恩诺沙星注射液在猪体内残留消除规律研究

目的研究恩诺沙星注射液在猪体内的残留消除规律。方法本实验采用30头约50 kg重长白猪,随机分为2组,给药组25头,对照组5头。给药组用药量为每次2.5mg恩诺沙星/kg,每日1次,连用3d(1个疗程),使用1个疗程,对照组不给任何抗菌药物,与给药组同环境饲养。在最后一次给药6 h、24 h(1 d)、72 h(3 d)、120 h(5 d)、168 h(7 d)时采集肉、肝、肾、脂肪样本,经液相色谱-串联质谱法(liquid chromatography-tandem mass spectrometry, LC-MS/MS)测定组织中的恩诺沙星及其代谢物环丙沙星残留量之和,并利用WT1.4软件计算休药期。结果恩诺沙星注射液在猪肉中的休药期为3.17 d;在肾脏中的休药期为3.75 d;在肝脏中的休药期为8.18 d;在脂肪总的休药期为4.09 d。结论为保证兽药使用安全、食品安全和消费者健康,推荐恩诺沙星注射液在猪体内的休药期为9 d。     

In vivo studies to highlight possible illegal treatments of rabbits with carbadox and olaquindox

For the treatment of rabbit dysentery and bacterial enteritis, veterinary practitioners often adopt veterinary medicinal products authorised for other food-producing species, but in some cases non-authorised drugs frequently used in the past, such as carbadox and olaquindox, might be illegally adopted. To verify the carbadox and olaquindox distribution and persistence in rabbit tissues, two independent in vivo studies were carried out. In the first study, 24 healthy rabbits received water medicated with carbadox at 100 mg l^?1 over a period 28 days, whereas in the second one, 24 healthy rabbits were administered water containing olaquindox at 100 mg l^?1. In each study rabbits were randomly assigned to four groups to be sacrificed respectively at 0, 5, 10 and 20 days from treatment withdrawal, for depletion studies. A control group of six animals was adopted for control and as a reservoir of blank tissues. Muscle and liver samples collected from each treated animal were stored at ?20°C pending the analysis. Sensitive and robust liquid chromatography-tandem mass spectrometry analytical methods were set up for the parent compounds and their main metabolites quinoxaline-2-carboxylic acid, desoxycarbadox and 3-methylquinoxaline-2-carboxylic acid to verify their residual. Data collected demonstrate that the combination of liver as target matrix, quinoxaline-2-carboxylic acid and 3-methylquinoxaline-2-carboxylic acid as marker residue and enzymatic digestion is strategic to evidence carbadox and/or olaquindox illegal treatments in rabbits, even 20 days after treatment withdrawal at concentration levels higher than 0.5 µg kg^?1. This findings suggests that liver should be proposed as target matrix for official control in national monitoring plan.     

Concentrations of heavy metals in the tissues of red deer (Cervus elaphus) from the region of Warmia and Mazury, Poland.

Cadmium, lead, copper and zinc were quantified using a validated ICP/MS method in the tissues and organs of 82 specimens of red deer of different sexes and ages, which had been hunted at the Great Lakes Land region in the north-eastern of Poland in 2000-01. Copper and zinc occurred in liver, kidney and muscle tissue of red deer at concentrations of 6.4-29, 3.3-7.2 and 1.9-6.4, and of 19-43, 17-41 and 19-64 mg kg(-1), respectively, which are considered typical for the species, age and gender compared with values noted for some other wild and domestic ruminant species elsewhere. For cadmium and lead, the concentrations decreased in the order kidney > liver > muscle tissue, with overall means of 2.2, 0.19, and 0.10, 0.31, and 0.26, 0.22 mg kg(-1) wet weight, respectively. The cadmium content of the kidney of a proportion of red deer sampled exceeded the legal tolerance limits set in Poland. The means (but not individual animal data) obtained for cadmium in kidney and liver correlated (0.99) with the age of red deer. Also, the lead content of the muscle meat of red deer for many carcasses exceeded the legal limit, which was probably due to contamination from the fine dust particle remains from the lead bullets used.     

