Feasibility of using rare earth elements (REEs) to mark and identify escaped farmed Atlantic salmon Salmo salar L.

A series of rare earth elements (REEs) were evaluated as potential markers in scales of Atlantic salmon 1⁺ and 0⁺ smolt by addition of these elements to the feed. Chlorides of 5 REEs were tested, alone or in combination: lanthanum (La), cerium (Ce), praseodymium (Pr), neodymium (Nd) and dysprosium (Dy). The labelled‐diets contained 125 or 250 mg REE kg^?1 feed and were administered for up to 10 weeks. Fish scales were collected and analysed by inductively coupled plasma‐mass spectrometry (ICP‐MS) before start, 5 and 10 weeks after labelling started and finally 2 or 4 months after marking. The results demonstrated that the five tested elements were clearly incorporated into the scales of the fish fed the supplemented diets. Uptake and concentrations increased gradually during the feeding period, and no principal differences were found between the two smolt types. Combining 2 REEs in the same feed did not affect the incorporation of either of them. After a ‘dilution’‐period of 2–4 months the concentrations of all markers (except La) in the scales of the treated‐fish were still significantly higher than those of the untreated‐fish. The background concentrations of the tested markers and some other elements were also measured and found to give interesting information.     

液相色谱-串联质谱法测定动物尿液中11种β-受体激动剂残留量的不确定度评估

采用液相色谱-串联质谱法测定动物尿液中11种β-受体激动剂残留量,对标准溶液、体积、质谱峰面积、浓缩过程及回收率等测定不确定度因素进行了分析,通过评定各不确定度分量及标准不确定度,得出11种β-受体激动剂的扩展不确定度在0.7 ～ 1.1 ng/mL范围内.由各因素对合成不确定度的贡献比分析可知,影响较大的因素为试验回收率及标准溶液浓度.     

超高效液相色谱-串联质谱法测定凡纳滨对虾中的硝基呋喃代谢物残留

采用超高效液相色谱-串联质谱（UPLC-MS/MS）法,测定了凡纳滨对虾（Litopenaeus vannam ei）中氨基脲（SEM）、1-氨基-2-内酰脲（AHD）、3-氨基-2-唑烷基酮（AOZ）和5-甲基吗啉-3-氨基-2-唑烷基酮（AMOZ）4种硝基呋喃类代谢物。采用2-硝基苯甲醛作为衍生化试剂,氘、碳-13、氮-15同位素标记的SEM1-3C1-5N2、AHD1-3C3、AOZ-D4和AMOZ-D5为内标物,样品经衍生、乙酸乙酯提取、正己烷净化,以甲醇0.5 mmol.L-1乙酸铵水溶液（含0.1%甲酸）为流动相进行梯度洗脱,8 m in可将4种目标化合物完全分离并测定。结果表明,4种待测物在0.4～20.0 ng.mL-1范围内线性关系良好（R〉0.999）,检出限为0.03～0.15μg.kg-1。在0.5μg.kg-1、1.0μg.kg-1和2.0μg.kg-13个水平上进行加标回收试验,平均回收率为92.0%～107.3%,RSD为3.1%～8.7%。采用该法参加FAPAS国际水平测试,获得了满意的结果。     

基于UHPLC–QTOF–MS技术的五倍子单宁成分分析

目的 基于超高效液相色谱–四极杆飞行时间–质谱（UHPLC–QTOF–MS）技术分析五倍子中单宁成分,建立一种有效的五倍子单宁成分测定方法,并解析单宁的裂解规律。 方法 使用高温和超声波辅助方法提取五倍子中的酚类化合物,基于二级质谱推定化合物的裂解途径。 结果 共鉴定到20种化合物,包含14种没食子单宁、3种酚酸、2种没食子酸酯和1种黄烷醇。以高温121℃为提取条件,均未鉴定到分子质量高于1 500 Da的没食子单宁,而在超声波辅助提取的五倍子水提取液中,成功地检测到1–O–没食子酰基葡萄糖至14–O–没食子酰基葡萄糖,其中,超声功率1 500 W,提取温度65℃条件下,鉴定到更多的没食子单宁异构体。MS/MS图谱显示,五倍子单宁主要通过没食子酸、没食子酰基、糖苷、水、羧基的损失进行裂解。 结论 本研究证明,超声波辅助提取条件下,应用UHPLC–QTOF–MS技术能够全面高效地分析五倍子中的单宁成分,本研究为富含单宁的植物的化学成分研究提供参考依据。     

