Determination of oxolinic acid in feeds and cultured fish using capillary electrophoresis

A capillary electrophoretic method was developed for the determination of the antibiotic oxolinic acid. The electrolyte composed of a buffer solution (10 mM phosphate, pH 9.00) and methanol (9:1) was found to be the most suitable for this separation. The effect of type of buffer, its pH and concentration as well as injection times and applied voltage on the migration of oxolinic acid was also studied. Key analytical characteristics of the method are as follows: detection limit (signal-to-noise ratio 3), 0.08 μg ml⁻¹; linear range, 0.5–40 μg ml⁻¹; migration time, 5.3 min; relative standard deviation for within-day and day-to-day variation of 1.67 and 2.24%, respectively. The method, in conjunction with a solid phase extraction procedure, was successfully applied for the analysis of spiked oxolinic acid in fish feeds and fish muscles. The recoveries of oxolinic acid from spiked feeds and muscle tissues were 81.15 and 84.80%, respectively.     

Reservoir of quinolone residues in fish.

Different tissues from salmon treated with the quinolones oxolinic acid, flumequine, enrofloxacin and sarafloxacin were analysed in search of possible reservoirs of the drugs. Residues of oxolinic acid and flumequine seem to be especially bound to bone, enrofloxacin to skin, and sarafloxacin to both skin and bone. The results showed that residues of these drugs were present in the fish for prolonged periods after the end of treatment.     

Rapid determination of 19 quinolone residues in spiked fish and pig muscle by high-performance liquid chromatography (HPLC) tandem mass spectrometry

A multiresidue method has been developed for the confirmation and quantification of 19 quinolones (enrofloxacin, ciprofloxacin, norfloxacin, ofloxacin, flumequine, oxolinic acid, difloxacin, sarafloxacin, sparfloxacin, danofloxacin, fleroxacin, marbofloxacin, enoxacin, orbifloxacin, pefloxacin, nalidixic acid, pipemidic acid, lomefloxacin and cinoacin) in pig and fish by liquid chromatography-tandem mass spectrometry (LC-MS/MS). The samples were extracted with acetonitrile, analytes separated by LC on a C₁₈ column using 0.1% formic acid–methanol with a linear gradient elution programme, and detected by MS/MS. The linear range was 0.3–50 µg kg^–1 with correlation coefficients (r) more than 0.9956. The limits of detection were 0.1 µg kg^–1. Mean recoveries for each analyte in pig muscle and fish ranged from 75.3% to 96.3% and from 79.7% to 94.2% with relative standard deviations below 10%. The method is fast, safe, sensitive and precise, and can be used simultaneously to analyse residual quinolones.     

Analysis of veterinary drug residues in fish and shrimp composites collected during the Canadian Total Diet Study, 1993-2004

Thirty shrimp, marine fish, freshwater fish, and canned fish composite samples collected and prepared as part of the Canadian Total Diet Study were analysed for 39 different veterinary drug residues. The analyses were undertaken to obtain baseline data that could be used to estimate the dietary exposure of Canadians to these residues. The most frequently observed residue was AOZ (four out of 30 samples), the metabolite of furazolidone, at a range of 0.50 to 2.0 ng g^-1 wet weight. Other residues detected included enrofloxacin (three samples; 0.3-0.73 ng g^-1), leucomalachite green (three samples; 0.73-1.2 ng g^-1), oxolinic acid (two samples; 0.3-4.3 ng g^-1), AMOZ (the metabolite of furaltadone; one sample; 0.40 ng g^-1), chloramphenicol (one sample; 0.40 ng g^-1), and SEM (the metabolite of nitrofurazone; one sample; 0.8 ng g^-1). The results of this survey indicate that Canadians are exposed to low ng g^-1 concentrations of some banned and unapproved veterinary drug residues via the consumption of certain fish and shrimp.     

云南省淡水湖泊鱼虾中多氯联苯食用安全性评估

目的对云南省5个淡水湖泊中鱼虾体内的多氯联苯(polychorinated biphenyl,PCBs)污染水平进行调查研究。方法采用气相色谱-质谱联用仪进行检测分析,根据检测结果对云南省淡水湖泊中的鱼虾体内多氯联苯的含量进行食用安全性评估。结果云南省淡水湖泊中鱼虾体内的多氯联苯检出率为90%,多氯联苯的含量范围为ND～1.16μg/kg,平均含量为0.27μg/kg,低于国家标准限量。云南省淡水湖泊中鱼虾体内的多氯联苯按照世界卫生组织(World Health Organization,WHO)规定的多氯联苯毒性当量(toxic equivalent quantity,TEQ)分布于ND～6.51×10~(-5)μg/kg,平均值为1.21×10~(-5)μg/kg,低于欧盟的行动标准限量。结论云南省居民从云南省淡水湖泊鱼虾体内摄入持久性有机污染物多氯联苯的剂量较低,引起的健康风险较低。     