Mineral analysis in rabbit meat from Galicia (NW Spain)

A total of 54 rabbits 50, 70 and 90 days old, were taken from farms in Galicia (NW Spain); 18 rabbits of each age were sampled. The minerals in the muscle meat from the back legs of the rabbits were analysed, and the following average concentrations were found: ash 1.21/100 g, potassium 388 mg/100 g; phosphorus 237 mg/100 g; sodium 60 mg/100 g; magnesium 27 mg/100 g; calcium 8.7 mg/100 g; zinc 10.9 mg/kg; iron 5.56 mg/kg; copper 0.78 mg/kg; and manganese 0.33 mg/kg.

The high potassium and low sodium concentration may make rabbit meat particularly recommended for hypertension diets. Rabbit meat is rich in phosphorus, and 100 g provides approximately 30% of the recommended daily intake. However, rabbit meat provides less zinc and iron than meats of other species. The Galician rabbit meat analysed in this study, shows higher copper and manganese, and lower calcium contents than those found in the literature for rabbit meat of other origins.     

Qualitative evaluation of tortellini meat filling by histology and image analysis

The aim of this study was to identify the presence of different animal tissues in tortellini meat‐filling with special emphasis on the percentage of skeletal muscle. Industrially packed and refrigerated tortellini filling from four different Italian commercial brands were examined and compared. From each brand, five different batches were sampled at intervals of 1 month. From each batch, four fillings were randomly sampled and coded to allow a blind examination. Histological sections were examined to identify the presence of various animal tissues. The presence of large fragments of skeletal muscle in specimens were assessed and semiquantitatively ranked. To evaluate the percentage area of skeletal muscle in the samples, a computerised image analysis system was used. Animal tissues were well preserved in all examined samples. The filling quality was quantified by histology and image analysis evaluating: skeletal muscle density, size of skeletal muscle fragments, and uniformity of batches. In addition to the effective enforcement of food labelling law and the protection of consumers, histology and image analysis are reliable tools to identify small amounts of various animal tissues in a processed meat product.     

磺胺甲噁唑和磺胺嘧啶在青石斑鱼组织中的分布及代谢规律

通过一次性投喂各含有200 mg/kg磺胺甲噁唑（sulfamethoxazole,SMZ）和磺胺嘧啶（sulfadiazine,SDZ）的饲料,研究两种药物在青石斑鱼中各组织分布与消除规律。采用超高效液相色谱-串联质谱检测青石斑鱼各组织中SMZ和SDZ的含量,并用内标法定量。结果表明,SMZ在青石斑鱼各组织中的最大含量：肝脏、背肌、血浆、肾脏和鳃依次为827.97μg/kg、776.70μg/kg、610.29μg/L、432.14μg/kg和345.18μg/kg。SDZ在青石斑鱼各组织中的最大含量：肝脏、背肌、鳃、血浆和肾脏依次为895.30μg/kg、660.55μg/kg、431.88μg/kg、419.56μg/L和310.67μg/kg。SMZ在青石斑鱼各组织中的半衰期：肾脏、鳃、背肌、血浆和肝脏半衰期依次为26.65、21.00、20.38、18.73h和16.90h。SDZ在青石斑鱼各组织中的半衰期：肾脏、血浆、鳃、背肌和肝脏依次为31.50、27.72、24.75、21.66h和18.24h。SMZ和SDZ在青石斑鱼肝脏中半衰期最短,代谢速度最快;在肾脏中半衰期最长,代谢速度最慢。在水温（25±2）℃条件下,SMZ和SDZ各200mg/kg的剂量同时单次投喂青石斑鱼,建议休药期不低于3d。SMZ和SDZ代谢规律研究为磺胺类药物在水产品中的合理使用提供了参考。     

Pharmacokinetics of marbofloxacin in lactating cows after repeated intramuscular administrations and pharmacodynamics against mastitis isolated strains

The plasma and milk pharmacokinetics of marbofloxacin, a fluoroquinolone antibacterial compound, were evaluated in dairy cows, as well as its pharmacodynamic characteristics against mastitis-isolated pathogens. Marbofloxacin was given intramuscularly as a 10% aqueous solution to dairy cows either at a single dose or at repeated doses of 2 mg/kg once daily for 3 d. Blood and milk samples were collected for the determination of the concentration of marbofloxacin and of its putative metabolites: N-desmethyl-marbofloxacin and N-oxide-marbofloxacin. Bacterial field isolates were from milk samples collected from dairy cows suspected of having an intramammary infection. After identification, the minimal inhibitory concentration (MIC) was determined against the isolated strains. The maximal marbofloxacin concentration (Cmax) observed in milk after the first administration was 1.024 microg/mL, and the area under the curve during the first dosing interval was 6.513 microg/h per milliliter. After the third administration, these parameters were slightly increased (about 20% at most). Both metabolites were detected in the milk, but their concentrations were below the limit of quantification. The MIC against 90% of the population (MIC90) of Escherichia coli was 0.016 microg/mL, and it was 0.229 microg/mL against Staphylococcus aureus. The following surrogate clinical outcome markers were obtained against E. coli strains: a Cmax/MIC ratio of 67 and an area under the curve/MIC ratio of 407 h. Hence, a possible efficacy of marbofloxacin in the treatment of E. coli-induced mastitis could be expected as the endpoints of 10 and 250 h, respectively, are reached.     

