Multiresidue determination of antibiotics in aquaculture fish samples by HPLC–MS/MS

An analytical method based on HPLC with MS/MS detection was developed and optimized in order to determine the most useful antibiotics (sulphonamides and tetracyclines) used in aquaculture. A simple extraction procedure, without any clean‐up step, was evaluated in order to obtain maximum analyte recovery from fish samples (Sparus aurata). A mixture of methanol:water 70:30 (v/v)+1 mL EDTA 0.1 M was selected as optimum extractant solution. Because no matrix effects were observed, a standard calibration curve prepared in mobile phase was used for quantification purposes. Antibiotic‐free fish samples were spiked at different concentration levels and analysed by the optimized HPLC method. The average recoveries (n=6) obtained were satisfactory, ranging from 88% to 110% at 100 μg kg^?1. The proposed methodology provided limits of detection for the tested antibiotics in the 1.2–16 μg kg^?1 range, lower than 100 μg kg^?1, the maximum residue level established by the European Union. Finally, commercial fish samples from different origins were analysed in order to confirm the usefulness of the developed methodology.     

Short‐term food deprivation before a fish oil finishing strategy improves the deposition of n‐3 LC‐PUFA,but not the washing‐out of C18 PUFA in rainbow trout

This study aimed to test the hypothesis that the efficiency of a finishing period can be improved by reducing the initial fat content of fish fillets, by means of a period of food deprivation. Two groups of rainbow trout (Oncorhynchus mykiss) were fed for an 18‐week grow‐out period on a vegetable oil‐based diet (VO) or a fish oil‐based diet (FO). VO fed fish were then split into two sub groups: one (VO/FO) was shifted to the FO diet for 8 weeks, whilst the other (UF/FO) was deprived of food (unfed) for 2 weeks and then fed the FO diet for the remaining 6 weeks. The control treatment (FO/FO) was represented by fish continuously fed FO. The subsequent reduction of total fat in the UF/FO treatment was then responsible for a much faster recovery towards a FO‐like fatty acid profile, validating the proposed hypothesis. However, the modification of the fatty acid composition of fish fillets during the feed withholding period, coupled with the postponement of the finishing diet, resulted in only minor beneficial effects of this strategy, and the loss of potential weight gain. However, the n‐3 LC‐PUFA content in UF/VO fish fillets was significantly higher than fish subjected to the VO/FO treatment.     

Bacterial degradation of antibiotic residues in marine fish farm sediments of Uranouchi Bay and phylogenetic analysis of antibiotic-degrading bacteria using 16S rDNA sequences

ABSTRACT:   Antibiotic residues in marine sediments of fish farms negatively influence microbial ecologic systems. The microbial degradation of antibiotic residues was experimentally examined in the marine sediments of Uranouchi Bay, to which one of five antibiotics was added. After incubation reducing physical factors, ampicillin, doxycycline, oxytetracycline, and thiamphenicol were significantly degraded, while josamycin maintained most of the initial amounts. The isolates resistant to ampicillin, josamycin, oxytetracycline, or thiamphenicol degraded each antibiotic in wide ranges of degrees, whereas the isolates degrading doxycycline were not obtained. Microbial degradation may contribute to the disappearance of ampicillin, doxycycline, oxytetracycline, and thiamphenicol in the fish farm. In contrast, the disappearance of josamycin would depend on physical factors, but the bacteria degrading josamycin at least exist in the marine sediments. Phylogenetic analysis using 16S rDNA sequences demonstrated that the antibiotic-resistant isolates formed several clusters in the Gram-positive bacterial group, the Flavobacterium–Cytophaga–Bacteroides group, and the proteobacteria subdivisions. The antibiotic-resistant bacterial population would be composed of various species including ubiquitous coastal bacterial groups. Several species of antibiotic resistant bacteria show antibiotic degradation activities, and appear to contribute to the disappearance of antibiotics in Uranouchi Bay.     

Current research on the use of plant‐derived products in farmed fish

Over the years, aquaculture has shown increasing development in terms of production. However, due to intensive farming practices, infectious diseases represent the main problem in fish farms, causing heavy economic losses. The use of antibiotics for controlling diseases is widely criticized for its negative impact, including selection of antibiotic‐resistant bacterial strains, immunosuppression, environmental pollution and accumulation of chemical residues in fish tissues. On the other hand, though vaccination is the most effective prophylactic method of preventing disease outbreaks, the development of effective formulations is often hindered by high production costs and the antigenic heterogeneity of the microbial strains. Recently, there has been increased interest in the possibility of using medicinal herbs as immunostimulants, capable of enhancing immune responses and disease resistance of cultured fish. Plant‐derived products seem to represent a promising source of bioactive molecules, being at the same time readily available, inexpensive and biocompatible. The aim of this article is to provide an overview of recent research dealing with the use of medicinal plants in aquaculture. Special attention is given to the information about the effects of plant extracts/products on fish growth, haematological profiles, immune responses and resistance to infectious diseases.     