不同地区、品种及养殖模式罗非鱼营养差异分析

以我国南方主要养殖产区的罗非鱼为对象,选择奥尼和吉富两个优势品种,采集池塘养殖(单养)、鱼虾混养、鱼鱼混养(罗非鱼-大宗淡水鱼)三种养殖模式的罗非鱼,分别测定其基本营养成分、氨基酸、脂肪酸组成及含量并分析不同品种、养殖模式及不同产地之间的差异。结果表明:不同品种罗非鱼基本营养成分差异不大;两者脂肪酸组成和含量基本一致;但奥尼罗非鱼氨基酸总量(19.51 g/100 g)和必需氨基酸含量(7.96 g/100 g)均高于吉富罗非鱼,其多种氨基酸含量也高于吉富(p<0.05)。鱼鱼混养罗非鱼天冬氨酸、谷氨酸、甘氨酸等风味氨基酸以及部分必需氨基酸、非必需氨基酸含量均高于鱼虾混养罗非鱼(p<0.05),单养模式与另外两种养殖模式相比差异不显著。四个主要罗非鱼产区中,广东罗非鱼的氨基酸、脂肪酸含量更高;其鲜味氨基酸含量(7.65 g/100 g)显著高于广西和海南地区(p<0.05),氨基酸总量(19.36 g/100 g)也为四个地区中最高。广东罗非鱼的油酸(1.44 mg/g)、亚油酸(1.02 mg/g)以及DHA含量(0.91 mg/g)均高于广西和福建地区(p<0.05),其不饱和脂肪酸含量也在四个地区中最高。综上分析,奥尼罗非鱼营养品质高于吉富罗非鱼;鱼鱼混养罗非鱼品质高于鱼虾混养;广东吉富罗非鱼品质高于其他三个地区。     

Validation of an optical surface plasmon resonance biosensor assay for screening (fluoro)quinolones in egg, fish and poultry

A surface plasmon resonance biosensor immunoassay has been developed for multi-residue determination of 13 (fluoro)quinolone antibiotics in poultry meat, eggs and fish. The following performance characteristics were determined according to the guidelines laid down for screening assay validation in European Decision 2002/657/EC: detection capability, specificity/selectivity, decision limit, repeatability, ruggedness and stability. The detection capability estimated for norfloxacin, the reference fluoroquinolone, was below 0.5, 1 and 1.5 ng g?1 for poultry meat, egg and fish, respectively. The screening assay proved specific and showed satisfactory sensitivity below the MRL levels even though flumequine and oxolinic acid had lower cross-reactivities. A wide range of non-MRL substances were also detected at concentrations below 10 ng g?1. Repeatability was good with both intra- and inter-assay coefficients of variation 56%; ruggedness was also demonstrated.     

Polyunsaturated fatty acid contents of some traditional fish and shrimp paste condiments of the Philippines

The fatty acid composition as well as the water, NaCl, ash and fat contents of six types of shrimp and fish paste condiments of the Philippines were determined. The condiments were prepared by incubating the fish or shrimp in high concentrations of salt and under high humidity at ambient temperature over several months. The primary objective was to assess the contents of polyunsaturated fatty acids, and in particular the content of all-cis-4,7,10,13,16,19-docosahexaenoic acid (DHA) in these products. The product derived from small shrimp fry (Acetes spp.) had the highest content of DHA. The contents of polyunsaturated fatty acids, including DHA, of this particular condiment, were not significantly different from that of fresh untreated shrimp fry, indicating the presence of mechanisms that protect against polyunsaturated fatty acid autoxidation during the preparation process. Also, the DHA contents of the condiment derived from juvenile Siganus approached that of the Acetes condiment because of its relatively high fat content. In conclusion, two of the fish and shrimp paste condiments tested may be sources of dietary DHA for those who consume this type of food.     