Composition of meat and offal from weaned and fattened rabbits and results of stereospecific analysis of triacylglycerols and phosphatidylcholines

BACKGROUND: Rabbit meat has excellent nutritive properties. The purpose of this study was to characterize rabbit meat and offal; in particular, the lipid fraction was studied in order to evaluate total and positional fatty acid (FA) compositions of triacylglycerol (TAG) and phosphatidylcholine (PC) fractions. Eight samples of weaned and eight of fattened rabbits were considered. RESULTS: Fattened rabbit meat contained slightly higher protein percentage content (P < 0.05) in comparison to weaned (20.1% versus 18.0%). Calcium content was higher in meat than in offal, unlike sodium, iron, zinc, manganese and copper. The cholesterol content in offal was much higher than in meat. FA profiles of total lipid showed a high percentage of unsaturated fatty acids and an n‐6/n‐3 ratio of 10.3 for fattened rabbit meat. Stereospecific analysis of TAG and PC was carried out on an eight‐sample pool of each meat and offal from weaned and fattened rabbits. In all samples the sn‐2‐position was prevalently esterified with oleic and linoleic acids in TAG, with polyunsaturated fatty acids in PC. CONCLUSION: Lipids from rabbit meat presented higher content of monounsaturated FA and lower n‐6/n‐3 ratio in comparison to offal, which was characterized by higher cholesterol and mineral levels. Copyright © 2011 Society of Chemical Industry     

Effect of dietary α-linolenic acid and vitamin E on the fatty acid composition, storage stability and sensory traits of rabbit meat

The synergistic effect of dietary linolenic acid and vitamin E on the oxidative stability and nutritional and eating characteristics of fresh and stored rabbit meat was studied. One-hundred hybrid male rabbits were divided into two homogenous groups and fed ad libitum two diets differing in the amount of sunflower and flaxseed and in the level of α-tocopherol, as follows: control diet: 0.08 kg kg(-1) sunflower, 50 mg kg(-1) α-tocopheryl-acetate and LNA-VE diet: 0.08 kg kg(-1) flaxseed, 200 mg kg(-1) α-tocopheryl-acetate. At 85 days, 20 rabbits per group were slaughtered and the thiobarbituric-acid reactive substances (TBA-RS), chemical composition, fatty acid profile and sensory quality were assessed on the longissimus dorsi muscles (fresh and stored for 8 days at 4?°C). The proximate composition of the fresh muscle was not significantly affected by the dietary treatment. Rabbits fed the LNA-VE diet showed a good capability to elongate and desaturate linolenic acid and this diet enriched the n-3 PUFA content of the meat without affecting its peroxidative stability. The sensory quality of the fresh and stored muscle was slightly affected by the dietary treatment, even though final tenderness (fresh meat) and overall acceptability (stored meat) of the LNA-VE rabbits showed significantly higher scores.     

Changes of the fatty acid composition and malondialdehyde concentration in rabbit Longissimus dorsi muscle after regular electrical stimulation

The experiment was carried out to investigate, whether in vivo transcutaneous electrical nerve stimulation (TENS) affects the fatty acid composition and antioxidant status of rabbit Longissimus dorsi muscle. Altogether 20 Pannon White meat type rabbits were divided into two groups, from which one was routinely exposed to TENS treatment with the following settings: 2 events (each 20 min) a day/50 days, 1 channel (2 electrodes)/animal, 30 Hz, 20 μs impulse length and 10 mA. The control group was not treated. After slaughtering gas chromatography analysis of the muscle showed significantly decreased stearic, arachidonic and docosahexaenoic acid proportions, while the estimated activity of the elongase enzyme decreased. The malondialdehyde concentration decreased insignificantly in the treated group, however, it followed the changes of the total highly unsaturated fatty acid amount (three or more double bonds), which decreased from 9.16% to 7.81%. The adaptation to the in vivo electrical treatment may significantly influence the meat fatty acid profile, especially PUFA proportion.     