超高效液相色谱-电喷雾串联质谱法同时测定鱼类加工品中12种杂环胺类化合物

建立了超高效液相色谱-电喷雾串联质谱法同时测定鱼类加工品中12种杂环胺类化合物（HAAs）的分析方法。经过条件优化,肉样选用乙酸乙酯、氨水和三乙胺提取,提取液经MCX固相萃取小柱净化,按V（甲醇）∶V（氨水）=9∶1洗脱,采用Thermo Hypersil Gold C18色谱柱,以甲醇和5 mmol.L-1乙酸铵溶液为流动相进行梯度洗脱分离,电喷雾离子源（ESI）,正离子模式,采用选择反应监测（SRM）扫描模式,内标法进行定量分析。结果表明,12种HAAs在1.0～100.0μg.L-1范围内线性关系良好,相关系数R〉0.99,在12 min内实现分离,3个加标水平的平均回收率为42.98%～125.00%（n=6）,相对标准偏差（RSD）为1.49%～9.88%,检测限（LOD）为0.3～1.0μg.kg-1。该方法简便快捷,准确度高,易推广应用,可作为快速测定鱼类加工品中多种HAAs的有效方法。     

Selectivity matters: Rules of thumb for management of plate‐sized,sex‐changing fish in the live reef food fish trade

Effective management of fisheries depends on the selectivity of different fishing methods, control of fishing effort and the life history and mating system of the target species. For sex‐changing species, it is unclear how the truncation of age‐structure or selection of specific size or age classes (by fishing for specific markets) affects population dynamics. We specifically address the consequences of plate‐sized selectivity, whereby submature, “plate‐sized” fish are preferred in the live reef food fish trade. We use an age‐structured model to investigate the decline and recovery of populations fished with three different selectivity scenarios (asymptotic, dome‐shaped and plate‐sized) applied to two sexual systems (female‐first hermaphroditism and gonochorism). We parameterized our model with life‐history data from Brown‐marbled grouper (Epinephelus fuscoguttatus) and Napoleon fish (Cheilinus undulatus). “Plate‐sized” selectivity had the greatest negative effect on population trajectories, assuming accumulated fishing effort across ages was equal, while the relative effect of fishing on biomass was greatest with low natural mortality. Fishing such sex‐changing species before maturation decreased egg production (and the spawning potential ratio) in two ways: average individual size decreased and, assuming plasticity, females became males at a smaller size. Somatic growth rate affected biomass if selectivity was based on size at age because in slow growers, a smaller proportion of total biomass was vulnerable to fishing. We recommend fisheries avoid taking individuals near their maturation age, regardless of mating system, unless catch is tightly controlled. We also discuss the implications of fishing post‐settlement individuals on population dynamics and offer practical management recommendations.     

浅析我国观赏鱼产业发展及鱼种变化(上)

目前我国水产业以养殖为主,捕捞为辅。在2022年的水产品产量中,淡水养殖占47.91%,海水养殖占33.15%,捕捞占18.94%。在水产养殖中,鱼类养殖产量占52.16%,呈现出举足轻重的地位。“良种良养良销”是水产业中三个重要的组成部分,“良种”是水产业的龙头,“良养”是水产业的保障,加工、销售等“良销”环节是拉动水产业发展的重要动力。20世纪50年代以来,我国水产业取得了长足发展,为广大人民提供了丰富的水产品,解决了“吃鱼难”的问题。然而,目前我国水产业中有种无业、有业无种等现象还比较严重,没有从根本上解决“吃好鱼”及“吃放心鱼”的问题,为了加快我国水产业的发展,作者认为很有必要建立和实施“良种良养良销”体系,以推动我国水产业高质量发展。

     

Proteome profile comparison of two differently fed groups of Atlantic cod (Gadus morhua) larvae

Proteome analysis was used to study the effects of feeding early Atlantic cod (Gadus morhua) larvae with a saithe (Pollachius virens) protein hydrolysate (SPH). Protein hydrolysates have previously been shown to beneficially affect fish larval development. Feeding was initiated on day 2 post hatch (ph) or as soon as the larvae opened their mouth and the protein expression was monitored 4 days later or in 6‐dph cod larvae. The results demonstrated changes in the abundance of 13 protein spots in the cod larvae fed SPH. Of these, seven protein spots were up‐regulated and six protein spots showed down‐regulation. Five of the up‐regulated proteins in cod larvae are known to be involved in energy metabolism. A few early larval specific proteins were down‐regulated in the SPH‐fed cod larvae possibly because of an enhanced development in this group relative to the control group. Two trypsin isoforms were detected within the cod larval proteome. The detection of the trypsin spots was made possible by co‐electrophoresis of known cod trypsins with the cod larval protein extract. Surprisingly, no difference in trypsin content was observed between the SPH‐fed and the control larval groups.     

