Summary
This study deals with the levels of toxic polychlorinated dibenzo‐p‐dioxin and furan congeners (PCDD/Fs) in the livers of piglets affected by infectious diseases using isotope dilution high‐resolution gas chromatography/high‐resolution mass spectrometry (HRGC/HRMS). Seventeen toxic congeners in the liver samples infected with bacterial and viral diseases were compared. For porcine reproductive and respiratory syndrome virus (PRRSV) samples, the North American‐ and European‐type PRRS diseases were observed. This study shows that there are significantly different levels of PCDD/Fs, present, which vary according to the types of diseases as evidenced by our analysis of the piglet liver samples.
Keywords: polychlorinated dibenzo‐p‐dioxins/furans, piglet, bacillus nature diseases, porcine reproductive and respiratory syndrome virus (PRRSV)
Dioxins [polychlorinated dibenzo‐p‐dioxins (PCDDs) and dibenzofurans (PCDFs)] persist in the environment and cause a risk of adverse effects to human health. Human exposure to PCDDs/Fs occurs mainly from the consumption of foodstuffs, and the major food sources are meat, fish, seafood and dairy products (Yang et al. 2004; Huwe & Larsen 2005; Brambilla et al. 2011; Chung et al. 2015). In particular, case of pigs contaminated by PCDDs/Fs was reported as a serious public health issue (Shen et al. 2012a,b) because pig breeding has increased faster than cattle breeding globally. The Korean population now consumes more pork than beef and chicken. In addition, a number of studies reported high levels of PCDD/Fs in animals, raising public concern (Fernandes et al. 2010; Watanabe et al. 2010; Marnane 2012; Mizukawa et al. 2015). Diseases in swine are classified as bacterial or viral. Porcine reproductive and respiratory virus (PRRSV) causes Porcine Reproductive and Respiratory Syndrome (PRRS) in pigs and is thus is an economically significant causative agent of disease, which was first observed in North America in 1987 (Collins et al. 1992; Allende et al. 1999) and in western Europe in 1990 (Wensvoort et al. 1991), and at the present, it is a worldwide disease (Mateu et al. 2003). Several studies have demonstrated the increased severity of clinical disease in animals co‐infected with PRRSV and various bacteria, including Streptococcus suis (Thanawongnuwech et al. 2000), Haemophilus parasuis (Olvera et al. 2009), Salmonella choleraesuis (Wills et al. 2000) and Mycoplasma hyopneumoniae (Thacker et al. 1999). Generally, PRRSV is classified into two distinct genotypes, namely the European and the North American genotypes (Labarque et al. 2004; Brambilla et al. 2011). One of the most known potent toxicants is dioxin (PCDD/Fs); especially, 2, 3, 7, 8‐tetrachlorodibenzo‐p‐dioxin (TCDD) has reported an association of immunologic effects in experimental animals. This includes the decreased host resistance to infectious diseases and suppressed humoral and cell‐mediated immune responses (Mandal 2005). To the best of authors' knowledge up to now, there are no studies related to the investigation of each specific dioxin congener according to the types of diseases in piglets. To ensure proper validation of the analytical method certified reference material (CRM) and limit of detection were verified in advance. Based on these findings, hepatic levels of PCDD/Fs were determined in various piglet diseases and evaluated according to the types of disease.