Lead, cadmium, arsenic and mercury in meat, liver and kidney of Swedish pigs and cattle in 1984-88

During the period 1984-88 several hundred samples of meat, liver and kidney from Swedish pigs and cattle were analysed for lead, cadmium, arsenic and mercury. Analysis was performed by AAS and extensive quality assurance was carried out. The mean lead levels in pig meat, liver and kidney were less than 0.005, 0.019 and 0.016 mg/kg, respectively: the mean levels in the corresponding bovine tissues were less than 0.005, 0.047 and 0.097 mg/kg. The mean cadmium levels in pig meat, liver and kidney were 0.001, 0.019 and 0.11 mg/kg, whilst those in the corresponding bovine tissues were 0.001, 0.070 and 0.39 mg/kg. The mean arsenic levels in pig meat, liver and kidney were 0.024, 0.023 and 0.019, respectively and those in the corresponding bovine tissues were lower, none exceeding 0.015 mg/kg. The mean mercury levels in pig meat, liver and kidney were 0.009, 0.015 and 0.019 mg/kg respectively, while those in the corresponding bovine tissues were 0.005, 0.006 and 0.010 mg/kg. A decrease in the levels of both arsenic and mercury in pig tissues was found during the period studied, which may be due to a decrease in the use of fish meal in pig feed.     

Manganese, copper, zinc, iron, cadmium, mercury and lead in muscle meat, liver and kidneys of poultry, rabbit and sheep slaughtered in the northern part of Poland, 1987

Manganese, copper, zinc, iron, cadmium, mercury and lead concentrations have been determined in muscle meat, livers and kidneys of ducks, geese, chickens, hens, rabbits and sheep slaughtered in the northern part of Poland in 1987. The mean values obtained related to wet weight for muscle meat, livers and kidneys of animals were: 0.11-0.27, 0.73-3.3 and 0.90-1.9 mg/kg Mn; 0.52-7.3, 3.8-88 and 2.8-15 mg/kg Cu; 5.7-40, 20-45 and 21-30 mg/kg Zn; 10-35, 27-83 and 50-180 mg/kg Fe; less than 5-5, 16-140 and 250-5100 micrograms/kg Cd; less than 1-3, 2-10 and 5-12 micrograms/kg Hg; and less than 10-20, 100-210 and 120-1300 micrograms/kg Pb, respectively. Substantial differences have been found in the mean copper concentration in muscle meat, livers and kidneys, zinc and iron in muscle meat, and cadmium in kidneys, between some of the species examined. The mean and maximum concentrations of mercury and lead found in muscle meat and organs of animals in the present study were low, and only in the case of cadmium were somewhat higher values found in kidneys of rabbit and hen. The results obtained are compared with the literature data on the concentrations of the metals examined in muscle meat, livers and kidneys of poultry, rabbit and sheep in Poland or elsewhere.     

Distribution and elimination of levamisole in eggs and tissues after oral administration to laying hens,determined by LC-MS/MS

Levamisole was administered to laying hens, and concentrations in eggs and tissues (thigh muscle, breast muscle, liver and kidney) were determined by a newly developed liquid chromatography tandem mass spectrometry method, which allowed trace level quantification of levamisole. The adopted analytical method showed good sensitivity, repeatability and percentage of recovery from spiked matrices. Maximum concentrations of levamisole were found on the first day after the administration (531.1 μg/kg in liver, 164.3 μg/kg in egg yolk, 130.7 μg/kg in kidney, 78.0 μg/kg in breast muscle, 70.7 μg/kg in thigh muscle and 64.0 μg/kg in egg white), after which there is a decline. The compound was rapidly eliminated from eggs, with a half-life of 1.3 days. Elimination appeared to be slower in thigh muscle (3.5 days), breast muscle (3.4 days) and liver (3.3 days). According to this experiment, the levamisole withdrawal periods calculated for eggs, liver, kidney, breast muscle and thigh muscle in laying hens were 14.1, 6.1, >4.0, 14.5 and 13.0 days, respectively. The longest time for levamisole residues to be completely released from tissues was seen in liver samples (37.4 days), followed by thigh muscle, breast muscle and kidney. Elimination from eggs was fastest (16.4 days for levamisole residues to drop below the method quantification limit).     

