbach M. Pfeifer H. Weissenbach 《Fisheries Management and Ecology》2000,7(1-2):15-22
15.
不同氮源加富对海带生长、光合固碳和氮吸收特性的影响 总被引：1，自引：0，他引：1
为比较海带在适应不同氮源加富后的生理特点,本研究设置了自然海水、氨氮加富和硝氮加富3种不同的氮培养条件,在不同氮条件下适应培养7 d后,分别测定海带孢子体的生长、不同无机碳浓度下的光合速率(P-Ci曲线)和氮吸收情况。结果显示,2种氮源加富均能促进藻体的生长,但二者之间没有显著差异。P-Ci曲线符合饱和动力学曲线,2种氮源加富均提高了最大光合速率(Vmax)和半饱和常数(Ks),但Vmax在2种氮源加富培养中没有显著差异,而氨氮加富的藻体具有较大的Ks值。与自然海水相比,硝氮加富提高了Vmax/Ks比值,氨氮加富对其没有影响。叶绿素a(Chl.α)和类胡罗卜素(Car)的含量均被氮加富提高,且在氨氮加富和硝氮加富之间没有显著差异。可溶性糖含量被2种氮加富降低,且在氨氮加富中具有更低的值。与自然海水相比,氨氮加富促进了海带对氨氮的吸收,同时抑制了对硝氮的吸收;而硝氮加富仅提高了硝氮的吸收速率,对氨氮吸收没有影响。综上所述,2种氮源加富虽都能提高海带的碳、氮吸收速率,但氨氮加富在氮利用中具有优势,而硝氮加富在碳固定中的促进作用更加明显,氨氮加富对氮利用的促进和硝氮加富对碳固定的促进作用互相抵消,因而2种氮源加富培养藻体之间的生长速率未出现显著差异。 相似文献
16.
水力停留时间、水温与氨氮浓度对浸没式生物滤池氨氮去除速率的效应 总被引：5，自引：0，他引：5
本文研究了采用浸没式生物滤池处理集约化养殖污水时 ,水力停留时间 (HRT/min)、水温(T/℃ )、总氨氮浓度 ([TAN] ,mgNH+4-N/L)对总氨氮去除速率 (R/gNH+4-N/m3 h)的效应。对实验数据的分析结果表明 ,它们之间的经验方程为 :当 [TAN]≥ 2 85mgNH+ 4-N/L ,R =0 2 6+ 0 2 9·HRT + 0 0 0 8·HRT·T -0 0 1·HRT2 ;当 [TAN]≤ 2 85mgNH+ 4-N /L ,R =(-0 78+ 0 2·HRT + 0 0 0 3·HRT·T -0 0 0 7·HRT2 )·[TAN ]+ 0 2 45。上述模型可说明在单因素作用时 ,氨氮去除速率与水温线性正相关 ,与总氨氮浓度为零级、一级反应关系 ,与水力停留时间呈双曲线相关。一定的水温、氨氮负荷条件下 ,存在使氨氮去除速率最大的水力停留时间 ,这对最优化设计与运行浸没式生物滤池有指导意义 相似文献
17.
Using different sources of nitrogen as fertilizers in nursery ponds may affect water quality and plankton responses. We evaluated water quality variables and plankton population responses when using different nitrogen sources for catfish nursery pond fertilization. We compared calcium nitrate (12% N), sodium nitrite (20% N), ammonium chloride (26% N), ammonium nitrate (34% N) and urea (45% N) in 190‐L microcosms at equimolar nitrogen application rates. Sodium nitrite‐fertilized microcosms had higher nitrite and nitrate levels during the first week; no other differences in the water quality were detected among fertilizer types (P>0.05). No differences in green algae, diatoms or cyanobacteria were detected among treatments; desirable zooplankton for catfish culture was increased in urea‐fertilized microcosms. Based on these results, any form of nitrogen used for pond fertilization should perform similarly without causing substantial water quality deterioration. Ammonium nitrate and urea contain a higher percentage of nitrogen, requiring less volume to achieve dosing levels. If both urea and ammonium nitrate are available, we recommend using the one with the least cost per unit of nitrogen. If both types of fertilizer have an equal cost per unit of nitrogen, we recommend using urea because of the potential advantage of increasing desirable zooplankton concentrations. 相似文献
18.
Frank Liebert Angela Sünder Khaled Mohamed 《Aquaculture (Amsterdam, Netherlands)》2006,261(4):1346-1355
Assessment of quantitative amino acid requirement data in fish nutrition is predominantly based on dose response studies with supplementation of the dietary limiting amino acid. Studies with modeling amino acid requirements are scarce. Three experiments were conducted with different genotypes of juvenile Tilapia [A: all male O. niloticus; B: red Tilpia (O. mossambicus × O. hornorum); C: hybrid Tilapia (A × B)] using fishmeal-wheat gluten diets with five graded levels of dietary protein supply (17.2-48.5% CP). The dietary amino acid ratio was similar, dietary energy contents were adapted to avoid limiting energy supply. Growth response was studied in a semi-closed in-door water recirculation system with 38 tanks (320 l/tank; water temperature 28 ± 0.5 °C; regulated photoperiod 12 h light/12 h dark). Four replicate groups (25 fish per tank) were utilized in a 70 d growth experiment with three times a day feeding until apparent satiation. Ten fish at the beginning and three fish per tank at the end of the growth study were analyzed for body composition to calculate N-deposition and N-excretion. The nitrogen maintenance requirement (NMR) was established based on nonlinear fitting of N-excretion depending on N-intake. The intersection of the applied exponential function with the y-axis was used as NMR, simulating protein free feeding. The theoretical potential for daily N-deposition of the genotypes under study (NDmaxT) was estimated as threshold value due to exponential fitting of N-deposition depending on N-intake. The observed average NMR (70 mg N/BWkg0.67/d) and threshold values for genotype A (NDmaxT = 388 mg/BWkg0.67/d), genotype B (NDmaxT = 389 mg/BWkg0.67/d) and genotype C (NDmaxT = 319 mg/BWkg0.67/d), respectively, are the starting point for the studied exponential N-utilization model and its subsequent application for assessing amino acid requirements depending on growth performance and dietary amino acid efficiency in fish feed. 相似文献
19.
A photoelectrocatalytic oxidation (PECO)3 device was developed for converting aqueous ammonia into nitrogen gas. The device uses a germicidal UV lamp to activate a titania (TiO2)-coated anode (photoanode) that is connected to a titanium or platinum wire cathode to form an electrolytic cell. When a small bias (2 V DC) was applied between the anode and cathode, ammonia (−3 oxidation state) was oxidized primarily into nitrogen gas (0 oxidation state) rather than nitrite (+3 oxidation state) or nitrate (+5 oxidation state). The ammonia oxidation rate changed as a function of the crystalline structure of the titania coating on the anode, the salinity of the water, the applied voltage, and the disruption of boundary layers near the photoanode surface. There was no ammonia removal in water without at least some NaCl in solution, suggesting that the device works by converting chloride ions into chlorine and hypochlorous acid, which then react with ammonia to form nitrogen gas. Varying the pH between pH = 5 and pH = 10 had no effect on the rate of ammonia removal. A continuous flow-through PECO reactor was tested using aquariums spiked with ammonium chloride or stocked with seawater-adapted tilapia fed a high protein diet, and found to effectively remove ammonia and limit nitrite and nitrate accumulation in the tanks. 相似文献