Materials and methods
Preparation of the samples
The experiment consisted of the analysis of PCDD/Fs levels in the liver of piglets infected with bacterial or viral diseases and analysis of PCDD/Fs with PRRSV of the North American or the European type. In the first experiment, three individual liver samples were taken from piglets infected with four different groups of pathogens (12 samples in total) and analysed. For bacterial diseases, the pathogens were Salmonella spp and Streptococcus suis. For PRRSV, the samples were classified according to site of pathological lesions: e.g. lymph, intestine and lung. In the second experiment, five individual piglet liver samples from two different groups (10 samples in total) infected with PRRSV of the North American and European types were analysed. In addition 14 liver samples from piglets related to North American‐type PRRSV were obtained later. Ground hepatic samples were mixed with powder of anhydrous sodium sulphate, and 15 congeners of 13C‐labelled PCDD/Fs (Wellington laboratories Inc., Ontario, Canada) were added prior to extraction. The extraction of native PCDD/Fs in the samples was performed by sonication in 100 ml of n‐hexane twice for 10 min. 37Cl‐labelled PCDD/Fs solutions were added prior to sulphuric acid treatment, which was used to remove lipids. The extract was then purified on a Power Prep instrument (Fluid Management Systems, Waltham, MA, USA). The recovered product‐containing fractions were spiked with the internal standards (13C‐labelled 1,2,3,4‐TCDD, 1,2,3,7,8,9‐HxCDD). For the quantification of trace level of PCDD/Fs, calibration standards CS1/2 through CS4 were used. Experiments to establish the method detection limits (MDL) were conducted with a pooled sample, containing none of the dioxin congeners. MDLs were measured by analysing seven replicate samples spiked with native standards of EPA 1613 PAR (Precision and Recovery Standard) per 10 g of control blank samples. EPA 1613 PAR and fortified fish reference material (EDF‐2526) as the CRM were purchased from Cambridge Isotope Laboratories (CIL Inc., MA, USA) to determine precision and accuracy of the analytical method. All organic solvents were of ultra‐residue‐grade analysis (J.T Baker, Philipsburg, NJ, USA). Anhydrous sodium sulphate and sulphuric acid were purchased from E. Merck (Darmstadt, Germany).
Instrumentation
The instrumental analysis was performed on a JEOL (Akishima, Tokyo, Japan) MStation JMS‐700D high‐resolution mass spectrometer (B/E configuration) equipped with an Agilent (Palo Alto, CA, USA) 6890 Plus gas chromatograph. A capillary GC column 60 m in length and 0.32 mm in inner diameter, coated with a DB‐5 MS stationary phase (film thickness of 0.25 μm), was used. Samples were injected in splitless mode at an injector temperature of 280°C and at an initial column temperature of 160°C. After 1 min, the temperature was ramped at 20°C/min to 200°C, at 5°C/min up to 235°C and at 3°C/min up to 310°C. The latter temperature was held for 3 min. The ion source was operated at 260°C, and the electron energy was 38 eV. The mass spectrometer was tuned to a mass resolution of 10,000. Quantification was carried out for tetra‐ through octachlorinated dioxins and furans by the isotopic dilution method, and congeners were recorded as non‐detected (n.d.) below the method detection limit. All congeners of PCDD/Fs were analysed according to the methodology of WHO (Shin et al. 2013).
Statistical analysis
In this study, a certified reference material CRM, EDF‐2526, which is the fish performance evaluation sample, and MDL, which is defined as the lowest concentration of PCDD/Fs, providing a greater than 99% confidence level, were carried out.
Ethical approval statement
Animal studies were approved by the Animal Care and Use Committee of the Institute of Laboratory Animal Resources, Seoul National University (Approval no. SNUCVM 05‐2701).
Results and discussion
Validation of analytical method
Dioxins are distributed throughout the environment at extremely low concentrations as femtogram levels, so validation studies to estimate accuracy and precision including the limit of detection are required for trace‐level analysis. We obtained a certificate of accreditation for food testing inspection from Korea Food & Drug Administration and applied proficiency tests in the analysis of dioxins every year to maintain high quality. The results were very satisfactory. To monitor method performance, all the samples were spiked with labelled compounds, and their recoveries through the analytical procedure were within the acceptance criteria for dioxin/furans analysis between 70 and 120%. The concentrations determined for the native 17 congeners of PCDD/Fs were in excellent agreement with the EDF‐2526 reference fish certified values as shown in Table 1. From the seven replicate analyses of spiking experiments, MDLs were obtained within the range of 0.0029–0.0066 pg/g. Generally, this sensitivity was satisfactory for the determination of dioxins and risk assessment.
Table 1.
