Exhaled breath condensate pH and FeNO as biomarkers of acute and chronic exposure to hazards at swine farms.

OBJECTIVE: The noninvasive biomarkers of respiratory impairment were assessed in 15 swine confinement (SC) workers and 9 respiratory healthy, nonsmoking volunteers (HV). METHODS: Spirometry, fraction of exhaled nitric oxide (FeNO), and exhaled breath condensate (EBC) pH were assessed in SC workers after one working shift and one working week and in HV after 5-hour exposure in SC. RESULTS: Half of the respiratory symptoms (in 8 of 15 SC workers) were work-related. Basal FeNO values were 7.5 ppb higher in the SC workers compared with HV. In the SC workers, EBC pH increased for 0.17 at the end of a working week (P < 0.001). In HV, 5-hour exposure in SC induced 8% drop in forced expiratory flow at 25% of the pulmonary volume (FEF25) (P = 0.008), EBC pH drop for 0.10 units (P = 0.003), and FeNO drop by 1.8 ppb (P = 0.047). CONCLUSIONS: EBC pH was suggested as a biomarker of acute airway acidification in HV, whereas the SC workers showed signs of the "healthy worker effect."

Biochemical changes in pig serum after ochratoxin A exposure.

The objective of this study was to investigate the effect of ochratoxin A (OTA) on serum biochemical parameters of pigs during subchronic treatment with 300 µg OTA/kg of feed for 30 days. OTA treatment resulted in significantly higher (p < 0.05) serum levels of creatinine, urea, potassium and alkaline phosphatase, and significantly lower levels of glucose and total protein. These changes in serum biochemical parameters in treated pigs were indicative of impaired liver and kidney function caused by OTA exposure.

UPLC-MS/MS determination of ractopamine residues in retinal tissue of treated food-producing pigs.

Ractopamine is a ß(2)-adrenergic agonist, which reduces fat deposition and promotes muscle growth in animals for meat production. In the European Union countries, systematic monitoring and control of this contaminant residue is regularly performed by use of validated analytical methods of detection in different biological materials. The aim of the present study was to assess persistence of ractopamine in retina as a pigmented tissue by determination of its residues using UPLC-MS/MS as a quantitative confirmatory method after pig exposure to a ractopamine dose of 0.51 mg/kg b.w. Experimental group (n=9) of pigs were orally administered ractopamine for 28 days and then randomly sacrificed (n=3) on days 1, 3 and 8 of treatment discontinuation, whereas control animals (n=3) were left untreated. Study results showed mean ractopamine residue concentrations of 110.36 µg/kg, 67.11 µg/kg and 89.93 µg/kg on days 1, 3 and 8 after withdrawal, respectively, indicating high accumulation of ractopamine in retina despite a low dose applied. These data pointed to high affinity of ractopamine for binding to the pigmented segment of the eye, thus supporting the use of pigmented tissues as matrices in the regulatory monitoring of this ß(2)-adrenergic agonist.

Determination of residual ractopamine concentrations by enzyme immunoassay in treated pig's tissues on days after withdrawal.

The objective of this study was to measure residual ractopamine concentrations in tissues of pigs as experimental animals after treatment with dietary ractopamine for 28 consecutive days. Ractopamine was administered orally to the experimental group (n=9) in a dose of 0.1mg/kg body mass per day, whereas control animals (n=3) were left untreated. Treated pigs (60kg) were sacrificed on days 1, 3 and 8 of treatment discontinuation and residues were determined in kidney, liver, muscle, brain and heart tissues using previously validated enzyme-linked immunosorbent assay (ELISA) as a quantitative screening method. Validation showed good mean recoveries (approx. 70-90%) with acceptable inter- and intra-day relative standard deviations (RSD<13%), demonstrating the method efficiency in determination of ractopamine tissue concentrations. The highest ractopamine concentration on day 1 (24h) after the last exposure was recorded in the kidney (12.49±7.96ng/g), followed by the liver (7.21±2.73ng/g), heart (1.26±0.12ng/g) and brain (0.63±0.05ng/g); at this time of withdrawal, residues were not detected in the muscle. Ractopamine was depleted rapidly from all study tissues, with mostly no detectable residues on day 8 of withdrawal.

Determination of clenbuterol residues in retinal tissue of food-producing pigs.

The aim of the present study was to assess the persistence of clenbuterol residues in retinal tissue of pigs after repeated administration in a growth-promoting dose, using enzyme-linked immunosorbent assay (ELISA) as a screening method for quantitative determination. A growth-promoting dose of clenbuterol (20 µg/kg body mass per day) was administered orally to the experimental group (n = 6) for 21 days, whereas control animals (n = 3) were left untreated. Clenbuterol-treated pigs were randomly sacrificed (n = 3) on days 0 and 45 of treatment discontinuation, and clenbuterol residues were determined in retinal tissue dissected from the eye. ELISA was found to be acceptable for quantitative determination of clenbuterol in retinal samples because previous method validation yielded mean recovery values of 84.3-96.5% with variation coefficients < 14%. The mean (± SD) retinal clenbuterol concentration was 1874 ± 114 ng/g immediately upon clenbuterol withdrawal (day 0) and 73 ± 4 ng/g on the last day post-withdrawal (day 45). Study results pointed to a very high potential of clenbuterol accumulation in retinal tissue and marked persistence of clenbuterol residues upon anabolic dose administration, suggesting retinal tissue to be a very useful matrix for effective control of residual clenbuterol in food-producing pigs.