Simple and rapid microbiological method for determination of residual antibacterials in meat

A simple and rapid screening method using bioassay for the simultaneous analysis of antibacterials (penicillins, cephalosporins, macrolides, tetracyclines, quinolones, etc.) in meat has been developed. A 5 g sample was homogenized with 5 mL of methanol, and the homogenate was centrifuged for 10 min with 3,000 rpm. The pulp disk method with Bacillus subtilis BGA (Antibiotic Medium 5 (pH 8) and 8 (pH 6)), Micrococcus luteus ATCC 9341 and Geobacillus stearothermophilus as test organisms was employed for the assay of the antibacterials. Typical antibacterials (penicillin G, ampicillin, cefapirin, cefalexin, erythromycin, spiramycin, oxytetracycline, chlortetracycline, streptomycin, dihydrostreptomycin, enrofloxacin and oxolinic acid) were detected at levels of ca. 0.005-2.5 microg/g in meat. Therefore, we recommend this proposed screening method for routine analysis of residual antibacterials in livestock products.     

Rapid screening method for quinolone residues in livestock and fishery products using immobilised metal chelate affinity chromatographic clean-up and liquid chromatography-fluorescence detection

An efficient LC method was developed for screening the presence of quinolones (QLs)--comprising fluoroquinolones (FQs) and acidic quinolones (AQs)--residues in various livestock and fishery products. Targeted analytes were for nine FQs of marbofloxacin (MAR), ofloxacin (OFL), norfloxacin (NOR), ciprofloxacin (CIP), enrofloxacin (ENR), danofloxacin (DAN), orbifloxacin (ORB), difloxacin (DIF) and sarafloxacin (SAR), and three AQs of oxolinic acid (OXA), nalidixic acid (NAL) and flumequine (FMQ). Samples comprised ten different food products covering five matrices: muscle (cattle, swine and chicken), liver (chicken), raw fish (shrimp and salmon), egg (chicken), and processed food (ham, sausage and fish sausage). This method involved a simple extraction with (1:1) acetonitrile-methanol, a highly selective clean-up with an immobilised metal chelate affinity column charged with Fe(3+), a fast isocratic LC analysis using a short column (20 mm × 4.6 mm, 3 μm) with a mobile phase of (15:85:0.1) methanol/water/formic acid, and fluorescence detection (excitation/emission wavelengths of 295 nm/455 nm for FQs (495 nm for MAR), and 320 nm/365 nm for AQs). Among FQs, pairs of NOR/OFL, ORB/DIF and ENR/DAN were incompletely resolved. A confirmatory LC run with a Mg(2+) containing methanolic mobile phase was also proposed for the samples suspected of being positive. The optimised method gave satisfactory recoveries of 88.5% (56.1-108.6%) and 78.7% (44.1-99.5%) for intra- and inter-day assays with relative standard deviations of 7.2% (0.7-18.4%) and 6.8% (1.4-16.6%), respectively. Limits of quantitation ranged from 0.8 μg kg(-1) (DAN) to 6.5 μg kg(-1) (SAR). This method was successfully employed to analyse 113 real samples and two positive samples were found: fish sausage (CIP 990 μg kg(-1)) and shrimp (ENR 20 μg kg(-1)).     

Total lipid,fatty acid composition and lipid oxidation of Indian white shrimp (Fenneropenaeus indicus) fed diets containing different lipid sources

BACKGROUND: Seafood is an important constituent of the human diet. In Iran, Indian white shrimp (Fenneropenaeus indicus) is the major cultured shrimp species as a result of market demand, local availability and growth rate. It is mainly reared using commercial feed. The purpose of this study was to evaluate the effects of replacing 50% of the fish oil by vegetable oils in shrimp feed on total lipid, fatty acid composition and lipid oxidation of shrimp muscle. RESULTS: No significant differences in total lipid content (6.1–7.3 g kg^?1) were found between edible tissues of shrimp fed different diets. The major fatty acids in shrimp muscle were palmitic, oleic, lionoleic, stearic, eicosapentaenoic (EPA) and docosahexaenoic (DHA) acids. Higher levels of EPA and DHA were observed in muscle of shrimp fed a diet containing fish oil. Oxidative rancidity, measured as thiobarbituric acid reactive substances, for all shrimps did not exceed 0.2 mg malonaldehyde kg^?1 muscle tissue, which was low and acceptable. CONCLUSION: This study had shown that the fatty acid composition of feed directly affects the fatty acid composition of Indian white shrimp muscle. Farmed Indian white shrimp can be considered as a species of low fat and shrimp muscle was quite stable to oxidation during storage. Copyright © 2009 Society of Chemical Industry     