Trace elements in Slovenian poultry tissues

In this paper, the contamination of poultry tissues by trace elements in Slovenia is examined from a public health standpoint. During systematic veterinary and sanitary monitoring of foodstuffs of animal origin from 1997 to 1999, 21 poultry meat samples, 70 poultry liver tissue samples, and 184 poultry kidney tissue samples were examined for Pb, Cd, and Hg contents. The levels of poultry tissue contamination in six regions of Slovenia were determined. All samples met Slovenian standards except one poultry kidney tissue sample, which exceeded the Hg level allowed. The difference between chicken and turkey contamination levels was statistically significant (P < 0.05) only for Cd content in kidney tissues. Poultry kidney tissue Cd contents differed for different geographical regions (P < 0.05).     

A theoretical approach of the relationships between collagen content, collagen cross-links and meat tenderness

This work concerns the relationship between meat tenderness and the rubber-like properties, i.e. pressure and elastic modulus, that endomysium and perimysium connective tissues develop when meat has been heated to a temperature above which collagen contracts. For rest length meats with similar intramuscular connective tissue morphology, and which are at the same ageing state and pH, the elastic modulus of the collagenous fraction of connective tissues is approximately proportional to the total number of collagen cross-links present per volume of meat. Calculations from various published experiments concerned with the effect on tenderness of muscle type, animal age, type, and sex from different species show that this modulus follows most of the variations of meat toughness. Moreover, the proportionality between the increase in this elastic modulus and the increase in meat toughness approaches unity in situations where toughness mainly depends on connective tissues. This work demonstrates the decisive role of rubber-like properties of connective tissues in meat tenderness variations.     

Stability during cooking of anthelmintic veterinary drug residues in beef

Anthelmintic drugs are widely used for treatment of parasitic worms in livestock, but little is known about the stability of their residues in food under conventional cooking conditions. As part of the European Commission-funded research project ProSafeBeef, cattle were medicated with commercially available anthelmintic preparations, comprising 11 active ingredients (corresponding to 21 marker residues). Incurred meat and liver were cooked by roasting (40?min at 190°C) or shallow frying (muscle 8–12?min, liver 14–19?min) in a domestic kitchen. Raw and cooked tissues and expressed juices were analysed using a novel multi-residue dispersive solid-phase extraction method (QuEChERS) coupled with ultra-performance liquid chromatography-tandem mass spectrometry. After correction for sample weight changes during cooking, no major losses were observed for residues of oxyclozanide, clorsulon, closantel, ivermectin, albendazole, mebendazole or fenbendazole. However, significant losses were observed for nitroxynil (78% in fried muscle, 96% in roast muscle), levamisole (11% in fried muscle, 42% in fried liver), rafoxanide (17% in fried muscle, 18% in roast muscle) and triclabendazole (23% in fried liver, 47% in roast muscle). Migration of residues from muscle into expressed cooking juices varied between drugs, constituting 0% to 17% (levamisole) of total residues remaining after cooking. With the exception of nitroxynil, residues of anthelmintic drugs were generally resistant to degradation during roasting and shallow frying. Conventional cooking cannot, therefore, be considered a safeguard against ingestion of residues of anthelmintic veterinary drugs in beef.     

GAMMA GLOBULIN ISOLATED FROM RABBIT ANTISERUM FOR RAPID DETECTION OF MEAT ADULTERATION

SUMMARY –A simple, rapid method for the qualitative identification of animal proteins as to species was developed for fresh meat. Gamma globulin isolated from species-specific rabbit antiserum was mixed with a heated extract of skeletal muscle of beef, horse lamb and pork. The mixture was allowed to set for 30 min at room temperature and then centrifuged. The presence of a precipitin indicated a positive reaction. There were no cross reactions between meat samples from different species. This method requires a maximum time of only 1–2 hr, as compared with the 3 days required for double-gel diffusion. In addition, it is much more sensitive than gel diffusion.     

