OTA Concentration Research Articles

Occurrence of ochratoxin A in feed and residue in porcine liver and kidney

The effect of ochratoxin A in feed for pigs, and the incidence of its residue in liver and kidney were investigated. The samples were taken from farms and corresponding slaughterhouse in different areas of Serbia. The criteria for OTA residue examination in the mentioned tissues were macroscopic alterations in kidneys, that is a marked kidney ischemia. 14 feed samples, 12 kidney samples and 12 liver samples in total were examined. The average OTA concentration in feed was 25,24 g/kg (0,0-85 g/kg). The presence of the OTA residue was found in all of examined tissues samples. The average OTA concentration in kidneys was 2,37 g/kg (1,0-8,2 g/kg), in liver was 2,66 g/kg (1,2-5,5 g/kg). The experiment showed that the average OTA concentration in feed of farm A in contrast to farm B was significantly low (p < 0,05), in liver was significantly lower (p < 0,01), while in kidneys was not significantly low (p < 0,05). The correlation between these three findings was postulated and discussed.

Effects of the mycotoxin ochratoxin A and some of its metabolites on human kidney cell lines

The modulations of complement-regulating surface proteins on a human embryonic and a renal carcinoma cell line are described regarding the effects of ochratoxin A and some of its metabolites on the surface markers CD46, CD55 and CD59. Membrane integrity, cell proliferation and metabolic activity were reduced to different extents, depending on the kind of mycotoxin and the dosage, which was ranging from 10 to 1000 ng/ml. The number of cells carrying surface markers was suppressed significantly at 1000 ng/ml, in some cases even at 100 ng/ml, whereas the intensity of receptor expression on the positive cells was found to be stimulated. The fraction RE2 (OTC) isolated from an OTA-containing crude toxin surpassed the effects of all other ochratoxin metabolites. Apart from well-known cytotoxic and genotoxic effects modulation of cell surface marker expression by low concentrations of OTA and OTC deserves more attention with regard to its immuno-pathogenic importance. Furthermore, occurrence and impact of the mycotoxin OTC should be studied more into detail.

Metabolism and toxicokinetics of the mycotoxin ochratoxin A in F344 rats

Male (n=18) and female (n=18) F344 rats were administered a single dose of OTA (0.5 mg/kg b.w.) in corn oil by gavage. Animals (n=3) were sacrificed 24, 48, 72, 96, 672 and 1,344 hours after OTA administration and concentrations of OTA and OTA-metabolites in urine, feces, blood, liver and kidney were determined by HPLC with fluorescence detection and/or by LC-MS/MS. Recovery of unchanged OTA in urine amounted to 2.1% of dose in males and 5.2% in females within 96 h. In feces, only 5.5% resp. 1.5% of dose were recovered. The major metabolite detected was OTalpha, low concentrations of OTA-glucosides were also present in urine. Other postulated metabolites were not observed. The maximal blood levels of OTA were observed between 24 and 48h after administration and were app. 4.6 µmol/l in males and 6.0 µmol/l in females. Elimination of OTA from blood followed first-order kinetics with a half-life of app. 230h calculated from 48h to 1344h. In liver of both male and female rats OTA-concentrations were less than 12 pmol/g tissue, with a maximum at 24h after administration. In contrast, OTA accumulated in the kidneys, reaching a concentration of 480 pmol/g tissue in males 24h after OTA-administration. In general, tissue concentrations in males were higher than in females. OTalpha was not detected in liver and kidney tissue of rats administered OTA and OTalpha concentrations in blood were low (10-15 nmol/1). The high concentrations of OTA in kidneys of male rats may explain the organ- and gender-specific toxicity of OTA.

Stoichiometric preference in copper-promoted oxidative DNA damage by ochratoxin A

The ability of the fungal carcinogen, ochratoxin A (OTA, 1), to facilitate copper-promoted oxidative DNA damage has been assessed using supercoiled plasmid DNA (Form I)–agarose gel electrophoresis and gas chromatography–mass spectrometry with selected-ion monitoring (GC–MS-SIM). OTA is shown to promote oxidative cleavage of Form I DNA with optimal cleavage efficiency occurring under excess Cu(II) conditions. As the concentration of OTA was increased and present in excess of Cu(II) the cleavage was less effective. Parallel findings were found for the ability of the OTA–Cu mixture to facilitate oxidative base damage. Yields (lesions per 10 6 DNA bases) of modified bases upon exposure of calf-thymus DNA (CT-DNA) to OTA–H 2O 2–Cu(II) were diminished when the OTA:Cu ratio was increased to 5:1. Electrochemical studies carried out in methanol implicate a ligand-centered 2e oxidation of OTA in the presence of excess Cu(II), while product analyses utilizing electrospray mass spectrometry support the intermediacy of the quinone, OTQ ( 3), in Cu-promoted oxidation of OTA. The implications of these findings with regard to the mutagenicity of OTA are discussed.