同时检测淡水鱼加工中土霉素和微囊藻毒素(MC-LR)残留量

目的:土霉素是限制我国淡水鱼深加工产品出口的关键抗生素之一;此外,由于水污染加重,淡水鱼中藻毒素残留问题也很严重。研究和开发同时快速检测技术已成为当前急需解决的问题。方法:鲫鱼鱼肉进行不同前处理,利用高效液相色谱测定毒素残留量。结果:土霉素和微囊藻毒素的最低检测限分别为0.1μg/kg、5ng/L。质量浓度范围0.1⁵.0μg/mL的土霉素、微囊藻毒素标准品制备标准曲线,线性关系较好,相关系数分别为0.995、0.998。精密度分别为1.82%、1.68%;回收率范围分别88.1%5.0μg/mL的土霉素、微囊藻毒素标准品制备标准曲线,线性关系较好,相关系数分别为0.995、0.998。精密度分别为1.82%、1.68%;回收率范围分别88.1%¹02.8%、90.6%102.8%、90.6%¹05%。结论:对比酶联免疫反应试剂盒的检测,2种方法结果没有太大差别。     

Composition of shrimp by-catch fish from the Gulf of California and effects on the qualities of the dried salt fish cake product

The gross chemical and physical characteristics of a range of common fish species found in shrimp by-catch from the Gulf of California have been studied. These fish represented about 90% by weight of all fish species found in the by-catch. The crude protein, fat, moisture and ash contents were all found to be within the normal ranges for demersal teleosts, though fat contents of several were as high as 6%. The heterogenous nature of the by-catch fish species was also apparent from a wide range in lengths and weights, and variation in the colours and textures of their flesh. These factors may necessitate pre-selection of fish types destined for specific food products. Dried salt fish cakes were prepared from two of these fish species that had been manually and acid eviscerated. Cakes from acid eviscerated fish minces to which 10–15% crude salt had been added dried well and were found to be as acceptable in taste panel trials as those from manually eviscerated fish minces prepared in the traditional way with higher additions of crude salt.     

Oxytetracycline residues in rainbow trout analysed by a rapid HPLC method

A rapid and sensitive HPLC method was developed for the determination of oxytetracycline in fish tissues (muscle and liver) based on a clean-up and concentration procedure on Sep-Pak C18. At a coastal fishfarm rainbow trout (Salmo gairdneri) suffering from Vibrio anguillarum were treated with 75 mg oxytetracycline per kg fish and day for ten days. Oxytetracycline residues above the limit of determination (0.005 micrograms/g) were found in fish 82 days after treatment. The recoveries from spiked tissues were about 60% and 70% for muscle and liver, respectively.     

Rapid screening method for quinolone residues in livestock and fishery products using immobilised metal chelate affinity chromatographic clean-up and liquid chromatography-fluorescence detection

An efficient LC method was developed for screening the presence of quinolones (QLs) – comprising fluoroquinolones (FQs) and acidic quinolones (AQs) – residues in various livestock and fishery products. Targeted analytes were for nine FQs of marbofloxacin (MAR), ofloxacin (OFL), norfloxacin (NOR), ciprofloxacin (CIP), enrofloxacin (ENR), danofloxacin (DAN), orbifloxacin (ORB), difloxacin (DIF) and sarafloxacin (SAR), and three AQs of oxolinic acid (OXA), nalidixic acid (NAL) and flumequine (FMQ). Samples comprised ten different food products covering five matrices: muscle (cattle, swine and chicken), liver (chicken), raw fish (shrimp and salmon), egg (chicken), and processed food (ham, sausage and fish sausage). This method involved a simple extraction with (1:1) acetonitrile–methanol, a highly selective clean-up with an immobilised metal chelate affinity column charged with Fe³⁺, a fast isocratic LC analysis using a short column (20?mm?×?4.6?mm, 3?µm) with a mobile phase of (15:85:0.1) methanol/water/formic acid, and fluorescence detection (excitation/emission wavelengths of 295?nm/455?nm for FQs (495?nm for MAR), and 320?nm/365?nm for AQs). Among FQs, pairs of NOR/OFL, ORB/DIF and ENR/DAN were incompletely resolved. A confirmatory LC run with a Mg²⁺ containing methanolic mobile phase was also proposed for the samples suspected of being positive. The optimised method gave satisfactory recoveries of 88.5% (56.1–108.6%) and 78.7% (44.1–99.5%) for intra- and inter-day assays with relative standard deviations of 7.2% (0.7–18.4%) and 6.8% (1.4–16.6%), respectively. Limits of quantitation ranged from 0.8?µg?kg^?1 (DAN) to 6.5?µg?kg^?1 (SAR). This method was successfully employed to analyse 113 real samples and two positive samples were found: fish sausage (CIP 990?µg?kg^?1) and shrimp (ENR 20?µg?kg^?1).     