Determination of Enrofloxacin Residues in Commercial Broilers Using High Performance Liquid Chromatography

The broad-spectrum antibacterial drugs are widely used in food producing animals. Suspected residues of these drugs in meat may have ill effects upon human health. The aim of the present study was to determine the enrofloxacin residues in broiler’s meat and liver samples. Detection of enrofloxacin residues in meat (n = 75) and liver (n = 75) samples was performed by high performance liquid chromatography with UV detector set at 268 nm using C₁₈ column. Overall mean residual concentrations of enrofloxacin in meat and liver samples were 208 ± 55 and 527 ± 84 µg/kg, respectively. This study revealed that 52% (39) meat and 78.7% (59) liver samples were positive for enrofloxacin, out of these 58.3% (21) meat and 71.2% (42) liver samples were having residual concentration above the maximum residual limits. So it can be concluded that the usage of this contaminated meat may cause resistance in consumers and seems to be a public health threat.     

Transfer and uptake of polychlorinated dibenzo-p-dioxins and furans (PCDD/Fs) and polychlorinated biphenyls (PCBs) into meat and organs of indoor and outdoor reared pigs

This study was designed to investigate how and to what extent PCDD/Fs and PCBs are transmitted from exposure sources to porcine muscle and other tissues derived from pigs. The experimental approach involved two longitudinal studies in which indoor and outdoor pigs were reared to market readiness using typical animal husbandry practices; closely matched samples of soil, feed, bedding, meat, etc. were collected and analysed for PCDD/Fs and PCBs. The total PCDD/F?+?PCB WHO-TEQs in pig liver were much higher than in meat and kidney samples from the same animals and exceeded the current relevant European Union maximum limits (6?ng PCDD/F-TEQ?kg?1?fat). Liver samples were also characterised by much lower PCB contributions to the total TEQ than for the corresponding meat and kidney samples, and by a predominance of many of the hepta- and octa-substituted PCDD/Fs. At ages approaching market readiness, TEQ values in meat samples from outdoor pigs tended to be slightly higher than those from comparable ages in the indoor programme, possibly due to additional intake from soil. Biotransfer factors (BTFs) were derived for each of the 39 PCDD/F and PCB congeners measured. Interpretation of the findings focused particularly on trends in four selected congeners, namely: 2,3,7,8-TCDD, 2,3,4,7,8-PeCDF, PCB 153 and PCB 169. Increases in the BTF for PCB 169 in the pig-rearing programmes were noticed when the diet changed from being dominated by sow's milk to feed. Much higher transfer factors for many of the more heavily chlorinated PCDD/Fs (e.g. 2,3,4,7,8-PeCDF) were found in liver compared with meat or kidney samples from the same animals. Soil consistently accounted for at least 30% of input for many hexa- or higher chlorinated PCDD/Fs, while it rarely representing more than 10% of the total intake.     

Transfer and uptake of polychlorinated dibenzo-p-dioxins and furans (PCDD/Fs) and polychlorinated biphenyls (PCBs) into meat and organs of indoor and outdoor reared pigs

This study was designed to investigate how and to what extent PCDD/Fs and PCBs are transmitted from exposure sources to porcine muscle and other tissues derived from pigs. The experimental approach involved two longitudinal studies in which indoor and outdoor pigs were reared to market readiness using typical animal husbandry practices; closely matched samples of soil, feed, bedding, meat, etc. were collected and analysed for PCDD/Fs and PCBs. The total PCDD/F?+?PCB WHO-TEQs in pig liver were much higher than in meat and kidney samples from the same animals and exceeded the current relevant European Union maximum limits (6?ng PCDD/F-TEQ?kg^?1?fat). Liver samples were also characterised by much lower PCB contributions to the total TEQ than for the corresponding meat and kidney samples, and by a predominance of many of the hepta- and octa-substituted PCDD/Fs. At ages approaching market readiness, TEQ values in meat samples from outdoor pigs tended to be slightly higher than those from comparable ages in the indoor programme, possibly due to additional intake from soil. Biotransfer factors (BTFs) were derived for each of the 39 PCDD/F and PCB congeners measured. Interpretation of the findings focused particularly on trends in four selected congeners, namely: 2,3,7,8-TCDD, 2,3,4,7,8-PeCDF, PCB 153 and PCB 169. Increases in the BTF for PCB 169 in the pig-rearing programmes were noticed when the diet changed from being dominated by sow's milk to feed. Much higher transfer factors for many of the more heavily chlorinated PCDD/Fs (e.g. 2,3,4,7,8-PeCDF) were found in liver compared with meat or kidney samples from the same animals. Soil consistently accounted for at least 30% of input for many hexa- or higher chlorinated PCDD/Fs, while it rarely representing more than 10% of the total intake.