孔雀石绿在凡纳滨对虾体内的残留与消除规律

研究了不同养殖环境下孔雀石绿在凡纳滨对虾（Litopenaeu svannamei）体内的残留和消除规律。试验对虾刚0．20mg·L^-1。的孔雀石绿溶液药浴2h后转移至室内或室外水泥池中用盐度为28的海水养殖,采用高效液相色谱一串联质谱法（LC／MS／MS）测定对虾头部和肌肉中的有色孔雀石绿（MG）及其代谢产物无色孔雀石绿（LMG）的残留量。结果表明,药浴2h时对虾体内孔雀石绿的残留量达到峰值,转入清水养殖168h,2种环境养殖对虾体内的孔雀石绿残留量均降低至检测限以下,孔雀石绿在对虾体内的消除速率是室外环境养殖的快于室内环境养殖,对虾头部快于肌肉组织,且MG的消除快于LMG。     

The importance of live‐feed traps – farming marine fish species

This article analyses the challenges of different live‐feed regimes for the rearing of marine finfish larvae and discusses the potential alternative live feeds to avert a future live‐feed trap. Live feeds are indispensable for the successful rearing of larvae of most marine fish species. Brine shrimps (Artemia) and rotifers comprise the live feeds of choice in marine aquaculture today. However, their nutritional composition is deficient in especially essential fatty acids, and enrichment with fish oil is needed. Fish oil is considered a limited resource owing to its origin in fully exploited wild fish stocks. Moreover, fluctuations of the natural population of Artemia will, most likely, influence future availability and prices. This emphasizes the need for optimal exploitation of available live‐feed resources and development of new sustainable alternatives, such as copepods. An array of solutions to these problems are presented to avoid a future live‐feed trap and to reduce dependence on limited resources that influence future production possibilities, species diversification, price volatility and productivity in the aquaculture sector.     

A weight‐of‐evidence approach to determine estuarine fish health using indicators from multiple levels of biological organization

相似文献   

水产品中7种大环内酯类抗生素残留量的HPLC-MS/MS测定法

建立了水产品中7种大环内酯类抗生素[竹桃霉素（OLD）、红霉素（ERM）、吉他霉素（KIT）、交沙霉素（JOS）、螺旋霉素（SPI）、替米考星（TIL）和泰乐菌素（TYL）]残留检测的HPLC-MS/MS法。样品经乙腈提取,中性氧化铝和正己烷净化后,以选择反应检测模式检测,基质匹配标准工作曲线定量。在1～100 ng·mL-1范围内,7种药物的峰面积与质量浓度的线性关系良好（R2〉0.995）。试验选择不同阴性样品为试样,在4μg·kg-1、20μg·kg-1和40μg·kg-1添加水平下的回收率为75.4%～108%,相对标准偏差为0.665%～12.9%。方法的检出限为1μg·kg-1,定量限为4μg·kg-1。该方法简单,灵敏度高,重现性好,可为水产品中7种大环内酯类抗生素残留的检测提供技术支持。     

Legislation and the capacity for rapid‐response management of nonindigenous species of fish in contiguous waters of Canada and the USA

• 1. The provision of Canadian and US hard, enforceable, law to authorize rapid response management of nonindigenous aquatic species originating from aquaculture, live fish sales, bait fish, and the pet trade was analysed at the provincial/state levels of government for the Atlantic, Laurentian Great Lakes, and Pacific regions of North America.
• 2. No federal legal capacity for rapid response management exists in either country. US state legislation is generally better developed than Canadian provincial laws to manage the exotic fish trade. However, much discrepancy exists among provincial and state law regarding provisions to restrict or prohibit potentially harmful species. Aquaculture and baitfish use is generally better regulated than live fish markets and the pet fish trade in both countries. Only the state of Maine has laws authorizing rapid‐response management to control escaped exotic fish.
• 3. Most species of nonindigenous fish arise from the aquarium, pet, and baitfish trades, and development of improved legislation containing provisions for rapid response management of escapees is warranted in all states and provinces.
• 4. It is recommended that Canada amends the Fisheries Act to create the appropriate enabling legislation to monitor, assess risk, and deploy rapid response management of nonindigenous aquatic species, including fish that enter federal fresh and sea waters. Two recently‐introduced US Bills, S. 725 and H.R. 1350, with their explicit measures for early detection and fast action response, could, if passed into law, create provisions to control introduced nuisance species throughout North American waters. They would also create precedents for states and provinces that have most jurisdiction over aquaculture and trade in exotic fish to amend and align their laws in a complementary manner.