Analytical results of certified reference material and MDL
| Congeners | CRM (EDF‐2526) | MDL (pg/g) | ||
|---|---|---|---|---|
| Experimental value (pg/g) | Certified value (pg/g) | Recovery 13C12 (%) | ||
| PCDD | ||||
| 2,3,7,8‐TCDD | 20.1 | 20.3 ± 2.59 | 98.3 | 0.0046 |
| 1,2,3,7,8‐PeCDD | 38.4 | 42.4 ± 11.7 | 103.2 | 0.0055 |
| 1,2,3,4,7,8‐HxCDD | 55.2 | 56.4 ± 5.29 | 78.2 | 0.0048 |
| 1,2,3,6,7,8‐HxCDD | 50.4 | 54.6 ± 13.5 | 78.4 | 0.0057 |
| 1,2,3,7,8,9‐HxCDD | 54.7 | 58.2 ± 11.7 | – | 0.0062 |
| 1,2,3,4,6,7,8‐HpCDD | 72.4 | 76.2 ± 7.41 | 79.9 | 0.0066 |
| OCDD | 185.9 | 199 ± 51.8 | 79.4 | 0.0047 |
| PCDF | ||||
| 2,3,7,8‐TCDF | 20.2 | 20.1 ± 0.77 | 90.8 | 0.0055 |
| 1,2,3,7,8‐PeCDF | 40.3 | 42.1 ± 9.30 | 96.5 | 0.0031 |
| 2,3,4,7,8‐PeCDF | 38.9 | 40.8 ± 4.86 | 99.1 | 0.0062 |
| 1,2,3,4,7,8‐HxCDF | 78.9 | 84.1 ± 9.53 | 72.6 | 0.0029 |
| 1,2,3,6,7,8‐HxCDF | 61.7 | 61.1 ± 13.1 | 77.2 | 0.0038 |
| 1,2,3,7,8,9‐HxCDF | 56.6 | 57.7 ± 9.34 | 90.9 | 0.0039 |
| 2,3,4,6,7,8‐HxCDF | 58.5 | 60.9 ± 4.55 | 81.6 | 0.0047 |
| 1,2,3,4,6,7,8‐HpCDF | 80.3 | 85.4 ± 9.38 | 78.4 | 0.0043 |
| 1,2,3,4,7,8,9‐HpCDF | 72.4 | 76.1 ± 31.6 | 85.8 | 0.0042 |
| OCDF | 181.8 | 202.0 ± 31.2 | – | 0.0032 |
MDL, method detection limit; PCDD/Fs, polychlorinated dibenzo‐p‐dioxins/furans.
Sample analysis
By comparing the results of PCDD/Fs levels in the organs from piglets with bacterial or viral infection, no detectable concentrations of PCDD/Fs were observed in the organs from piglets with bacterial diseases of Salmonella spp. and Streptococcus. In contrast the results from piglet livers infected with viral disease of PRRSV showed significant difference. Few studies have considered the effect of only 2, 3, 7, 8‐tetrachlorodibenzo‐p‐dioxin (TCDD) on the infectious disease of animal dose (Zhang et al. 2013); however, total TEQ concentrations required accuracy in predicting the toxicity. Because all dioxin congeners are thought to act in the same way, they are not all equally toxic (Assmuth & Vartiainen 1995). Each congener in the samples was represented as their dioxin toxic equivalent (TEQ), which is determined by toxicity potency factors in this study. In the case of samples for piglet disease due to the PRRSV in lymph and intestine, the most potent dioxins 1,2,3,7,8‐PeCDD, 1,2,3,4,7,8‐HxCDD, 2,3,7,8‐TCDF, 1,2,3,4,6,7,8‐HpCDF and 1,2,3,4,7,8,9‐HpCDF were detected as shown in Table 2. In one of the lung samples due to the PRRSV octachlorodibenzofuran (OCDF), was detected and none of PCDD/Fs were detected in the other two samples. Overall, PCDD/Fs were detected in higher quantities from the samples with PRRSV in lymph and intestine than from those with PRRSV in lung. On this basis, analysis of the livers for piglet according to disease type was performed because the liver sample accumulates more dioxin compounds than other organs (Fernandes et al. 2010; Conka et al. 2012; Rose et al. 2012). It is known that due to its detoxification properties, liver gathers toxic compounds in the greater extent when