Ochratoxin A (OTA) in Kaffee — Vergleichende Auswertung bundesweiter Daten der Jahre 1995–1999 und 2000–2002

Ochratoxin A concentrations from a total of 1223 samples from green, roasted and ground, decaffeinated and low acid and instant coffee analysed during 1995–1999 and 2000–2002 by German Official Food Control Laboratories were compared. Median concentrations, determined by statistical process analysis decreased within each group from the early group up to 2002. The rates of rejection were calculated on the basis of the recent data for green and roasted and ground coffee which may occur when particular maximum residue limits were set. Contamination rates from green coffee showed significant differences in their OTA concentrations depending on their geographical origin.

Mycotoxins in the food chain: the role of ochratoxins

Mycotoxins are widespread contaminants of food and feeds, of meat, cheese, spices, fruits, and grapes and also of some beverages. The toxins are mainly produced by the four genera of fungi Fusarium, Claviceps, Aspergillus and Penicillium that grow on almost every kind of nourishing medium. In the past, the main concerns about OTA addressed the carcinogenic and nephrotoxic potential of this mycotoxin; however, recent studies have documented significant alterations of immune responses. Since these effects were observed even at OTA concentrations far below the doses used in cancerogenicity studies, such additional effects by OTA have gained increased attention now. Since the immune response processes are inevitably involved in the defence against microbial invasion and tumour cell propagation, it is predictable that this research provides important new information about OTA and other mycotoxins. This report deals with OTA food contamination, consumer exposure and recent toxicological data related to effect on cytokine release in the liver by OTA.

Bildung von Ochratoxin A bei der Lagerung von Triticale nach künstlicher Infektion mitPenicillium verrucosum in Abhängigkeit unterschiedlicher Feuchtegehalte

Triticale is a frequently cultivated and used in feed rations because of high yields of kernels and straw. Furthermore triticale is cosidered in a culturelandscape program. The storage of triticale and storage conditions become more and more important. In our study Triticale was remoistered to a watercontent of 14, 16, 18, und 19% as well, inoculated withP verrucosum and stored for 28 weeks from november till july in a research granary (tower silo). This experiment should simulate the storage situation in farmscale from cold wintermonths to warm spring times. Every four weeks CO2 was measured, and samples for moisture, OTA- and CT-analysis were taken. At week 20 and a MC of 19 % 22 μg OTA/kg triticale were found. The maximum of OTA-production in this humidity stage was at week 28 with 635 μg/kg. Also at a MC of 18 % OTA could be found with levels near to the detection limit. In contrast to former investigations with oatsP verrucosum produced in triticale no citrinin even when the OTA concentrations were higher than in our investigations.

Evaluation of mycotoxin-contaminated cereals for their use in animal feeds in Hungary

In the period between December 5, 1991 and September 17, 1998, 760 maize, 367 wheat, 119 soybean, 222 barley, 85 bran, 32 triticale, 60 oat, 14 rye and 22 sunflower samples were investigated for the presence and concentration of seven fusariotoxins (T-2 toxin, zearalenone, deoxynivalenol, nivalenol, diacetoxyscirpenol, HT-2 toxin, fusarenone-X) and OTA. The comparison of analytical data with those of the relevant literature revealed that although the incidence rate and/ or concentration of Fusarium mycotoxins and OTA in Hungarian-grown cereals is occasionally considerable, the position of the country is not worse than the average of countries. Our findings indicate that soybean tends to be good substrate for trichothecene-producing fungi and the rate of contamination is regarded as substantial. The commodities were assorted into one of three quality categories. The proportion of objectionable samples was only 3.0, 2.2, 2.3 and 1.7% in maize, wheat, barley and soybean samples, respectively. However, this low rate of objection might still be a source of great economic loss. The proportion of objectionable samples was much higher in the case of bran, oat and triticale (7.1, 6.7, and 6.3%, respectively). The results of the present investigation indicate a need for regular screening for mycotoxins of importance and individual appraisal of each commodity from the point of their use in animal feeds.