罗非鱼不同组织脂肪酸含量的分析

分别取罗非鱼(Oreochromis niloticus)的肉、脂肪、肝、眼和皮等组织,用氯仿-甲醇(2∶1,v/v)提取,以C17∶0为内标物,利用气相色谱-质谱法(GC/MS)分析了各组织脂肪酸种类及含量。结果显示:罗非鱼各种组织中含有16种脂肪酸,富含多不饱和脂肪酸。脂肪组织中的脂肪酸含量最高,其次是眼睛、肝脏、鱼肉和鱼皮;各组织中饱和脂肪酸(SFA)含量为202~8869 mg/kg,主要为棕榈酸(C16∶0)和硬脂酸(C18∶0);单不饱和脂肪酸(MUFA)含量为293~11219 mg/kg,主要为棕榈油酸(C16∶1)和油酸(C18∶1);多不饱和脂肪酸(PUFA)含量为362~8293 mg/kg,主要是亚油酸(C18∶2)、亚麻酸(C18∶3)和二十二碳六烯酸(DHA,C22∶6);n-6/n-3为1.20~2.46。     

Silver catfish Rhamdia quelen immersion anaesthesia with essential oil of Aloysia triphylla (L'Hérit) Britton or tricaine methanesulfonate: effect on stress response and antioxidant status

Responses to anaesthesia with essential oil (EO) of Aloysia triphylla (135 and 180 mg L^?1) and tricaine methanesulfonate (MS222) (150 and 300 mg L^?1) were assessed in silver catfish. Exposure to the anaesthetics elicited a stress response in the species. In the case of MS222, it was displayed as a release of cortisol into bloodstream, elevation in hematocrit and plasma ion loss. The EO presented cortisol‐blocking properties, but increased haematocrit and disturbances of hydromineral balance were observed. Liver antioxidant/oxidant status of EO and MS222‐anaesthetized silver catfish was also estimated. The synthetic anaesthetic induced lipoperoxidation, notwithstanding increased catalase contents, whereas the naturally occurring product was capable of preventing the formation of lipid peroxides, possibly due to combined actions of catalase and glutathione‐S‐transferase. Anaesthetic efficacy was also tested via induction and recovery times. Overall, the promising results obtained for the physiological parameters of the EO‐treated fish counterbalanced the slight prolonged induction time observed for 180 mg L^?1. As for 135 mg L^?1, both induction and recovery times were lengthy; despite that, the EO was able to promote oxidative protection and mitigate stress. None of the MS222 concentrations prompted such responses concomitantly.     

Anaesthetic efficacy of MS‐222 and AQUI‐S® in advanced size fry of rohu,Labeo rohita, (Hamilton‐Buchanan)

Anaesthetic agents are very useful for reducing the stress caused by handling, sorting, transportation, artificial reproduction, tagging, administration of vaccines and surgical procedures in fish. The efficacy of two anaesthetics: MS‐222 and AQUI‐S^® were tested on rohu, Labeo rohita advanced size fry. The lowest effective doses that produced induction in 3 min or less and recovery times 5 min or less and meet the most criteria of good anaesthetic characteristics were 125 mg L^?1 of MS‐222, and 30 mg L^?1 of AQUI‐S^® in rohu, Labeo rohita advanced size fry. Induction times were significantly decreased with increased in the concentrations of any of the two tested anaesthetic agents. The lowest doses suitable for transportation of rohu advanced size fry observed were: 10–15 mg L^?1 of MS‐222 and 2.5 mg L^?1 AQUI‐S^®. Both anaesthetics showed promising to be used as anaesthetics for handling and transportation in rohu (Labeo rohita) advanced fry.     