compared with the other internal organs (Shen et al. 2012b; Holma‐Suutari et al. 2016) (Table 3). Five liver samples of each North American‐type and European‐type PRRSV that cause a disease of pigs were analysed. In the case of the livers for piglet disease with North American‐type PRRSV, more congeners and high level of dioxins were detected than European‐type PRRSV. The most toxic dioxin, 1, 2, 3, 7, 8‐pentachlorodibenzo‐p‐dioxin (PCDD) was detected in one sample (NA‐15) and their concentration range of total PCDD/Fs was 0.00288–0.42814 pg WHO‐TEQ/g. On the other hand, low chlorinated congeners that have high toxicity were not detected in the livers for piglet disease with European‐type PRRSV. The level of toxic dioxins was significantly higher in the samples of piglet liver from North American‐type PRRSV than from European‐type PRRSV. Thus, additional 14 liver samples of piglets related to North American‐type PRRSV were obtained and analysed for the determination of PCDD/Fs. The TEQ concentrations of PCDD/Fs in the samples of piglet liver are shown in Table 4. Even though the total concentrations in the samples ranged from 0.00002 to 0.42633 pg, the more toxic congeners such as tetra‐ or penta‐CDD/F as well as multiple congeners were detected, especially for two samples (S4 and S9). The representative chromatograms of OCDD that were frequently detected congeners in the samples are shown in Figures 1, 2. The levels of PCDD/Fs in the livers for piglet disease with North American‐type PRRSV were obviously higher compared with those of European‐type PRRSV.
Table 2.
The levels of PCDD/Fs in organs of piglet according to types of diseases
| (pg WHO‐TEQ/g) | |||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Compounds | TEF | Salmonella spp. and Streptococcus suis | Streptococcus suis | PRRS (lymph, intestine) | PRRS (lung) | ||||||||
| 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | ||
| 2,3,7,8‐TCDD | 1 | N.D | N.D | N.D | N.D | N.D | N.D | N.D | N.D | N.D | N.D | N.D | N.D |
| 1,2,3,7,8‐PeCDD | 1 | N.D | N.D | N.D | N.D | N.D | N.D | N.D | 0.43001 | N.D | N.D | N.D | N.D |
| 1,2,3,4,7,8‐HxCDD | 0.1 | N.D | N.D | N.D | N.D | N.D | N.D | N.D | 0.00552 | N.D | N.D | N.D | N.D |
| 1,2,3,6,7,8‐HxCDD | 0.1 | N.D | N.D | N.D | N.D | N.D | N.D | N.D | N.D | N.D | N.D | N.D | N.D |
| 1,2,3,7,8,9‐HxCDD | 0.1 | N.D | N.D | N.D | N.D | N.D | N.D | N.D | N.D | N.D | N.D | N.D | N.D |
| 1,2,3,4,6,7,8‐HpCDD | 0.001 | N.D | N.D | N.D | N.D | N.D | N.D | N.D | N.D | N.D | N.D | N.D | N.D |
| OCDD | 0.0003 | N.D | N.D | N.D | N.D | N.D | N.D | N.D | N.D | N.D | N.D | N.D | N.D |
| 2,3,7,8‐TCDF | 0.1 | N.D | N.D | N.D | N.D | N.D | N.D | 0.05501 | N.D | N.D | N.D | N.D | N.D |
| 1,2,3,7,8‐PeCDF | 0.03 | N.D | N.D | N.D | N.D | N.D | N.D | N.D | N.D | N.D | N.D | N.D | N.D |
| 2,3,4,7,8‐PeCDF | 0.3 | N.D | N.D | N.D | N.D | N.D | N.D | N.D | N.D | N.D | N.D | N.D | N.D |
| 1,2,3,4,7,8‐HxCDF | 0.1 | N.D | N.D | N.D | N.D | N.D | N.D | N.D | N.D | N.D | N.D | N.D | N.D |