Oxytetracycline Residues in Cultured White Shrimp Tissue by HPLC and a Microbial Receptor Assay

The residue depletion of oxytetracycline (OTC) from muscle tissue of cultured shrimp (Penaeus vannamei) was evaluated. OTC was measured using high performance liquid chromatography (HPLC) and a microbial receptor assay. Samples were taken on days 7, 14 and 21 during the treatment and 23, 25 and 28 after the treatment. OTC was detectable in all groups after 7 days depletion time at concentrations of 0.28, 0.19 and 0.05 μg/g for diets containing 500, 250 and 100 mg/kg OTC, respectively. Results by the microbial receptor assay were in good agreement with those by HPLC.     

Substitution of fish silage protein and a free amino acid mixture for fish meal protein in a chicken diet

White Leghorn chickens were fed a basal diet with about 550 g kg^?1 of the protein from fish meal. Graded amounts of fish silage protein or an amino acid mixture simulating fish meal protein were substituted for parts of the dietary fish meal protein. In two experiments 150 and 300 g kg^?1 of fish meal protein were replaced by fish silage protein or by an amino acid mixture simulating fish meal. In one experiment graded amounts of 0, 50, 100, 200, 300 and 400 g kg^?1 of fish meal protein were replaced by fish silage protein. Growth and feed efficiency were the same or better when some of the protein was from fish silage. The results showed that replacement of dietary fish meal with fish silage did not reduce the dietary quality of the feed for young growing chickens. It is concluded that it might be advantageous to substitute fish silage for some of the fish meal under the experimental conditions used.     

Nutritive value of diets containing fish silage for juvenile Litopenaeus vannamei (Bonne, 1931)

BACKGROUND: Fish wastes has been used for many years as an alternative in feeds for aquaculture. In the present study weight gain of juvenile white shrimp Litopenaeus vannamei fed diets including fish waste silage (WS), fish waste silage with soybean meal SBM (WS + S) or fish waste meal (WM) was compared. A conventional acidic silage process was applied to obtain from wastes (skin, heads, bones and viscera) of snapper (Lutjanus spp.), grunt (Haemulon plumieri), and grouper (Epinephelus spp.) an ingredient rich in protein. RESULTS: After 3 days ensilage more than 90% protein was hydrolysed. Waste material processed at pH 3.8 lost about 24% tryptophan. Butylated hydroxytoluene (BHT) prevented lipid oxidation, as shown after 45 days with malonaldehyde production. Shrimp fed WS + S diet gained 0.7 g per week higher than those fed WS and WM diets with 0.3 g per week (P < 0.05). CONCLUSION: WS processed with formic acid under conditions of low pH is beneficial for the white shrimp L. vannamei. It sustained reasonable weight gain combined with soybean meal in practical diets. On the other hand, BHT addition was beneficial in preventing oxidative action during silage preparation. Copyright © 2012 Society of Chemical Industry     

Survival of amine-forming bacteria during the ice storage of fish and shrimp

Survival of amine-forming bacteria during the ice storage of fish and shrimp was investigated up to 14 days of storage. On iced storage the total bacterial load was reduced to one log from an initial load of 10⁵ cfu g⁻¹ in fresh fish/shrimp due to cold shock. The total incidence of biogenic amine-forming bacteria was found to be 74·63% in fish and the same was recorded as 56·05% in shrimp. The amine-forming bacteria recorded were cadaverine- and putrescine-forming bacteria in fish/shrimp, and no histamine former was detected. Gram-negative, non-fermentative rods, viz. Alcaligenes. Flavobacterium, Acinetobacter. Shewanella andPseudomonas , were the predominant amine-forming bacteria during the ice storage of fish and shrimp, in addition to the only Gram-positive genus Micrococcus. The genera Aeromonas and Photobacterium also survived ice storage to a certain extent and may also be responsible for the formation of amines in fish and shrimp.     

Survey of residual antibiotic agents in cultured fish and shellfish]

A survey of residual antibiotic agents in cultured fish and shellfish purchased from the Tokyo Central Market was carried out. Out of 240 samples tested, OTC was detected in 14 samples which consisted of flatfish, yellowtail, seriola and eel. Synthetic antibiotic agents were not detected. The highest level of OTC was 0.36 microgram/g in skin of flatfish. In the case of flatfish, the concentration of OTC was highest in skin, followed by liver, then muscle. OTC was detected in livers of all yellowtail, seriola and eel, and the concentration was higher than that in muscle or skin.