Copyright © 2008 John Wiley & Sons, Ltd.     

渔用配合饲料中左旋肉碱含量的测定

建立了亲水作用色谱-串联质谱法(HILIC-MS/MS)检测渔用配合饲料中左旋肉碱含量的方法。样品用超纯水超声提取,提取液稀释后经HILIC色谱柱分离,以乙腈和乙酸铵(含0.15%甲酸)溶液为流动相梯度洗脱,三重四级杆串联质谱多反应监测(MRM)方式扫描,外标法定量。结果表明,左旋肉碱在0.2~100 ng/mL范围线性良好(r>0.999);检出限0.5μg/kg,定量限1.5μg/kg。在20、50和100 mg/kg添加水平下,回收率为75.2%~111%,相对标准偏差RSD为3.4%~9.9%(n=6)。该方法前处理简单、快速,定性定量准确,适合于渔用配合饲料中左旋肉碱的准确定性定量。     

Effects of water flow velocity and fish culture on net biofouling in fish cages

The effects of water flow, fish feed and cage position on net biofouling was examined in a floating cage fish farm. Fouling of 16 mm mesh net panels suspended inside and outside net cages and exposed to different treatments were monitored weekly until net apertures were completely occluded by the fouling organisms (8 weeks). Results indicate a dramatic reduction in water flow velocity throughout the fish farm due to the cage units themselves and net biofouling. The reduced water flow (<10 cm s^?1) inside net cages promoted rapid net biofouling, while rapid water flow outside the net cages (>25 cm s^?1) kept the net fouling organisms at bay. Although fish rearing in net cages with inputs of commercial pellet feed increased sessile biofouling (222% higher than outside the net cages) and non‐sessile biofouling (570% higher), the type of fish feed used did not significantly affect biofouling development. The study recommends that the geometry of serially arranged net cages, as commonly deployed in tropical tidal estuaries, be reconfigured to improve flow through in order to minimize the impact of fouling.     

The effect of C/N ratio on bacterial community and water quality in a mussel‐fish integrated system

A 30‐day experiment was conducted to evaluate the effect of C/N ratio on water quality and bacterial community in an integrated system comprising one molluscan species (pearl mussel Hyriopsis cumingii) and two fish species (gibel carp Carassius gibelio and silver carp Hypophthalmichthys molitrix) at five C/N ratios (6, 8, 10, 12 and 14). The mussel and fishes were reared in the experimental tanks (400 L), but gibel carp received formulated feed. Water quality in the experimental tanks was analysed on day 0, 10, 20 and 30, and bacterial community in the water column and sediment was analysed on day 30. Total nitrogen, total phosphorus and total organic carbon accumulated in the tanks over time. Ammonia and nitrite decreased with the increase in C/N ratio. Bacterial community in the water column and sediment changed at the phylum and genus levels with the increase in C/N ratio, and the critical C/N ratio causing a functional shift of bacterial community occurred at 10 in water column and 12 in sediment. The increase in C/N ratio benefited the growth of both potential probiotics and pathogenic bacteria. The high C/N ratio enhanced the bacterial functions of chemoheterotrophy and hydrocarbon degradation, but depressed the functions of nitrification and denitrification in the water column and sediment respectively. This study reveals that the C/N ratio can be used as a tool to manipulate the bacterial community and water quality in the mussel‐fish integrated system.     

Catch‐related fish injury and catch efficiency of stow‐net‐based fish recovery installations for fish‐monitoring at hydropower plants

Hydropower‐related damage to fish remains a great challenge, making objective monitoring of turbine‐related fish injury a necessity. The catch of fish at turbine outlets is currently realised by net fishing, but potential catch‐related injuries are largely unknown. Catch efficiency and fish‐friendliness in relation to fish handling, exposure time, floating debris and fish biomass of four fish recovery installations were assessed using seven species. Highly species‐specific lethal and sublethal effects were observed. Exposure time had the strongest effects on catch‐related damage, being up to 150‐fold increase after 12 hr compared to 1 hr. Up to 84% mortality occurred in the most sensitive species Thymallus thymallus L. Besides exposure time, higher current speed and biomass within the net resulted in greater fish damage. To minimise catch‐related effects, keeping emptying periods <1–2 hr and considering the effects of current speed, fish and debris biomass are crucial to increase data comparability among studies.