| 1,2,3,6,7,8‐HxCDF | 0.1 | N.D | N.D | N.D | N.D | N.D | N.D | N.D | N.D | N.D | N.D | N.D | N.D |
| 1,2,3,7,8,9‐HxCDF | 0.1 | N.D | N.D | N.D | N.D | N.D | N.D | N.D | N.D | N.D | N.D | N.D | N.D |
| 2,3,4,6,7,8‐HxCDF | 0.1 | N.D | N.D | N.D | N.D | N.D | N.D | N.D | N.D | N.D | N.D | N.D | N.D |
| 1,2,3,4,6,7,8‐HpCDF | 0.001 | N.D | N.D | N.D | N.D | N.D | N.D | 0.00672 | 0.00448 | 0.00420 | N.D | N.D | N.D |
| 1,2,3,4,7,8,9‐HpCDF | 0.001 | N.D | N.D | N.D | N.D | N.D | N.D | N.D | 0.00490 | N.D | N.D | N.D | N.D |
| OCDF | 0.0003 | N.D | N.D | N.D | N.D | N.D | N.D | N.D | N.D | N.D | N.D | N.D | 0.00021 |
| ΣPCDD/F | N.D | N.D | N.D | N.D | N.D | N.D | 0.06173 | 0.44491 | 0.00420 | N.D | N.D | 0.00021 | |
N.D, not detected; PCDD/Fs, polychlorinated dibenzo‐p‐dioxins/furans; OCDF, octachlorodibenzofuran.
A certified reference material CRM, EDF‐2526, which is the fish performance evaluation sample, and MDL, which is defined as the lowest concentration of PCDD/Fs, providing a greater than 99% confidence level, were used.
Table 3.
The levels of PCDD/Fs in the livers of piglet according to PRRSV genotype
| (pg WHO‐TEQ/g) | ||||||||||
|---|---|---|---|---|---|---|---|---|---|---|
| Compounds | North American‐type PRRs | European‐type PRRs | ||||||||
| NA‐1 | NA‐3 | NA‐5 | NA‐7 | NA‐15 | EU‐1 | EU‐3 | EU‐5 | EU‐7 | EU‐10 | |
| 2,3,7,8‐TCDD | N.D | N.D | N.D | N.D | N.D | N.D | N.D | N.D | N.D | N.D |
| 1,2,3,7,8‐PeCDD | N.D | N.D | N.D | N.D | 0.20947 | N.D | N.D | N.D | N.D | N.D |
| 1,2,3,4,7,8‐HxCDD | N.D | N.D | N.D | N.D | N.D | N.D | N.D | N.D | N.D | N.D |
| 1,2,3,6,7,8‐HxCDD | N.D | N.D | N.D | N.D | N.D | N.D | N.D | N.D | N.D | N.D |
| 1,2,3,7,8,9‐HxCDD | N.D | N.D | N.D | N.D | N.D | N.D | N.D | N.D | N.D | N.D |
| 1,2,3,4,6,7,8‐HpCDD | N.D | 0.00112 | N.D | N.D | 0.00279 | N.D | N.D | N.D | N.D | N.D |
| OCDD | N.D | 0.00002 | 0.00007 | 0.00005 | 0.00006 | 0.00029 | 0.00020 | 0.00012 | N.D | N.D |
| 2,3,7,8‐TCDF | N.D | N.D | N.D | N.D | N.D | N.D | N.D | N.D | N.D | N.D |
| 1,2,3,7,8‐PeCDF | 0.00650 | 0.00312 | N.D | N.D | N.D | N.D | N.D | N.D | N.D | N.D |
| 2,3,4,7,8‐PeCDF | 0.06503 | 0.04369 | N.D | N.D | 0.13965 | N.D | N.D | N.D | N.D | N.D |
| 1,2,3,4,7,8‐HxCDF | 0.02081 | N.D | N.D | N.D | 0.03491 | N.D | N.D | N.D | N.D | N.D |
| 1,2,3,6,7,8‐HxCDF | N.D | N.D | N.D | N.D | N.D | N.D | N.D | N.D | N.D | N.D |
| 1,2,3,7,8,9‐HxCDF | N.D | N.D | N.D | 0.01827 | N.D | N.D | N.D | N.D | N.D | N.D |
| 2,3,4,6,7,8‐HxCDF | N.D | 0.00499 | N.D | N.D | 0.03491 | N.D | N.D | N.D | N.D | N.D |
| 1,2,3,4,6,7,8‐HpCDF | 0.00364 | N.D | 0.00076 | N.D | N.D | N.D | N.D | 0.00402 | N.D | N.D |
| 1,2,3,4,7,8,9‐HpCDF | N.D | 0.00100 | N.D | N.D | 0.00638 | N.D | N.D | N.D | N.D | N.D |
| OCDF | N.D | N.D | 0.00004 | N.D | 0.00007 | N.D | N.D | N.D | N.D | N.D |
| ΣPCDD/F | 0.09598 | 0.05394 | 0.00288 | 0.01832 | 0.42814 | 0.00029 | 0.00020 | 0.00414 | N.D | N.D |
N.D, not detected; PCDD/Fs, polychlorinated dibenzo‐p‐dioxins/furans; PRRSV, porcine reproductive and respiratory syndrome virus.