超高效液相色谱-串联质谱法测定鱼粉中喹噁啉类药物及其主要代谢物的残留量

文章建立了超高效液相色谱-串联质谱法同时检测鱼粉中5种喹噁啉类药物及其2种主要代谢物残留量的方法。样品经乙腈-乙酸乙酯(1∶1,V∶V)和1 mol·L^–1盐酸分步提取,盐酸提取液进一步用乙酸乙酯反萃取,有机相经浓缩后,均用乙腈复溶,用PRiME HLB通过性固相萃取柱净化处理。样品以乙腈和0.1%甲酸水溶液为流动相,经Phenomenex Kinetex C18柱梯度洗脱分离,质谱采取正离子多反应监测模式进行检测。代谢物采用内标法定量,原药采用基质匹配外标法定量。结果表明,7种化合物在对应的浓度范围内线性关系良好(R≥0.994),2种代谢产物检测限为2μg·kg–1,定量限为5μg·kg^–1;5种喹噁啉类药物检测限为1~10μg·kg^–1;定量限为2~20μg·kg^–1。在高、中、低3种添加浓度下7种化合物的平均回收率为64.4%~102.2%,相对标准偏差为3.2%~10.2%。方法灵敏度高、精密度好,能同时测定鱼粉中的喹噁啉类药物及其主要代谢物。     

水产品中氯霉素、甲砜霉素、氟苯尼考、氟苯尼考胺多残留的同时测定—GC/MS法

采用气相色谱-质谱法建立基质加标标准曲线,对中国对虾、大菱鲆、鲫鱼、鳗鱼、蟹、甲鱼6种主要养殖水产品肌肉组织中氯霉素类药物:氯霉素(CAP)、甲砜霉素(TAP)、氟苯尼考(FF)及其代谢物氟苯尼考胺(FFA)的多残留同时进行检测。结果显示,CAP在2–200 ng/ml浓度范围内,线性关系良好;TAP、FF和FFA在5–200 ng/ml浓度范围内,线性关系良好,其相关系数均大于0.990。加标回收率在76.4%–94.3%之间,相对标准偏差在5.7%–13.9%之间。检出限:CAP为0.2μg/kg,TAP、FF和FFA均为1.0μg/kg。定量限:CAP为0.5μg/kg,TAP、FF和FFA均为3.0μg/kg。研究表明,该方法具有准确、高效、灵敏、特异性强的特点,可以满足水产品中CAP、TAP、FF和FFA多残留的同时检测的要求。     

Lactococcus lactis,causative agent of an endocarditis valvularis and parietalis thromboticans in the allis shad,Alosa alosa (L.)

Since the 1940s, the anadromous allis shad, Alosa alosa (L.), has suffered population declines throughout its distribution range in Europe. In context of EU‐LIFE projects for the reintroduction of the allis shad in the Rhine system, a comprehensive study was started in 2012 to investigate infectious diseases occurring in allis shad. In course of the study, 217 mature and young‐of‐the‐year allis shad originating from the wild population from the Gironde–Garonne–Dordogne system (GGD‐system) and the Rhine system as well as 38 allis shad from the breeding population were examined by use of bacteriological and histological methods. In 2012 and 2014, an endocarditis valvularis thromboticans caused by a coccoid bacterium was detected in 16% and 25% of mature allis shad originating from the GGD‐system. Results of microbiologic examinations, including biochemical characteristics, matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry (MALDI‐TOF MS) and 16S rRNA gene sequence analysis, revealed Lactococcus lactis as causative agent of this infection. This is the first report of an endocarditis valvularis and parietalis thromboticans caused by Lactococcus lactis in fish. Possible sources of infection as well as the impact for the reintroduction programme are discussed.