A certified reference material CRM, EDF‐2526, which is the fish performance evaluation sample, and MDL, which is defined as the lowest concentration of PCDD/Fs, providing a greater than 99% confidence level, were used.
Table 4.
The TEQ concentrations of PCDD/Fs in piglet livers of North American‐type PRRSV
| (pg WHO‐TEQ/g) | |||||||
|---|---|---|---|---|---|---|---|
| Compounds | 1 | 2 | 3 | 4 | 5 | 6 | 7 |
| 2,3,7,8‐TCDD | N.D | N.D | N.D | 0.07845 | N.D | N.D | N.D |
| 1,2,3,7,8‐PeCDD | N.D | N.D | N.D | 0.17738 | N.D | N.D | N.D |
| 1,2,3,4,7,8‐HxCDD | N.D | N.D | N.D | 0.02183 | N.D | N.D | N.D |
| 1,2,3,6,7,8‐HxCDD | N.D | N.D | N.D | 0.01092 | N.D | N.D | N.D |
| 1,2,3,7,8,9‐HxCDD | N.D | N.D | N.D | 0.02422 | N.D | N.D | N.D |
| 1,2,3,4,6,7,8‐HpCDD | 0.00125 | N.D | N.D | 0.00136 | N.D | N.D | 0.00037 |
| OCDD | N.D | N.D | N.D | 0.00009 | 0.00002 | N.D | N.D |
| 2,3,7,8‐TCDF | 0.00470 | N.D | N.D | N.D | N.D | N.D | N.D |
| 1,2,3,7,8‐PeCDF | N.D | 0.00099 | N.D | 0.00460 | N.D | 0.0012 | N.D |
| 2,3,4,7,8‐PeCDF | N.D | N.D | N.D | 0.03991 | N.D | N.D | N.D |
| 1,2,3,4,7,8‐HxCDF | N.D | N.D | 0.00409 | 0.01876 | N.D | N.D | N.D |
| 1,2,3,6,7,8‐HxCDF | N.D | N.D | N.D | 0.01330 | N.D | N.D | N.D |
| 1,2,3,7,8,9‐HxCDF | N.D | N.D | N.D | 0.01671 | N.D | N.D | N.D |
| 2,3,4,6,7,8‐HxCDF | N.D | N.D | N.D | 0.01637 | N.D | N.D | N.D |
| 1,2,3,4,6,7,8‐HpCDF | N.D | N.D | 0.00057 | 0.00235 | N.D | N.D | N.D |
| 1,2,3,4,7,8,9‐HpCDF | N.D | N.D | N.D | N.D | N.D | N.D | N.D |
| OCDF | N.D | N.D | N.D | 0.00008 | N.D | N.D | N.D |
| ΣPCDD/F | 0.00595 | 0.00099 | 0.00466 | 0.42633 | 0.00002 | 0.0012 | 0.00037 |
| (pg WHO‐TEQ/g) | |||||||
|---|---|---|---|---|---|---|---|
| Compounds | 8 | 9 | 10 | 11 | 12 | 13 | 14 |
| 2,3,7,8‐TCDD | N.D | 0.08173 | 0.03233 | N.D | N.D | N.D | N.D |
| 1,2,3,7,8‐PeCDD | N.D | 0.04791 | N.D | N.D | N.D | N.D | N.D |
| 1,2,3,4,7,8‐HxCDD | N.D | 0.00761 | N.D | N.D | N.D | N.D | N.D |
| 1,2,3,6,7,8‐HxCDD | N.D | N.D | N.D | N.D | N.D | N.D | N.D |
| 1,2,3,7,8,9‐HxCDD | N.D | 0.00733 | N.D | N.D | N.D | N.D | N.D |
| 1,2,3,4,6,7,8‐HpCDD | N.D | 0.00042 | N.D | N.D | N.D | N.D | 0.00091 |
| OCDD | 0.00001 | 0.00004 | 0.00001 | 0.00004 | 0.00005 | 0.00002 | N.D |
| 2,3,7,8‐TCDF | N.D | N.D | N.D | N.D | N.D | N.D | N.D |
| 1,2,3,7,8‐PeCDF | N.D | 0.00220 | N.D | N.D | N.D | N.D | N.D |
| 2,3,4,7,8‐PeCDF | N.D | 0.01184 | N.D | N.D | N.D | N.D | N.D |
| 1,2,3,4,7,8‐HxCDF | N.D | 0.00507 | N.D | N.D | N.D | N.D | N.D |
| 1,2,3,6,7,8‐HxCDF | N.D | 0.00845 | N.D | N.D | N.D | N.D | 0.00866 |
| 1,2,3,7,8,9‐HxCDF | N.D | 0.00451 | N.D | N.D | 0.01124 | N.D | N.D |
| 2,3,4,6,7,8‐HxCDF | N.D | 0.00676 | N.D | N.D | N.D | N.D | N.D |
| 1,2,3,4,6,7,8‐HpCDF | N.D | 0.00051 | N.D | N.D | N.D | N.D | N.D |
| 1,2,3,4,7,8,9‐HpCDF | N.D | 0.00132 | N.D | N.D | N.D | N.D | N.D |
| OCDF | N.D | 0.00007 | N.D | N.D | N.D | N.D | N.D |
| ΣPCDD/F | 0.00001 | 0.18573 | 0.03234 | 0.00004 | 0.01129 | 0.00002 | 0.00957 |
N.D, not detected; PRRSV, porcine reproductive and respiratory syndrome virus; PCDD/Fs, polychlorinated dibenzo‐p‐dioxins/furans; toxic equivalent (TEQ). A certified reference material CRM, EDF‐2526, which is the fish performance evaluation sample, and MDL, which is defined as the lowest concentration of PCDD/Fs, providing a greater than 99% confidence level, were used.
Figure 1.
The chromatograms of octachlorinated dibenzo‐p‐dioxin (OCDD) in the livers of piglets infected with disease of North American‐type porcine reproductive and respiratory syndrome virus (PRRSV).
Figure 2.
Detailed process of determination of polychlorinated dibenzo‐p‐dioxins and dibenzofurans levels in piglet liver with various diseases. [Colour figure can be viewed at wileyonlinelibrary.com].
Conclusions
The present results found the relationship between the TEQ levels of toxic dioxin congeners in the organs of piglet and the types of disease. The total concentrations of PCDD/Fs in piglet infected with viral diseases were higher than the concentrations of PCDD/Fs in piglet with Bacillus nature diseases. By comparing the level of PCDD/Fs in piglet liver between the North American‐type and European‐type PRRS diseases, the TEQ concentrations of PCDD/Fs in piglet livers from the North American‐type PRRS were observed to be higher than those from the European‐type PRRS. Investigation of the relationship between exposure to PCDD/Fs and diseases is increasing and HRGC/HRMS could be a useful tool for the assessment.
Funding source
This work was supported by the Korea Basic Science Institute Grant (C37705).
Conflict of interest
The authors declare that there are no conflicting interests.
Contributor Information
Shela Gorinstein, Email: shela.gorin@mail.huji.ac.il, Email: gorin@cc.huji.ac.il.
Yun Gyong Ahn, Email: ygahn@kbsi.re.kr.
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